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  • 301.
    Govindarajan, Venkatesh
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Nyflött, Åsa
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Bonnerup, Chris
    Stora Enso.
    Lestelius, Magnus
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    An economic-environmental analysis of selected barrier coating materials used in packaging food products: A Swedish case study2017In: Environment, Development and Sustainability, ISSN 1387-585X, E-ISSN 1573-2975, Vol. 20, no 4, p. 1483-1497Article in journal (Refereed)
    Abstract [en]

    The purpose of a barrier coating in food packaging is primarily to increase the shelf life of the foodstuff contained within the packaging, preserve its colour, odour, taste and quality, and thereby reduce food wastage (both at retail outlets and households). While most publications hitherto have compared packaging and barrier-coating materials on the basis of their environmental impacts alone, this paper adopts a more holistic approach by factoring in the economic aspect as well. Four barrier material alternatives—starch, polyethylene, EVOH + kaolin and latex + kaolin are analysed. Two well-defined end-of-life handling scenarios, relevant to Sweden, are: one in which everything except starch is recycled, with starch being composted, and the other in which everything is incinerated. Among the several environmental impact categories which can be analysed, this paper considers only global warming. Two approaches are tested to combine the economic and environmental aspects—normalisation, weighting and aggregating on the one hand, and using the carbon tax to internalise the externality caused by GHG emissions on the other. For the set of weighting factors obtained thanks to a survey conducted by the authors (40.6% for environmental and 59.4% for economic), starch emerges as the most sustainable alternative, followed by polyethylene for both the end-of-life handling scenarios. This tallies with the result obtained by using the carbon tax for internalisation of the externality. The case study, methodology and results presented in this paper, will hopefully be a springboard for more detailed studies of this nature, under the umbrella of sustainability.

  • 302. Groning, M.
    et al.
    Eriksson, Henrik
    KTH, School of Computer Science and Communication (CSC), Numerical Analysis and Computer Science, NADA.
    Hakkarainen, Minna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Albertsson, Ann-Christine
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Phenolic prepreg waste as functional filter with antioxidant effect in polypropylene and polyamide-62006In: Polymer degradation and stability, ISSN 0141-3910, E-ISSN 1873-2321, Vol. 91, no 8, p. 1815-1823Article in journal (Refereed)
    Abstract [en]

    Milled phenol-formaldehyde glass-fibre scrap (prepreg) was mixed with polypropylene (PP) and polyamide-6 (PA6). The oxidation induction time (OIT) of PP/prepreg composite measured by both chemiluminescence (CL) and Differential Scanning Calorimetry (DSC) was significantly longer than the oxidation induction time of unstabilised base PP. In addition, mechanical testing showed that the prepreg filter stabilised both PP and PA6 towards oxidation during long-term accelerated ageing. Headspace-gas chromatography/mass spectrometry (HS-GC/MS) showed that PP/prepreg composites emit somewhat larger amounts of volatile compounds compared to the reference PP/glass fibre composites, while the amount of volatile components emitted from PA6/prepreg composites was similar to the reference PA6/glass fibre composites. The new prepreg composites could have potential in thermally demanding applications especially if a secondary phosphite stabiliser is added to further increase the oxidative stability through synergy effects.

  • 303. Groning, M.
    et al.
    Hakkarainen, Minna
    KTH, Superseded Departments, Polymer Technology.
    Headspace solid-phase microextraction with gas chromatography/mass spectrometry reveals a correlation between the degradation product pattern and changes in the mechanical properties during the thermooxidation of in-plant recycled polyamide 6,62002In: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 86, no 13, p. 3396-3407Article in journal (Refereed)
    Abstract [en]

    The increased susceptibility of in-plant recycled polyamide 6,6 toward thermooxidation was shown by headspace solid-phase microextraction with gas chromatography/mass spectrometry (HS-SPME/GC-MS), tensile testing, differential scanning calorimetry (DSC), and Fourier transform infrared spectroscopy (FTIR). A correlation between the deterioration in mechanical properties and the formation of degradation products due to thermooxidation was found, and the most prominent decrease in mechanical properties coincided with the largest increase in the abundance of degradation products. The recycled materials had a shorter induction period toward oxidation, and their mechanical properties deteriorated faster than the mechanical properties of virgin material. The same trend was observed with HS-SPME/GC-MS because degradation products were found for recycled materials after oxidation times shorter than those for virgin material. Furthermore, larger amounts of degradation products were formed in the recycled materials. The high sensitivity of HS-SPME/GC-MS as an analytical tool was demonstrated because it was able to detect changes caused by oxidation considerably earlier than the other methods. Unlike DSC and FTIR, it could also show differences between samples recycled for different times. Four groups of degradation products-cyclic imides, pyridines, chain fragments, and cyclopentanones-were identified in thermooxidized polyamide 6,6. After 1200 h of thermooxidation, 1-pentyl-2,5-pyrrolidinedione was the most abundant degradation product. Approximately four times more 1-pentyl-2,5-pyrrolidinedione was formed in polyamide recycled three times than in virgin polyamide. Pyridines and chain fragments behaved toward oxidation and repeated processing like cyclic imides; that is, their amounts increased during oxidation, and larger amounts were formed in recycled materials than in virgin material. The cyclopentanone derivatives were present already in unaged material, and their amounts decreased during oxidation. Cyclopentanones were not formed because of the thermooxidation of polyamide 6,6.

  • 304.
    Groning, Mikael
    et al.
    KTH, Superseded Departments, Fibre and Polymer Technology.
    Hakkarainen, Minna
    KTH, Superseded Departments, Polymer Technology.
    Multiple headspace solid-phase microextraction of 2-cyclopentyl-cyclopentanone in polyamide 6.6: possibilities and limitations in the headspace analysis of solid hydrogen-bonding matrices2004In: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 1052, no 02-jan, p. 61-68Article in journal (Refereed)
    Abstract [en]

    The interactions between a polar analyte, 2-cyclopentyl-cyclopentanone, and a solid polar matrix, polyamide 6.6, during multiple headspace solid-phase microextraction (MHS-SPME) were studied. Strong hydrogen bonding between the analyte and the matrix was observed and shown to cause slow migration and adsorption of the analyte. These matrix effects led to erroneous quantitation despite the use of multiple headspace extraction. Addition of water disrupted the hydrogen bonding between the analyte and the matrix and a valid quantitation was achieved. The addition of water also increased the sensitivity and allowed the identification of 2,5-bis(cyclopentyl)-1-cyclopentanone. The amount of 2-cyclopentyl-cyclopentanone in five different polyamide 6.6 samples was measured using the developed multiple headspace solid-phase microextraction method with water-displacer. The measured concentrations were in the range of 1.44-15.61 mug/g. These concentrations were up to 30% higher than the concentrations measured after microwave-assisted extraction (MAE), which indicates incomplete recovery by MAE. The use of water as a displacer eliminated the matrix effects and complete recovery of the analyte was achieved by MHS-SPME.

  • 305. Gröning, M.
    et al.
    Hakkarainen, Minna
    KTH, Superseded Departments, Polymer Technology.
    Headspace solid-phase microextraction - a tool for new insights into the long-term thermo-oxidation mechanism of polyamide 6.62001In: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 932, no 02-jan, p. 1-11Article in journal (Refereed)
    Abstract [en]

    Low-molecular-mass products formed. during thermo-oxidation of polyamide 6.6 at 100 degreesC were extracted by headspace solid-phase microextraction and identified by GC-MS. A total of 18 degradation products of polyamide 6.6 were identified. In addition some low-molecular-mass products originating from the lubricants were detected. The identified degradation products were categorized into four groups where compounds within each group contain the same structural feature. In groups A, B and C several new thermo-oxidation products of polyamide 6.6 were identified including cyclic imides, pyridines and structural fragments from the original polyamide chain. 1-Pentyl-2,5-pyrrolidinedione (pentylsuccinimide) showed the largest increase in abundance during oxidation. The cyclopentanones in group D were already present in the un-aged material. Their amounts decreased during ageing and they are thus not formed during thermo-oxidation of polyamide 6.6 at 100 degreesC. The identified thermo-oxidation products can be formed as a result of extensive oxidation of the hexamethylenediamine unit in the polyamide backbone. The degradation products pattern shows that the long-term thermo-oxidative degradation, just like thermal degradation and photo-oxidation of polyamide 6.6, starts at the N-vicinal methylene groups.

  • 306.
    Gröning, Mikael
    et al.
    KTH, Superseded Departments, Polymer Technology.
    Hakkarainen, Minna
    KTH, Superseded Departments, Polymer Technology.
    Correlation between emitted and total amount of 2-cyclopentyl-cyclopentanone in polyamide 6.6 allows rapid assessment by HS and HS-SPME under non-equilibrium conditions2004In: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 1052, no 02-jan, p. 151-159Article in journal (Refereed)
    Abstract [en]

    A correlation was found between the emitted and total amount of 2-cyclopentyl-cyclopentanone in polyamide 6.6. The emitted amounts were measured by GC-MS after headspace (HS) or headspace solid-phase microextraction (HS-SPME) and the total content was determined after microwave-assisted extraction (MAE). The correlation was valid also under non-equilibrium conditions, which allows rapid assessment of 2-cyclopentyl-cyclopentanone content in polyamide 6.6 by headspace techniques. The incubation time needed for non-equilibrium headspace analysis could be reduced from 5 h to 45 min if the PA66 granules were milled to powder prior to extraction. However, to reach equilibrium between the analyte in the solid sample and the headspace still required 12 h of incubation at 80degreesC. The long incubation time is explained by slow diffusion rate due to the strong hydrogen bonding between analyte and matrix and the relatively high crystallinity of polyamide 6.6. The headspace extraction profile showed several equilibrium-like patterns that are easily mistaken for the real equilibrium.

  • 307.
    Gröning, Mikael
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Hakkarainen, Minna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Albertsson, Ann-Christine
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Quantitative determination of volatiles in polymers and quality control of recycled materials by static headspace techniques2008In: CHROMATOGRAPHY FOR SUSTAINABLE POLYMERIC MATERIALS: RENEWABLE, DEGRADABLE AND RECYCLABLE, Berlin: Springer Verlag , 2008, Vol. 211, p. 51-84Chapter in book (Refereed)
    Abstract [en]

    A presentation is given of headspace (HS) extraction and headspace solid-phase microextraction (HS-SPME) techniques and their combination with multiple headspace (MHS) extraction to enable quantitative determination of volatiles in solid polymer matrixes. As an example, the development of HS, HS-SPME, and MHS-SPME methods for extraction of volatiles from thermo-oxidized and/or recycled polyamide 6.6 is reviewed with special focus on the problems encountered when extracting analytes from solid-sample matrixes including excessively long equilibrium times and adsorption of analytes to the sample matrix. Examples are also given of the application of HS-SPME in quality control of recycled materials, in durability assessment of polymeric materials and in degradation studies.

  • 308.
    Gröning, Mikael
    et al.
    KTH, Superseded Departments, Fibre and Polymer Technology.
    Hakkarainen, Minna
    KTH, Superseded Departments, Polymer Technology.
    Albertsson, Ann-Christine
    KTH, Superseded Departments, Polymer Technology.
    Recycling of glass fibre reinforced phenolic prepreg waste. part 1. Recovery and reuse of glass fibres in PP and PA62004In: Polymers & polymer composites, ISSN 0967-3911, E-ISSN 1478-2391, Vol. 12, no 6, p. 491-500Article in journal (Refereed)
    Abstract [en]

    The present paper describes a feasible process to reuse glass fibres separated from phenolic prepreg waste as reinforcing filler in polypropylene (PP) and polyamide 6 (PA6). Prior to compounding, the recovered glass fibres were cut into 50 mm long fibre bundles and surface treated with gamma-aminopropyltriethoxysilane (APS) for increased composite interfacial strength. Electron Spectroscopy for Chemical Analysis (ESCA) and Atomic Force Microscopy (AFM) showed that the silane coupling agent was attached to the surface of the glass fibres but the silane layer was somewhat uneven, probably due to the presence of small amounts of organic contaminants. In addition it was found necessary to clean the glass fibres from organic contaminants by thermal treatment in order to attach silane coupling agent to the surfaces. The tensile strengths obtained for PP and PA6 composites with 30 wt% filler level of surface treated recovered glass fibres were 49 MPa and 101 MPa, respectively. This should be compared to 30 MPa and 75 MPa for composites containing untreated glass fibres and 19 MPa and 52 MPa for pure PP and PA6. Addition of 5 wt% PP-g-MA compatibiliser to the PP composite increased the tensile strength by another 14%, i.e. to 56 MPa. The good interfacial compatibility achieved by APS surface treatment and compatibilisation was verified by Scanning Electron Microscopy (SEM).

  • 309.
    Gröning, Mikael
    et al.
    KTH, Superseded Departments, Fibre and Polymer Technology.
    Hakkarainen, Minna
    KTH, Superseded Departments, Polymer Technology.
    Albertsson, Ann-Christine
    KTH, Superseded Departments, Polymer Technology.
    Recycling of glass-fibre reinforced phenolic prepreg waste. Part 2. Milled prepreg as functional filler in PP and PA62004In: Polymers & polymer composites, ISSN 0967-3911, E-ISSN 1478-2391, Vol. 12, no 6, p. 501-509Article in journal (Refereed)
    Abstract [en]

    Phenolic resin impregnated glass-fibre prepreg waste was milled and used as reinforcing filler in polypropylene (PP) and polyamide 6 (PA6). Prepreg was particularly suitable to be used as filler in PA6. The fibres were homogeneously distributed during compounding and the addition of 20 wt% prepreg increased the tensile strength of PA6 by 63%, from 52 MPa to 85 MPa. Milled prepreg alone did not significantly increase the tensile strength of PP. However, if compounded together with maleic anhydride grafted polypropylene (PP-g-MA, Epolene G3003) compatibiliser, prepreg can be used as reinforcing filler in PP as well. Addition of 20 wt% prepreg together with 5 wt% Epolene G3003 increased the tensile strength of PP from 26 MPa to 43 MPa. In order to mill the prepreg for compounding with thermoplastics it has to be cured. A 2 kg batch of prepreg had to be cured for at least 2 hours at 200 degreesC to prevent the phenolic resin from falling off the glass-fibres. Milling should be performed using screens with holes larger than 3 mm in diameter to reduce the amount of prepreg fibres shorter than 2 mm, as they jam the hopper when feeding the recyclate to the extruder. The initial prepreg fibre length is of little importance to the composite mechanical properties, as the fibres are shortened to approximately the same length during compounding.

  • 310.
    Guerzoni, Samuele
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Deplaine, Harmony
    El Haskouri, Jamal
    Amoros, Pedro
    Monleon Pradas, Manuel
    Edlund, Ulrica
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Gallego Ferrer, Gloria
    Combination of silica nanoparticles with hydroxyapatite reinforces poly (L-lactide acid) scaffolds without loss of bioactivity2014In: Journal of bioactive and compatible polymers (Print), ISSN 0883-9115, E-ISSN 1530-8030, Vol. 29, no 1, p. 15-31Article in journal (Refereed)
    Abstract [en]

    Composite scaffolds of poly(l-lactide acid) and hydroxyapatite are of great interest in bone tissue engineering, but their mechanical properties are typically inferior to scaffolds of pure poly(l-lactide acid) due to agglomeration of the particles and weak interfacial component interaction. Fabrication strategies like double sonication of hydroxyapatite or increasing the amount of this inorganic filler do not effectively enhance the mechanical performance. In this study, poly(l-lactide acid) composites combining two types of fillers, mesoporous silica (SiO2) nanoparticles and hydroxyapatite, were developed to reinforce the poly(l-lactide acid) scaffold without any loss of bioactivity. A 5% addition of SiO2 nanoparticles to hydroxyapatite nanopowder and subjecting the scaffold formulation to double sonication increased the Young's modulus from 5 MPa (pure poly(l-lactide acid) scaffold) to almost 7 MPa (poly(l-lactide acid)/hydroxyapatite/SiO2 scaffold). In addition, the composite was able to deposit a layer of biomimetic hydroxyapatite both on the surface and interior of the scaffold after 21 days of immersion in a simulated body fluid. The manufacturing method was straightforward and economically viable and does not require any chemical modification of the particles' surfaces.

  • 311. Guo, Juan
    et al.
    Song, Kunlin
    Salmen, Lennart
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. Innventia AB, Sweden .
    Yin, Yafang
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Changes of wood cell walls in response to hygro-mechanical steam treatment2015In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 115, p. 207-214Article in journal (Refereed)
    Abstract [en]

    The effects of compression combined with steam treatment (CS-treatment), i.e. a hygro-mechanical steam treatment on Spruce wood were studied on a cell-structure level to understand the chemical and physical changes of the secondary cell wall occurring under such conditions. Specially, imaging FT-IR microscopy, nanoindentation and dynamic vapour absorption were used to track changes in the chemical structure, in micromechanical and hygroscopic properties. It was shown that CS-treatment resulted in different changes in morphological, chemical and physical properties of the cell wall, in comparison with those under pure steam treatment. After CS-treatment, the cellular structure displayed significant deformations, and the biopolymer components, e.g. hemicellulo se and lignin, were degraded, resulting in decreased hygroscopicity and increased mechanical properties of the wood compared to both untreated and steam treated wood. Moreover, CS-treatment resulted in a higher degree of degradation especially in earlywood compared to a more uniform behaviour of wood treated only by steam.

  • 312.
    Gustafsson, Emil
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Tailoring Adhesion and Wetting Properties of Cellulose Fibres and Model Surfaces Using Layer-by-Layer Technology2014Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The versatile layer-by-layer (LbL) technique, for consecutive adsorption of polyelectrolytes and charged nanoparticles onto a substrate, was used to modify cellulose fibres and model surfaces for improved mechanical and wetting properties. In addition to being used to modify cellulose substrates, the LbL technique was also used to create cellulose surfaces suitable for high resolution adhesion measurements. LbL assembly of cellulose nanofibrils and polyethylenimine was used to prepare cellulose model surfaces on polydimethylsiloxane hemispheres which allowed for the first known Johnson-Kendall-Roberts (JKR) adhesion measurements between cellulose and smooth, well-defined model surfaces of cellulose, lignin and glucomannan. The work of adhesion on loading and the adhesion hysteresis were comparable for all three systems which suggest that adhesion between wood constituents is similar. The LbL technique was also used to decrease the hydrophilicity of paper, while improving the dry strength, by coating cellulose fibres with a polylallylamine hydrochloride (PAH) and polyacrylic acid (PAA) LbL film, followed by adsorption of anionic wax particles. Paper sheets made from the modified fibres were highly hydrophobic with a contact angle of 150°, while retaining, and in some cases improving, the tensile index of the paper. It was also observed that PAH/PAA modified sheets without the addition of wax became hydrophobic when heat treated. The mechanism behind the increased hydrophobicity was studied by the interface sensitive technique, vibrational sum frequency spectroscopy, which indicated that the increased hydrophobicity is a result of the reorientation of polymer chains to expose more hydrophobic CH2 and CH groups at the polymer-air interface. Paper sheets prepared from LbL-modified bleached softwood fibres using PAH and the biopolymer hyaluronic acid (HA) exhibited a 6.5% strain at break and a tensile index which was increased 3-fold compared to unmodified fibres. The wet adhesive properties of the PAH/HA system were studied by colloidal probe atomic force microscopy and correlated to film growth and viscoelastic behavior. The presence of background salt was a crucial parameter for achieving high adhesion but time in contact and LbL film thickness also strongly affected the adhesion. Finally, the wet adhesive properties of carboxymethylcellulose (CMC), which had been irreversibly adsorbed to regenerated cellulose, and polyvinylamine (PVAm) were evaluated by means of 90° peel tests. Strong wet adhesion was achieved for dried rewetted samples without any obvious chemical crosslinking, which was attributed to interdigitation and complex formation in PVAm-CMC films. This system also gave significant wet adhesion for non-dried systems at water contents around 45%.

  • 313.
    Gustafsson, Emil
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Hedberg, Jonas
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Larsson, Per A.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology.
    Wågberg, Lars
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Johnson, C. Magnus
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Vibrational sum frequency spectroscopy on polyelectrolyte multilayers – effect of molecular surface structure on macroscopic wetting propertiesManuscript (preprint) (Other academic)
  • 314.
    Gustafsson, Emil
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology.
    Pelton, Robert
    McMaster University.
    Wågberg, Lars
    KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology.
    Polyelectrolyte Entanglement across Interfaces and Wet Adhesion- Influence of Polyvinylamine on Wet Adhesion between Cellulose Model Surfaces Modified with CarboxymethylcelluloseManuscript (preprint) (Other academic)
  • 315.
    Gustafsson, Emil
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center. McMaster University, Canada.
    Pelton, Robert
    Wågberg, Lars
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Rapid Development of Wet Adhesion between Carboxymethylcellulose Modified Cellulose Surfaces Laminated with Polyvinylamine Adhesive2016In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 8, no 36, p. 24161-24167Article in journal (Refereed)
    Abstract [en]

    The surface of regenerated cellulose membranes was modified by irreversible adsorption-of carboxymethylcellulose (CMC). Pairs of wet CMC-modified membranes were laminated with polyvinylamine (PVAm) at room, temperature, and the delamination force for wet membranes was measured for both dried and never-dried laminates. The wet adhesion was, studied as a function of PVAm molecular weight, amine :content,: and deposition pH of the polyelectrolyte. Surprisingly the PVAm CMC system gave substantial wet adhesion that exceeded that of TEMPO-oxidized membranes with PVAm for both dried and never-dried laminates. The greatest wet adhesion was achieved for fully hydrolyzed high molecular weight PVAm. Bulk carboxymethylation of cellulose membranes gave inferior wet adhesion combined with PVAm as compared to CMC adsorption which indicates,that a CMC layer of the order of 10 nm Was necessary. There are no obvious covalent cross linking reactions between CMC and PVAm at room temperature, and on the basis of our results, we are instead attributing the wet adhesion to complex formation between the PVAm and the irreversibly adsorbed CMC at the cellulose surface. We propose that interdigitation of PVAm chains into the CMC layer is responsible for the wet adhesion values.

  • 316.
    Gustafsson, Emil
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Utsel, Simon
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center BiMaC Innovation.
    Marais, Andrew
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center BiMaC Innovation.
    Johansson, Erik
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center BiMaC Innovation.
    Pettersson, Torbjörn
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology.
    Wågberg, Lars
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology.
    The use of thin, tailored Layer-by-Layer (LbL) films to improve the mechanical properties of fibrous networks2012Conference paper (Other academic)
  • 317.
    Göransson, Helena
    KTH, School of Chemical Science and Engineering (CHE).
    Biodegradable PLA-g-PEG Bioconjugates for Targeted Drug Delivery2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Polymer therapeutics as drug delivery systems have gained significant interest during the last years. The reason being their possibility to circumvent many of the drawbacks connected to drugs used today. Conventional polyesters have several favorable properties necessary for the mentioned purpose but their lack of functional groups often limits their use.

     

    In this study we will try to overcome this limitation by presenting the first steps of a new synthesis pathway to achieve a telechelic-functionalized polymer scaffold. By providing the polymer with functional handles further post-polymerization steps are made possible. Polylactide (PLA) chains featuring azide functionality were successfully grafted from an initiating species on a peptide with the amino acid sequence Gly-Arg-Gly-Asp-Ser (GRGDS) via ring-opening polymerization. Incorporation of oligo(ethylene glycol) chains featuring azide moieties into the PLA backbone will allow for active drug delivery. In future studies, a cell-penetrating peptide for improved cellular uptake and a third functionality enabling attachment of homing devices to promote targeted delivery will be installed.

     

    Ring-opening polymerization of lactide showed to initiate successfully from the peptide as was confirmed by proton nuclear magnetic resonance spectroscopy (1H NMR). Liquid chromatography mass spectrometry (LCMS) and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-ToF MS) also confirmed the formation of a polymer-peptide conjugate and PLA chains with a degree of polymerization (DP) between 1 and 4 were detected. 1H NMR and Correlation spectroscopy (COSY) showed a downfield shift of the peak originating by the protons next to the terminal hydroxyl group. This indicates that initiation solely occurs from the hydroxyl group and not from other nucleophilic groups also present on the peptide. This was further confirmed by Nuclear Overhauser Effect spectroscopy (NOESY) and Heteronuclear single quantum coherence spectroscopy (HSQC) where a correlation between the PLA chain and the peptide strand was detected.

  • 318.
    Göthe, Viktoria
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Green Nanocomposites from Cereal Husk2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The aim of this master thesis study was to investigate the possibility to extract cellulose nanocrystals (CNC) from cereal husks and their capability to be used as reinforcement systems of hemicellulosic biopolymers. CNC were isolated from rye husk and used as reinforcement in nanocomposites. To obtain the isolated CNC the rye husk was processed through alkaline treatments, bleaching treatments and finally an acid hydrolysis. The cellulose extraction was optimized and optimal conditions were reached when 3wt% of rye husk were used for both alkaline and bleaching treatments. Acid hydrolysis was performed at 45°C for 30 minutes. The total yield from the rye husk to the CNCs was approximately 11wt%. The isolation process from macro to nano size was monitored via different chemico-physical characterization methods.

    Via Scanning Electron Microscopy (SEM) analysis, the isolation of the cellulose fibers from rye husk could be assessed. The chemical composition was evaluated via carbohydrate analysis, ash, extractives and lignin Klason determination. From these chemical data, it was verified that most of the amorphous components of the rye husk were removed reaching 73.17% of cellulose for the isolated cellulose fibers. Fourier transform infrared spectroscopy (FTIR) was used to follow the chemical structural changes through the CNC isolation process. From the FTIR spectra, it could be seen that the bleached husk and CNC materials were similar to a cellulose fiber compared to the rye husk and alkaline treated husk, which had FTIR spectra typical for lignocellulosic biomass. This fact indicates that most of the hemicellulose and lignin were removed due to the chemical treatments the rye husk was submitted to. Crystalline index of the samples was also determined with FTIR and an increasing crystallinity trend was observed through the isolation, from rye husk to CNC. The Thermogravimetric Analysis (TGA) was used to assess the thermal stability and it was observed that the bleached and CNC samples had an increased thermal stability with respect to the lignocellulosic and alkaline samples, indicating the most labile components of the rye husk were removed. The rye husk CNC exhibited a length of 335.4 nm, diameter of 2.86 nm and a zeta potential of -35.8 mV together with a high purity (>98% of cellulose) crystallinity and thermal stability.

    Green nanocomposites based on commercial arabinoxylan from rye and CNC isolated from rye husk were prepared. The method employed to produce the nanocomposite films was solvent casting. Different amounts of CNC were added to the arabinoxylan matrix: 0, 5, 10 and 20wt% of CNC. Mechanical and thermal properties of the nanocomposites were evaluated. The nanocomposite films exhibited an increase in the thermal stability, Young modulus and tensile strength due to the addition of the CNC indicating a good compatibility and interaction between the raw materials.

  • 319.
    Hafeez, Asif
    KTH, School of Chemical Science and Engineering (CHE).
    Synthesis and characterization of renewable cellulose based plasticizer for polyvinyl chloride (PVC)2011Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Acid catalyzed liquefaction of brown paper handtowel was performed using a mixture of diethylene glycol and glycerol andaddition of minute amount of p-toluenesulphonic acid as a catalyst. TheLiquefied brown paper was used as a polyhydroxy alcohol during the estersynthesis as large number of hydroxyl groups is available in liquefied brownpaper products. Esterification was performed by using hexanoic acid along withdibutyl tin (IV) oxide as a catalyst. The product was characterized by usingFTIR, SEC and SEM. PVC films were prepared by solution casting. They wereplasticized by the prepared liquefied brown paper ester and by traditionaldiisooctyl phthalate. Comparison of both plasticizers on the basis ofmechanical, thermal properties and plasticizer migration was elaborated.

  • 320. Haider, Nadejzda
    et al.
    Karlsson, Sigbritt
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    A rapid ultrasonic extraction technique to identify and quantify additives in poly(ethylene)1999In: Analyst (Cambridge, United Kingdom), Vol. 124, no 5, p. 797-800Article in journal (Refereed)
  • 321. Haider, Nadejzda
    et al.
    Karlsson, Sigbritt
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Migration and release profile of Chimassorb 944 from low-density polyethylene film (LDPE) in simulated landfills1999In: Polymer degradation and stability, ISSN 0141-3910, E-ISSN 1873-2321, Vol. 64, no 2, p. 321-328Article in journal (Refereed)
  • 322.
    Hakkarainen, Minna
    KTH, Superseded Departments, Polymer Technology.
    Aliphatic polyesters: Abiotic and biotic degradation and degradation products2002In: Advances in Polymer Science, ISSN 0065-3195, E-ISSN 1436-5030, Vol. 157, p. 113-138Article, review/survey (Refereed)
    Abstract [en]

    This paper reviews the degradation behavior of aliphatic polyesters of current interest, including polylactide, polycaprolactone, poly(3-hydroxybutyrate) and their copolymers. Special focus is given to degradation products formed in different abiotic and biotic environments. The influence of processing and processing additives on the properties and degradation behavior is also briefly discussed.

  • 323.
    Hakkarainen, Minna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Developments in multiple headspace extraction2007In: Journal of Biochemical and Biophysical Methods, ISSN 0165-022X, E-ISSN 1872-857X, Vol. 70, no 2, p. 229-233Article, review/survey (Refereed)
    Abstract [en]

    This paper reviews new developments in multiple headspace extraction (MHE), especially its combination with two miniaturized extraction techniques, solid-phase microextraction (SPME) and single-drop microextraction (SDME). The combination of the techniques broadens the applicability of SPME and SDME to quantitative determination of analytes in complex liquid and solid matrixes. These new methods offer several advantages over traditional liquid-solid, liquid-liquid and headspace extraction techniques. The potential applications include extraction of volatiles and semivolatiles from environmental and physiological samples and from different polymer products such as medical and biomedical materials, food packaging and building materials. The theoretical principals of the techniques are also briefly reviewed.

  • 324.
    Hakkarainen, Minna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Electrospray Ionization-Mass Spectrometry for Molecular Level Understanding of Polymer Degradation2012In: Advances in Polymer Science, ISSN 0065-3195, E-ISSN 1436-5030, Vol. 248, p. 175-204Article in journal (Refereed)
    Abstract [en]

    The stability and durability of polymeric materials under different external influences (e.g., sunlight, humidity, heat, chemicals, or microorganisms) is of outmost importance in applications such as coatings, building materials, and automotive parts, whereas a rapidly degradable material is preferable in temporary short-term applications. There are considerable economic and environmental benefits if we can design polymers for short or long lifetimes as well as prevent the release of harmful substances from the materials during their lifetime. The recent developments in mass spectrometric techniques facilitate possibilities for molecular level characterization of the changes taking place in the polymer matrix as well as for identification of the released degradation products. This review presents an overview of the application of electrospray ionization-mass spectrometry (ESI-MS) for the analysis of polymer degradation. The great potential of the technique for revealing detailed insights into the degradative reactions taking place is demonstrated with examples ranging from degradable polymers and biomaterials to degradation of coatings, paints, polymer electrolyte membranes, food packaging, and materials in the nuclear industry.

  • 325.
    Hakkarainen, Minna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Migration of monomeric and polymeric PVC plasticizers2008In: Advances in Polymer Science, ISSN 0065-3195, E-ISSN 1436-5030, Vol. 211, p. 159-185Article, review/survey (Refereed)
    Abstract [en]

    This paper summarizes current literature on the migration of monomeric and polymeric PVC plasticizers from medical materials, food packaging, and toys. Especially highlighted is macromolecular engineering as a tool to increase the plasticizing efficiency and migration resistance for polymeric plasticizers. The effect of branching, molecular weight, end-group functionality, and polydispersity on plasticizer performance was evaluated by quantification of low-molecular-weight hydrolysis products, measurements of mechanical properties, weight loss, surface segregation, as well as the preservation of material properties during aging. A more migration-resistant polymeric plasticizer that also better preserved its material properties during aging was obtained by combining a low degree of branching, hydrolysis-protecting end-groups, and higher molecular weight.

  • 326.
    Hakkarainen, Minna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Multiple headspace single-drop micro-extraction for quantitative determination of lactide in thermally-oxidized polylactide2010In: Polymer degradation and stability, ISSN 0141-3910, E-ISSN 1873-2321, Vol. 95, no 3, p. 270-273Article in journal (Refereed)
    Abstract [en]

    Single-drop micro-extraction (SDME), an emerging micro-extraction technique, was combined with multiple headspace (MHS) extraction to allow quantitative determination of lactide in thermally-oxidized polylactide Different solvents, drop sizes and extraction times were tested to obtain best extraction efficiency and the method was further developed to obtain a linear regression plot for the Multiple extractions. The combination of SDME and MHS extraction offered several advantages over traditional liquid-solid and headspace extraction techniques No concentration step was needed and loss of volatiles was prevented as the ageing and extraction were performed in a closed system Matrix effects, that disturb the quantitation of analytes in solid samples, were removed by the multiple headspace extraction.

  • 327.
    Hakkarainen, Minna
    KTH, Superseded Departments, Polymer Technology.
    New PVC materials for medical applications - the release profile of PVC/polycaprolactone-polycarbonate aged in aqueous environments2003In: Polymer degradation and stability, ISSN 0141-3910, E-ISSN 1873-2321, Vol. 80, no 3, p. 451-458Article in journal (Refereed)
    Abstract [en]

    Medical grade PVC plasticised with polycaprolactone-polycarbonate (PCL-PC) was subjected to aqueous environments at different temperatures. The release profile during ageing was determined by solid phase microextraction (SPME) and GC-MS. At the same time changes in the surface composition due to, for example, migration of PCL-PC from the blend were followed by FTIR. Almost no changes in the material or its surface composition were observed during 98 days at 37 degreesC in water or phosphate buffer. Only trace amount of 6-hydroxyhexanoic acid the final hydrolysis product of PCL-PC was detected in the GC-MS chromatograms and the weight loss was negligible. Even when the ageing temperature was raised to 70 degreesC only minor increase in the amount of 6-hydroxyhexanoic acid was observed and the weight loss after 98 days was under 1%. Changes in the FTIR spectra indicating migration of PCL-PC towards the surface of the PVC/PCL-PC tubing were observed first after 70 days at 70 degreesC. Large increase in the hydrolysis rate of PCL-PC and almost complete depletion of PCL-PC from the blend was observed when the ageing temperature was raised to 100 degreesC.

  • 328.
    Hakkarainen, Minna
    KTH, Superseded Departments, Polymer Technology.
    Qualitative and quantitative solid-phase microextraction gas chromatographic-mass spectrometric determination of the low-molecular-mass compounds released from poly(vinyl chloride)/polycaprolactone-polycarbonate during ageing2003In: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 1010, no 1, p. 9-16Article in journal (Refereed)
    Abstract [en]

    A solid-phase microextraction (SPME) method was developed to quantitatively determine the amount of 6-hydroxyhexanoic acid in aqueous solutions. The SPME method in combination with GC-MS was then applied to identify and quantify the low-molecular-mass compounds migrating from a new poly(vinyl chloride) (PVC) material, PVC/polycaprolactone-polycarbonate (PCL-PC) during ageing in water. It was shown that only a small amount of 6-hydroxyhexanoic acid, the final hydrolysis product of PCL-PC, migrated from the blend during ageing at 37 and 70 degreesC. If, however, the temperature was raised to 100 degreesC rapid hydrolysis of PCL-PC resulted. In addition to 6-hydroxyhexanoic acid, 6-hydroxyhexanoic acid dimer, caprolactone, different carboxylic acids, acetophenone and phenol were identified. SPME-GC-MS was also applied to monitor the low-molecular-mass compounds migrating from the PVC/PCL-PC blend during thermo-oxidation.

  • 329.
    Hakkarainen, Minna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Solid phase microextraction for analysis of polymer degradation products and additives: Renewable, Degradable and Recyclable2008In: Advances in Polymer Science, ISSN 0065-3195, E-ISSN 1436-5030, Vol. 211, no 1, p. 23-50Article, review/survey (Refereed)
    Abstract [en]

    Commercial plastics and rubbers always contain low molecular weight additives. Other low molecular weight compounds are formed due to degradation of polymers and additives during synthesis, processing, use and after disposal. Knowledge of these compounds is important for evaluating the environmental impact and interaction of polymeric materials, to investigate long-term properties and degradation mechanisms, to verify ingredients, to investigate manufacturing problems, to quality control polymeric materials, to identify odorants, to avoid workplace exposure and to insure safety of food packaging and medical products. Solid-phase microextraction (SPME) is a solvent-free extraction technique that has in recent years found an increasing number of applications in different fields. This paper presents a review of SPME technique in different polymer related applications including analysis of degradation products and polymer additives, monomer-rests, odor compounds, migrants from food packaging and medical products, extraction of polymer additives from environmental samples and biological fluids. Future possibilities are also discussed.

  • 330.
    Hakkarainen, Minna
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Adamus, Grazyna
    Centre of Polymer and Carbon Materials, Polish Academy of Sciences.
    Höglund, Anders
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Kowalczuk, Marek
    Centre of Polymer and Carbon Materials, Polish Academy of Sciences.
    Albertsson, Ann-Christine
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    ESI-MS reveals the influence of hydrophilicity and architecture on the water-soluble degradation product patterns of biodegradable homo- and copolyesters of 1,5-dioxepan-2-one and epsilon-caprolactone2008In: Macromolecules, ISSN 0024-9297, E-ISSN 1520-5835, Vol. 41, no 10, p. 3547-3554Article in journal (Refereed)
    Abstract [en]

    The hydrolytic degradation process and degradation product patterns of biodegradable homo- and copolyesters of 1,5-dioxepan-2-one (DXO) and epsilon-caprolactone (CL) were monitored by electrospray ionization mass spectrometry (ESI-MS). The degradation product patterns were compared to mass loss, molecular weight changes, copolymer composition, and pH changes after various hydrolysis times. Water-soluble oligomers up to heptadecamer were identified after hydrolysis of hydrophilic PDXO, while only oligomers up to hexamer were detected after hydrolysis of the more hydrophobic PCL. The product pattern of DXO-CL-DXO triblock copolymer mainly consisted of DXO-based oligomers, whereas the CL/DXO multiblock copolymer degradation product pattern contained DXO and CL oligomers as well as oligomers containing both DXO and CL units. The DXO-rich oligomers, however, dominated the product patterns. ESI-MS gave valuable insights into the hydrolysis process of hydrophobic and hydrophilic polyesters and showed that hydrophilicity of the polymer as well as copolymer architecture both greatly influenced the water-soluble degradation product patterns.

  • 331.
    Hakkarainen, Minna
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Albertsson, Ann-Christine
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Degradation products of aliphatic and aliphatic-aromatic polyesters2008In: Chromatography For Sustainable Polymeric Materials: Renewable, Degradable And Recyclable, BERLIN: SPRINGER-VERLAG , 2008, Vol. 211, p. 85-116Chapter in book (Refereed)
    Abstract [en]

    Analysis of degradation products needs to be included in degradability testing to ensure the environmental adaptability of degradable polymers. Identification of breakdown products from environmental degradation is important for understanding the degradation process, environmental interaction and impact of degradable polymers. with regard to degradability aliphatic polyesters are a particularly interesting group of polymers. They are susceptible to hydrolysis and biological attack due to the ester groups in the main chain. This paper summarizes the work done on the chromatographic analysis of degradation products from the most common aliphatic and aliphatic-aromatic polyesters under different abiotic and biotic conditions including simulated, accelerated and real environmental conditions.

  • 332.
    Hakkarainen, Minna
    et al.
    KTH, Superseded Departments, Polymer Technology.
    Albertsson, Ann-Christine
    KTH, Superseded Departments, Polymer Technology.
    Environmental degradation of polyethylene2004In: LONG-TERM PROPERTIES OF POLYOLEFINS, Berlin, 2004, Vol. 169, p. 177-199Chapter in book (Refereed)
    Abstract [en]

    The environmental degradation of polyethylene proceeds by synergistic action of photo- and thermo-oxidative degradation and biological activity. Since biodegradation of commercial high molecular weight polyethylene proceeds slowly, abiotic oxidation is the initial and rate-determining step. Enhanced environmentally degradable polyethylene is prepared by blending with biodegradable additives or photo-initiators or by copolymerisation. One of the key questions for successful development and use of environmentally degradable polymers is to understand the interaction between degradation products and nature. Polymer fragments and degradation products should be environmentally assimilable and should not accumulate or negatively affect the environment. Determination of abiotic and biotic oxidation products is an important step towards establishing the environmental degradation mechanism and environmental impact of the material. More than 200 different degradation products including alkanes, alkenes, ketones, aldehydes, alcohols, carboxylic acid, keto-acids, dicarboxylic acids, lactones and esters have been identified in thermo- and photo-oxidised polyethylene. In biotic environment these abiotic oxidation products and oxidised low molecular weight polymer can be assimilated by microorganisms. In future we will probably see a development of new polyethylenes with tailor-made structures specially designed for environmental degradation through different pathways. Paralleled with the development of these new materials we need to obtain better understanding of the environmental impact of degradable polymers and the interactions between nature and degradation products in a dynamic system.

  • 333.
    Hakkarainen, Minna
    et al.
    KTH, Superseded Departments (pre-2005), Polymer Technology.
    Albertsson, Ann-Christine
    KTH, Superseded Departments (pre-2005), Polymer Technology.
    Heterogeneous biodegradation of polycaprolactone - Low molecular weight products and surface changes2002In: Macromolecular Chemistry and Physics, ISSN 1022-1352, E-ISSN 1521-3935, Vol. 203, no 11-okt, p. 1357-1363Article in journal (Refereed)
    Abstract [en]

    Gas chromatography-mass spectrometry (GC-MS) analysis showed that caprolactone, 6-hydroxyhexanoic acid, cyclic dimer and cyclic trimer were rapidly assimilated from the surface of polycaprolactone (PCL) films aged in mineral medium inoculated with a mixed culture of compost microorganisms. The degradation in biotic medium proceeded heterogeneously and scanning electron micrographs revealed the formation of parallel grooves, spherical and non-spherical holes in the films. The parallel grooves seen in the scanning electron micrographs after 14 d suggest that the degradation starts preferentially at the amorphous regions. At longer time scales, even the crystalline regions are degraded producing large spherical and non-spherical holes. Comparison of the degradation of melt-pressed and film-blown films made from the same PCL granules in different biotic and abiotic environments showed that both the type of microorganism used and the initial morphology of the films influence the surface erosion pattern and biodegradation mechanism. Rapid degradation and molecular weight decrease required the combined effect of temperature and microorganisms obtained during a biodegradation process, such as composting.

  • 334.
    Hakkarainen, Minna
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Albertsson, Ann-Christine
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Indicator products: A new tool for lifetime prediction of polymeric materials2005In: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 6, no 2, p. 775-779Article in journal (Refereed)
    Abstract [en]

    The possible correlation between the degree of degradation in the polymer matrix and the release of indicator products was investigated. The degree of degradation was measured by following the molar mass changes by size exclusion chromatography, while indicator products were analyzed by gas chromatography -mass spectrometry. The degree of degradation in polyethylene and polyethylene vinyl acetate matrix after thermooxidation was found to be in correlation with the amount of dicarboxylic acids and lactones formed during aging, while the degree of degradation in photooxidized polyethylene could be predicted from the amount of dicarboxylic acids. The relative amount of lactones compared to the relative amount of dicarboxylic acids increased if the oxidation temperature was increased. However, the total amount of indicator products was in correlation with the remaining number average molar mass and the number of chain scissions caused by oxidation. The amount of butanedioic acid and butyrolactone correlated well with the total amount of dicarboxylic acids and lactones, respectively. Thus, instead of the whole compound classes, butanedioic acid or butyrolactone alone could be used as indicators of oxidation. The detected correlation offers a novel tool for making lifetime predictions and studying the long-term properties of polymeric materials.

  • 335.
    Hakkarainen, Minna
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Albertsson, Ann-Christine
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Kalrsson, Sigbritt
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Weight losses and molecular weight changes correlated with the evolution of hydroxyacids in simulated in vivo degradation of homo-and copolymers of PLA and PGA1996In: Polymer degradation and stability, ISSN 0141-3910, E-ISSN 1873-2321, Vol. 52, p. 283-291Article in journal (Refereed)
  • 336.
    Hakkarainen, Minna
    et al.
    KTH, Superseded Departments, Polymer Technology.
    Albertsson, Ann-Christine
    KTH, Superseded Departments, Polymer Technology.
    Karlsson, Sigbritt
    KTH, Superseded Departments, Polymer Technology.
    Migration and emission of plasticizer and its degradation products during thermal aging of nitrite rubber2003In: IJPAC. International journal of polymer analysis and characterization, ISSN 1023-666X, E-ISSN 1563-5341, Vol. 8, no 4, p. 279-293Article in journal (Refereed)
    Abstract [en]

    The behavior of nitrile rubber during long-term thermal aging was evaluated by following the migration of low-molecular-weight additives and additive degradation products from the material. Headspace-GC-MS analysis showed that at 60degreesC the number of low-molecular-weight compounds released was rather low, but a significant increase in the number and amount of products was observed when the temperature was raised from 60degrees to 80degreesC, e.g., several degradation products of tris(2-butoxyethyl)phosphate plasticizer including 2-butoxyethanol and 1-butanol were identified. Oxidation of the plasticizer was also seen in the FTIR spectra. The color of the material changed from light brown to almost black during the aging.

  • 337.
    Hakkarainen, Minna
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Albertsson, Ann-Christine
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Karlsson, Sigbritt
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Solid phase microextraction (SPME) as an effective means to isolate degradation products in polymers1997In: Journal of environmental polymer degradation, ISSN 1064-7546, E-ISSN 1572-8900, Vol. 5, p. 67-73Article in journal (Refereed)
    Abstract [en]

    A new sample preparation technique, solid phase microextraction (SPME), was compared with direct headspace-GC-MS with respect to the type and amount of identified compounds. Three types of LDPE films containing photosensitising additives according to the Scott-Gilead patents and pure LDPE were used as model substances. The polyethylene films were thermally aged at 80 degrees C after the induction period was surpassed by subjecting the materials to 100 h of UV radiation. The new SPME method was developed using nonpolar poly(dimethylsiloxane) and polar carbowax fibers to extract the low molecular weight products formed in the polyethylene films during aging. Many more products were identified after SPME followed by CC-MS than after direct headspace-GC-MS of the samples. The SPME method allowed the identification of homologous series of carboxylic acids, ketones, and furanones, while direct headspace-GC-MS identified only a few carboxylic acids (C1-C6) and small amounts of some ketones and furanones. In general, SPME was more effective in extracting less volatile products, and in particular, the polar carbowax fiber identified also C7-C12 carboxylic acids and 4-oxopentanoic acid. By SEC and FTIR we confirmed that the number and amount of former degradation products correlated well with the decrease in molecular weights and the amount of formed carbonyl compounds.

  • 338.
    Hakkarainen, Minna
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Albertsson, Ann-Christine
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Karlsson, Sigbritt
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Solid-phase extraction and subsequent gas-chromatography-mass spectrometry analysis for identification of complex mixtures of degradation products in starch-based polymers1996In: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 741, p. 251-263Article in journal (Refereed)
  • 339.
    Hakkarainen, Minna
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Albertsson, Ann-Christine
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Karlsson, Sigbritt
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Susceptibility of starch-filled and starch-based LDPE to oxygen in water and air1997In: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 66, p. 959-967Article in journal (Refereed)
  • 340. Hakkarainen, Minna
    et al.
    Albertsson, Ann-Christine
    Karlsson, Sigbritt
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Weight losses and molecular weight changes correlated with the evolution of hydroxy acids in simulated in vivo degradation of homo- and copolymers of PLA and PGA1996In: Polymer degradation and stability, ISSN 0141-3910, E-ISSN 1873-2321, Vol. 52, no 3, p. 283-291Article in journal (Refereed)
  • 341.
    Hakkarainen, Minna
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Burman, Lina
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Albertsson, Ann-Christine
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Chromatographic Analysis and Total Luminescence Intensity as Tools for Early Degradation Detection and Degradation State Estimation2006In: ACS Symposium Series: Degradable Polymers and Materials, Principles and Practice / [ed] Kishan Khemani and Carmen Scholz, American Chemical Society (ACS), 2006, 1, p. 307-319Chapter in book (Refereed)
    Abstract [en]

    Indicator product concept, chromatographic fingerprinting in combination with multivariate data analysis and total luminescence intensity (TLI) are presented as tools for product evaluation, quality control and testing of degradable polymers. A correlation was shown between the number of chain scission and the release of dicarboxylic acids during photo-and thermo-oxidation of polyethylene. This opens for degradation state prediction from the amount of indicator products released. Multivariate data analysis of chromatographic fingerprints of dicarboxylic acids allowed classification of polyethylene materials both with respect to the degradation state and pro-oxidant system. Total luminescence intensity proved to be an excellent tool for early degradation detection and classification of polyethylene materials. Further applications could include classification of materials with respect to durability or degradability, evaluation of antioxidant or pro-oxidant

  • 342.
    Hakkarainen, Minna
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Finne-Wistrand, Anna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Update on polylactide based materials2011 (ed. 1)Book (Other academic)
    Abstract [en]

    Today both scientists and industry are working to develop more environmentally friendly processes and materials. One of the most current topics is the development of energy and materials from renewable resources. There are fascinating developments in this area and advanced designed products can today be formed in an environmentally friendly way. Polylactide based materials are among the most promising synthetic renewable resource based materials. There is currently extensive research going on to develop polylactide based materials for different applications. These developments include both the use of new resources, development of more effective and environmentally friendly processes as well as modification and tailoring of material properties and degradability to broaden the application range.

    This book discusses recent developments in polylactide based materials including the whole spectra from different material modifications, applications and properties to new advanced synthesis procedures. When it comes to degradable materials, an important aspect is also the influence of different modifications on material properties, degradability and degradation products. The different chapters present new emerging processes and synthetic techniques as well as different material modifications obtained by copolymerization or blending with degradable or inert, natural or synthetic polymers. In addition advancements and developments in polylactide stereocomplexes, nanocomposites and biocomposites are presented. The book is of interest both from the basic and applied science point of view as it presents the latest trends and demonstrates the versatility and great potential of polylactide based materials. Hopefully the book can inspire the reader to further develop synthesis procedures or new ways to modify polylactide materials to broaden the properties to suit new applications.

  • 343.
    Hakkarainen, Minna
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Gallet, Guillaume
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Karlsson, Sigbritt
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Prediction by multivariate data analysis of long-term properties of glassfiber reinforced polyester composites1999In: Polymer degradation and stability, ISSN 0141-3910, E-ISSN 1873-2321, Vol. 64, p. 91-99Article in journal (Refereed)
    Abstract [en]

    The prediction of long-term properties of polymers has been analysed by identifiction of low molecular weight compounds in glassfibre-reinforced polyester composites which were subjected to accelerated ageing at 40 and 60 degrees C and 80 %-RH for periods up to 6 years. Before the accelerated ageing the materials were stored for 20 years at ambient temperature. After different ageing times the low molecular weight products in the materials were identified with GC-MS and headspace-GC-MS. Several different alcohols, phthalates and other aromatic compounds were identified. Temperature had a large influence on the degradation of phthalates and the formation of alcohols. In the first step we used principal component analysis (PCA) and partial least square (PLS) to locate outliers and to identify the products that were not connected to degradation time or temperature. After that PCA and PLS were used to reveal if unsaturated polyesters have different degradation mechanisms at 40 and 60 degrees C by comparing the amounts and types of degradation products. The relative influence of each factor on the degradation rate was studied and groups were made among the degradation products to define which degradation products are correlated with ageing time and temperature. Finally the ageing time was predicted from the amounts of degradation products (in that case the amount of products are considered as X factors and the time of degradation as a Y response). PCA showed that it was not possible to find a pattern in the HS-GC-MS chromatograms, due to the different volatility of the compounds. The score plots revealed the existence of domains which depended on the degradation temperature. Some of the compounds (diethyl phthalate, 2-propenyl ester of bensoic acid and bensoic acid) could not be predicted by the models. These products are not related to the degradation of the material itself. At 60 degrees C, 80% RH in air, PLS models showed a good correlation between amount of identified products and degradation time and it was possible to estimate the degradation time directly from the quantity of the 13 identified degradation products.

  • 344.
    Hakkarainen, Minna
    et al.
    KTH, Superseded Departments, Polymer Technology.
    Gröning, M.
    Albertsson, Ann-Christine
    KTH, Superseded Departments, Polymer Technology.
    Solid-phase microextraction (SPME) in polymer characterization - Long-term properties and quality control of polymeric materials2003In: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 89, no 3, p. 867-873Article in journal (Refereed)
    Abstract [en]

    Solid-phase microextraction (SPME) in combination with GG-MS was applied to quality control polyamide 6.6 collected for recycling and to study the long-term properties and degadation of nitrile rubber, polyethylene, and polyamide 6.6. The migration of plasticizer and other additives reduces the service-life and changes the properties of the material. It is also a possible health hazard, for example, legislation against the use of brominated flame retardants in plastic materials, is under discussion, and fast and reliable methods are required to detect such compounds in plastic materials collected for recycling. SPME rapidly and effectively extracted several brominated compounds from in-plant collected polyamide 6.6. Migration of tris(2-butoxy-ethyl)phosphate plasticizer and its degradation products from nitrile rubber during long-term thermal ageing at 60 and 80degreesC was shown by SPME-GC-MS, while the plasticizer was not volatile enough to be detected by traditional HS-GC-MS. In accordance the number of degradation products extracted from thermo-oxidized PE by HS-SPME was three times larger than the number detected after HS-GC-MS analysis. SPME-GC-MS could also detect early signs of degradation in thermo-oxidized virgin and in-plant recycled polyamide 6.6 before any signs of degradation were observed by, for example, tensile testing or FTIR.

  • 345.
    Hakkarainen, Minna
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Höglund, Anders
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Odelius, Karin
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Albertsson, Ann-Christine
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Tuning the release rate of acidic degradation products through macromolecular design of caprolactone-based copolymers2007In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 129, no 19, p. 6308-6312Article in journal (Refereed)
    Abstract [en]

    Macromolecular engineering is presented as a tool to control the degradation rate and release rate of acidic degradation products from biomedical polyester ethers. Three different caprolactone/1,5-dioxepan-2-one (CL/DXO) copolymers were synthesized: DXO/CL/DXO triblock, CL/DXO multiblock, and random cross-linked CL/DXO copolymer. The relation of CL and DXO units in all three copolymers was 60/40 mol %. The polymer discs were immersed in phosphate buffer solution at pH 7.4 and 37 degrees C for up to 364 days. After different time periods degradation products were extracted from the buffer solution and analyzed. In addition mass loss, water absorption, molecular weight changes, and changes in thermal properties were determined. The results show that the release rate of acidic degradation products, a possible cause of acidic microclimates and inflammatory responses, is controllable through macromolecular design, i.e., different distribution of the weak linkages in the copolymers.

  • 346.
    Hakkarainen, Minna
    et al.
    University of Helsinki, Finland.
    Jansson, Robert
    University of Helsinki, Finland.
    Sundholm, Francesca
    University of Helsinki, Finland.
    Liquid-Crystalline Behavior Of Some Carboxylic-Acids1993In: Polymer Bulletin, ISSN 0170-0839, E-ISSN 1436-2449, Vol. 31, no 1, p. 43-48Article in journal (Refereed)
    Abstract [en]

    A series of 4-omega-carboxyalkoxyphenyl-4'-methoxybenzoates 2 underbar has been prepared. Compounds with a spacer length of n=3 and n=5 show liquid crystalline behaviour. The products were characterized by IR and H-1NMR -spectroscopy, mass spectrometry, optical microscopy and DSC -measurements. The compounds are potentially useful as side-groups in liquid-crystalline polymers.

  • 347.
    Hakkarainen, Minna
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Karlsson, Sigbritt
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Gas Chromatography in analysis of polymers and rubbers2000In: Encyclopedia of Analytical Chemistry / [ed] R.A. Meyers, John Wiley & Sons, 2000, p. 7608-7623Chapter in book (Refereed)
  • 348.
    Hakkarainen, Minna
    et al.
    KTH, Superseded Departments, Polymer Technology.
    Karlsson, Sigbritt
    KTH, Superseded Departments, Polymer Technology.
    Albertsson, Ann-Christine
    KTH, Superseded Departments, Polymer Technology.
    Influence of low molecular weight lactic acid derivatives on degradability of polylactide2000In: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 76, no 2, p. 228-239Article in journal (Refereed)
    Abstract [en]

    The presence of low molecular weight lactic acid derivatives in films enhanced the degradability of polylactide in a biotic medium. Two different biotic and abiotic series were investigated. The films used for the first abiotic and biotic series (a-l and b-1 films) initially contained some lactic acid and lactoyl lactic acid, while the films used for the second abiotic and biotic series (a-2 and b-2 films) did not originally contain them. The b-1 films decreased in molecular weight during 3 weeks in the biotic medium, while no molecular weight decrease was seen in the a-1 films aged in a corresponding abiotic mineral medium. The molecular weight for the a-2 and b-2 films without lactic and lactoyl lactic acid remained almost constant. Scanning electron microscopy micro-graphs showed a larger amount of bacteria and fungi growing on the surface of b-1 films compared to b-2 films; thus, the presence of easily assimilated lactic acid and lactoyl lactic acid in the films improved the initial growth of microorganisms on the film surfaces. Gas chromatography and mass spectrometry analysis showed that lactic acid and lactoyl lactic acid were rapidly assimilated from the films aged in a biotic medium. New degradation products (e.g., ethyl ester of lactoyl lactic acid, acetic acid, and propanoic acid) were formed during aging in a biotic medium. Acetic acid and propanoic acid were formed as intermediate degradation products during the initial stages, but they were no longer detected after prolonged aging. The concentration of the ethyl ester of lactoyl lactic acid increased with aging time.

  • 349.
    Hakkarainen, Minna
    et al.
    KTH, Superseded Departments, Polymer Technology.
    Karlsson, Sigbritt
    KTH, Superseded Departments, Polymer Technology.
    Albertsson, Ann-Christine
    KTH, Superseded Departments, Polymer Technology.
    Rapid (bio)degradation of polylactide by mixed culture of compost microorganisms - low molecular weight products and matrix changes2000In: Polymer, ISSN 0032-3861, E-ISSN 1873-2291, Vol. 41, no 7, p. 2331-2338Article in journal (Refereed)
    Abstract [en]

    Poly(L-lactide) (PLLA) was rapidly (bio)degraded by a mixed culture of compost microorganisms. After 5 weeks in biotic environment, the films had fragmented to fine powder, while the films in corresponding abiotic medium still looked intact. Analysis of the low molecular weight products by GC-MS showed that microorganisms rapidly assimilated lactic acid and lactoyl lactic acid from the films. At the same time, a new degradation product, ethyl ester of lactoyl lactic acid was formed in the biotic environment. This product cannot be formed by abiotic hydrolysis and it was not detected in the abiotic medium. The degradation of the PLLA matrix was monitored by differential scanning calorimetry (DSC), size exclusion chromatography (SEC) and scanning electron microscopy (SEM). A rapid molecular weight decrease and increasing polydispersity was observed in the biotic environment. In the abiotic environment only a slight molecular weight decrease was seen and the polydispersity started decreasing towards 2.0. This indicates different degradation mechanisms, i.e. preferred degradation near the chain ends in the biotic environment and a random hydrolysis of the ester bonds in the abiotic environment. SEM micrographs showed the formation of patterns and cracks on the surface of the films aged in biotic medium, while the surface of the sterile films remained smooth. The SEM micrographs showed a large number of bacteria and mycelium of fungi growing on the surface of the biotically aged films.

  • 350.
    Hakkarainen, Minna
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Khabbaz, Farideh
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Albertsson, Ann-Christine
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Biodegradation of polyethylene followed by assimilation of degradation products2003In: Biopolymers: Volume 9: Miscellaneous Biopolymers and Biodegradation of synthetic Polymers / [ed] Alexander Steinbüchel, Wiley-VCH Verlagsgesellschaft, 2003, p. 369-394Chapter in book (Refereed)
45678910 301 - 350 of 925
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