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  • 1.
    Aaen, Ragnhild
    et al.
    NTNU Norwegian University of Science and Technology, Norway.
    Lehtonen, Mari
    University of Helsinki, Finland.
    Mikkonen, Kirsi
    University of Helsinki, Finland.
    Syverud, Kristin
    RISE Research Institutes of Sweden, Bioekonomi och hälsa, Material- och ytdesign. NTNU Norwegian University of Science and Technology, Norway.
    Combining cellulose nanofibrils and galactoglucomannans for enhanced stabilization of future food emulsions2021Ingår i: Cellulose, ISSN 0969-0239, E-ISSN 1572-882X, Vol. 28, nr 16, s. 10485-10500Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The use of wood-derived cellulose nanofibrils (CNFs) or galactoglucomannans (GGM) for emulsion stabilization may be a way to obtain new environmentally friendly emulsifiers. Both have previously been shown to act as emulsifiers, offering physical, and in the case of GGM, oxidative stability to the emulsions. Oil-in-water emulsions were prepared using highly charged (1352 ± 5 µmol/g) CNFs prepared by TEMPO-mediated oxidation, or a coarser commercial CNF, less charged (≈ 70 µmol/g) quality (Exilva forte), and the physical emulsion stability was evaluated by use of droplet size distributions, micrographs and visual appearance. The highly charged, finely fibrillated CNFs stabilized the emulsions more effectively than the coarser, lower charged CNFs, probably due to higher electrostatic repulsions between the fibrils, and a higher surface coverage of the oil droplets due to thinner fibrils. At a constant CNF/oil ratio, the lowest CNF and oil concentration of 0.01 wt % CNFs and 5 wt % oil gave the most stable emulsion, with good stability toward coalescence, but not towards creaming. GGM (0.5 or 1.0 wt %) stabilized emulsions (5 wt % oil) showed no creaming behavior, but a clear bimodal distribution with some destabilization over the storage time of 1 month. Combinations of CNFs and GGM for stabilization of emulsions with 5 wt % oil, provided good stability towards creaming and a slower emulsion destabilization than for GGM alone. GGM could also improve the stability towards oxidation by delaying the initiation of lipid oxidation. Use of CNFs and combinations of GGM and CNFs can thus be away to obtain stable emulsions, such as mayonnaise and beverage emulsions. © 2021, The Author(s).

  • 2.
    Abali, Bilen Emek
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för materialvetenskap, Tillämpad mekanik.
    Yardimci, Mert Yucel
    Univ Ghent, Magnel Vandepitte Lab, Dept Struct Engn & Bldg Mat, Technol Pk Zwijnaarde 60, B-9052 Ghent, Belgium.;Istanbul Okan Univ, Dept Civil Engn, TR-34959 Istanbul, Turkey..
    Zecchini, Michele
    Univ Nat Resources & Life Sci, Christian Doppler Lab LiCRoFast, LiCRoFast, Peter Jordan Str 82, A-1190 Vienna, Austria..
    Daisse, Gilda
    Univ Nat Resources & Life Sci, Christian Doppler Lab LiCRoFast, LiCRoFast, Peter Jordan Str 82, A-1190 Vienna, Austria..
    Marchesini, Flavio H.
    Univ Ghent, Dept Mat Text & Chem Engn, Technol Pk Zwijnaarde 130, B-9052 Ghent, Belgium..
    De Schutter, Geert
    Univ Ghent, Magnel Vandepitte Lab, Dept Struct Engn & Bldg Mat, Technol Pk Zwijnaarde 60, B-9052 Ghent, Belgium..
    Wan-Wendner, Roman
    Univ Nat Resources & Life Sci, Christian Doppler Lab LiCRoFast, LiCRoFast, Peter Jordan Str 82, A-1190 Vienna, Austria.;Univ Ghent, Magnel Vandepitte Lab, Dept Struct Engn & Bldg Mat, Technol Pk Zwijnaarde 60, B-9052 Ghent, Belgium..
    Experimental investigation for modeling the hardening of thermosetting polymers during curing2021Ingår i: Polymer testing, ISSN 0142-9418, E-ISSN 1873-2348, Vol. 102, artikel-id 107310Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    During curing of thermosetting polymers, crosslinking results in hardening or stiffening of the material. In electronics, for example in encapsulating integrated circuits (die bonding), thermosets are fully cured in a controlled environment (under UV-light or within a thermal oven) such that the highest stiffness possible has been achieved. In building materials, specifically in thermosets used in fastening systems (adhesive anchoring), hardening occurs at environmental temperature. Daily temperature variations alter the curing process and possibly lead to a lower stiffness. We demonstrate a modeling approach for the mechanical response dependency on the degree of cure by means of rheometer measurements under a specific temperature profile. Precisely, we perform oscillatory rheometric tests and convert the storage and loss moduli to material parameters depending on the degree of cure. Moreover, the temperature dependency as well as chemical shrinkage have been determined by the same experimental protocol. The presented approach has been applied to a commercially available (epoxy) thermoset used as an adhesive. We have observed a hardening after a gelation point of 0.7 and an adequate fit for mechanical response by polynomial functions of degree four.

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  • 3.
    Abbadessa, Anna
    et al.
    KTH Royal institute of Technology, Sweden.
    Dogaris, Ioannis
    KTH Royal institute of Technology, Sweden.
    Kishani Farahani, Saina
    KTH Royal institute of Technology, Sweden.
    Reid, Michael S.
    KTH Royal institute of Technology, Sweden.
    Rautkoski, Hille
    VTT Technical Research Centre of Finland, Finland.
    Holopainen-Mantila, Ulla
    VTT Technical Research Centre of Finland, Finland.
    Oinonen, Petri
    Ecohelix, Sweden.
    Henriksson, Gunnar
    KTH Royal institute of Technology, Sweden.
    Layer-by-layer assembly of sustainable lignin-based coatings for food packaging applications2023Ingår i: Progress in organic coatings, ISSN 0300-9440, E-ISSN 1873-331X, Vol. 182, artikel-id 107676Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Packaging plays a critical role in ensuring food safety and shelf life by protecting against e.g., moisture, gases, and light. Polyethylene (PE) is widely used in food packaging, but it is mainly produced from non-renewable resources and it is an inefficient oxygen and light barrier. In this study, the layer-by-layer (LbL) assembly of a sustainably produced lignin-based polymer (EH) with polyethylenimine (PEI) or chitosan (CH) was used to fabricate (partially or fully) bio-based coatings with the aim of improving barrier properties of PE films. The charge density of EH was calculated using a polyelectrolyte titration method and the hydrodynamic diameters of EH, PEI and CH were determined by Dynamic Light Scattering (DLS). LbL assembly was monitored in situ via Quartz Crystal Microbalance with Dissipation (QCM-D) and Stagnation Point Adsorption Reflectometry (SPAR). PE films were coated with a variable number of PEI/EH or CH/EH bilayers (BL) using an immersive LbL assembly method. Coated films were studied in terms of light-blocking ability, wettability, thermal behaviour, surface structure, as well as oxygen and water vapor barrier properties. QCM-D and SPAR data showed a stepwise multilayer formation and strong interactions between the oppositely charged polymers, with PEI/EH coating having a greater amount of deposited polymer compared to CH/EH coating at the same number of BL. Overall, light barrier properties and wettability of the coated films increased with the number of deposited bilayers. Coated PE films maintained the overall thermal behaviour of PE. A number of BL of 20 was found to be the most promising based on the studied properties. Selected samples showed improved oxygen and water vapor barrier properties, with PEI/EH coating performing better than CH/EH coating. Taken altogether, we demonstrated that a novel and sustainable lignin-based polymer can be combined with PEI or CH to fabricate (partially or fully) bio-based coatings for food packaging. 

  • 4.
    Abbas, Malik Waseem
    et al.
    Natl Inst Biotechnol and Genet Engn, Pakistan.
    Soomro, Razium Ali
    Natl Inst Biotechnol and Genet Engn, Pakistan; Univ Sindh, Pakistan; Univ Bristol, England.
    Kalwar, Nazar Hussain
    Shah Abdul Latif Univ, Pakistan.
    Zahoor, Mehvish
    Natl Inst Biotechnol and Genet Engn, Pakistan.
    Avci, Ahmet
    Selcuk Univ, Turkey.
    Pehlivan, Erol
    Selcuk Univ, Turkey.
    Hallam, Keith Richard
    Univ Bristol, England.
    Willander, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik, elektroteknik och matematik. Linköpings universitet, Tekniska fakulteten.
    Carbon quantum dot coated Fe3O4 hybrid composites for sensitive electrochemical detection of uric acid2019Ingår i: Microchemical journal (Print), ISSN 0026-265X, E-ISSN 1095-9149, Vol. 146, s. 517-524Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The study explores carbon quantum dots (C-dots) as potential candidates for enhancing the signal sensitivity of an electrochemical sensor devised for biologically important molecule, such as uric acid (UA). The C-dots were evaluated for their electrochemical characteristics in combination with Fe3O4 nanoparticles (Fe3O4 NPs), which were applied as the primary electro-catalytic promoter. The hybrid nanocomposite (C-dots/Fe3O4 HCs) formation was achieved by facilitating the adsorption of C-dots over Fe3O4 NPs using amine-carbonyl interactions. Unlike, one pot method, the proposed strategy enables aggregation-free coverage of Fe3O4 NPs with highly conductive layer of C-dots that can act as conduction centres to support ultra-fast electron transfer kinetics to satisfy the need of high signal sensitivity. The hybrid composite demonstrated remarkable signal improvement when tested against the electrochemical oxidation of UA. The heighten current response and lower over-potential values enabled development of a DC-amperometric (DC-AMP) sensor for UA with a linear working range of 0.01 to 0.145 mu M and signal sensitivity measurable up to 6.0 x 10(-9) M. The said improvement was manifested as a synergetic outcome of active redox couple (Fe (III/II)), larger surface area of Fe3O4 NPs engulfed with a layer of highly conductive C-dots acting as efficient charge sensitisers.

  • 5.
    Abdi, Sofia
    KTH, Skolan för kemivetenskap (CHE).
    Preparation and process optimization of encapsulating cellulose microspheres2015Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Microspheres are spherically shaped particles within the size range of 1-1000 μm in diameter.

    Due to the their small size and round shape, microspheres show many advantages in various

    applications such as pharmaceuticals, composites and coatings. The microspheres can be

    customized to fit a specific application and are manufactured in various forms such as solid,

    hollow and encapsulating.

    Encapsulating cellulose microspheres have been produced in this project by the emulsionsolvent

    evaporation technique. The purpose of this study was to further investigate the

    possibility of producing encapsulating microspheres with a size range of 10-50 μm that will

    have a high encapsulation. A second purpose of this study was optimizing the emulsifier

    system for the preparation of these spheres. This has been accomplished by varying several

    process parameters such as type of emulsifiers and solvents to study the effect on morphology

    and encapsulation efficiency. The analyses of the spheres were performed with optical

    microscopy, thermal gravimetric analyzer (TGA) and scanning electron microscopy (SEM).

    The emulsifier type and concentration affected the encapsulation and size distribution but had

    no direct effect on the internal and external structure, which was multi-cellular and porous,

    respectively. The highest encapsulation in relation to average size was obtained with 0.1 v/v-

    % of the emulsifier mixture Emulsifier 1 (E1)/Emulsifier 2 (E2) (70/30 %). The solvent used

    to dissolve the polymer had a direct effect on encapsulation, a combination of Solvent 2 (S2)

    and Solvent 1 (S1) proved best for the three tested cellulose derivatives with low, medium and

    high number average molecular weight. The solvent also had an effect on the internal

    structure of the microspheres, becoming more core-shell when using the S1/S2 combination.

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  • 6.
    Adamopoulos, Stergios
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Ahmed, Sheikh Ali
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Lankveld, Chiel
    Accsys Group, Netherlands.
    Acoustic properties of acetylated wood under different humid conditions and its relevance for musical instruments2018Ingår i: Proceedings of the 9th European Conference on Wood Modification 2018, Arnhem, The Netherlands / [ed] Jos Creemers, Thomas Houben, Bôke Tjeerdsma, Holger Militz and Brigitte Junge, The Netherlands: Practicum , 2018, s. 236-243Konferensbidrag (Refereegranskat)
    Abstract [en]

    In musical instrument making, less expensive wood species and materials with good characteristics and acoustical properties can provide potentials to find alternatives to the traditional exotic wood species used today. Modified wood could be such a choice if shows similar sound characteristics to wood coming from endangered and expensive tropical species with problematic commercial availability. In musical instruments, the overall functionality depends on the contribution of wood to different material performance indexes like sound radiation coefficient (R), characteristic impedance (z) and acoustic conversion efficiency (ACE). In this study, the performance indexes were measured for acetylated beech, maple and radiata pine and compared with these obtained for the reference wood materials maple, mahogany, alder and ash. A non-destructive free-free flexural vibration test method was used at constant temperature (20oC) but in different humid conditions- dry (35% RH), standard (65% RH) and wet (85% RH). Dimensional changes in the different humid conditions were also taken in account. Acetylated wood showed lower EMC with higher dimensional stability at each humidity level as compared with the reference wood materials. These properties are considered important factors for making quality musical instruments. Based on the acoustical properties, acetylated wood materials, especially radiata pine, showed good potential for use for musical instruments where specific characteristics of sound are required. However, the other types of acetylated wood can also be used for specific musical instruments.

  • 7. Adamus, Grazyna
    et al.
    Hakkarainen, Minna
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Höglund, Anders
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Kowalczuk, Marek
    Albertsson, Ann-Christine
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    MALDI-TOF MS Reveals the Molecular Level Structures of Different Hydrophilic-Hydrophobic Polyether-esters2009Ingår i: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 10, nr 6, s. 1540-1546Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Multi- and triblock copolymers based on 1,5-dioxepan-2-one/epsilon-caprolactone (DXO/CL) were investigated by MALDI-TOF MS to determine the influence of copolymer composition and architecture on the molecular structures at the individual chain level. The copolymer compositions, average block lengths, and molecular weights were determined by H-1 and C-13 NMR and by SEC, respectively. The structures of polyether-ester oligomers (linear, cyclic) as well as the chemical structures of their end groups were established on the basis of their MALDI-TOF mass spectra. The mass spectrum of PDXO homopolymer was relatively simple, however, complex mass spectra were obtained in the case of multi- and triblock copolymers and the mass spectra clearly discerned the molecular level effect of copolymer composition and copolymer type.

  • 8.
    Adolfsson, Karin H.
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymerteknologi.
    Huang, Ping
    Department of Chemistry – Ångström Laboratory, Uppsala University, Box 523, Uppsala, 751 20, Sweden, Box 523.
    Golda-Cepa, Monika
    Faculty of Chemistry, Jagiellonian Universityul, Krakow, 30–387, Poland.
    Xu, Huan
    School of Materials Science and Physics, China University of Mining and Technology, Xuzhou, 221116, P. R. China.
    Kotarba, Andrzej
    Faculty of Chemistry, Jagiellonian Universityul, Krakow, 30–387, Poland.
    Hakkarainen, Minna
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymerteknologi.
    Scavenging of DPPH by Persistent Free Radicals in Carbonized Particles2023Ingår i: Advanced Sustainable Systems, E-ISSN 2366-7486, Vol. 7, nr 3, artikel-id 2200425Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Persistent free radicals (PFR) in carbonized particles may play a role in degradation of environmental compounds. The influence of PFR is evaluated in various carbonized particles on their radical scavenging efficiency upon the common radical indicator 2-2-diphenyl-1-picrylhydrazyl (DPPH). Carbonized particles are derived by hydrothermal carbonization of glucose (C-W) or glucose and urea (NC-W) and ionothermal carbonization of glucose and urea ionic liquid (IL) (NC-IL). The carbonized materials contain OH/COOH, C=C, and C-O functionalities. The addition of urea introduces NH/NH2 functionalities. The content of polar surface groups is lower in IL-processed NC-IL. The scavenging ability, measured as DPPH UV–vis absorption decline, increases with concentration and time for all particles, while the efficiency changes are in the order of C-W > NC-W > NC-IL. Electron paramagnetic resonance analysis reveals similar radical concentration in all carbonized materials studied. The difference in efficiency is, thus, not directly related to the PFR concentration but rather to the type of PFR, surface functionalities and/or scavenging mechanism. According to the g-values, radicals in these particles are carbon-centered. The minor variation in g-values suggests interactions between the radicals and their environmental functional groups. This provides insights into the influence of PFR in carbonized materials on their radical scavenging efficiency.

  • 9.
    Adolfsson, Karin H.
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Lin, Chia-feng
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymerteknologi.
    Hakkarainen, Minna
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymerteknologi.
    Microwave Assisted Hydrothermal Carbonization and Solid State Postmodification of Carbonized Polypropylene2018Ingår i: ACS Sustainable Chemistry and Engineering, E-ISSN 2168-0485, Vol. 6, nr 8, s. 11105-11114Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Functional carbon materials produced through a hydrothermal treatment of waste products have gained interest. Particularly, the method is considered more facile and green compared to conventional decomposition methods. Here, we demonstrated an upcycling of polypropylene (PP) waste to carbon materials by a microwave assisted hydro thermal treatment. The solid product obtained from the hydrothermal treatment was analyzed by multiple techniques to reveal the structure and the influence of processing conditions on PP degradation and hydrothermal carbonization. Chemical analyses showed the presence of carbonaceous material independent of acid amount (20 and 30 mL), temperature (210 and 250 degrees C), and time (20-80 min). A complete transformation of PP content to amorphous carbon required 60 min at 250 degrees C. The mass yield of the solid product decreased as a function of harsher processing conditions. At the same time, thermogravimetric analysis illustrated products with increasing thermal stability and a larger amount of remaining residue at 600 degrees C. The solid products consisted of irregular fragments and sheet-like structures. A solid state microwave process in air atmosphere was performed on a product with incomplete carbonization. The modification resulted in a decreased C/O ratio, and TGA analysis in nitrogen showed high thermal stability and degree of carbonization as indicated by the remaining residue of 86.4% at 600 degrees C. The new insights provided on the hydrothermal carbonization, and postmodification in air atmosphere, can catalyze effective handling of plastic waste by enabling transformation of low quality waste into functional carbon materials.

  • 10.
    Adolfsson, Karin H.
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymerteknologi.
    Sjöberg, I.
    Höglund, O. V.
    Wattle, O.
    Hakkarainen, Minna
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymerteknologi.
    In Vivo Versus In Vitro Degradation of a 3D Printed Resorbable Device for Ligation of Vascular Tissue in Horses2021Ingår i: Macromolecular Bioscience, ISSN 1616-5187, E-ISSN 1616-5195, Vol. 21, nr 10, artikel-id 2100164Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A resorbable 3D printed polydioxanone (PDO) device is manufactured to facilitate ligation of vascular tissue during surgery. The device must provide sufficient mechanical performance throughout the healing period. Therefore, degradation and mechanical performance of the device are investigated as a function of in vivo and in vitro aging. During aging the PDO device released cyclic and linear water-soluble products. In vivo aging resulted in higher relative number of linear oligomers in comparison to in vitro aging. A major loss of mechanical performance is observed after only 10 days in vivo and the Young’s modulus (E) and tensile strength at break (σb) decreased by 28% and 54%, respectively. This is in contrast to in vitro aging, where no loss of mechanical properties is observed during the same period. The in vivo aged devices exhibit clear holes in the matrices after 28 days, while apparent cracks are observed first after 140 days in vitro. These results highlight the sensitivity of the degradation process of resorbable devices with regards to the interactions of the device with the surrounding environment (tissues) and demonstrate the importance of in vivo testing as compliment to in vitro testing before clinical use of devices.

  • 11.
    Aguilar-Sanchez, Andrea
    et al.
    Stockholm Univ, Div Mat & Environm Chem, Frescativagen 8, S-10691 Stockholm, Sweden..
    Jalvo, Blanca
    Stockholm Univ, Div Mat & Environm Chem, Frescativagen 8, S-10691 Stockholm, Sweden..
    Mautner, Andreas
    Univ Vienna, Fac Chem, Inst Mat Chem & Res, Polymer & Composite Engn PaCE Grp, Wahringer Str 42, A-1090 Vienna, Austria..
    Nameer, Samer
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Ytbehandlingsteknik.
    Pohler, Tiina
    VTT Tech Res Ctr Finland, Solut Nat Resources & Environm, POB 1000, FI-02044 Espoo, Finland..
    Tammelin, Tekla
    VTT Tech Res Ctr Finland, Solut Nat Resources & Environm, POB 1000, FI-02044 Espoo, Finland..
    Mathew, Aji P.
    Stockholm Univ, Div Mat & Environm Chem, Frescativagen 8, S-10691 Stockholm, Sweden..
    Waterborne nanocellulose coatings for improving the antifouling and antibacterial properties of polyethersulfone membranes2021Ingår i: Journal of Membrane Science, ISSN 0376-7388, E-ISSN 1873-3123, Vol. 620, artikel-id 118842Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This article presents a waterborne nanocellulose coating process to change the surface characteristics and mitigate fouling of commercially available polyethersulfone (PES) microfiltration membranes. An extensive comparative study between nanoporous and nano-textured layers composed of cellulose nanocrystals (CNC) or TEMPO-oxidized cellulose nanofibrils (T-CNF), which were coated on the PES membrane by taking advantage of the electrostatic interactions between the PES substrate, a polyallylamine hydrochloride (PAHC1) anchoring layer, and the nanocellulose functional layer. Coated PES membranes exhibited decreased surface roughness and pore sizes as well as rejection of compounds with a M-w above 150 kDa, while the water permeability and mechanical properties of remained largely unaffected. The coatings improved the wettability as confirmed by a reduction of the contact angle by up to 52% and exhibited a higher negative surface charge compared to the uncoated membranes over a pH range of 4-8. A significant reduction in organic fouling was observed for the coated membranes demonstrated by bovine serum albumin (BSA) adsorption studies on T-CNF and CNC surfaces using Quartz Crystal Microbalance with Dissipation monitoring (QCM-D), UV-vis spectroscopy and FTIR mapping after exposing the membranes to dynamic adsorption of BSA. The T-CNF coating exhibited effective antibacterial action against Escherichia coli (E. coli) attributed to the pH reduction effect induced by the carboxyl groups; while CNC coatings did not show this property. This work demonstrates a simple, green, and easy-to-scale layer-by-layer coating process to tune the membrane rejection and to improve antifouling and antibacterial properties of commercially available membranes.

  • 12.
    Ahlinder, Astrid
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymerteknologi. KTH Royal Institute of Technology.
    Degradable copolymers in additive manufacturing: controlled fabrication of pliable scaffolds2021Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [sv]

    Inom vävnadsregenerering är produktionen av väldefinieradematriser med en porös arkitektur av nedbrytbara polymerer av stortintresse, dessa kan nu skapas genom additiva tillverkningsprocesser. Vidadditiv tillverkning krävs ett smalt munstycke för att skapa detaljrikastrukturer och detta ställer krav på att de reologiska egenskapernaanpassat. Lägre viskositet av smältan gör de lättare att använda, men enhög molmassa krävs för tillverka matriser där de mekaniska egenskapernakan bibehållas under tiden som krävs för vävnadsregenerering. Ytterligareen utmaning uppstår när nedbrytbara polymerer används i smältbaseradadditiva tillverkningsprocesser är att termisk nedbrytning ofta reducerarmolmassan redan under produktionsfasen. För att kunna användanedbrytbara polymerer av medicinsk kvalitet i smältbaserad additivtillverkning och samtidigt minimera den termiska nedbrytningen har, idenna avhandling, reologiska fingeravtryck av nedbrytbara syntetiskapolymerer med medicinsk kvalitet använts för att bestämmaprocessparametrar. Termisk nedbrytning beroende av processparamaterar har analyserats och minimeras i två smältbaserade additivatillverkningsprocesser.En additiv tillverkningsprocess var designad där nedbrytbarapolymerer av hög molmassa kunde användas utan termisk nedbrytning närprocessparametrar hade valts utifrån polymerens egenskaper. Kunskapenom användningen av dessa polymerer inom additiv tillverkning kundeappliceras på en sampolymer som utvecklats inom forskningsgruppen förmjukvävnad, poly(ε-kaprolakton-co-p-dioxanon) för att skapa böjbaramatriser. Genom att använda reologisk analys och polymerkarakteriseringerhölls processparametrar som möjliggjorde additiv tillverkning utantermisk nedbrytning. I tillägg till val av polymer och processparametrar såkan mekaniska egenskaper också styras av den strukturella designen.Poly(ε-kaprolakton) användes som modellmaterial för att reducerastyvheten med hjälp av designen, resultatet visade att det var möjligt medmer än en faktor 10 och mjuka böjbara matriser skapades.

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  • 13.
    Ahlström, Leon
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Evaluation of Woodmer/plastic composites2023Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Plast ger otroliga möjligheter i form av stor variation för materialanvändning. Tyvärr sker det dock på bekostnad av miljön då de ackumuleras i naturen. En kompromiss mellan hållbarhet och fortsatt plastanvändning skulle kunna vara att använda biomassa som fyllnadsmaterial i plastkompositer istället för plast. Detta skulle i sin tur minska mängden plast och öka användningen av förnybara råvaror. Naturligtvis måste de mekaniska och termiska egenskaperna också vara av acceptabel kvalitet för materialtillämpningar och helst även erbjuda någon form av uppgradering av det redan existerande materialet. Ett potentiellt fyllnadsmaterial är Woodmer, en LCC (lignin kolhydrat komplex) som produceras av Ecohelix. Woodmers förmåga att agera som ett termoplastiskt kompositmaterial analyserades och jämfördes med de respektive jungfruliga termoplasterna. Tre olika plaster används som bas för kompositerna och dessa plaster var akrylnitril-butadien-styren (ABS), polymjölksyra (PLA) och lågdensitetspolyeten (LDPE).

    Resultaten visar att det är möjligt att skapa homogena Woodmer/termoplast kompositmaterial. När det gäller de termiska egenskaperna, så gav inte UL 94 någon brandklassificering på materialen, några positiva effekter observerades i TGA och resultaten från DSC var mestadels oförändrade jämfört med respektive jungfrulig plast. Dragprovning visade å andra sidan att de mekaniska egenskaperna påverkas negativt av högre Woodmer tillsatser men effekten varierade kraftigt mellan de olika plasterna då LDPE var minst påverkad och PLA mest påverkad. Framtida forskning bör fokusera på att tillverka material genom dubbelskruv extrudering eftersom det tyvärr fanns problem med blandningen i enkelskruv extrudering. Ytterligare forskning kring materialens morfologi, löslighet och så vidare krävs också för att se om kompositerna är lämpliga material eller om det finns några oförutsedda problem.

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  • 14.
    Ahmed, Fareed
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Ding, Penghui
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Ail, Ujwala
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Warczak, Magdalena
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Grimoldi, Andrea
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Ederth, Thomas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biofysik och bioteknik. Linköpings universitet, Tekniska fakulteten.
    Håkansson, Karl M. O.
    RISE Bioeconomy, Stockholm, Sweden.
    Vagin, Mikhail
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Gueskine, Viktor
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Berggren, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Crispin, Xavier
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Manufacturing Poly(3,4-Ethylenedioxythiophene) Electrocatalytic Sheets for Large-Scale H2O2 Production2022Ingår i: Advanced Sustainable Systems, E-ISSN 2366-7486, Vol. 6, nr 1, artikel-id 2100316Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Producing thick films of conducting polymers by a low-cost manufacturing technique would enable new applications. However, removing huge solvent volume from diluted suspension or dispersion (1-3 wt%) in which conducting polymers are typically obtained is a true manufacturing challenge. In this work, a procedure is proposed to quickly remove water from the conducting polymer poly(3,4-ethylenedioxythiophene:poly(4-styrene sulfonate) (PEDOT:PSS) suspension. The PEDOT:PSS suspension is first flocculated with 1 m H2SO4 transforming PEDOT nanoparticles (approximate to 50-500 nm) into soft microparticles. A filtration process inspired by pulp dewatering in a paper machine on a wire mesh with apertures dimension between 60 mu m and 0.5 mm leads to thick free-standing films (approximate to 0.5 mm). Wire mesh clogging that hinders dewatering (known as dead-end filtration) is overcome by adding to the flocculated PEDOT: PSS dispersion carbon fibers that aggregate and form efficient water channels. Moreover, this enables fast formation of thick layers under simple atmospheric pressure filtration, thus making the process truly scalable. Thick freestanding PEDOT films thus obtained are used as electrocatalysts for efficient reduction of oxygen to hydrogen peroxide, a promising green chemical and fuel. The inhomogeneity of the films does not affect their electrochemical function.

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  • 15.
    Akan, Rabia
    KTH, Skolan för kemivetenskap (CHE).
    Oorganiska-organiska nanopartikelbaserade supramolekylära strukturer för biomedicinska applikationer2015Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Denna studie utfördes i syfte att se över möjligheter att via supramolekylär kemi skapa ett multifunktionellt system för biomedicinska applikationer med kombinerad förmåga att selektivt rikta, bota och diagnostisera. Superparamagnetiska järnoxidnanopartiklar syntetiserades genom samutfällning och ytmodifierades på tre skilda tillvägagångssätt med den cykliska oligosackariden karboximetyl-β-cyklodextrin. De olika ytmodifieringssätten involverade ett, två eller tre reaktionssteg innan de slutgiltiga oligosackaridfuntionaliserade nanopartiklarna erhölls. Huvudskillnaderna mellan de olika modifieringssätten är utförandet av kondensationsreaktionerna. Antingen utfördes förestring genom nyttjandet av de inneboende hydroxylgrupper på järnoxidnanopartiklarna eller så aminfunktionaliserades ytorna för att skapa en bas för karboximetyl-β-cyklodextrin att fästa. Vidare bildades ett supramolekylärt system via inkorporering av folsyrafunktionaliserat Pluronic® L-35. De polymerinkorporerade nanopartikelbaserade supramolekylära systemen karaktäriserades med TEM, TGA, FT-IR och zeta potential.

     

    Det supramolekylära systemets kolloidala stabilitet undersöktes i fosfatbuffrad saltlösning med pH 7.4 med syfte att imitera kroppsförhållanden. Av de tre olika ytmodifieringsmetoderna som undersöktes visade det sig att trestegsmodifieringen med citronsyra, hexametylenediamin och slutligen karboximetyl-β-cyklodextrin gav den mest stabila ferrofluiden. Den genomsnittliga storleken på de erhållna karboximetyl-β-cyklodextrinfunktionaliserade nanopartiklarna var 25 nm. De resulterande supramolekylära strukturerna efter polymerinkludering var genomsnittligen 50 nm. Mängden oligosackarid bunden till nanopartiklarna bestämdes till 25 vikts %. Den lyckade formuleringen av det nanopartikelbaserade supramolekylära systemet medför sålunda en effektiv plattform med flera potentiella användningsområden inom biomedicin. De superparamagnetiska järnoxidnanopartiklarna medför kontrastförstärkning för MRI samt möjlighet att rikta systemet via ett externt magnetfält, den omslutande polymeren skapar förmåga att transportera hydrofoba läkemedel och folsyran ger egenskapen att selektivt binda till tumörceller för riktad frisättning av läkemedel.

  • 16.
    Akhlaghi, Shahin
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Degradation of acrylonitrile butadiene rubber and fluoroelastomers in rapeseed biodiesel and hydrogenated vegetable oil2017Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Biodiesel and hydrotreated vegetable oil (HVO) are currently viewed by the transportation sector as the most viable alternative fuels to replace petroleum-based fuels. The use of biodiesel has, however, been limited by the deteriorative effect of biodiesel on rubber parts in automobile fuel systems. This work therefore aimed at investigating the degradation of acrylonitrile butadiene rubber (NBR) and fluoroelastomers (FKM) on exposure to biodiesel and HVO at different temperatures and oxygen concentrations in an automated ageing equipment and a high-pressure autoclave. The oxidation of biodiesel at 80 °C was promoted by an increase in the oxygen partial pressure, resulting in the formation of larger amounts of hydroperoxides and acids in the fuel. The fatty acid methyl esters of the biodiesel oxidized less at 150 °C on autoclave aging, because the termination reactions between alkyl and alkylperoxyl radicals dominated over the initiation reactions. HVO consists of saturated hydrocarbons, and remained intact during the exposure. The NBR absorbed a large amount of biodiesel due to fuel-driven internal cavitation in the rubber, and the uptake increased with increasing oxygen partial pressure due to the increase in concentration of oxidation products of the biodiesel. The absence of a tan δ peak (dynamical mechanical measurements) of the bound rubber and the appearance of carbon black particles devoid of rubber suggested that the cavitation was caused by the detachment of bound rubber from particle surfaces. A significant decrease in the strain-at-break and in the Payne-effect amplitude of NBR exposed to biodiesel was explained as being due to the damage caused by biodiesel to the rubber-carbon-black network. During the high-temperature autoclave ageing, the NBR swelled less in biodiesel, and showed a small decrease in the strain-at-break due to the cleavage of rubber chains. The degradation of NBR in the absence of carbon black was due only to biodiesel-promoted oxidative crosslinking. The zinc cations released by the dissolution of zinc oxide particles in biodiesel promoted reduction reactions in the acrylonitrile part of the NBR. Heat-treated star-shaped ZnO particles dissolved more slowly in biodiesel than the commercial ZnO nanoparticles due to the elimination of inter-particle porosity by heat treatment. The fuel sorption was hindered in HVO-exposed NBR by the steric constraints of the bulky HVO molecules. The extensibility of NBR decreased only slightly after exposure to HVO, due to the migration of plasticizer from the rubber. The bisphenol-cured FKM co- and terpolymer swelled more than the peroxide-cured GFLT-type FKM in biodiesel due to the chain cleavage caused by the attack of biodiesel on the double bonds formed during the bisphenol curing. The FKM rubbers absorbed biodiesel faster, and to a greater extent, with increasing oxygen concentration. It is suggested that the extensive biodiesel uptake and the decrease in the strain-at-break and Young’s modulus of the FKM terpolymer was due to dehydrofluorination of the rubber by the coordination complexes of biodiesel and magnesium oxide and calcium hydroxide particles. An increase in the CH2-concentration of the extracted FKM rubbers suggested that biodiesel was grafted onto the FKM at the unsaturated sites resulting from dehydrofluorination.

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  • 17.
    Akhlaghi, Shahin
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Amir Masoud, Pourrahimi
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Christian, Sjöstedt
    Martin, Bellander
    Mikael S., Hedenqvist
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Ulf W., Gedde
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Degradation of fluoroelastomers in rapeseed biodiesel at different oxygen concentrations2017Ingår i: Polymer degradation and stability, ISSN 0141-3910, E-ISSN 1873-2321, Vol. 136, s. 10-19Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The degradation of fluoroelastomers (FKM) based on different monomers, additives and curing systems was studied after exposure to rapeseed biodiesel at 100 °C and different oxygen partial pressures. The sorption of fuel in the carbon black-filled FKM terpolymer was promoted by the fuel-driven cavitation in the rubber. The bisphenol-cured rubbers swelled more in biodiesel than the peroxide-cured FKM, presumably due to the chain cleavage caused by the attack of biodiesel on the double bonds formed during the bisphenol curing. With any of the selected types of monomer, the FKM rubbers absorbed biodiesel faster and to a greater extent with increasing oxygen partial pressure due to the increase in concentration of the oxidation products of biodiesel. Water-assisted complexation of biodiesel on magnesium oxide and calcium hydroxide particles led to dehydrofluorination of FKM, resulting in an extensive fuel uptake and a decrease in the strain-at-break and the Young's modulus of the rubbers. An increase in the CH2-concentration determined by infrared spectroscopy, and the appearance of biodiesel flakes in scanning electron micrographs of the extracted rubbers, were explained as being due to the presence of insoluble biodiesel grafted onto FKM on the unsaturated sites resulting from dehydrofluorination. The extensibility of the GFLT-type FKM was the least affected on exposure to biodiesel because this rubber contained less unsaturation and metal oxide/hydroxide particles.

  • 18.
    Akhlaghi, Shahin
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Pourrahimi, A. M.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Christian, Sjöstedt
    Martin, Bellander
    Mikael S., Hedenqvist
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Ulf W., Gedde
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Effects of ageing conditions on degradation of acrylonitrile butadiene rubber filled with heat-treated ZnO star-shaped particles in rapeseed biodiesel2017Ingår i: Polymer degradation and stability, ISSN 0141-3910, E-ISSN 1873-2321Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The degradation of acrylonitrile butadiene rubber (NBR) after exposure to biodiesel at different oxygen partial pressures in an automated ageing equipment at 80 °C, and in a high-pressure autoclave at 150 °C was studied. The oxidation of biodiesel was promoted by an increase in oxygen concentration, resulting in a larger uptake of fuel in the rubber due to internal cavitation, a greater decrease in the strain-at-break of NBR due to the coalescence of cavity, and a faster increase in the crosslinking density and carbonyl index due to the promotion of the oxidation of NBR. During the high-temperature autoclave ageing, less fuel was absorbed in the rubber, because the formation of hydroperoxides and acids was impeded. The extensibility of NBR aged in the autoclave decreased only slightly due to the cleavage of rubber chains by the biodiesel attack. The degradation of NBR in the absence of carbon black was explained as being due to oxidative crosslinking. The dissolution of ZnO crystals in the acidic components of biodiesel was retarded by removing the inter-particle porosity and surface defects through heat treating star-shaped ZnO particles. The rubber containing heat-treated ZnO particles swelled less in biodiesel than a NBR filled with commercial ZnO nanoparticles, and showed a smaller decrease in the strain-at-break and less oxidative crosslinking.

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  • 19.
    Al Husseinat, Ali
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Lignin Biorefining: Swelling and activation of fibers for lignin extraction2023Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    I världens omvandling mot en bioekonomi kommer lignocellulosa material spela en stor roll i ersättningen av fossila resurser. Lignin är den mest tillgängliga källan av förnybara och naturligt förekommande aromatiska ämne och den utgör 15–30% av ved. Det lignin som är för nuvarande tillgängligt i marknaden är begränsat i sina appliceringar på grund av ämnets komplexa och outforskade kemisk struktur. I ett försök att bidra till ’lignin-först’ bioraffinaderi konceptet, undersöker detta arbete effekten av urea och karboxymetylering som förbehandlingsmetoder på utbyte av lignin såväl som de kemiska och fysiska egenskaperna av lignin. Karaktäriseringstekniker som Fourier-transform infra-red och nuclear magnetic resonance spectroscopy används för att analysera den kemiska strukturen av ligninet efter extraktion. Det resulterade i att båda förbehandlingsmetoder ökade utbytet av lignin med mellan 1% och 16%. Urea förbehandlingen hade ingen effekt på den kemiska strukturen av varken fibrer eller lignin. Men, karboxymetylering förbehandlingen ändrade i kemiska strukturen av lignin genom att lägga till karboxymetyl-grupper i både den alifatiska och den fenoliska regionen. Medans att öka förbehandlingstiden ökade utbyte i båda förbehandlingsmetoder, hade detta effekten att minska mängden kvantifierbara bindningar mellan enheterna för karboxymetylering förbehandlingen. Dessa diskuterade metoder har potential att användas i valorisering av lignin.

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  • 20.
    Alam, Parvez
    et al.
    Univ Edinburgh, Inst Mat & Proc, Sch Engn, Edinburgh, Midlothian, Scotland.
    Sanka, Immanuel
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för biologisk grundutbildning. Univ Gadjah Mada, Fac Biol, KSK Biogama Marine Biol Study Grp, Yogyakarta, Indonesia.
    Alam, Lilja Piuli
    Int Baccalaureate Sch, Turku, Finland.
    Wijaya, Saka
    Univ Gadjah Mada, Fac Biol, Dept Trop Biol, Yogyakarta, Indonesia.
    Sintya, Erly
    Univ Edinburgh, Inst Mat & Proc, Sch Engn, Edinburgh, Midlothian, Scotland; Univ Gadjah Mada, Fac Biol, KSK Biogama Marine Biol Study Grp, Yogyakarta, Indonesia; Kings Coll London, Dept Imaging Sci, London, England; Kings Coll London, Biomed Engn Res Div, London, England.
    Handayani, Niken Satuti Nur
    Univ Gadjah Mada, Fac Biol, Lab Genet & Breeding, Yogyakarta, Indonesia.
    Rivero-Mueller, Adolfo
    Univ Turku, Turku Ctr Biotechnol, Turku, Finland; Åbo Akad Univ, Turku, Finland; Med Univ Lublin, Dept Biochem & Mol Biol, Lublin, Poland.
    The snapping shrimp dactyl plunger: a thermomechanical damage-tolerant sandwich composite2018Ingår i: Zoology (Jena), ISSN 0944-2006, E-ISSN 1873-2720, Vol. 126, s. 1-10Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The dactyl plunger of Alpheus sp. was found to be a layered composite, with mineral-rich outer and inner layers and a chitin-rich middle layer of high porosity. The chitin-rich middle layer is itself composed of several porous chitin laminae. Modelling heat conduction through the plunger cross-section revealed that the chitin-rich layer is able to insulate heat and retard its progress through the material. Heat accumulates in the plunger after a series of successive snaps and as such, its thermally resistant design can be considered most useful under the conditions of successive snapping. The plunger has a concurrent mechanical damage-tolerant design with biogenic mineral layers, viscous (chitin–mineral) interfaces, energy-dissipating porous chitin, and sidewalls composed of ordered, layered aragonite. The snapping shrimp plunger has a design that may protect it and internal soft tissues from thermomechanical damage during plunger–socket compression prior to cavitation bubble release.

  • 21.
    Al-Ashor, Safana
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Sustainable food packaging based on polyhydroxyalkanoate2024Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    The Norwegian Food Research Institute (Nofima) and the University of Borås worked together to develop this project. The commonly used packaging materials pose a serious threat to the environment, as they are produced from nonrenewable crude oil and cannot decompose naturally. Despite some manufacturers' claims of their products being eco-friendly or sustainable, they are not entirely made from renewable resources and are not biodegradable. Nevertheless, some bio-based materials have emerged as a viable alternative that can naturally break down and safely decompose in the environment. Despite many studies, biopolymers possess limited mechanical and barrier properties, which restricts their potential for use in products. To overcome this limitation, polymer blending can be employed to enhance their final properties and make them more suitable for various applications.

    The objective of this project was to design sustainable food packaging using biopolymers. PHBV, one of the PHA’s bio-based polymers, was blended with other polymers to enhance its properties as a sustainable food packaging material. Through blending, PHAs'physical, chemical, and thermal properties can be enhanced to obtain exceptional films for food packaging purposes.

    Finally, in this work, a bio-based polymer, polyhydroxyalkanoate, was used to producea biodegradable packaging system for potential food packaging applications. The effect of the physical modification of PHBV on mechanical and barrier properties was studied by blending it with biodegradable polymers such as PLA and PBAT. Thermal properties were analyzed using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and FourierIItransform infrared spectroscopy (FTIR) while the mechanical properties were evaluated by tensile test. Barrier properties were characterized using water vapor transmission rate (WVTR).

    The mechanical performance of PHBV 50%: PBAT 50% blend has been significantly improved, leading to better tensile properties. The high crystallinity of the PHBV 50%: PBAT 50% blend than other blends have been found to enhance the barrier properties of the polymer film, according to DSC analysis. FTIR investigations have suggested no difference in absorption peaks between the blends and the neat material. Furthermore, WVTR investigations have shown that PHBV50%: PBAT50% exhibits excellent barrier properties against water vapor, making it a highly promising material.

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  • 22.
    Alberdi-Muniain, Ane
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Strukturakustik.
    Gil-Negrete, N.
    Department of Applied Mechanics, CEIT and Tecnun (University of Navarra).
    Kari, Leif
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Strukturakustik.
    Influence of carbon black and plasticisers on dynamic properties of isotropic magnetosensitive natural rubber2012Ingår i: Plastics, rubber and composites, ISSN 1465-8011, E-ISSN 1743-2898, Vol. 41, nr 7, s. 310-317Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The dynamic shear modulus of magnetosensitive (MS) natural rubber composites is experimentallystudied, where influences of carbon black, plasticiser and iron particle concentrations areinvestigated at various dynamic shear strain amplitudes and external magnetic fields within thelower structure borne frequency range. The iron particles embedded in natural rubber areirregularly shaped and randomly distributed; the plasticisers simplify the iron particle blendingprocess, while carbon black reduces the production costs and improves the mechanicalproperties. The results show that the relative MS effect on the shear modulus magnitude increaseswith increased plasticiser and iron particle concentration and decreases with increased carbonblack concentration. Furthermore, their relative contributions are quantified. Consequently, thestudy provides a basis for optimising the composition of MS natural rubber to meet a variety ofrequirements, including those of vibration isolation, a promising application area for MS materials.

  • 23.
    Albertsson, A-C.
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Andersson, S-O.
    Karlsson, S.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    The mechanism of biodegradation of polyethylene1987Ingår i: Polymer degradation and stability, ISSN 0141-3910, E-ISSN 1873-2321, Vol. 18, s. 73-87Artikel i tidskrift (Refereegranskat)
  • 24. Albertsson, A-C.
    et al.
    Barenstedt, C.
    Karlsson, S.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Degradation of enhanced environmentally degradable polyethylene in biological aqueous media: mechanisms during the first stages1994Ingår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 51, nr 6, s. 1097-1105Artikel i tidskrift (Refereegranskat)
  • 25. Albertsson, A-C.
    et al.
    Barenstedt, C.
    Karlsson, S.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Increased biodegradation of a low-density polyethylene (LDPE) matrix in starch-filled LDPE materials1993Ingår i: Journal of environmental polymer degradation, ISSN 1064-7546, E-ISSN 1572-8900, Vol. 1, nr 4, s. 241-245Artikel i tidskrift (Refereegranskat)
  • 26. Albertsson, A-C.
    et al.
    Barenstedt, C.
    Karlsson, S.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Solid-phase extraction and gas chromatographic-mass spectrometric identification of degradation products from enhanced environmentally degradable polyethylene1995Ingår i: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 690, nr 2, s. 207-217Artikel i tidskrift (Refereegranskat)
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    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Susceptibility of enhanced environmentally degradable polyethylene to thermal and photo-oxidation1992Ingår i: Polymer degradation and stability, ISSN 0141-3910, E-ISSN 1873-2321, Vol. 37, nr 2, s. 163-171Artikel i tidskrift (Refereegranskat)
  • 28. Albertsson, A-C.
    et al.
    Barenstedt, C.
    Karlsson, S.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Lindberg, T.
    Degradation product pattern and morphology changes as means to differentiate abiotically and biotically aged degradable polyethylene1995Ingår i: Polymer, ISSN 0032-3861, E-ISSN 1873-2291, Vol. 36, nr 16, s. 3075-83Artikel i tidskrift (Refereegranskat)
  • 29. Albertsson, A-C.
    et al.
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    Karlsson, S.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Nishimoto, K.
    Watanabe, Y.
    Spectroscopic and mechanical changes in irradiated starch-filled LDPE1994Ingår i: Polymer degradation and stability, ISSN 0141-3910, E-ISSN 1873-2321, Vol. 45, nr 2, s. 173-178Artikel i tidskrift (Refereegranskat)
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    et al.
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    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Abiotic degradation products from enhanced environmentally degradable polyethylene1994Ingår i: Acta Polymerica, ISSN 0323-7648, E-ISSN 1521-4044, Vol. 45, nr 2, s. 97-103Artikel i tidskrift (Refereegranskat)
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    et al.
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    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Aspects of biodeterioration of inert and degradable polymers1993Ingår i: International Biodeterioration & Biodegradation, ISSN 0964-8305, E-ISSN 1879-0208, Vol. 31, nr 3, s. 161-170Artikel i tidskrift (Refereegranskat)
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    et al.
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    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Biodegradable polymers1992Ingår i: Comprehensive Polymer Science, Supplement Series, Midland, Michigan: Pergamon Press, 1992, s. 285-Kapitel i bok, del av antologi (Refereegranskat)
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    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Biodegradation and testmethods for environmental and biomedical applications of polymers1990Ingår i: Degradable Materials, Boca Raton: CRC Press, 1990, s. 263-Kapitel i bok, del av antologi (Refereegranskat)
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    Chemistry and biochemistry of polymer biodegradation1994Ingår i: Chemistry and Technology of Biodegradable Polymers / [ed] G.J.L. Griffin, London, England: Blackie Academic & Professional , 1994, s. 7-17Kapitel i bok, del av antologi (Refereegranskat)
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    Chromatographic fingerprinting as a means to predict degradation mechanisms1996Ingår i: Journal of environmental polymer degradation, ISSN 1064-7546, E-ISSN 1572-8900, Vol. 4, nr 1, s. 51-3Artikel i tidskrift (Refereegranskat)
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    Controlled degradation by artificial and biological processes1996Ingår i: Macromol. Design of Polymeric Materials, Marcel Dekker, 1996, s. 54-Kapitel i bok, del av antologi (Refereegranskat)
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    Degradable polyethylene-starch complex1991Ingår i: Makromolekulare Chemie, Macromolecular Symposia, Vol. 48-49, nr Eur. Polym. Fed. Symp. Polym. Mater., 3rd, 1990, s. 395-402Artikel i tidskrift (Refereegranskat)
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    Degradable Polymers1996Ingår i: The Polymeric Materials Encyclopedia: Synthesis, Properties and Applications / [ed] J. C. Salamone, Boca Raton, USA: CRC Press, 1996, s. 150-Kapitel i bok, del av antologi (Refereegranskat)
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    Increased biodegradation of LDPE-matrix in starch-filled LDPE materials1992Ingår i: Materials Science and Engineering, Vol. 67, s. 296-297Artikel i tidskrift (Refereegranskat)
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  • 47.
    Albertsson, Ann-Christine
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Frontiers in Biomacromolecules: Functional Materials from Nature2012Ingår i: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 13, nr 12, s. 3901-3901Artikel i tidskrift (Övrigt vetenskapligt)
  • 48.
    Albertsson, Ann-Christine
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Micro- and macromolecular design of aliphatic polyesters2015Ingår i: Abstracts of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 249Artikel i tidskrift (Övrigt vetenskapligt)
  • 49.
    Albertsson, Ann-Christine
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Edlund, Ulrica
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Barrier layers for packaging laminates and packaging laminates comprising such barrier layers2009Patent (Övrig (populärvetenskap, debatt, mm))
  • 50.
    Albertsson, Ann-Christine
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Erlandsson, Bengt
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Hakkarainen, Minna
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Karlsson, Sigbritt
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Molecular weight changes and polymeric matrix changes correlated with the formation of degradation products in biodegraded polyethylene1999Ingår i: Journal of environmental polymer degradation, ISSN 1064-7546, E-ISSN 1572-8900, Vol. 64, s. 91-99Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The molecular weight changes in abiotically and biotically degraded LDPE and LDPE modified with starch and/or prooxidant were compared with the formation of degradation products, The samples were thermooxidized for 6 days at 100 degrees C to initiate degradation and then either inoculated with Arthobacter paraffineus or kept sterile. After 3.5 years homologous series of mono- and dicarboxylic acids and ketoacids were identified by GC-MS in abiotic samples, while complete disappearance of these acids was observed in biotic environments. The molecular weights of the biotically aged samples were slightly higher than the molecular weights of the corresponding abiotically aged samples, which is exemplified by the increase in (M) over bar(n) from 5200 g/mol for a sterile sample with the highest amount of prooxidant to 6000 g/mol for the corresponding biodegraded sample. The higher molecular weight in the biotic environment is explained by the assimilation of carboxylic acids and low molecular weight polyethylene chains by microorganisms. Assimilation of the low molecular weight products is further confirmed by the absence of carboxylic acids in the biotic samples. Fewer carbonyls and more double bonds were seen by FTIR in the biodegraded samples, which is in agreement with the biodegradation mechanism of polyethylene.

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