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  • 1.
    Adekunle, K.
    et al.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Cho, S.-W.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Ketzscher, R.
    Skrifvars, M.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Mechanical properties of natural fiber hybrid composites based on renewable thermoset resins derived from soybean oil, for use in technical applications2012Ingår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 124, nr 6, s. 4530-4541Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Natural fiber composites are known to have lower mechanical properties than glass or carbon fiber reinforced composites. The hybrid natural fiber composites prepared in this study have relatively good mechanical properties. Different combinations of woven and non-woven flax fibers were used. The stacking sequence of the fibers was in different orientations, such as 0°, +45°, and 90°. The composites manufactured had good mechanical properties. A tensile strength of about 119 MPa and Young's modulus of about 14 GPa was achieved, with flexural strength and modulus of about 201 MPa and 24 GPa, respectively. For the purposes of comparison, composites were made with a combination of woven fabrics and glass fibers. One ply of a glass fiber mat was sandwiched in the mid-plane and this increased the tensile strength considerably to 168 MPa. Dynamic mechanical analysis was performed in order to determine the storage and loss modulus and the glass transition temperature of the composites. Microstructural analysis was done with scanning electron microscopy.

  • 2.
    Adekunle, K.
    et al.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Cho, S.-W.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Patzelt, C.
    Blomfeldt, T.
    Skrifvars, M.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Impact and flexural properties of flax fabrics and Lyocell Fiber reinforced bio-based thermoset for automotive and structural applications2012Konferensbidrag (Refereegranskat)
  • 3.
    Adekunle, K.
    et al.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Ghoreishi, R.
    Ehsani, M.
    Cho, S.-W.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Skrifvars, M.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Jute fiber reinforced methacrylated soy bean oil based thermoset composites prepared by vacuum injection molding technique2012Ingår i: Journal of Biobased Materials and Bioenergy, ISSN 1556-6560, E-ISSN 1556-6579, Vol. 6, nr 2, s. 172-177Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Bio-based composites based on soybean oil thermoset resin were manufactured with vacuum injection molding technique. Methacrylated soybean oil (MMSO) was processed with vacuum injection molding technique without blending with styrene. The composites produced had comparatively good mechanical properties like jute composite reinforced acrylated epoxidised soybean oil (AESO) resin blended with styrene. Although the tensile strength of the jute reinforced AESO composites are slightly higher than the jute reinforced MMSO composites which was attributed to blending of AESO with styrene. However, the difference in Youngs' modulus was negligible because they have approximately equal stiffness between 2.6 GPa and 2.8 GPa. The jute reinforced AESO composites showed relatively higher flexural strengths and moduli than the MMSO counterparts. This difference was also attributed to the blending of AESO with reactive diluent such as styrene. In order to determine the dimensional stability of the composite manufactured, water absorption test was carried out and the conclusion was that the moisture uptake of the jute reinforced composites was the same, this was expected.

  • 4.
    Adekunle, Kayode
    et al.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Cho, Sung-Woo
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Patzelt, Christian
    Blomfeldt, Thomas
    Skrifvars, Mikael
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Impact and flexural properties of flax fabrics and Lyocell fiber-reinforced bio-based thermoset2011Ingår i: Journal of reinforced plastics and composites (Print), ISSN 0731-6844, E-ISSN 1530-7964, Vol. 30, nr 8, s. 685-697Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A bio-based thermoset resin was reinforced with flax fabrics and Lyocell fiber. The effect of different weave architectures was studied with four flax fabrics with different architectures: plain, twill (two different types), and dobby. The effect of the outer ply thickness was studied and characterized with flexural and impact testing. Composites manufactured with plain weave reinforcement had the best mechanical properties. The tensile strength, tensile modulus, flexural strength, flexural modulus, and impact strength were 280 MPa, 32 GPa, 250 MPa, 25 GPa, and 75 kJ/m2, respectively. Reinforcements with twill-weave architecture did not impart appreciable flexural strength or flexural modulus even when the outer thickness was increased. Plain- and dobby (basket woven style)-weave architectures gave better reinforcing effects and the flexural properties increased with an increase in outer thickness.Water absorption properties of the composites were studied and it was observed that the hybridization with Lyocell fiber reduced the water uptake. Fieldemission scanning electron microscopy was used to study the micro-structural properties of the composites.

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  • 5.
    Adekunle, Kayode
    et al.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Ketzscher, Richard
    Skrifvars, Mikael
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    High performance natural fibre hybrid composites based on biobased thermoset resins for use in technical applications2009Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Health related issues, stringent environmental protection policies, search for cost effective and alternative materials and quest for renewability, sustainability and high performance materials for technical applications has led to an intense research in manufacturing biobased composites which are based on renewable thermosetting resins and natural fibres. The combination of biobased thermosetting resins with two different natural fibre reinforcements could lead to improved mechanical properties of the composite. Biobased thermoset polymers are comparable to the synthetic thermosetting polymers from petrochemicals. In this study, two different biobased resins were used as matrix and both non woven flax fibre and woven flax fabric were combined as reinforcements. The composites were made by compression moulding process. The fibres were hand laid-up and impregnation was done manually. The curing temperature was 170°С and at 40 bar. The stacking sequence of the fibres was in different orientations such as 0º, +45º and 90º. The manufactured hybrid composites have high tensile strength and stiffness and the flexural strength and modulus was also high. These composites can compete favourably with glass fibre reinforced composites in terms of strength and stiffness.1, 2 A tensile strength of about 119 MPa and Young’s modulus of 13.8 GPa was achieved, while the flexural strength and modulus is about 201 MPa and 24 GPa respectively. For the purpose of comparison, composites were made with the combination of woven fabric and e-glass fibre. One ply of an e-glass fibre mat was put in the mid-plane and this increased the tensile strength considerably up to 168 MPa. Some of the composites were made with the resin blended with styrene and the results show a higher modulus.

  • 6.
    Adekunle, Kayode
    et al.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Patzelt, Christian
    Kalantar, Adib
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Skrifvars, Mikael
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Mechanical and Viscoelastic Properties of Soybean Oil Thermoset Reinforced with Jute Fabrics and Carded Lyocell Fiber2011Ingår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 122, nr 5, s. 2855-2863Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Composites and hybrid composites were manufactured from renewable materials based on jute fibers, regenerated cellulose fibers (Lyocell), and thermosetting polymer from soybean oil. Three different types of jute fabrics with biaxial weave architecture but different surface weights, and carded Lyocell fiber were used as reinforcements. Hybrid composites were also manufactured by combining the jute reinforcements with the Lyocell. The Lyocell composite was found to have better mechanical properties than other composites. It has tensile strength and modulus of about 144 MPa and 18 GPa, respectively. The jute composites also have relatively good mechanical properties, as their tensile strengths and moduli were found to be between 65 and 84 MPa, and between 14 and 19 GPa, respectively. The Lyocell-reinforced composite showed the highest flexural strength and modulus, of about 217 MPa and 13 GPa, respectively. In all cases, the hybrid composites in this study showed improved mechanical properties but lower storage modulus. The Lyocell fiber gave the highest impact strength of about 35 kJ/m2, which could be a result of its morphology. Dynamic mechanical analysis showed that the Lyocell reinforced composite has the best viscoelastic properties.

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  • 7.
    Adekunle, Kayode
    et al.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Patzelt, Christian
    Kalantar, Adib
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Skrifvars, Mikael
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Mechanical properties of renewable soyean oil thermoset reinforced with jute fabricsand lyocell fiber2011Konferensbidrag (Refereegranskat)
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  • 8.
    Adekunle, Kayode
    et al.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Skrifvars, Mikael
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Synthesis of reactive soybean oils for use as thermoset resins in composites.2007Konferensbidrag (Refereegranskat)
  • 9.
    Adekunle, Kayode
    et al.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Åkesson, Dan
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Bakare, Fatimat
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Skrifvars, Mikael
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Bio-based thermoset resins from soybean and linseed oils for structural composites2011Konferensbidrag (Refereegranskat)
    Ladda ner fulltext (pdf)
    FULLTEXT01
  • 10.
    Adekunle, Kayode
    et al.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Åkesson, Dan
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Skrifvars, Mikael
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Biobased Composites Prepared by Compression Molding with a Novel Thermoset Resin from Soybean Oil and a Natural-Fiber Reinforcement2010Ingår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 116, nr 3, s. 1759-1765Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Biobased composites were manufactured with a compression-molding technique. Novel thermoset resins from soybean oil were used as a matrix, and flax fibers were used as reinforcements. The air-laid fibers were stacked randomly, the woven fabrics were stacked crosswise (0/90 ), and impregnation was performed manually. The fiber/resin ratio was 60 : 40. The prepared biobased composites were characterized by impact and flexural testing. Scanning electron microscopy of knife-cut cross sections of the specimens was also done to investigate the fiber–matrix interface. Thermogravimetric analysis of the composites was carried out to provide indications of thermal stability. Three resins from soybean oil [methacrylated soybean oil, methacrylic anhydride modified soybean oil (MMSO), and acetic anhydride modified soybean oil] were used as matrices. The impact strength of the composites with MMSO resin reinforced with air-laid flax fibers was 24 kJ/m2, whereas that of the MMSO resin reinforced with woven flax fabric was between 24 and 29 kJ/m2. The flexural strength of the MMSO resin reinforced with air-laid flax fibers was between 83 and 118 MPa, and the flexural modulus was between 4 and 6 GPa, whereas the flexural strength of the MMSO resin reinforced with woven fabric was between 90 and 110 MPa, and the flexural modulus was between 4.87 and 6.1 GPa.

  • 11.
    Adekunle, Kayode
    et al.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Åkesson, Dan
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Skrifvars, Mikael
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Biobased Composites Prepared by Compression Moulding using a Novel Thermoset Resin from Soybean oil and a Natural Fibre Reinforcement2009Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Biobased composites were manufactured by using a compression moulding technique. Novel thermoset resins from soybean oil were used as matrix while flax fibres were used as reinforcement. The airlaid fibres were stacked randomly while woven fabrics were stacked crosswisely (90°) and impregnation was done manually. The fibre/ resin ratio was 60% to 40%.

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    FULLTEXT01
  • 12.
    Adekunle, Kayode
    et al.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Åkesson, Dan
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Skrifvars, Mikael
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Preparation of biobased composites using novel thermoset polymers from soybean oil and a natural fibre reinforcement2009Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Health related issues, stringent environmental protection policies, search for cost effective and alternative materials, crave for renewability and sustainability and quest for high performance materials for structural applications give the motivation for research in polymer composites and material science. Due to the health, safety and environmental concerns over the conventional synthetic materials and the legislation against their usage both in domestic and industrial applications, alternatives sources that will be comparable in properties are being sought. There is an emerging market for biodegradable polymers which is expected to increase substantially in the coming years.[1] Preparation of Composites Airlaid and woven flax fibre mats were first treated with 4% sodium hydroxide solution for one hour and then washed with plenty of water. This was done in order to remove any residual impurities. The fibres were dried at room temperature for 24 hr and then dried in a vacuum oven for 1hr at a temperature of 105°С. The 8 sheets of the fibre were hand laid cross- wisely and the impregnation was done manually. The fibre/ resin ratio was about 60% to 40%. Methacrylated soybean oil, methacrylic anhydride and acetic anhydride modified soybean oil were the synthesized matrices used. The compression moulding was done at a temperature of 170°С for 5 min at 40bar. Characterisations The tensile testing was performed based on an ISO-test method for tensile tests on plastic materials. The Charpy impact strength of unnotched specimens was evaluated in accordance with ISO 179 using a Zwick test instrument and scanning electron microscopy analysis was done on the fractured specimens. The composites showed various mechanical properties, having impact strengths between 24 and 63 kJ/m² and tensile strength up to 51MPa.

  • 13.
    Adekunle, Kayode
    et al.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Åkesson, Dan
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Skrifvars, Mikael
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Synthesis of reactive soybean oils for use as a biobased thermoset resins in structural natural fiber composites2009Ingår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 115, nr 6, s. 3137-3145Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Biobased thermosets resins were synthesized by functionalizing the triglycerides of epoxidized soybean oil with methacrylic acid, acetyl anhydride, and methacrylic anhydride. The obtained resins were characterized with FTIR, 1H-NMR, and 13C-NMR spectroscopy to confirm the functionalization reactions and the extent of epoxy conversion. The viscosities of the methacrylated soybean oil resins were also measured for the purpose of being used as a matrix in composite applications. The cross-linking capability was estimated by UV and thermally initiated curing experiments, and by DSC analysis regarding the degree of crosslinking. The modifications were successful because up to 97% conversion of epoxy group were achieved leaving only 2.2% of unreacted epoxy groups, which was confirmed by 1H-NMR. The 13C-NMR confirms the ratio of acetate to methacrylate methyl group to be 1 : 1. The viscosities of the methacrylated soybean oil (MSO) and methacrylic anhydride modified soybean oil (MMSO) were 0.2 and 0.48 Pas, respectively, which indicates that they can be used in resin transfer molding process.

  • 14.
    Adekunle, Kayode
    et al.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Åkesson, Dan
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Skrifvars, Mikael
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Synthesis of reactive soybean oils for use as biobased thermoset resins in structural natural fibre composites2008Konferensbidrag (Refereegranskat)
  • 15.
    Adekunle, Kayode
    et al.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Åkesson, Dan
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Skrifvars, Mikael
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Synthetic modification of reactive soybean oils for use as biobased thermoset resins in structural natural fiber composites2008Konferensbidrag (Övrigt vetenskapligt)
  • 16.
    Adekunle, Kayode
    et al.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Åkesson, Dan
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Skrifvars, Mikael
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Synthetic modification of reactive soybean oils for use as biobased thermoset resins in structural natural fiber composites2008Ingår i: Polymer Preprints, ISSN 0551-4657, Vol. 49, nr 1, s. 279-Artikel i tidskrift (Refereegranskat)
  • 17.
    Akbari, Samira
    et al.
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Root, Andrew
    MagSol, Tuhkanummenkuja 2, 00970, Helsinki, Finland.
    Skrifvars, Mikael
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Kumar Ramamoorthy, Sunil
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Åkesson, Dan
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Novel Bio-based Branched Unsaturated Polyester Resins for High-Temperature Applications2023Ingår i: Journal of Polymers and the Environment, ISSN 1566-2543, E-ISSN 1572-8919Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Unsaturated polyester resins, one of the most important thermosets, are invariably produced from oil-based monomers. Their application is limited in areas where high thermal stability is required due to their low Tg. Besides, these resins contain 30–40% hazardous styrene as a reactive solvent. Therefore, developing bio-based solventless unsaturated polyester resin with medium to high thermomechanical properties compared to petrochemical-based counterparts is important. In order to achieve this, a series of branched bio-based unsaturated polyester resins were synthesized using bulk polymerization method in two steps. In the first step, four different intermediates were prepared by reacting glycerol (as a core molecule) with either isosorbide (diol), 1,3-propanediol (diol), 2,5-furandicarboxylic acid (saturated diacid), or adipic acid (saturated diacid). In the second step, the branched intermediate was end capped with methacrylic anhydride to introduce reactive sites for cross-linking on the branch ends. The chemical structure of the resins was characterized by 13C-NMR. FT-IR confirmed the polycondensation reaction in the first step and the end functionalization of the resins with methacrylic anhydride in the second step. The effect of 2,5-furandicarboxylic acid and isosorbide on thermomechanical and thermal properties was investigated using dynamic mechanical analysis, differential scanning calorimetry, and thermo-gravimetric analysis. Results indicated that 2,5-furandicarboxylic acid based resins had superior thermomechanical properties compared to a commercial reference unsaturated polyester resin, making them promising resins for high-temperature composite applications. For example, the resin based on 2,5-furandicarboxylic acid and isosorbide and the resin based on 2,5-furandicarboxylic acid and 1,3-propanediol gave glass transition temperatures of 173 °C and 148 °C, respectively. Although the synthesized 2,5-furandicarboxylic acid based resins had higher viscosity (22.7 Pas) than conventional unsaturated polyester (0.4–0.5 Pas) at room temperature, preheated resins can be used for making high-temperature-tolerance fiber-reinforced composite. 

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  • 18. Ali, Majid
    et al.
    Bashir, Tariq
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Persson, Nils-Krister
    Skrifvars, Mikael
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Optimization of oCVD Process for the Production of Conductive Fibers2011Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Electro active textile fibers are key components in smart and interactive textile applications. In our previous study, we produced poly(3,4-ethylenedioxythiophene) (PEDOT) coat edviscose fibers by using oxidative chemical vapordeposition (OCVD) technique. We tried FeCl3 as oxidant and found optimum reaction conditions at which better electrical as well as mechanical properties of conductive fibers could be achieved.

  • 19. Ali, Majid
    et al.
    Bashir, Tariq
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Persson, Nils-Krister
    Skrifvars, Mikael
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Stretch Sensing Properties of PEDOT Coated Conductive Yarns Produced by OCVD Process2011Konferensbidrag (Refereegranskat)
  • 20. Arshad, Khubaib
    et al.
    Skrifvars, Mikael
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Vivod, Vera
    Valh, Julija
    Voncina, Bojana
    Biodegradation of natural textile materials in soil2014Ingår i: Tekstilec, ISSN 0351-3386, Vol. 57, nr 2, s. 118-132Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    World is facing numerous environmental challenges, one of them being the increasing pollution both in the atmosphere and landfi lls. After the goods have been used, they are either buried or burnt. Both ways of disposal are detrimental and hazardous to the environment. The term biodegradation is becoming more and more important, as it converts materials into water, carbon dioxide and biomass, which present no harm to the environment. Nowadays, a lot of research is performed on the development of biodegradable polymers, which can “vanish” from the Earth surface after being used. In this respect, this research work was conducted in order to study the biodegradation phenomenon of cellulosic and non-cellulosic textile materials when buried in soil, for them to be used in our daily lives with maximum effi ciency and after their use, to be disposed of easily with no harmful eff ects to the environment. This research indicates the time span of the use life of various cellulosic and non-cellulosic materials such as cotton, jute, linen, fl ax, wool when used for the reinforcement of soil. The visual observations and applied microscopic methods revealed that the biodegradation of cellulose textile materials proceeded in a similar way as for non-cellulosic materials, the only difference being the time of biodegradation. The non-cellulosic textile material (wool) was relatively more resistant to microorganisms due to its molecular structure and surface. Keywords: biodegradation, composting, natural textile materials, FT-IR

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  • 21.
    Arya, Mina
    et al.
    Högskolan i Borås, Akademin för textil, teknik och ekonomi. Faculty of Textiles, Engineering and Business (Swedish Centre for Resource Recovery), University of Borås, 510 90 Borås, Sweden.
    Malmek, Else-Marie
    Juteborg AB, 426 79 Västra Frölunda, Sweden.
    Ecoist, Thomas Koch
    Ecoist AB, 262 72 Ängelholm, Sweden.
    Pettersson, Jocke
    RISE Research Institutes of Sweden, 431 53 Mölndal, Sweden.
    Skrifvars, Mikael
    Högskolan i Borås, Akademin för textil, teknik och ekonomi. Faculty of Textiles, Engineering and Business (Swedish Centre for Resource Recovery), University of Borås, 510 90 Borås, Sweden.
    Khalili, Pooria
    Högskolan i Borås, Akademin för textil, teknik och ekonomi. Faculty of Textiles, Engineering and Business (Swedish Centre for Resource Recovery), University of Borås, 510 90 Borås, Sweden.
    Enhancing Sustainability: Jute Fiber-Reinforced Bio-Based Sandwich Composites for Use in Battery Boxes2023Ingår i: Polymers, E-ISSN 2073-4360, Vol. 15, nr 18, artikel-id 3842Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The rising industrial demand for environmentally friendly and sustainable materials has shifted the attention from synthetic to natural fibers. Natural fibers provide advantages like affordability, lightweight nature, and renewability. Jute fibers’ substantial production potential and cost-efficiency have propelled current research in this field. In this study, the mechanical behavior (tensile, flexural, and interlaminar shear properties) of plasma-treated jute composite laminates and the flexural behavior of jute fabric-reinforced sandwich composites were investigated. Non-woven mat fiber (MFC), jute fiber (JFC), dried jute fiber (DJFC), and plasma-treated jute fiber (TJFC) composite laminates, as well as sandwich composites consisting of jute fabric bio-based unsaturated polyester (UPE) composite as facing material and polyethylene terephthalate (PET70 and PET100) and polyvinyl chloride (PVC) as core materials were fabricated to compare their functional properties. Plasma treatment of jute composite laminate had a positive effect on some of the mechanical properties, which led to an improvement in Young’s modulus (7.17 GPa) and tensile strength (53.61 MPa) of 14% and 8.5%, respectively, as well as, in flexural strength (93.71 MPa) and flexural modulus (5.20 GPa) of 24% and 35%, respectively, compared to those of JFC. In addition, the results demonstrated that the flexural properties of jute sandwich composites can be significantly enhanced by incorporating PET100 foams as core materials. 

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  • 22.
    Asadi, Milad
    et al.
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Bashir, Tariq
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Skrifvars, Mikael
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Development of eco-friendly flame retardant polypropylene fibers2017Konferensbidrag (Refereegranskat)
  • 23.
    Baghaei, Behnaz
    et al.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Berglin, Lena
    Högskolan i Borås, Institutionen Textilhögskolan.
    Skrifvars, Mikael
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Tailoring of the mechanical and thermal properties of hemp/PLA hybrid yarn composites2013Konferensbidrag (Övrigt vetenskapligt)
    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.

  • 24.
    Baghaei, Behnaz
    et al.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Berglin, Lena
    Högskolan i Borås, Institutionen Textilhögskolan.
    Skrifvars, Mikael
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Tailoring of the mechanical and thermal properties of hemp/PLA hybrid yarn composites2013Konferensbidrag (Övrigt vetenskapligt)
    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.

  • 25.
    Baghaei, Behnaz
    et al.
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Compiet, Sam
    Department of Textile Technology, Faculty of Textiles, Engineering and Business, University of Borås, SE-501 90, Borås, Sweden.
    Skrifvars, Mikael
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Mechanical properties of all-cellulose composites from end-of-life textiles2020Ingår i: Journal of polymer research, ISSN 1022-9760, E-ISSN 1572-8935, Vol. 27, nr 9Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper reports the recycling of end-of-life cellulose containing textiles by fabrication of all-cellulose composites (ACCs). Discharged denim fabrics were used as the reinforcement while dissolved cellulose from two different cellulose resources was used as the matrix phase. Virgin cotton fibres and recovered cotton from polyester/cotton (polycotton) waste fabrics were used to form the matrix phase. The process comprises preparing a 6 wt% cellulose solution by dissolving cellulose solution in a ionic liquid, 1-butyl-3-methyl imidazolium acetate ([BMIM][Ac]), this solution acted as a precursor for the matrix component. The denim fabrics were first embedded in the cellulose/IL solution followed by removal of the IL by washing to form the composite. The effect of reuse of the recovered IL by distillation was also investigated. The mechanical properties of the obtained ACCs were determined regarding tensile, impact and flexural properties. Fabricated ACC composite laminates were further characterised regarding structure by scanning electron microscopy.

  • 26.
    Baghaei, Behnaz
    et al.
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Johansson, Belinda
    Skrifvars, Mikael
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Kadi, Nawar
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    All-Cellulose Composites Properties from Pre- and Post-Consumer Denim Wastes: Comparative Study2022Ingår i: Journal of Composites Science, E-ISSN 2504-477X, Vol. 6, nr 5, artikel-id 130Artikel i tidskrift (Övrig (populärvetenskap, debatt, mm))
    Abstract [en]

    This study reports the recycling of discarded denim textiles by the production of all-cellulose composites (ACCs). Discarded denim fabrics were shredded into fibers and then made into nonwoven fabrics by carding and needle punching. The produced nonwoven fabrics were converted to ACCs by one-step and two-step methods using an ionic liquid (IL), 1-butyl-3-methyl imidazolium acetate ([BMIM][Ac]). In this study, the effect of different ACC manufacturing methods, denim fabrics with different contents (a 100% cotton denim (CO) and a blend material (cotton, poly-ester and elastane (BCO)) and reusing of IL as a recycled cellulose solvent on the mechanical pro-perties of the formed ACCs were investigated. The ACCs were characterized according to their tensile and impact properties, as well as their void content. Microscopic analysis was carried out to study the morphology of a cross-section of the formed composites. The choice of the one-step method with recycled IL, pure IL or with a blend material (BCO) had no influence on the tensile properties. Instead, the result showed that the two-step method, with and without DMSO, will influence the E-modulus but not the tensile strength. Regarding the impact properties of the samples, the only factor likely to influence the impact energy was the one-step method with CO and BCO.

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  • 27.
    Baghaei, Behnaz
    et al.
    Högskolan i Borås, Akademin för textil, teknik och ekonomi. Högskolan i Borås.
    Skrifvars, Mikael
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    All-Cellulose Composites: A Review of RecentStudies on Structure, Properties and Applications2020Ingår i: Molecules, ISSN 1431-5157, E-ISSN 1420-3049, ISSN 1420-3049, Vol. 25, nr 2Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Nowadays, there is greater demand for greener materials in societies due to environmental consciousness, depleting fossil fuels and growing ecological concerns. Within the foreseeable future, industries and suppliers will be required to be more aware of challenges faced due to the availability of resources and use more sustainable and renewable raw materials. In this context, cellulose can be expected to become a vital resource for materials owing to its abundance, versatility as a biopolymer, several different forms and potential applications. Thus, all-cellulose composites (ACCs) have gained significant research interest in recent years. ACC is a class of biocomposites in which the matrix is a dissolved and regenerated cellulose, while the reinforcement is undissolved or partly dissolved cellulose. This review paper is intended to provide a brief outline of works that cover recent progress in the manufacturing and processing techniques for ACCs, various cellulose sources, solvents and antisolvents, as well as their properties.

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  • 28.
    Baghaei, Behnaz
    et al.
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Skrifvars, Mikael
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Characterisation of polylactic acid biocomposites made from prepregs composed of woven polylactic acid/hemp–Lyocell hybrid yarn fabrics2016Ingår i: Composites Part A: Applied Science and Manufacturing, ISSN 1359-835X, Vol. 81, s. 139-144Artikel i tidskrift (Refereegranskat)
    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.

  • 29.
    Baghaei, Behnaz
    et al.
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Skrifvars, Mikael
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Characterization of thermoplastic natural fibre composites made from woven hybrid yarn prepregs with different weave pattern2015Ingår i: Composites Part A: Applied Science and Manufacturing, Vol. 81, nr February 2016, s. 139-144Artikel i tidskrift (Övrigt vetenskapligt)
  • 30.
    Baghaei, Behnaz
    et al.
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Skrifvars, Mikael
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Investigation of pattern style of woven fabrics produced from hybrid wrap spun yarns on fabricated composite2015Konferensbidrag (Övrigt vetenskapligt)
  • 31.
    Baghaei, Behnaz
    et al.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Skrifvars, Mikael
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Berglin, Lena
    Högskolan i Borås, Institutionen Textilhögskolan.
    Hybrid natural fibre reinforcements and prepregs for thermoplastic composites with improved performance and properties2014Konferensbidrag (Övrigt vetenskapligt)
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    FULLTEXT01
  • 32.
    Baghaei, Behnaz
    et al.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Skrifvars, Mikael
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Berglin, Lena
    Högskolan i Borås, Institutionen Textilhögskolan.
    Manufacture and characterisation of thermoplastic composites made from PLA/hemp co-wrapped hybrid yarn prepregs2013Ingår i: Composites. Part A, Applied science and manufacturing, ISSN 1359-835X, E-ISSN 1878-5840, Vol. 50, s. 93-101Artikel i tidskrift (Refereegranskat)
    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.

  • 33.
    Baghaei, Behnaz
    et al.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Skrifvars, Mikael
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Berglin, Lena
    Högskolan i Borås, Institutionen Textilhögskolan.
    Ramamoorthy, Sunil Kumar
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Hemp/PLA Co-Wrapped Hybrid Yarns For Structured Thermoplastic Composites2013Konferensbidrag (Refereegranskat)
    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.

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  • 34.
    Baghaei, Behnaz
    et al.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Skrifvars, Mikael
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Masoud, Salehi
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Aligned hemp yarn reinforced biocomposites: porosity, water absorption, thermal and mechanical properties2014Konferensbidrag (Refereegranskat)
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    FULLTEXT01
  • 35.
    Baghaei, Behnaz
    et al.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Skrifvars, Mikael
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Salehi, Masoud
    Bashir, Tariq
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Rissanen, Marja
    Nousiainen, Pertti
    Novel aligned hemp fibre reinforcement for structural biocomposites: Porosity, water absorption, mechanical performances and viscoelastic behaviour2014Ingår i: Composites. Part A, Applied science and manufacturing, ISSN 1359-835X, E-ISSN 1878-5840, Vol. 61, s. 1-12Artikel i tidskrift (Refereegranskat)
    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.

  • 36.
    Baghaei, Behnaz
    et al.
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Temmink, Robin
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Skrifvars, Mikael
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    RECYCLING OF END-OF-LIFE TEXTILE MATERIALS BY FABRICATION OF GREEN COMPOSITES2017Konferensbidrag (Refereegranskat)
    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.

  • 37.
    Bakare, Fatimat O.
    et al.
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Ramamoorthy, Sunil Kumar
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Åkesson, Dan
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Skrifvars, Mikael
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Thermomechanical properties of bio-based composites made from a lactic acid thermoset resin and flax and flax/basalt fibre reinforcements2016Ingår i: Composites. Part A, Applied science and manufacturing, ISSN 1359-835X, E-ISSN 1878-5840, Vol. 83, s. 176-184Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Low viscosity thermoset bio-based resin was synthesised from lactic acid, allyl alcohol and pentaerythritol. The resin was impregnated into cellulosic fibre reinforcement from flax and basalt and then compression moulded at elevated temperature to produce thermoset composites. The mechanical properties of composites were characterised by flexural, tensile and Charpy impact testing whereas the thermal properties were analysed by dynamic mechanical thermal analysis (DMTA) and thermogravimetric analysis (TGA). The results showed a decrease in mechanical properties with increase in fibre load after 40 wt.% for the neat flax composite due to insufficient fibre wetting and an increase in mechanical properties with increase fibre load up to 60 wt.% for the flax/basalt composite. The results of the ageing test showed that the mechanical properties of the composites deteriorate with ageing; however, the flax/basalt composite had better mechanical properties after ageing than the flax composite before ageing.

  • 38.
    Bakare, Fatimat Oluwatoyin
    et al.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Skrifvars, Mikael
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Wang, Yanfei
    Afshar, Shahrzad Javanshir
    Esmaeli, Nima
    Åkesson, Dan
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Morphological and mechanical properties of a biobased composite from a lactic acid based thermoset resin and viscose fiber reinforcement2014Konferensbidrag (Refereegranskat)
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  • 39.
    Bakare, Fatimat Oluwatoyin
    et al.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Skrifvars, Mikael
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Wang, Yanfei
    Afshar, Shahrzad Javanshir
    Esmaeli, Nima
    Åkesson, Dan
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Synthesis and Preparation of Biobased Composites with A Novel Thermoset Resin from Lactic Acid2014Konferensbidrag (Refereegranskat)
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    FULLTEXT01
  • 40.
    Bakare, Fatimat Oluwatoyin
    et al.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Skrifvars, Mikael
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Åkesson, Dan
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Wang, Yanfei
    Afshar, Shahrzad Javanshir
    Esmaeili, Nima
    Synthesis and Characterization of Bio-Based Thermosetting Resins from Lactic Acid and Glycerol2014Ingår i: Journal of Applied Polymer Science, E-ISSN 1097-4628, Vol. 131, nr 12, s. 1-9Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A bio-based thermoset resin has been synthesized from glycerol reacted with lactic acid oligomers of three different chain lengths: n=3, 7 and 10. Lactic acid was first reacted with glycerol by direct condensation and the resulted branched molecule was then end-functionalized with methacrylic anhydride. The resins were characterized using FTIR, 13C-NMR spectroscopy to confirm the resins chemical structure and by DSC and DMTA to obtain the thermal properties. The resin flow viscosities were also measured using a Rheometer with different stress levels for each temperature used, as this is an important characteristic for resins which are intended to be used as a matrix in composite applications. The results showed that the resin with chain length n=3 have a better mechanical, thermal and rheological properties than resin with n=7 and 10. Also with its biobased content of 78% and glass transition temperature at 97°C makes it comparable with the commercial unsaturated polyester resins.

  • 41.
    Bakare, Fatimat Oluwatoyin
    et al.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Wang, Yanfei
    Esmaeili, Nima
    Afshar, Shahrzad Javanshir
    Åkesson, Dan
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Skrifvars, Mikael
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Biobased Composites Prepared From a Lactic Acid Based Thermoset Resin and Natural-Fiber Reinforcement2013Konferensbidrag (Refereegranskat)
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  • 42.
    Bakare, Fatimat Oluwatoyin
    et al.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Wang, Yanfei
    Esmaeili, Nima
    Afshar, Shahrzad Javanshir
    Åkesson, Dan
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Skrifvars, Mikael
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    The Effect of Glycerol in the Synthesis of a Lactic Acid Based Thermoset Resin2013Konferensbidrag (Övrigt vetenskapligt)
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  • 43.
    Bakare, Fatimat Oluwatoyin
    et al.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Wang, Yanfei
    Esmaeili, Nima
    Afshar, Shahrzad Javanshir
    Åkesson, Dan
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Skrifvars, Mikael
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    The Effect of Glycerol in the Synthesis of a Lactic Acid Based Thermoset Resin2013Konferensbidrag (Refereegranskat)
    Ladda ner fulltext (pdf)
    FULLTEXT01
  • 44.
    Bakare, Fatimat
    et al.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Åkesson, Dan
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Skrifvars, Mikael
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Bashir, Tariq
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Ingman, Petri
    Srivastava, Rajiv
    Synthesis and characterization of unsaturated lactic acid based thermoset bio-resins2014Ingår i: European Polymer Journal, ISSN 0014-3057, E-ISSN 1873-1945, Vol. 67, s. 570-582Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Bio-based thermoset resins have been synthesized using lactic acid oligomers, which were functionalized with carbon–carbon double bonds, in order to allow their crosslinking by a free radical mechanism. Two different resin structures were synthesized. One resin was composed of an allyl alcohol terminated lactic acid oligomer, which was end-functionalized with methacrylic anhydride (MLA resin). The second resin was a mixture of the same allyl alcohol-lactic acid oligomer, and penthaerythritol. This mixture was end-functionalized with methacrylic anhydride, in order to get a methacrylate functionalized lactic acid oligomer, and methacrylate functionalized penthaerythritol (PMLA resin). The synthesized resins were characterized using FT-IR, 1H NMR and 13C NMR spectroscopy, differential scanning calorimetry as well as dynamic mechanical analysis to confirm the resin structure and reactivity. The flow viscosities were also measured in order to evaluate the suitability of the resins to be used as a matrix in composite applications. The results showed that the PMLA resin has better mechanical, thermal and rheological properties than the MLA resin, and both had properties which were comparable with a commercial unsaturated polyester resin. The high biobased content of 90% and the high glass transition temperature at 100 °C for the PMLA resin makes it an attractive candidate for composite applications where crude oil based unsaturated polyester resins are normally used.

  • 45.
    Barghi, Hamidreza
    et al.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Skrifvars, Mikael
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Taherzadeh, Mohammad J.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Catalytic Synthesis of Bulk Hydrophilic Acetaldehyde-Modified Polyamide 462014Ingår i: Current Organic Synthesis, ISSN 1570-1794, E-ISSN 1875-6271, Vol. 11, nr 6, s. 288-294Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Hydrophilization of Polyamide 46 (PA46) via modification with acetaldehyde in continuous phase was studied. The chemical modification of PA 46 with acetaldehyde resulted in a water-swollen polymer with hydrophilic property. The polyamide 46 undergoes a nucleophilic addition with acetaldehyde in the presence of aluminum chloride as a catalyst. The extent of bulk hydroxyethylation using AlCl3 resulted in 95.65% modification counted as total N-hydroxyethylated polyamide 46. The modification resulted in improved hydrophilic properties, and a maximum surface free energy of 44.6 mJ/m2 was achieved after 3 h reaction, whereas the unmodified PA46 had a surface free energy of 11.2 mJ/m2. In addition, thermal properties of the polymers were studied using differential scanning calorimetry and thermogravimetric analyses. The functionalization leads to decrease in the crystallization energy from 88 J/g to 51 J/g, while the melting energy is changed from 110 J/g to 53 J/g. Furthermore, the thermal stability of the PA46 to pyrolysis was diminished after hydroxylation.

  • 46.
    Barghi, Hamidreza
    et al.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Skrifvars, Mikael
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Taherzadeh, Mohammad J.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Synthesis and characterization of novel bulk hydrophilic acetaldehyde modified polyamide 462011Konferensbidrag (Övrigt vetenskapligt)
  • 47.
    Bashir, Tariq
    et al.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Ali, Majid
    Cho, Sung-Woo
    Persson, Nils-Krister
    Högskolan i Borås, Institutionen Textilhögskolan.
    Skrifvars, Mikael
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    OCVD polymerization of PEDOT: effect of pre-treatment steps on PEDOT-coated conductive fibers and a morphological study of PEDOT distribution on textile yarns2013Ingår i: Polymers for Advanced Technologies, ISSN 1042-7147, E-ISSN 1099-1581, Vol. 24, nr 2, s. 210-219Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The functionalization of textile fibers with intrinsically conductive polymers has become a prominent research area throughout the world. A number of coating techniques have already been utilized and optimized to get the uniform layers of conductive polymers on the surface of different substrates. In our previous study, we produced poly(3,4-ethylenedioxythiophene) (PEDOT)-coated conductive fibers by employing oxidative chemical vapor deposition (oCVD) technique. This paper describes the effects of pre-treatment steps, such as surface treatment of textile fibers with organic solvents, drying of oxidant-enriched fibers at variable temperatures and time, and oxidant type on the electrical, mechanical, and thermal properties of PEDOT-coated conductive fibers. Two well-known oxidants, ferric(III)chloride and ferric(III)p-toluenesulfonate (FepTS), were studied, and then their results were compared. In order to verify the PEDOT-coated layer and, to some extent, its impregnation inside the viscose yarns, a morphological study was carried out by using the attenuated total reflectance Fourier transform infrared spectroscopic imaging technique and computed tomography scanning across the obtained conductive fibers. Differential scanning calorimetric and thermogravimetric analysis were utilized to investigate the thermal properties and the contents of PEDOT in PEDOT-coated fibers. The mechanical properties of conductive fibers were evaluated by tensile strength testing of produced fibers. Effects of all of these pre-treatment steps on electrical properties were analyzed with Kiethly picoammeter. This study cannot only be exploited to improve the properties of conductive fibers but also to optimize the oCVD process for the production of conductive textile fibers by coating with different conjugated polymers.

  • 48.
    Bashir, Tariq
    et al.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Ali, Majid
    Persson, Nils-Krister
    Högskolan i Borås, Institutionen Textilhögskolan.
    Ramamoorthy, Sunil Kumar
    Skrifvars, Mikael
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Stretch Sensing Properties of Conductive Knitted Structures of PEDOT-coated Viscose and Polyester Yarns2013Ingår i: Textile research journal, ISSN 0040-5175, E-ISSN 1746-7748, Vol. 84, nr 3, s. 323-334Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Wearable textile-based stretch sensors for health-care monitoring allow physiological and medical evaluation without interfering in the daily routine of the patient. In our previous work, we successfully coated viscose and polyester (PES)fibers with the conjugated polymer poly(3,4-ethylenedioxythiophene) (PEDOT), using a chemical vapor deposition (CVD) process. In the present paper we report the possibility of producing a large quantity of PEDOT-coated conductive fibers with acceptable mechanical strength and frictional properties, so that knitted stretch sensors can be produced. In utilizing these knitted structures we have demonstrated the possibility of producing a textile-based monitoring device which is more readily integrated into wearable clothing than the previous metal-containing structures. The performance of viscose and PES knitted structures as stretch sensors has been investigated using a cyclic tester of our own design. For imitation of respiratory and joint movement, the variation in electrical properties of the knitted structures was examined at 5 to 50% elongation, and the performance of knitted viscose and PES structures was then compared on the basis of the cyclic testing results. In order to determine the effect of washing on PEDOT coatings and the knitted structures, two washing cycles were performed. After washing, the persistence of PEDOT coating on knitted structures was investigated using FT–IR spectroscopy and thermogravimetric analysis. In the case of PES fiber, it was revealed that stretch sensing behavior persisted even after the washing cycles. These structures thus have the potential to be utilized in medical textiles for monitoring the physiological activities of patients, such as breathing rate and joint movement.

  • 49.
    Bashir, Tariq
    et al.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Bakare, Fatimat
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Baghaei, Behnaz
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Mehrjerdi, Adib Kalantar
    Skrifvars, Mikael
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Influence of different organic solvents and oxidants on insulating and film-forming properties of PEDOT polymer2013Ingår i: Iranian polymer journal, ISSN 1026-1265, E-ISSN 1735-5265, Vol. 22, nr 8, s. 599-611Artikel i tidskrift (Refereegranskat)
    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.

  • 50.
    Bashir, Tariq
    et al.
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Fast, Lars
    Skrifvars, Mikael
    Högskolan i Borås, Institutionen Ingenjörshögskolan.
    Persson, Nils-Krister
    Högskolan i Borås, Institutionen Textilhögskolan.
    Electrical Resistance Measurement Methods and Electrical Characterization of Poly(3,4-ethylenedioxythiophene)- Coated Conductive Fibers2012Ingår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 124, nr 4, s. 2954-2961Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Textile fibers and yarns of high conductivity, and their integration into wearable textiles for different electronic applications, have become an important research field for many research groups throughout the world. We have produced novel electrically conductive textile yarns by vapor-phase polymerization (VPP) of a conjugated polymer, poly(3,4-ethylenedioxythiophene) (PEDOT), on the surface of commercially available textile yarns (viscose). In this article, we have presented a novel setup for electrical resistance measurements, which can be used not only for fibrous structures but also for woven structures of specific dimensions. We have reported a two-point resistance- measuring method using an already manufactured setup and also a comparison with the conventionally used method (so-called crocodile clip method). We found that the electrical properties of PEDOT-coated viscose fibers strongly depend on the concentration of oxidant (FeCl3)and the doping (oxidation) process of PEDOT. To evaluate the results, we used mass specific resistance values of PEDOT-coated viscose yarns instead of normal surface resistance values. The voltage–current (V–I) characteristics support the ohmic behavior of coated fibers to some extent. Monitoring of the charging effect of the flow of current through conductive fibers for prolonged periods of time showed that conductivity remains constant. The change in electrical resistance values with increase in the length of coated fibers was also reported. The resistance measuring setup employed could also be used for continuous measurement of resistance in the production of conductive fibers, as well as for four-point resistance measurement.

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