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  • 1.
    Baghaei, Behnaz
    University of Borås, Faculty of Textiles, Engineering and Business.
    Development of thermoplastic biocomposites based on aligned hybrid yarns for fast composite manufacturing2015Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The interest in natural fibres as reinforcement for composite materials has been steadily increasing due to their attractive mechanical properties and the possibility of making more eco-friendly materials. Currently, various alternatives are being introduced for commercial applications, as fibres such as hemp, jute and flax exhibit properties, which make them appropriate for structural composite components. Biocomposites offer reductions in weight and cost and have less reliance on foreign oil resources, making them attractive. Several investigations have revealed that the full utilisation of fibre mechanical properties in the final composites can be exploited, provided an aligned fibre orientation is chosen. In fact, a major challenge for natural fibre reinforced composites is to achieve high mechanical performance at competitive prices. The use of commingled/hybrid yarns is one of the more promising methods for manufacturing structural thermoplastic composites.

    Commingled yarns of thermoplastic and reinforcing fibres offer a potential for cost-effective production of composite parts, thanks to reduced applied pressures and impregnation times during processing. Besides economic advantages, there is also direct control over fibre placements and ease of handling of fibres in yarn process. The yarn technologies provide homogenous distribution of reinforcing fibre and matrix. Variation in natural fibre properties has been a major problem facing composite manufacturers, compared to carbon and glass fibres that have well-defined production processes. This issue can be addressed by regenerated cellulose fibres. These fibres can be reproduced easily with high surface evenness and even quality, making it possible to get consistent results, which is not possible with natural fibres. Combination of natural and regenerated cellulose fibre brings together the best of both materials. The end result is a product with superior properties, which could not be obtained by the individual components.

    This thesis describes the development of aligned hybrid yarns with low fibre twist, for high performance natural (hemp) and man-made (Lyocell) cellulose fibre-reinforced biocomposites, suitable for use in structural or semi-structural applications. The properties of composites in terms of fibre orientation, off-axis angle and alkali treatment were investigated, focusing on determining void%, water absorption, mechanical and thermo-mechanical properties. The results show that combining hemp and Lyocell in PLA composite leads to the reduction of moisture absorption and can improve the mechanical properties. The mechanical properties of the composites were highly affected by the fibre direction. The alkali treatment on hemp fibre improved the mechanical properties of the composites.

  • 2.
    Baghaei, Behnaz
    et al.
    University of Borås, School of Engineering.
    Berglin, Lena
    University of Borås, Swedish School of Textiles.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Tailoring of the mechanical and thermal properties of hemp/PLA hybrid yarn composites2013Conference paper (Other academic)
    Abstract [en]

    In this study, we worked on improving the orientation of hemp fibres in composites by using our recent development of co-wrapped yarn structures. We investigated the influence of fibre content and wrap density on the properties of composites. Composites were fabricated by compression moulding of 0/90 bidirectional prepregs. Compared to neat PLA, the tensile and flexural modulus and the strength of the PLA-hemp composites were significantly higher as a result of the increased fibre content. Impact strength of the composites decreased initially up to 10 mass % fibre loading, but even higher fibre loading caused an improvement in impact strength. From the DMTA results, it was evident that incorporation of the fibres gives a considerable increase in storage modulus and a decrease in tan δ values. From the general trend in the results obtained, it can be affirmed that co-wrapped hybrid yarn with lower wrapping density leads to lower mechanical properties in the composite. The study performed with DSC revealed that the crystallisation temperature of the hemp-reinforced PLA composites decreased compared to pure PLA, which indicates that the hemp fibres hinder the migration and diffusion of PLA molecular chains to the surface of the nucleus in the composites.

  • 3.
    Baghaei, Behnaz
    et al.
    University of Borås, School of Engineering.
    Berglin, Lena
    University of Borås, Swedish School of Textiles.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Tailoring of the mechanical and thermal properties of hemp/PLA hybrid yarn composites2013Conference paper (Other academic)
    Abstract [en]

    In this study, we worked on improving the orientation of hemp fibres in composites by using our recent development of co-wrapped yarn structures. We investigated the influence of fibre content and wrap density on the properties of composites. Composites were fabricated by compression moulding of 0/90 bidirectional prepregs. Compared to neat PLA, the tensile and flexural modulus and the strength of the PLA-hemp composites were significantly higher as a result of the increased fibre content. Impact strength of the composites decreased initially up to 10 mass % fibre loading, but even higher fibre loading caused an improvement in impact strength. From the DMTA results, it was evident that incorporation of the fibres gives a considerable increase in storage modulus and a decrease in tan δ values. From the general trend in the results obtained, it can be affirmed that co-wrapped hybrid yarn with lower wrapping density leads to lower mechanical properties in the composite. The study performed with DSC revealed that the crystallisation temperature of the hemp-reinforced PLA composites decreased compared to pure PLA, which indicates that the hemp fibres hinder the migration and diffusion of PLA molecular chains to the surface of the nucleus in the composites.

  • 4.
    Baghaei, Behnaz
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Skrifvars, Mikael
    University of Borås, Faculty of Textiles, Engineering and Business.
    Characterisation of polylactic acid biocomposites made from prepregs composed of woven polylactic acid/hemp–Lyocell hybrid yarn fabrics2016In: Composites Part A: Applied Science and Manufacturing, ISSN 1359-835X, Vol. 81, p. 139-144Article in journal (Refereed)
    Abstract [en]

    This paper describes the mechanical properties and water absorption characteristics for biocomposites made from woven PLA/hemp/Lyocell prepregs. The aim was to improve the properties with the addition of Lyocell fibre into a hybrid yarn. Well-aligned hybrid yarns composed of hemp/PLA, hemp-Lyocell/PLA, respective, Lyocell/PLA were made by wrap spinning. Unidirectional satin fabrics were made by weaving with PLA (warp) and the hybrid yarns (weft). Uniaxial composites were fabricated with 30 fibre mass% using compression moulding. The composites were investigated for tensile, flexural and impact properties. Combining hemp with Lyocell in a PLA matrix improves the mechanical properties, compared to hemp/PLA composites. The composite made from the satin Lyocell/PLA fabric gave the best mechanical properties. The type of fibre reinforcement compositions did not significantly affect the water absorption of the biocomposites. Scanning electron microscopy showed that fibre pull-outs appear more often in hemp/PLA composites than in composites also including Lyocell fibre. © 2015 Elsevier Ltd. All rights reserved.

  • 5.
    Baghaei, Behnaz
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Skrifvars, Mikael
    University of Borås, Faculty of Textiles, Engineering and Business.
    Characterization of thermoplastic natural fibre composites made from woven hybrid yarn prepregs with different weave pattern2015In: Composites Part A: Applied Science and Manufacturing, Vol. 81, no February 2016, p. 139-144Article in journal (Other academic)
  • 6.
    Baghaei, Behnaz
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Skrifvars, Mikael
    University of Borås, Faculty of Textiles, Engineering and Business.
    Investigation of pattern style of woven fabrics produced from hybrid wrap spun yarns on fabricated composite2015Conference paper (Other academic)
  • 7.
    Baghaei, Behnaz
    et al.
    University of Borås, School of Engineering.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Berglin, Lena
    University of Borås, Swedish School of Textiles.
    Hybrid natural fibre reinforcements and prepregs for thermoplastic composites with improved performance and properties2014Conference paper (Other academic)
  • 8.
    Baghaei, Behnaz
    et al.
    University of Borås, School of Engineering.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Berglin, Lena
    University of Borås, Swedish School of Textiles.
    Manufacture and characterisation of thermoplastic composites made from PLA/hemp co-wrapped hybrid yarn prepregs2013In: Composites. Part A, Applied science and manufacturing, ISSN 1359-835X, E-ISSN 1878-5840, Vol. 50, p. 93-101Article in journal (Refereed)
    Abstract [en]

    PLA/hemp co-wrapped hybrid yarns were produced by wrapping PLA filaments around a core composed of a 400 twists/m and 25 tex hemp yarn (Cannabis Sativa L) and 18 tex PLA filaments. The hemp content varied between 10 and 45 mass%, and the PLA wrapping density around the core was 150 and 250 turns/metre. Composites were fabricated by compression moulding of 0/90 bidirectional prepregs, and characterised regarding porosity, mechanical strength and thermal properties by dynamic mechanical thermal analysis (DMTA) and differential scanning calorimetry (DSC). Mechanical tests showed that the tensile and flexural strengths of the composites markedly increased with the fibre content, reaching 59.3 and 124.2 MPa when reinforced with 45 mass% fibre, which is approximately 2 and 3.3 times higher compared to neat PLA. Impact strength of the composites decreased initially up to 10 mass% fibre; while higher fibre loading (up to 45 mass%) caused an increase in impact strength up to 26.3 KJ/m2, an improvement of about 2 times higher compared to neat PLA. The composites made from the hybrid yarn with a wrapping density of 250 turns/metre showed improvements in mechanical properties, due to the lower porosity. The fractured surfaces were investigated by scanning electron microscopy to study the fibre/matrix interface.

  • 9.
    Baghaei, Behnaz
    et al.
    University of Borås, School of Engineering.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Berglin, Lena
    University of Borås, Swedish School of Textiles.
    Ramamoorthy, Sunil Kumar
    University of Borås, School of Engineering.
    Hemp/PLA Co-Wrapped Hybrid Yarns For Structured Thermoplastic Composites2013Conference paper (Refereed)
    Abstract [en]

    In recent years, natural fibre-reinforced polymer composites have been attracting attention from the viewpoint of reducing the impact on the natural environment. Currently, the use of thermoplastic resins in composites is clearly of higher potential than the use of thermoset. There are many thermoplastic polymers derived from renewable raw materials, which are also biodegradable. Polylactic acid (PLA) is one such candidate, and it shows rather good properties that are suitable for applications that do not require long-term durability or elevated mechanical performance at higher temperatures. In order to make their possible use in many technical applications more attractive, the mechanical properties of the PLA can be enhanced by using reinforcements. Hemp fibres can be considered to be a good choice for reinforcing polymer composites, due to their high stiffness, strength, and aspect ratio. Highly ordered textile reinforcements, such as interlaced woven fabrics and unidirectional fabrics made from natural-fibre yarns, perform considerably better than random non-woven mats in natural-fibre composites. At present, the commercially available plant-fibre yarns are not intended for structural composites, but for textiles, which have entirely different demands on the yarns. Thus, work is needed to tailor-make the best plant-fibre yarn for reinforcement of composites. This also includes investigation of the possibility of combining plant-fibre yarns with the matrix polymer in fibre form into one hybrid yarn (a composite preform), and how to do it (twisting or blending). It is well known that fibres provide the highest strength and stiffness when they are continuous and aligned in the direction of the applied load. Natural fibres are naturally discontinuous and conventional spun staple yarns tend to be highly twisted, which leads to fibre misalignment and poor resin wet-out. The structured natural-fibre composites reported so far are based on twisted yarns produced by long-established conventional spinning methods, mainly ring spinning. In this paper, we report our work on improving the orientation of hemp fibres in composites by using our recent development of co-wrapped yarn structures. This novel co-wrapped yarn consists of low twist and very fine hemp yarns next to PLA filaments in the core part, which are wrapped by PLA filaments. By varying the composition of hybrid yarn, it is possible to vary the hemp fibre content from 10 to 45 wt %. An exciting recent advancement has been a new family of aligned natural-fibre reinforcements, which has overcome these issues by using low twist yarns. We also report the influence of fibre content and wrap density (number of wraps per unit length) on the properties of composites. Before compression moulding, multilayer 0/90 bidirectional hybrid yarn prepregs were prepared by winding the hybrid yarn around a steel rectangular frame. We investigated the mechanical and thermo-mechanical properties of hemp-reinforced PLA composites. Compared to neat PLA, the tensile and flexural modulus and the strength of the PLA-hemp composites were significantly higher as a result of the increased fibre content. Impact strength of the composites decreased initially up to 10 wt % fibre loading, but even higher fibre loading caused an improvement in impact strength. From the DMTA results, it is evident that incorporation of the fibres gives a considerable increase in storage modulus and a decrease in tan δ values. These results show the reinforcing effect of hemp on PLA matrix. From the general trend in the results obtained, it can be affirmed that co-wrapped hybrid yarn with lower wrapping density leads to lower mechanical properties in the composite. The study performed with DSC revealed that the glass transition temperature and the crystalline melting point of PLA were not affected significantly after reinforcement with hemp. The crystallisation temperature of the hemp-reinforced PLA composites decreased compared to pure PLA, which indicates that the hemp fibres hinder the migration and diffusion of PLA molecular chains to the surface of the nucleus in the composites. No noteworthy differences in calorimetric data from DSC for composites were observed between the hybrid yarn preforms with different wrapping density. Future work will concentrate on efforts to evaluate the biodegradability of these developing and promising composites.

  • 10.
    Baghaei, Behnaz
    et al.
    University of Borås, School of Engineering.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Masoud, Salehi
    University of Borås, School of Engineering.
    Aligned hemp yarn reinforced biocomposites: porosity, water absorption, thermal and mechanical properties2014Conference paper (Refereed)
  • 11.
    Baghaei, Behnaz
    et al.
    University of Borås, School of Engineering.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Salehi, Masoud
    Bashir, Tariq
    University of Borås, School of Engineering.
    Rissanen, Marja
    Nousiainen, Pertti
    Novel aligned hemp fibre reinforcement for structural biocomposites: Porosity, water absorption, mechanical performances and viscoelastic behaviour2014In: Composites. Part A, Applied science and manufacturing, ISSN 1359-835X, E-ISSN 1878-5840, Vol. 61, p. 1-12Article in journal (Refereed)
    Abstract [en]

    This paper examines the thermal and mechanical behaviour as well as moisture absorption of aligned hemp composites using hemp/PLA wrap spun yarns. Uniaxial composites were fabricated with 30 mass% hemp using compression moulding. The properties of composites in terms of hemp fibre orientation (aligned and random), off-axis angle and alkali treatment were investigated. It was found that the testing direction influenced the mechanical properties of the composites. Compared with all the fabricated composites, the aligned alkali hemp/PLA yarn composite possessed the best mechanical properties, including tensile, flexural and impact strengths, lower porosity and water absorption. The water absorption for all composites was higher than for neat PLA, both at room temperature and 80 C. The PLA in its treated composites had higher crystallinity, which was attributed to effective heterogeneous nucleation induced by hemp. Based on SEM observation and theoretical analysis of DMTA data, there was a favourable interfacial adhesion in all composites.

  • 12.
    Baghaei, Behnaz
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Temmink, Robin
    University of Borås, Faculty of Textiles, Engineering and Business.
    Skrifvars, Mikael
    University of Borås, Faculty of Textiles, Engineering and Business.
    RECYCLING OF END-OF-LIFE TEXTILE MATERIALS BY FABRICATION OF GREEN COMPOSITES2017Conference paper (Refereed)
    Abstract [en]

    Material recycling requires rather pure and non-contaminated waste streams, which can be converted by technical processes into new materials and products by economically and technically feasible techniques. It is also required that there is a secondary market for these recycled materials, and preferably in use areas with high economic value. End-of-life textiles cannot yet be recycled as a raw material in a feasible way. Structural composites are an excellent use area for recycled materials, as they are durable and light-weight products, with excellent mechanical properties.

    In this study, denim woven fabrics as end-of-life textiles were employed to improve the mechanical and thermal properties of high bio-content epoxy resin. Entropy Resin, manufacturer of commercial bio-based epoxy resin, claimed that bio-based content of system is 37 % and the resin is derived from by-products of industrial processes including wood pulp and biofuel. Bioepoxy was used as bio resins in composite manufacturing, and a conventional polyester resin served as a reference material. To create a wide scope of possibilities the composites were manufacturing using the four techniques: (1) vacuum infusion (VI), (2) resin transfer moulding (RTM), and (3) hand lay-up (HND). To determine the suitability for structural applications the biocomposites were tested for their mechanical and thermal properties. Mechanical tests for tensile, flexural strength and impact behaviour were conducted on composites. Moreover, viscoelastic properties of the composites were evaluated through dynamic mechanical analysis (DMA). Fabricated composites were characterised regarding porosity, water absorption and analysed through microscopic images of the composite cross section. Different manufacturing technique showed varying results. For bioepoxy both HND and VI give superior mechanical properties over RTM, as the latter gives a higher void content, and lower tensile and flexural properties.

  • 13.
    Bashir, Tariq
    et al.
    University of Borås, School of Engineering.
    Bakare, Fatimat
    University of Borås, School of Engineering.
    Baghaei, Behnaz
    University of Borås, School of Engineering.
    Mehrjerdi, Adib Kalantar
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Influence of different organic solvents and oxidants on insulating and film-forming properties of PEDOT polymer2013In: Iranian polymer journal, ISSN 1026-1265, E-ISSN 1735-5265, Vol. 22, no 8, p. 599-611Article in journal (Refereed)
    Abstract [en]

    Processing of conjugate polymers has always been a challenge because of their poor solubility and infusibility in organic and inorganic solvents. The processibility and applications of intrinsically conductive polymers (ICPs) can be enhanced by producing their solutions or dispersions in different suitable solvents. It can also be achieved by preparing un-doped or electrically neutral polymers, which can further be transformed in semiconductor after oxidation/reduction reaction. The present study focuses on the preparation of active dispersions of poly (3,4-ethylenedioxythiophene) (PEDOT) conductive polymer in various organic solvents. For this purpose, the polymerization of 3,4-ethylenedioxythiophene (EDOT) monomer was carried out in three different organic solvents, ethanol, 1-butanol and acetonitrile with two commonly used oxidants, ferric (III) chloride (FeCl3) and ferric (III) p-toluenesulfonate (FepTS). In this regard, the oxidant and monomer solutions with variable molar concentrations (0.25, 0.5, 1.0 M) were prepared in particular solvents and then these solutions were mixed with different monomer/oxidant volume ratios. The obtained dispersions of PEDOT can readily be polymerized on the surface of different materials after solvent evaporation and a uniform film can be achieved. The effect of molar as well as volume concentrations of EDOT monomer and oxidant on insulating (undoped/neutral) and film forming properties of PEDOT was investigated. These dispersions were applied on a transparent PET film and cellulosic fibers (viscose), dried at room temperature and analyzed using scanning electron microscope (SEM), optical microscope and ATR-FTIR spectroscopic analysis. The electrical characterization of undoped PEDOT-coated fibers was performed on Keithly picoammeter. This study contributes to obtain a simpler and instantaneous polymerization method of PEDOT preparation and to enhance its application area.

  • 14. Garrote Jurado, Ramon
    et al.
    Pettersson, Tomas
    Baghaei, Behnaz
    University of Borås, Faculty of Textiles, Engineering and Business.
    Persson, Anders
    University of Borås, Faculty of Textiles, Engineering and Business.
    Preparing for Masters´ Studies: A Web Based Tool For Self-Assessment and Knowledge Gap Mitigation2018Conference paper (Refereed)
    Abstract [en]

    This paper presents a project, conducted by three European universities and a software company, funded by Erasmus +, Strategic Partnership. The project addresses the problem that sometime masters´ students do not get their degree within the allocated time, if at all. Apparently some students with the formal prerequisites to register for a master's programme still lacked the actual abilities to manage their studies.

    The solution was to design an online HTML5 platform to house self-assessment and learning resource modules for four different master's programmes in Europe. The modules were intended to illustrate the level and abilities that potential applicants were supposed to bring into their studies by a self-assessment test. In case lacking abilities were revealed, the modules offer learning resources to mitigate those gaps.

    The access modules provides potential students with a visualization of twelve different skills and knowledge as compared to those identified by lecturers as necessary for study on the master's course. If there are weak spots identified, the students are presented with a series of learning interventions designed to remedy their ability flaws.  

    The authors suggest that providing potential students with this kind of material can raise their awareness of what the programme really takes. In this way students with false expectations can be avoided and the ones who applies come better prepared, which the use of access modules potentially can leads to improved enrolment, completion rate, time-to-degree and retention in a wide range of academic programmes.

  • 15.
    Kadi, Nawar
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business. University of Borås.
    Baghaei, Behnaz
    University of Borås, Faculty of Textiles, Engineering and Business. University of Borås.
    Skrifvars, Mikael
    University of Borås, Faculty of Textiles, Engineering and Business. University of Borås.
    Effect of Textile structure in the process parameters of thermoplastic bio-composite2019In: MATEC Web of Conferences, E-ISSN 2261-236X, Vol. 261, no 01005, p. 1-3Article in journal (Other academic)
    Abstract [en]

    Thermoplastic bio-composite have a higher potential of use based on the sustainability benefits. Natural fibres today are a popular choice for applications in biocomposite manufacturing. Hybrid yarns are a satisfactory solution to improve the fabrication of composites containing a thermoplastic matrix and plant-based fibres. Nevertheless, it is still difficult to produce bio-composites with superior mechanical properties, due to problematic impregnation and consolidation results during the production process. This paper investigates the processing parameters for the compression moulding of two different hemp/PLA textiles structure bio-composites (warp knitting and weaving structure). Finite element simulations are used to optimise the processing parameters (pressure, temperature, and time). The results demonstrated that the textile structure has a small effect on the time of production. Main while the pressure and temperature of processing parameters depend only on the type of matrix and the thickness of biocomposite has a big impact on the time of production.

  • 16.
    Kadi, Nawar
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Baghaei, BehnazUniversity of Borås, Faculty of Textiles, Engineering and Business.Skrifvars, MikaelUniversity of Borås, Faculty of Textiles, Engineering and Business.
    The effect of process parameters on the mechanical properties of thermoplastic bio-composite2018Conference proceedings (editor) (Refereed)
  • 17.
    Kadi, Nawar
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Baghaei, Behnaz
    University of Borås, Faculty of Textiles, Engineering and Business.
    Skrifvars, Mikael
    University of Borås, Faculty of Textiles, Engineering and Business.
    Using Finite Element Simulation to Optimize Thermoplastic Bio - Composites Process Parameters2018In: International Journal of Management and Applied Science, ISSN 2394-7926, Vol. 4, p. 73-75Article, book review (Refereed)
    Abstract [en]

    The use of thermoplastic composite is clearly of higher potential because of: good impact strength, easier recycling, faster processing conditions (no time for curing is required), possibility of production in longer series, lower cost, absence of toxic solvents and higher fracture toughness and elongation on the fracture. Natural fibres today are a popular choice for applications in composite manufacturing. In fact, a major challenge for natural fibre reinforced composites is to achieve high mechanical performance at competitive prices. This paper investigates the processing parameters for the compression moulding of hemp/PLA hybrid yarn bio-composites and their effect on the final mechanical properties. Finite element simulations are used to develop and assess the processing parameters pressure, temperature, and time. The application of the simulation analysis results in considerably reduced the processing times from initially 10 minutes to only 2 minutes, and improved the mechanical bio-composite

  • 18.
    Persson, Nils-Krister
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Baghaei, Behnaz
    University of Borås, Faculty of Textiles, Engineering and Business.
    Bashir, Tariq
    University of Borås, Faculty of Textiles, Engineering and Business.
    Brorström, Björn
    University of Borås, Faculty of Textiles, Engineering and Business.
    Hedegård, Lars
    University of Borås, Faculty of Textiles, Engineering and Business.
    Carlson Ingdahl, Tina
    University of Borås, Faculty of Textiles, Engineering and Business.
    Larsson, Jonas
    University of Borås, Faculty of Textiles, Engineering and Business.
    Lindberg, Ulla
    University of Borås, Faculty of Textiles, Engineering and Business.
    Löfström, Mikael
    University of Borås, Faculty of Textiles, Engineering and Business.
    Oudhuis, Margaretha
    University of Borås, Faculty of Textiles, Engineering and Business.
    Pal, Rudrajeet
    University of Borås, Faculty of Textiles, Engineering and Business.
    Pettersson, Anita
    University of Borås, Faculty of Textiles, Engineering and Business.
    Påhlsson, Birgitta
    University of Borås, Faculty of Textiles, Engineering and Business.
    Kumar Ramamoorthy, Sunil
    University of Borås, Faculty of Textiles, Engineering and Business.
    Richards, Tobias
    University of Borås, Faculty of Textiles, Engineering and Business.
    Skrifvars, Mikael
    University of Borås, Faculty of Textiles, Engineering and Business.
    Worbin, Linda
    University of Borås, Faculty of Textiles, Engineering and Business.
    Åkesson, Dan
    University of Borås, Faculty of Textiles, Engineering and Business.
    Re: en ny samhällssektor spirar2016Report (Other academic)
    Abstract [sv]

    Resurser och hållbarhet är nära förknippade. Hållbarhet innebär att hushålla med resurser - materiella, miljömässiga och mänskliga. Och hushållning är per definition kärnan i ekonomi. Man börjar alltmer se framväxten av en hel arsenal av verktyg och förhållnings- och angreppssätt för att bygga hållbarhet. Detta förenas av ett synsätt att det som hitintills setts  om avfall och värdelöst, och rent utav besvärligt att ta hand om, nu blir en värdefull resurs. Det glömda och gömda kommer åter. Faktum är att många ord och begrepp kring detta börjar på just åter- eller re- . Internationellt talar man om Redesign, Recycling, Remake, Recycle, Recraft, Reuse, Recreate, Reclaim, Reduce, Repair, Refashion.

    Vad är då allt detta? Ja, vill man dra det långt, är det inte mindre än framväxten av ett nyvunnet sätt att tänka, ja av en ny samhällssektor, en bransch och en industri,  sammanbundet av filosofin att återanvändningen, spillminskningen, vidarebruket, efterlivet anses som viktiga faktorer för ett miljömedvetet samhälle. Re: blir paraplytermen för detta. I denna antologi av forskare från skilda discipliner vid Högskolan i Borås lyfts ett antal av dessa begrepp inom Re: fram.

  • 19.
    Ramamoorthy, Sunil Kumar
    et al.
    University of Borås, School of Engineering.
    Kundu, Chanchal Kumar
    Baghaei, Behnaz
    University of Borås, School of Engineering.
    Adekunle, Kayode
    University of Borås, School of Engineering.
    Bashir, Tariq
    University of Borås, School of Engineering.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Green Composites Based On Regenerated Cellulose Textile Fibers For Structural Composites2013Conference paper (Refereed)
    Abstract [en]

    Composites were manufactured from regenerated cellulose and biobased matrix by compression molding. The reinforcing materials used were Lyocell and viscose, while the matrix used was chemically modified soybean oil. Hybrid composites were prepared by mixing both the fibers. The total fiber content in the composites was between 40-60 weight %. Lyocell based composites had better tensile properties than viscose based composites; composites consisting 60 weight % Lyocell impregnated with matrix had tensile strength of 135 MPa and tensile modulus of 17 GPa. These composites also showed better flexural properties; flexural strength of 127 MPa and flexural modulus of 7 GPa. Dynamic mechanical thermal analysis results showed that these composites had good viscoelastic properties. Viscose based composites had better percentage elongation; these composites also showed relatively good impact and viscoelastic properties. Hybrid composites showed good mechanical and viscoelastic properties. Scanning electron microscope images showed that the composites had good fiber-matrix adhesion.

  • 20.
    Ramamoorthy, Sunil Kumar
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Åkesson, Dan
    University of Borås, Faculty of Textiles, Engineering and Business.
    Skrifvars, Mikael
    University of Borås, Faculty of Textiles, Engineering and Business.
    Baghaei, Behnaz
    University of Borås, Faculty of Textiles, Engineering and Business.
    Preparation and Characterization of Biobased Thermoset Polymers from Renewable Resources and Their Use in Composites2017In: Handbook of Composites from Renewable Materials, Physico-Chemical and Mechanical Characterization / [ed] Vijay Kumar Thakur, Manju Kumari Thakur, Michael R. Kessler, Hoboken, New Jersey, USA: John Wiley & Sons, 2017, p. 425-457Chapter in book (Refereed)
    Abstract [en]

    This chapter focuses on physicochemical and mechanical characterization of compositesmade from renewable materials. Most common renewable materials used in composites arenatural fibers and polymers based on starch or vegetable oil. The extent of using renewablematerials in biocomposites has increased during the past decade due to extensive research oncellulosic fibers and biobased polymers. Earlier, the research was focused on using the naturalfibers as reinforcement in crude oil-based polymers such as polypropylene. Later, the emphasisshifted to increase the amount of renewable components in the biocomposites which led tothe introductionof biobased resins in the composites. The properties of some biocompositesare today comparable to the properties for commercially available nonrenewable composites.Several plant biofibers have been used as reinforcement in biobased thermoplastics or thermosetsto manufacture biocomposites. Material characterization is important to understand theperformance of these composites under specific environment. Detailed discussion about themechanical and physicochemical characterization is provided in this chapter. Physicochemicalcharacterization includes chemical composition, density, viscosity, molecular weight, meltingtemperature, crystallinity,morphology, wettability, surface tension, water binding capacity,electricalconductivity, flammability, thermal stability, and swelling. Mechanical characterizationincludes tensile, flexural, impact, compressive, shear, toughness, hardness, brittleness, ductility,creep, fatigue, and dynamic mechanical analysis.

  • 21.
    Skrifvars, Mikael
    et al.
    University of Borås, School of Engineering.
    Baghaei, Behnaz
    University of Borås, School of Engineering.
    Kumar Ramamoorthy, Sunil
    University of Borås, School of Engineering.
    Berglin, Lena
    University of Borås, Swedish School of Textiles.
    Development of hybrid natural fibre reinforcements for structural composites: Concepts and opportunities2013Conference paper (Refereed)
  • 22.
    Skrifvars, Mikael
    et al.
    University of Borås, School of Engineering.
    Baghaei, Behnaz
    University of Borås, School of Engineering.
    Kumar Ramamoorthy, Sunil
    University of Borås, School of Engineering.
    Rajan, Rathish
    Berglin, Lena
    University of Borås, Swedish School of Textiles.
    Regenerated cellulose fibres for structural composites2014Conference paper (Other academic)
  • 23.
    Skrifvars, Mikael
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Baghaei, Behnaz
    University of Borås, Faculty of Textiles, Engineering and Business.
    Rissanen, Marja
    Tampere University of Technology.
    Ramamoorthy, Sunil Kumar
    University of Borås, Faculty of Textiles, Engineering and Business.
    Mechanical and thermal characterization of compression moulded polylactic acid natural fiber composites reinforced with hemp and Lyocell fibers2014In: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 131, no 15Article in journal (Refereed)
  • 24.
    Skrifvars, Mikael
    et al.
    University of Borås, School of Engineering.
    Ramamoorthy, Sunil Kumar
    University of Borås, School of Engineering.
    Baghaei, Behnaz
    University of Borås, School of Engineering.
    Development Of Regenerated Cellulose Reinforcements And Their Use In Structural Composites For Automotive Applications2013Conference paper (Refereed)
    Abstract [en]

    There is need for the bio‐based materials which could fully or partly replace the synthetic materials in automotive components. Several studies have been suggested to incorporate natural fiber based materials into automotives, and regenerated cellulose fibers could have a great potential several automotive applications. In the paper we will describe ongoing research where we study non‐woven viscose and Lyocell as well as uniaxial continuous viscose filament reinforcements for the use in structural composites. Hybrid reinforcements based on regenerated cellulose fibers and glass fibers have also been studied, with the intention to optimize the reinforcement durability. The uniaxial viscose filament reinforcements were prepared by a winding technique, and we have also combined the viscose filament with continuous hemp yarns as well as different thermoplastic yarns. Both thermoset and thermoplastic composites were then produced by compression moulding with a pressure of 40 bar and at the temperature between 160‐170°C for 5 minutes. The resulting composites have been characterized regarding mechanical and thermal properties.

  • 25.
    Temmink, Robin
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Baghaei, Behnaz
    University of Borås, Faculty of Textiles, Engineering and Business.
    Skrifvars, Mikael
    University of Borås, Faculty of Textiles, Engineering and Business.
    Development of biocomposites from denim waste and thermoset bio-resins2018In: Composites. Part A, Applied science and manufacturing, ISSN 1359-835X, E-ISSN 1878-5840, Vol. 106, p. 59-69Article in journal (Refereed)
    Abstract [en]

    This paper examines the use of post-consumer denim fabric in combination with thermoset bio-resins in composite manufacturing for structural applications. Bio-epoxy and acrylated epoxidized soybean oil resin (AESO) were used as bio-resins with four different manufacturing techniques in order to create a wide scope of possibilities for research. The four techniques are: compression moulding (COM), vacuum infusion (VAC), resin transfer moulding (RTM) and hand lay-up (HND). The bio-resins were compared to a conventional polyester resin, as this is highly used for structural applications. To determine suitability for structural applications, the biocomposites were tested for their mechanical and thermal properties. Fabricated composites were characterised regarding porosity, water absorption and analysed through microscopic images of the composite. Results show both bio-epoxy and AESO are suitable for use in structural applications over a range of manufacturing techniques. Furthermore, biocomposites from bio-epoxy are superior to those from AESO resin. The conventional polyester has shown to be unsuitable for structural applications.

  • 26.
    Vogt, Sarah
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Baghaei, Behnaz
    University of Borås, Faculty of Textiles, Engineering and Business.
    Kadi, Nawar
    University of Borås, Faculty of Textiles, Engineering and Business.
    Skrifvars, Mikael
    University of Borås, Faculty of Textiles, Engineering and Business.
    Determination of Processing Parameters for Thermoplastic Biocomposites Based on Hybrid Yarns Using Finite Elements Simulation2018In: Journal of Composites Science, ISSN 2504-477X, Vol. 2, no 1Article in journal (Refereed)
    Abstract [en]

    This paper investigates the processing parameters for the compression molding of hemp/PLA hybrid yarn biocomposites and their effect on the final mechanical properties. Finite element simulations are used to develop and assess the processing parameters, pressure, temperature, and time. These parameters are then evaluated experimentally by producing the composites by two different methods, to compare the results of experimentally determined processing conditions to parameters determined by the simulation analysis. The assessment of mechanical properties is done with several experimental tests, showing small improvements for the composites produced with the simulation method. The application of the simulation analysis results in considerably reduced processing times, from the initial 10 min to only three minutes, thereby vastly improving the processing method. While the employed methods are not yet able to produce composites with greatly improved mechanical properties, this study can be seen as a constructive approach, which has the ability to lead to further improvements.

1 - 26 of 26
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