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- Khalili, Pooria, et al.
(författare)
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Mechanical Properties of Bio-Based Sandwich Composites Containing Recycled Polymer Textiles
- 2023
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Ingår i: Polymers. - 2073-4360. ; 15:18, s. 1-14
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, sandwich composites were produced by compression moulding techniques, and they consisted of regenerated cellulose fabric (rayon) and bio-based polypropylene (PP) to form facings, while virgin and recycled polyamide (PA) textiles were used as core materials. To compare the mechanical performance between sandwich composites and typical composite designs, a control composite was produced to deliver the same weight and fiber mass fraction from rayon and PP. To evaluate the influence of recycled textile on the mechanical properties of the composites, a series of flexural, low velocity impact (LVI) and tensile tests were performed. It was found that the incorporation of thicker PA textile enhanced the bending stiffness by two times and the peak flexural force by 70% as compared to those of control. Substitution of a layer of recycled textile for two layers of rayon provided a good level of impact energy absorption capacity (~28 J) and maximum force (~4893–5229 N). The tensile strength of the four sandwich composites was reported to be in the range of 34.20 MPa and 46.80 MPa. This value was 91.90 for the control composite. The 2D cross-section slices of the composite specimens did not show any evidence of fiber tow debonding, fiber bundle splitting, or delamination.
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| 4. |
- Persson, Nils-Krister, et al.
(författare)
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Re: en ny samhällssektor spirar
- 2016
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- 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.
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| 5. |
- Åkesson, Dan, 1970-, et al.
(författare)
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Mechanical recycling of polylactic acid composites reinforced with wood fibres by multiple extrusion and hydrothermal ageing
- 2016
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Ingår i: Journal of reinforced plastics and composites (Print). - : Sage Publications. - 0731-6844 .- 1530-7964. ; 35:16, s. 1248-1259
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Tidskriftsartikel (refereegranskat)abstract
- The mechanical recycling of polylactic acid composites reinforced with wood fibres was studied by multiple extrusions. The composite material was extruded seven times, and the mechanical and thermal properties were monitored by tensile tests, flexural tests, differential scanning calorimetry, Fourier-transform infrared and scanning electron microscopy. The results showed that the material retained its mechanical properties relatively well, for up to five cycles after which the tensile strength decreased by 23%. Thermal characterisation further showed that the glass transition temperature ( Tg) shifted several degrees centigrade towards lower temperatures, further indicating degradation of the polylactic acid polymer. Characterisation was also done on composite material, which was aged hydrothermally between each extrusion cycle in order to simulate post-consumer recycling of composite products, which had been exposed to water. Samples were aged at 50℃ in distilled water for 5 days. The thermal and mechanical testing showed that the material survived the ageing test fairly well.
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| 6. |
- Åkesson, Dan, 1970-, et al.
(författare)
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Thermo-oxidative aging of high-density polyethylene reinforced with multiwalled carbon nanotubes
- 2021
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Ingår i: Journal of Applied Polymer Science. - : College of William and Mary. - 0021-8995 .- 1097-4628. ; 138:26
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this study was to investigate the influence of aging on the properties of high-density polyethylene (HDPE) reinforced with multi-wall carbon nanotubes (MWCNTs). Nanocomposites were prepared with nanotubes at 0, 1, 3, and 5 wt%. The long-term durability of the prepared materials was evaluated by thermo-oxidative aging test. Test bodies were aged at 110°C for up to 10 weeks. The nanocomposites were characterized by differential scanning calometry, thermogravimetric analysis (TGA), 13C-NMR, elongation at break, and transmission electron microscopy. The aging mainly occurred on the surface of the samples and the neat HDPE showed a strong yellowing after the aging. A strong reduction in elongation at break was seen. For neat HDPE, the elongation at break was reduced from roughly 1400–25%. When HDPE was reinforced with the nanotubes, the reduction was less dramatic
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| 8. |
- Adekunle, Kayode, et al.
(författare)
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Biobased Composites Prepared by Compression Molding with a Novel Thermoset Resin from Soybean Oil and a Natural-Fiber Reinforcement
- 2010
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Ingår i: Journal of Applied Polymer Science. - : John Wiley & Sons, Inc.. - 0021-8995 .- 1097-4628. ; 116:3, s. 1759-1765
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 10. |
- Adekunle, Kayode, et al.
(författare)
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High performance natural fibre hybrid composites based on biobased thermoset resins for use in technical applications
- 2009
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- 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.
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