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  • 1.
    Adekunle, Kayode
    et al.
    University of Borås, School of Engineering.
    Åkesson, Dan
    University of Borås, School of Engineering.
    Bakare, Fatimat
    University of Borås, School of Engineering.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Bio-based thermoset resins from soybean and linseed oils for structural composites2011Conference paper (Refereed)
  • 2.
    Adekunle, Kayode
    et al.
    University of Borås, School of Engineering.
    Åkesson, Dan
    University of Borås, School of Engineering.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Biobased Composites Prepared by Compression Molding with a Novel Thermoset Resin from Soybean Oil and a Natural-Fiber Reinforcement2010In: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 116, no 3, p. 1759-1765Article in journal (Refereed)
    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.

  • 3.
    Adekunle, Kayode
    et al.
    University of Borås, School of Engineering.
    Åkesson, Dan
    University of Borås, School of Engineering.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Biobased Composites Prepared by Compression Moulding using a Novel Thermoset Resin from Soybean oil and a Natural Fibre Reinforcement2009Conference paper (Other academic)
    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%.

  • 4.
    Adekunle, Kayode
    et al.
    University of Borås, School of Engineering.
    Åkesson, Dan
    University of Borås, School of Engineering.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Preparation of biobased composites using novel thermoset polymers from soybean oil and a natural fibre reinforcement2009Conference paper (Other academic)
    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.

  • 5.
    Adekunle, Kayode
    et al.
    University of Borås, School of Engineering.
    Åkesson, Dan
    University of Borås, School of Engineering.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Synthesis of reactive soybean oils for use as a biobased thermoset resins in structural natural fiber composites2009In: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 115, no 6, p. 3137-3145Article in journal (Refereed)
    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.

  • 6.
    Adekunle, Kayode
    et al.
    University of Borås, School of Engineering.
    Åkesson, Dan
    University of Borås, School of Engineering.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Synthesis of reactive soybean oils for use as biobased thermoset resins in structural natural fibre composites2008Conference paper (Refereed)
  • 7.
    Adekunle, Kayode
    et al.
    University of Borås, School of Engineering.
    Åkesson, Dan
    University of Borås, School of Engineering.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Synthetic modification of reactive soybean oils for use as biobased thermoset resins in structural natural fiber composites2008Conference paper (Other academic)
  • 8.
    Adekunle, Kayode
    et al.
    University of Borås, School of Engineering.
    Åkesson, Dan
    University of Borås, School of Engineering.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Synthetic modification of reactive soybean oils for use as biobased thermoset resins in structural natural fiber composites2008In: Polymer Preprints, ISSN 0551-4657, Vol. 49, no 1, p. 279-Article in journal (Refereed)
  • 9.
    Bakare, Fatimat O.
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Ramamoorthy, Sunil Kumar
    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.
    Thermomechanical properties of bio-based composites made from a lactic acid thermoset resin and flax and flax/basalt fibre reinforcements2016In: Composites. Part A, Applied science and manufacturing, ISSN 1359-835X, E-ISSN 1878-5840, Vol. 83, p. 176-184Article in journal (Refereed)
    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.

  • 10.
    Bakare, Fatimat Oluwatoyin
    et al.
    University of Borås, School of Engineering.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Wang, Yanfei
    Afshar, Shahrzad Javanshir
    Esmaeli, Nima
    Åkesson, Dan
    University of Borås, School of Engineering.
    Morphological and mechanical properties of a biobased composite from a lactic acid based thermoset resin and viscose fiber reinforcement2014Conference paper (Refereed)
  • 11.
    Bakare, Fatimat Oluwatoyin
    et al.
    University of Borås, School of Engineering.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Wang, Yanfei
    Afshar, Shahrzad Javanshir
    Esmaeli, Nima
    Åkesson, Dan
    University of Borås, School of Engineering.
    Synthesis and Preparation of Biobased Composites with A Novel Thermoset Resin from Lactic Acid2014Conference paper (Refereed)
  • 12.
    Bakare, Fatimat Oluwatoyin
    et al.
    University of Borås, School of Engineering.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Åkesson, Dan
    University of Borås, School of Engineering.
    Wang, Yanfei
    Afshar, Shahrzad Javanshir
    Esmaeili, Nima
    Synthesis and Characterization of Bio-Based Thermosetting Resins from Lactic Acid and Glycerol2014In: Journal of Applied Polymer Science, E-ISSN 1097-4628, Vol. 131, no 12, p. 1-9Article in journal (Refereed)
    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.

  • 13.
    Bakare, Fatimat Oluwatoyin
    et al.
    University of Borås, School of Engineering.
    Wang, Yanfei
    Esmaeili, Nima
    Afshar, Shahrzad Javanshir
    Åkesson, Dan
    University of Borås, School of Engineering.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Biobased Composites Prepared From a Lactic Acid Based Thermoset Resin and Natural-Fiber Reinforcement2013Conference paper (Refereed)
  • 14.
    Bakare, Fatimat Oluwatoyin
    et al.
    University of Borås, School of Engineering.
    Wang, Yanfei
    Esmaeili, Nima
    Afshar, Shahrzad Javanshir
    Åkesson, Dan
    University of Borås, School of Engineering.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    The Effect of Glycerol in the Synthesis of a Lactic Acid Based Thermoset Resin2013Conference paper (Other academic)
  • 15.
    Bakare, Fatimat Oluwatoyin
    et al.
    University of Borås, School of Engineering.
    Wang, Yanfei
    Esmaeili, Nima
    Afshar, Shahrzad Javanshir
    Åkesson, Dan
    University of Borås, School of Engineering.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    The Effect of Glycerol in the Synthesis of a Lactic Acid Based Thermoset Resin2013Conference paper (Refereed)
  • 16.
    Bakare, Fatimat
    et al.
    University of Borås, School of Engineering.
    Åkesson, Dan
    University of Borås, School of Engineering.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Bashir, Tariq
    University of Borås, School of Engineering.
    Ingman, Petri
    Srivastava, Rajiv
    Synthesis and characterization of unsaturated lactic acid based thermoset bio-resins2014In: European Polymer Journal, ISSN 0014-3057, E-ISSN 1873-1945, Vol. 67, p. 570-582Article in journal (Refereed)
    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.

  • 17.
    Bátori, Veronika
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Jabbari, Mostafa
    University of Borås, Faculty of Textiles, Engineering and Business.
    Åkesson, Dan
    University of Borås, Faculty of Textiles, Engineering and Business.
    Lennartsson, Patrik R.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Taherzadeh, Mohammad J
    University of Borås, Faculty of Textiles, Engineering and Business.
    Zamani, Akram
    University of Borås, Faculty of Textiles, Engineering and Business.
    Production of Pectin-Cellulose Biofilms: A New Approach for Citrus Waste Recycling2017In: International Journal of Polymer Science, ISSN 1687-9422, E-ISSN 1687-9430, Vol. 2017, p. 1-9, article id 9732329Article in journal (Refereed)
    Abstract [en]

    While citrus waste is abundantly generated, the disposal methods used today remain unsatisfactory: they can be deleterious for ruminants, can cause soil salinity, or are not economically feasible; yet citrus waste consists of various valuable polymers. This paper introduces a novel environmentally safe approach that utilizes citrus waste polymers as a biobased and biodegradable film, for example, for food packaging. Orange waste has been investigated for biofilm production, using the gelling ability of pectin and the strength of cellulosic fibres. A casting method was used to form a film from the previously washed, dried, and milled orange waste. Two film-drying methods, a laboratory oven and an incubator shaker, were compared. FE-SEM images confirmed a smoother film morphology when the incubator shaker was used for drying. The tensile strength of the films was 31.67 ± 4.21 and 34.76 ± 2.64 MPa, respectively, for the oven-dried and incubator-dried films, which is within the range of different commodity plastics. Additionally, biodegradability of the films was confirmed under anaerobic conditions. Films showed an opaque appearance with yellowish colour.

  • 18.
    Bátori, Veronika
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Åkesson, Dan
    University of Borås, Faculty of Textiles, Engineering and Business.
    Zamani, Akram
    University of Borås, Faculty of Textiles, Engineering and Business.
    Taherzadeh, Mohammad J
    University of Borås, Faculty of Textiles, Engineering and Business.
    Pectin-based Composites2017In: Handbook of Composites from Renewable Materials: Biodegradable Materials, John Wiley & Sons, 2017, p. 487-518Chapter in book (Other academic)
    Abstract [en]

    One third of the cell wall of vascular plants is composed of pectin, which serves as the cementing material for the cellulosic network, behaving as a stabilized gel. Industrially, pectin is produced from juice and sugar production waste. Different sources and extraction conditions result in diversity in characteristics and applications of pectin. Most commonly, pectin is used in the food industry as a gelling and thickening agent and it is favored in the pharmaceutical industry as a carrier for colon-specific drugs. Pectin has good potential to be utilized as a matrix in production of environmentally friendly film packaging as well as biocomposite materials. Pectin is sensitive to chemical reactions and promotes the homogeneous immobilization of cells, genes, and proteins. However, due to limited mechanical properties pectin is not used for structural applications but instead rather for composites in which its biodegradable properties can be utilized. Pectin is often reinforced with hydroxyapatite and biphasic calcium phosphate for bone regeneration and tissue engineering applications. It can also be used as a biosorbent for copper removal from aqueous solutions. Active packaging of nanohybrids composed of pectin and halloysite nanotubes that are loaded with rosemary essential oil is another application of pectin-based composites.

  • 19.
    Esmaeili, Nima
    et al.
    University of Bolton.
    Jahandideh, Arash
    South Dakota State University.
    Muthukumarappan, Kasiviswanathan
    South Dakota State University.
    Åkesson, Dan
    University of Borås, Faculty of Textiles, Engineering and Business.
    Skrifvars, Mikael
    University of Borås, Faculty of Textiles, Engineering and Business.
    Synthesis and characterization of methacrylated star-shaped poly(lactic acid) emplying core moilecules with different hydroxyl groups2017In: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 134, no 39, article id 45341Article in journal (Refereed)
    Abstract [en]

    A set of novel bio-based star-shaped thermoset resins was synthesized via ring-opening polymerization of lactide and employing different multi-hydroxyl core molecules, including ethylene glycol, glycerol, and erythritol. The branches were end-functionalized with methacrylic anhydride. The effect of the core molecule on the melt viscosity, the curing behavior of the thermosets and also, the thermomechanical properties of the cured resins were investigated. Resins were characterized by Fourier-transform infrared spectroscopy, 13C-NMR, and 1H-NMR to confirm the chemical structure. Rheological analysis and differential scanning calorimetry analysis were performed to obtain the melt viscosity and the curing behavior of the studied star-shaped resins. Thermomechanical properties of the cured resins were also measured by dynamic mechanical analysis. The erythritol-based resin had superior thermomechanical properties compared to the other resins and also, lower melt viscosity compared to the glycerol-based resin. These are of desired characteristics for a resin, intended to be used as a matrix for the structural composites. Thermomechanical properties of the cured resins were also compared to a commercial unsaturated polyester resin and the experimental results indicated that erythritol-based resin with 82% bio-based content has superior thermomechanical properties, compared to the commercial polyester resin. Results of this study indicated that although core molecule with higher number of hydroxyl groups results in resins with better thermomechanical properties, number of hydroxyl groups is not the only governing factor for average molecular weight and melt viscosity of the uncured S-LA resins.

  • 20. Esmaeli, Nima
    et al.
    Bakare, Fatimat Oluwatoyin
    University of Borås, School of Engineering.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Afshar, Shahrzad Javanshir
    Åkesson, Dan
    University of Borås, School of Engineering.
    Mechanical properties for bio-based thermoset composites made from lactic acid, glycerol and viscose fibers2014In: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 22, no 1, p. 603-613Article in journal (Refereed)
    Abstract [en]

    Regenerated cellulose fibers were used to produce thermoset composites from a bio-based thermoset resin synthesized from lactic acid and glycerol. The resin was impregnated into the regenerated cellulose fiber and compression molded at elevated temperature to produce thermoset composites. Different fiber alignments (unidirectional and bidirectional), different reinforcement type (warp-knitted and non-woven) and varying fiber loading (65, 70 and 75 wt%) were investigated. The composites were characterized by flexural, tensile and Charpy impact testing and by dynamical mechanical thermal analysis. Water uptake and ageing properties in climate chamber were also characterized for the composites. The results showed that the composites had good mechanical properties. They can be produced with up to 70 wt% fiber content when using unidirectional (UD) and bidirectional fiber (BD) alignment, and with up to 65 wt% fiber content when using the non-woven (NW) reinforcement. The tensile modulus ranged between 11 and 14 GPa for UD composites, 7 and 8.5 GPa for BD composites and 5 and 7.5 GPa for NW composites. The flexural modulus ranged between 10 and 11.5 GPa for UD composites, 5 and 6.5 GPa for BD composites and 5 and 6 GPa for NW composites. The impact strength ranged between 130 and 150 kJ/m2 for UD composites, 98 and 110 kJ/m2 for BD composites and 17 and 20 kJ/m2 for NW composites. The result of the ageing test showed that the mechanical properties of the composites deteriorate with ageing but the addition of styrene somewhat counteracts the degradation, making the composite applicable for indoor use.

  • 21.
    Fazelinejad, Samaneh
    et al.
    University of Borås, School of Engineering.
    Åkesson, Dan
    University of Borås, School of Engineering.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Mechanical Recycling of Polylactic Acid Reinforced with Calcium Carbonate2014Conference paper (Other academic)
    Abstract [en]

    Biopolymers are becoming increasingly popular and may help reduce oil dependency. As a result, industries’ attentions have been directed towards polylactic acid (PLA) which combines the advantages of being renewable and biodegradable resources at the same time. The upward trend of the bioplastics and biocomposites usage among consumers could have great consequence for the recycled plastics industry in the next few decades. While the mechanical recycling of many of the traditional, petro-based polymers have been studied in detail, bio-based polymers still need to be better characterized. The mechanical recycling of neat PLA has previously studied and tests show that it is possible to process PLA several times without significant loss of mechanical properties. However, commercial plastics are often used with some kind of filler. Due to the low production cost of chalk (mainly consisting of CaCO3) it is often added to commercial polymers. PLA can be filled with chalk and other fillers in order to improve the toughness and lowering the cost. The purpose of this project was to investigate the mechanical recycling of PLA compounded with chalk. PLA was compounded with 30 wt-% chalk and 5 wt-% plasticizer using a twin screw extruder. The mechanical recycling was simulated by multiple extrusion. Samples for mechanical testing were prepared by compress molding. The prepared compound was recycled up to 6 times by multiple extrusion. The mechanical and thermal properties were characterized after each cycle by TGA, DSC, DMTA, FTIR and tensile tests.

  • 22. Fazelinejad, Samaneh
    et al.
    Åkesson, Dan
    University of Borås, School of Engineering.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Recycling of Poly Lactic Acid Reinforced with Calcium Carbonate by Multiple Processing2014Conference paper (Other academic)
    Abstract [en]

    The upward trend of the bioplastics and biocomposites usage among consumers could have great consequence for the recycled plastics industry in the next few decades. As a result,industries’ attentions have been directed towards Poly Lactic Acid (PLA) which combines the advantages of renewable and biodegradable resources at the same time. Since PLA is more environmentally friendly compared to traditional petroleum-based commodity polymers, it has benefited from an upturned trend of interest in different markets, like the packaging, textile, and automotive industries. However, it is not applicable in many fields due to its inherent brittleness; even though it is very beneficial as the result of high strength and high modulus. Due to the low production cost of Nano calcium carbonate (nano-CaCO3) (NCC) which is useful to improve the toughness of PLA, it has reached a wide market in such industries as plastics, paints, and inks. By adding Nano calcium carbonate to polymer, thermal,crystallization, mechanical, biodegradability and melt rheological properties will be improved. The mechanical recycling of neat PLA has previously studied as well as some research on blend PLA/NCC by Sabzi et al. However, the purpose of this project is to investigate the characterization of PLA blend with Chalk (CaCo3) and Plasticizer by focusing on thermaland mechanical properties. The filler, which is 30% calcium carbonate, and 5% plasticizer compound with PLA in a two screws extruder. Plasticizer is added to composite to make it softer and it is consider constant in all samples. Multiple extrusions and compress molding are methods which can help in studying the recyclability of polymeric materials containing bioplastic and its derivatives and in figuring out the stability or service life respectively. In addition, these methods make it possible to determine the impacts of thermal and thermo mechanical degradation. Bio composite was recycled up to 6 times by using extruder equipment and crushing. The mechanical and thermal properties were characterized after each cycle by TGA, DSC,DMTA, FTIR, tensile machine and flexural test. The study represents that by introducing 30% calcium carbonate to PLA, it can be recycled up to 6 times without meeting any significant change in the mechanical and thermal properties.

  • 23.
    Fazelinejad, Samaneh
    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.
    Repeated mechanical recycling of polylactic acid filled with chalk2017In: Progress in Rubber, Plastics and Recycling Technology, ISSN 0266-7320, E-ISSN 1478-2413, p. 1-16Article in journal (Refereed)
    Abstract [en]

    Polylactic acid (PLA) was compounded with 30 wt% chalk and 5 wt% of a biobased plasticiser on a twin screw extruder. Mechanical recycling of the obtained compound was studied by multiple extrusions up to six cycles. The degradation was monitored by mechanical and thermal tests. Tensile and flexural tests did not reveal any major degradation after six cycles of processing. Characterising the material with differential scanning calorimetry (DSC) did not detect any significant change of the thermal properties. The material was also characterised by FTIR and, again, no significant change was detected. The material was finally characterised by melt flow index and by proton nuclear magnetic resonance (1H-NMR). Both tests revealed that some degradation had occurred. The 1H-NMR clearly showed that the chain length had been reduced. Also, the MFI test showed that degradation had occurred. However, the study reveals that PLA filled with chalk can be recycled by repeated extrusion for up to 6 cycles, without severe degradation. This should be of relevance when considering the end-of-life treatment of polymer products made from PLA.

  • 24. Foltynowicz, Zenon
    et al.
    Åkesson, Dan
    University of Borås, School of Engineering.
    Christéen, Jonas
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Microwave pyrolysis as a method to glass fibre recovery from used blades of wind turbines2012Conference paper (Refereed)
    Abstract [en]

    Wind turbine blades made of composite materials at the end of their life cycle become the waste very difficult for final utilization. There are three possible routes for dismantled wind mill wings: landfill, incineration or recycling. In the paper the method of recycling of waste glass fiber reinforced plastic, coming from used wind turbine blades with microwave pyrolysis is described. Microwave pyrolysis of the fragmented blade from a wind mill blades were carried out at 300 to 600ºC in nitrogen atmosphere in special reactor at Stena AG facilities. The pyrolysis generated gas, oil and recovered glass fibres. The hydrocarbon pyrolysis products were analysed in terms of chemical composition and energy content while the recovered glass fibres were used to produce new thermoset composites. Further developments on pilot plants are in progress.

  • 25. George, Gejo
    et al.
    Tomlal Jose, E.
    Åkesson, Dan
    University of Borås, School of Engineering.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Nagarajan, E.R.
    Kuruvilla, Joseph
    Viscoelastic behaviour of novel commingled biocomposites based on polypropylene/jute yarns2012In: Composites. Part A, Applied science and manufacturing, ISSN 1359-835X, E-ISSN 1878-5840, Vol. 43, no 6, p. 893-902Article in journal (Refereed)
    Abstract [en]

    Jute yarn reinforced polypropylene commingled composites were prepared by an environmentally benign technique called commingling method in which the matrix fibres and reinforcing fibres are intermingled together with good alignment. The dynamic mechanical properties or viscoelastic behaviour of these commingled composites were studied with reference to fibre content and various chemical treatments. The storage and loss modulus increased with fibre content where as tan δ decreased. KMnO4 and MAPP treated composites showed much higher storage and loss modulus values at all temperatures compared to untreated one. The glass transition temperature showed a marginal increasing tendency with fibre content and chemical treatments. The surface treatment mechanisms were supported by FT-IR spectra and the increase in interfacial adhesion after chemical treatments were supported by SEM images. Theoretical modelling was used to predict the values of storage modulus and tan δ and was found to be comparable with that of experimentally obtained results.

  • 26.
    Jabbari, Mostafa
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Skrifvars, Mikael
    University of Borås, Faculty of Textiles, Engineering and Business.
    Åkesson, Dan
    University of Borås, Faculty of Textiles, Engineering and Business.
    Taherzadeh, Mohammad J
    University of Borås, Faculty of Textiles, Engineering and Business.
    Introducing all-polyamide composite coated fabrics: A method to produce fully recyclable single-polymer composite coated fabrics2016In: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 133, no 7Article in journal (Refereed)
    Abstract [en]

    Novel all-polyamide composite (APC) has been developed to replace traditional coated fabrics with good interfacial adhesionand enhanced recyclability. The composite is fully recyclable since it contains no other materials except polyamide. APC was preparedby partially dissolving a polyamide fabric by treatment with a film-forming polyamide solution. The effect of the polyamidesolution concentration and gelling time on tensile and viscoelastic properties of APCs was investigated to explore the optimum processingparameters for balancing the good interfacial adhesion. The composite properties were studied by dynamic mechanical thermalanalysis (DMTA), tensile testing and scanning electron microscopy (SEM). The results showed a good adhesion between the coatingand the fabric. A new method was introduced to convert a low value added textile waste to a high value-added product. The compositeis tunable, in terms of having a dense or a porous top-layer depending on the end-use requirements.

  • 27.
    Jabbari, Mostafa
    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.
    Taherzadeh, Mohammad J
    University of Borås, Faculty of Textiles, Engineering and Business.
    Novel lightweight and highly thermally insulative silica aerogel-doped poly (vinyl chloride)-coated fabric composite2015In: Journal of reinforced plastics and composites (Print), ISSN 0731-6844, E-ISSN 1530-7964, Vol. 34, no 19, p. 1581-1592Article in journal (Refereed)
    Abstract [en]

    Novel lightweight and highly thermal insulative aerogel-doped poly(vinyl chloride)-coated fabric composites wereprepared on woven fabrics made of polyester fibres using knife coating method, and their performances were comparedwith neat composite. The composites were prepared by incorporating a commercial aerogel to a ‘green’ poly(vinylchloride) (PVC) plastisol. The effect of aerogel-content, thermal insulating property, thermal degradation, surface characteristics,tensile and physical properties of the composites were investigated. Results revealed that aerogel couldreduce thermal conductivity, density and hydrophilicity of the composites dramatically without significant decrease inother properties. Experimental results showed that thermal insulation properties were enhanced by 26% (from 205 to152 mW/m-K), density decreased by 17% (from 1.132 to 0.941 g/cm3) and hydrophobicity increased by 16.4% (from76.02 to 88.671.48) with respect to the unmodified coated fabric. Analyses proved that composite with 3% aerogel isthe lightest by weight, while 4% showed the highest thermal insulation. The results showed that 4% is the criticalpercentage, and preparation of composites with aerogel content higher than 4% has limitations with the given formulationdue to high viscosity of plastisol. The prepared composite has potential applications in many fields such asdevelopment of textile bioreactors for ethanol/biogas production from waste materials, temporary houses and tents,facade coverings, container linings and tarpaulins. The prepared composite can be considered ‘green’ due to usage of anon-phthalate environment-friendly plasticiser.

  • 28.
    Kalantar Mehrjerdi, Adib
    et al.
    University of Borås, School of Engineering.
    Abebe Mengistu, Bemnet
    Åkesson, Dan
    University of Borås, School of Engineering.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Effects of a titanate coupling agent on the mechanical and thermo-physical properties of talc-reinforced polyethylene compounds2014In: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 131, no 13, p. 40449-40449Article in journal (Refereed)
    Abstract [en]

    An experimental study was carried out to investigate the effects of a titanate coupling agent on the mechanical properties, moisture absorption, and thermal conductivity of talc-filled high-density polyethylene (HDPE). Talc (0–35 wt %) was used as reinforcement particulate filler in an HDPE matrix and samples were prepared in a micro-compounder and an injection molding machine. Isopropyl tri(dioctyl)phosphate titanate (0.5 wt %) was used as coupling agent. Composites with and without coupling agent were evaluated for changes in mechanical and thermo-physical properties, morphology, and void content. Addition of the titanate coupling agent most often resulted in an increase in stiffness and tensile strength. Furthermore, both the void content and the elongation at break of composites were reduced. Results also showed that the coupling agent had no effects on the thermal conductivity, thermal diffusivity, and specific heat capacity of the composites. In addition, it was observed that the coupling agent was more effective at low concentrations of filler. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40449.

  • 29.
    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.

  • 30. Pettersson, Carina
    et al.
    Åkesson, Dan
    University of Borås, School of Engineering.
    Återvinning av komposit med mikrovågspyrolys2010Conference paper (Other academic)
  • 31. Rahimiashtiyani, Samaneh
    et al.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Åkesson, Dan
    University of Borås, School of Engineering.
    Preparation and characterization of bio-nanocomposites from biobased thermoset resin, montmorillonite and natural fiber2011Conference paper (Other academic)
    Abstract [en]

    In this study bio-nanocomposites were manufactured, using a thermoset resin based on lactic acid and nanoclay (montmorillonite) as a matrix for flax fibers. The obtained composites were characterized by dynamic-mechanical thermal analysis (DMTA) and flexural testing. The aim of this study was to evaluate the mechanical properties of bio-nanocomposites without any surface treatment of the nanoclay and to use the resin/clay blend as a matrix for natural fiber composite. Results showed the nanoclay improved the mechanical properties.

  • 32. Rahimiashtiyani, Samaneh
    et al.
    Åkesson, Dan
    University of Borås, School of Engineering.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Preparation and characterization of bio-nanocomposites from biobased thermoset resin and montmorillonite2011Conference paper (Other academic)
    Abstract [en]

    Bio-nanocomposites are a new class of particle-based composites that have attracted much attention due to their environmental and economic advantages these years [1, 2]. In this study a biobased thermoset resin based on lactic acid was used and reinforced with montmorillonite (MMT). This resin consists of star-shaped oligomers of lactic acid, end-capped with methacrylate groups [3]. Thus, the resin can be cross-linked by a free radical polymerization. MMT consists of 1 nm thick aluminosilicate layers. Due to the high surface area, MMT has been evaluated as a reinforcement for several commercial polymers. While most commercial resins are non-polar, MMT is intrinsically polar. Therefore, MMT is usually surface treated in order to make it less polar. However, the resin used in this study is relatively polar and the purpose of this study was to evaluate if untreated MMT could be used to reinforce this resin. The curing was studied with isothermal differential scanning calorimetry (DSC) and the obtained composite were characterized by dynamic-mechanical thermal analysis (DMTA). Also transmission electronic spectroscopy (TEM) was used to characterize the structure. The result showed some improvements in mechanical properties. The DMTA results showed that the storage modulus and also loss modulus of the nanocomposite improved with respect to neat resin. Intercalated structures could be seen from the TEM micrographs.

  • 33.
    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.

  • 34.
    Skrifvars, Mikael
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Bakare, Fatimat
    University of Borås, Faculty of Textiles, Engineering and Business.
    Åkesson, Dan
    University of Borås, Faculty of Textiles, Engineering and Business.
    Bashir, Tariq
    University of Borås, Faculty of Textiles, Engineering and Business.
    Ingman, Petri
    University of Turku.
    Srivastava, Rajiv
    Indian Institute of Technology Delhi.
    Synthesis and characterisation of unsaturated lactic acid based thermoset bio-resins2015In: European Polymer Journal, ISSN 0014-3057, E-ISSN 1873-1945, Vol. 67, no June 2015, p. 570-582Article in journal (Refereed)
  • 35.
    Skrifvars, Mikael
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Dhakal, Hom
    Advanced Polymer and Composites (APC) Research Group, University of Portsmouth, Portsmouth, UK.
    Åkesson, Dan
    University of Borås, Faculty of Textiles, Engineering and Business.
    Zhang, Z
    Advanced Polymer and Composites (APC) Research Group, University of Portsmouth, Portsmouth, UK.
    Hybrid composites and biocomposites: concepts, opportunities and research challenges2016Conference paper (Refereed)
  • 36.
    Skrifvars, Mikael
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Esmaeili, Nima
    Bakare, Fatimat Oluwatoyin
    University of Borås, Faculty of Textiles, Engineering and Business.
    Afshar, Shahrzad
    Åkesson, Dan
    University of Borås, Faculty of Textiles, Engineering and Business.
    Mechanical properties for bio-based thermoset composites made from lactic acid, glycerol and viscose fibers2015In: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 22, no 1, p. 603-613Article in journal (Refereed)
  • 37.
    Skrifvars, Mikael
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Mabille, Colinne
    University of Borås, Faculty of Textiles, Engineering and Business.
    Wojno, Sylvia
    University of Borås, Faculty of Textiles, Engineering and Business.
    Åkesson, Dan
    University of Borås, Faculty of Textiles, Engineering and Business.
    Dhakal, Hom
    University of Portsmouth.
    Zhang, Zhongyi
    University of Portsmouth.
    Resin transfer moulding processing of biocomposites from warp knitted and carded cellulose reinforcements2015Conference paper (Refereed)
  • 38.
    Skrifvars, Mikael
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Åkesson, Dan
    University of Borås, Faculty of Textiles, Engineering and Business.
    Mabille, Coline
    Wojno, Sylwia
    Zhang, Zhongyi
    University of Portsmouth.
    Dhakal, Hom
    University of Portsmouth.
    Warp knitted and carded regenerated cellulose reinforced biocomposites2015Conference paper (Other academic)
  • 39.
    Skrifvars, Mikael
    et al.
    University of Borås, School of Engineering.
    Åkesson, Dan
    University of Borås, School of Engineering.
    Pettersson, C.
    Andreassson, S.
    Återvinning av kompositer genom mikrovågspyrolys2010Conference paper (Other academic)
  • 40.
    Åkesson, Dan
    University of Borås, Faculty of Textiles, Engineering and Business.
    Mekanisk återvinning av biopolymerer och deras blandningar och kompositer2015Other (Other (popular science, discussion, etc.))
    Abstract [sv]

    Mekanisk återvinning av biopolymerer och deras blandningar och kompositer

    Biopolymerer blir allt vanligare på marknaden. Det är därför viktigt att utveckla återvinningssystem för att ta hand om dessa nya plaster. I ett pågående projekt, ’Hållbar återvinning av ”gröna” plaster och industriellt avfall’ studeras mekanisk återvinning av bioplaster. Återvinning av polymjölksyra (PLA) samt blandningar och kompositer av PLA har studerats genom upprepad bearbetning. Delar av dessa resultat kommer att presenteras.

  • 41.
    Åkesson, Dan
    University of Borås, Faculty of Textiles, Engineering and Business.
    Mekanisk återvinning av PLA förstärkt med cellulosafibrer2015Other (Other (popular science, discussion, etc.))
  • 42.
    Åkesson, Dan
    University of Borås, School of Engineering.
    Preparation and Characterization of UV-cured Nano Reinforced Biobased Coatings2011Conference paper (Other academic)
    Abstract [en]

    Polymers are typically produced from crude oil which is a non-renewable resource. With the fast depletion of the petroleum resources, the development of materials based on renewable resources is becoming important. Polymers prepared from renewable resources are under development, but has mainly focused on thermoplastic polymers such as polylactic acid. For some applications, such as composites and coatings, thermoset polymers are often preferred. Consequently, it is important to develop thermoset resins from renewable resources as well. Plant oils, such as soybean oil and linseed oil, have been utilized by mankind for a long time. Soybean oil is produced in large quantities and soybean oil is an excellent starting material for the synthesis of thermoset resins. A possible strategy to prepare thermoset resins from plant oils is to introduce pendant methacrylate groups in the structure. Thus, the resins can be cured by a free radical polymerization. Such a resin is very susceptible to photopolymerization when exposed to ultraviolet (UV) radiation, which is a common technique to cure coatings. In the present study, three different thermoset resins were studied. Two of the resins were based on soybean oil while the third resin was based on lactic acid. The latter resin was prepared by a direct condensation of lactic acid and pentaerythritol and was finally end-capped with methacrylate groups. Several authors have studied the addition of nano-reinforcements to thermoset resins. One of the most promising nano-reinforcements is layered silicate which has shown to improve several properties. Layered silicate has been used to reinforce conventional resins with good results. The addition of layered silicates to the biobased resins can be used to improve the properties and to broaden the applications. The resins used in this study were therefore reinforced with layered silicate and UV-cured. The cured resins were characterized by Soxhlet extraction, photo-FTIR, DMTA and tensile tests which will be presented during the presentation.

  • 43.
    Åkesson, Dan
    University of Borås, School of Engineering.
    Renewable composites prepared from biobased thermoset resins2009Doctoral thesis, monograph (Other academic)
    Abstract [en]

    In our efforts to create a more sustainable society, several researchers have tried to prepare composites from renewable materials in recent years. The use of natural fibres for reinforcement of composites has been relatively well studied. To date, most studies of natural fibre-reinforced composites have either involved the use of conventional thermoset resins or thermoplastic biopolymers. While there are currently several thermoplastic polymers on the market that are produced from renewable resources, thermosets are inevitably produced from petroleum resources. The development of biobased thermoset resins is therefore of considerable importance. Such resins could be used in future for composite applications, for coating applications or in adhesives. This thesis describes the development of biobased thermoset resins for composite applications. Thermoset resins were synthesised from both epoxidised soybean oils as well as from lactic acid. These resins have been characterised neat as well as together with various reinforcements. The main objective has been to study these biobased resins together with natural fibres for reinforcement, though to some extent nano-reinforcements and glass fibres have also been used as reinforcements. Natural fibre-reinforced composites were prepared from several different biobased thermoset resins. Resins based on soybean oil as well as a resin based on lactic acid were evaluated. The soybean resins were prepared by introducing acrylate or methacrylate groups into the molecules of soybean oil. The second type of thermoset resin used was based on lactic acid. This resin consists of star-shaped methacrylated oligomers of lactic acid. Natural fibres were impregnated by several impregnation techniques. Composites were prepared from the biobased resins together with various natural fibres, such as flax and hemp fibres. The resulting composites were evaluated by tensile testing, flexural testing, impact testing, DMTA and SEM. The results show that composites prepared from biobased resin have relatively good mechanical properties and can be used for indoor applications such as furniture and construction elements.

  • 44.
    Åkesson, Dan
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Bourmaud, Alain
    Beaugrand, Johnny
    Le Duigou, Antoine
    Skrifvars, Mikael
    University of Borås, Faculty of Textiles, Engineering and Business.
    Baley, Christophe
    Recycling of L-Poly-(lactide)-Poly-(butylene-succinate)-flax biocomposite2016In: Polymer degradation and stability, ISSN 0141-3910, E-ISSN 1873-2321, Vol. 128, p. 77-88Article in journal (Refereed)
    Abstract [en]

    The development of new plant fibre composites is a key point in the development of semi-structural biodegradable or biobased parts, especially for automotive applications. The aim of this original and innovating work is to study, at different scales, the recycling ability of a fully biodegradable L-Poly-(lactide)-Poly-(butylene-succinate)-flax (PLLA-PBS-flax) biocomposite. The biocomposites were manufactured by twin-screw extrusion followed by injection moulding, then the recycling behaviour was studied during successive injection moulding cycles. Firstly, we investigated the length of the flax fibre after compounding and injection, as well as the cell wall stiffness and hardness, by in-situ nanoindentation tests. Secondly, we focused on the effects of recycling on thermal, rheological and tensile properties. We highlighted a severe evolution of the cell wall properties, especially concerning the polysaccharidic matrix after the first thermal cycle, nanoindentation properties remaining quasi-stable after this first drop. Furthermore, the biocomposites did not show any significant evolution of their mechanical performances during cycle three or four of the first injection cycles; after this plateau, the tensile strength and strain as well as impact energy were significantly altered due to the conjugated fibre length decrease and degradation of the PLLA, the latter being emphasized when the flax fibre is embedded. Nevertheless, this fully biodegradable composite exhibits a suitable recycling behaviour for 3 or 4 cycles, which is sufficient for industrial applications.

  • 45.
    Åkesson, Dan
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Fazelinejad, Samaneh
    Skrifvars, Ville-Viktor
    University of Borås, Faculty of Textiles, Engineering and Business.
    Skrifvars, Mikael
    University of Borås, Faculty of Textiles, Engineering and Business.
    Mechanical recycling of polylactic acid composites reinforced with wood fibres by multiple extrusion and hydrothermal ageing2016In: Journal of reinforced plastics and composites (Print), ISSN 0731-6844, E-ISSN 1530-7964, Vol. 35, no 16, p. 1248-1259Article in journal (Refereed)
  • 46.
    Åkesson, Dan
    et al.
    University of Borås, School of Engineering.
    Foltynowicz, Zenon
    Christeen, Jonas
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Products obtained from decomposition of glass fiber-reinforced composites using microwave pyrolysis2013In: Polimery, ISSN 0032-2725, Vol. 58, no 7-8, p. 582-586Article in journal (Refereed)
    Abstract [en]

    The possibility to obtain useful products from used glass fiber-reinforced composites using microwave pyrolysis were examined. A scrap of blade from a wind turbine was fragmented and microwave-pyrolysed. The oil and gas formed during the pyrolysis were characterized by gas chromatography-mass spectrometry (GC-MS). The oil from pyrolysis consisted mainly of various aromatic compounds and had an energy content of about 36 MJ/kg. The main component of the gaseous products was methane. The glass fiber recovered after pyrolysis represented 70 % of the initial mass of glass fiber-reinforced plastic.

  • 47.
    Åkesson, Dan
    et al.
    University of Borås, School of Engineering.
    Foltynowicz, Zenon
    Christéen, Jonas
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Microwave pyrolysis as a method of recycling glass fibre from used blades of wind turbines2012In: Journal of reinforced plastics and composites (Print), ISSN 0731-6844, E-ISSN 1530-7964, Vol. 31, no 17, p. 1136-1142Article in journal (Refereed)
    Abstract [en]

    The possibility of recycling glass fibre-reinforced composites by using microwave pyrolysis was examined. A scrap blade from a wind turbine was fragmented and microwave-pyrolysed. The glass fibre recovered after pyrolysis represented 70% of the initial mass of glass fibre-reinforced composites. The tensile strength of the glass fibre recovered was measured after pyrolysis and compared to the tensile strength of untreated glass fibre. The test showed that the fibres lost about 25% of their tenacity. Non-woven fibre mats were prepared from the recovered fibres. Laminates were then prepared from the non-woven mats obtained, together with virgin glass fibre mats. Mechanical testing of the laminates showed that it is possible to prepare composites using 25 wt% of recycled fibres, with relatively good mechanical properties.

  • 48.
    Åkesson, Dan
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Fuchs, Torsten
    Stöss, Michael
    Root, Andrew
    MagSol, Helsinki, Finland.
    Stenvall, Erik
    Chalmers tekniska högskola.
    Skrifvars, Mikael
    University of Borås, Faculty of Textiles, Engineering and Business.
    Recycling of wood fiber-reinforced HDPE by multiple reprocessing2016In: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 133, no 35Article in journal (Refereed)
    Abstract [en]

    The mechanical recycling of high-density polyethylene (HDPE) reinforced with wood fiber was studied by means of repeated injection moulding. The change in properties during the recycling was monitored by tensile and flexural tests, Charpy impact tests, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), FTIR spectroscopy, and by measuring the fiber lengths. Tests were also done where injection moulding was combined with subsequent accelerated thermo-oxidative ageing and thereafter repeated numerous times. The results showed that the HDPE composites were relatively stable toward both the ageing conditions and the repeated injection moulding. The change of the mechanical properties was mainly observed as an increased elongation at max. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43877. © 2016 Wiley Periodicals, Inc.

  • 49.
    Åkesson, Dan
    et al.
    University of Borås, School of Engineering.
    Khrishnamoorthi, Ramesh
    Foltynowicz, Zenon
    Christeen, Jonas
    Kalantar Mehrjerdi, Adib
    University of Borås, School of Engineering.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Glass Fibres Recovered by Microwave Pyrolysis as a Reinforcement for Polypropylene2013In: Polymers & polymer composites, ISSN 0967-3911, E-ISSN 1478-2391, Vol. 21, no 6, p. 333-339Article in journal (Refereed)
    Abstract [en]

    Glass fibre composites were recycled by microwave pyrolysis. The glass fibres recovered were evaluated as a reinforcement agent for polypropylene (PP). Samples were prepared with a micro-compounder and the resulting compounds were evaluated with tensile testing, flexural testing, Charpy impact testing and scanning electron microscopy (SEM). The adhesion between fibre and glass was relatively poor, and an attempt was made to improve it. Various coupling agents were evaluated, in addition to the use of maleic anhydride-grafted PP (MA-PP). Tests showed that MA-PP had a relatively strong effect on the mechanical properties.

  • 50.
    Åkesson, Dan
    et al.
    University of Borås, School of Engineering.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Development of lactic acid and soy bean oil based thermoset resins and their natural fibre composites2007Conference paper (Refereed)
12 1 - 50 of 62
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