Open Collections

Margoto, Olivia Helena

University of British Columbia

Growing concerns on climate change have been leading many manufacturing sectors to be more environmentally conscious, valuing renewable materials, and reusing resources and waste. Aligned with the same trend, biobased polymer composites and natural fibre reinforcements are being considered widely as an alternative to non-renewable composites, while targeting similar properties. This study primarily aims to investigate the weathering resistance of a set of natural fibre reinforced biobased polymer composites towards expanding their outdoor structural applications. For this, three subsequent tasks were carried out. In task 1, a flax fibre fabric and its monofilaments’ physical, mechanical, and thermal properties were characterized. The flax fibre fabric characterized was then used as a composite reinforcement in tasks 2 and 3. Next, task 2 investigated the mechanical and thermal performance of a flax fibre reinforced green high-density polyethylene, made through compression moulding. Task 3 then focused primarily on the effect of natural and accelerated weathering on the mechanical (including tensile, impact, damping, hardness) and physical (density, roughness) properties of flax fibre (FF) and carbon fibre (CF) reinforced thermoset bioresins. For the latter study, the biocomposite samples were fabricated using two different manufacturing techniques. Flax fibre reinforced biobased epoxy (Bioepoxy/35%FF) was made through vacuum infusion. Flax and carbon fibre pre-impregnated with a Polyfurfuryl Alcohol (PFA) resin were used, on the other hand, to fabricate PFA/60%FF, PFA/45%FF-15%CF and PFA/60%CF through vacuum bagging. Bioepoxy/35%FF and PFA/60%FF showed similar density, tensile, and impact properties and performed at least 150% better in damping than CF composites. Notably, by replacing only 15 % of flax with carbon fibre, PFA/45%FF-15%CF had an increase of 130 % in tensile strength and 90 % in modulus. Natural weathering exposures for 30 and 90 days did not statistically affect the tensile and hardness properties of the tested thermoset biocomposites compared to the respective controls. Finally, a multicriteria decision-making method, namely PROMETHEE II, was used to rank the biocomposite options characterized in task 3. PFA/60%CF was ranked first, followed by PFA/45%FF-15%CF, PFA/60%FF and lastly, Bioepoxy/35%FF. This shows that a hybrid biocomposite solution can be an excellent option to fulfill both mechanical performance and weathering concerns for outdoor structural applications.

Text

2022-12-01

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/83337

Mechanical Engineering

University of British Columbia

UBCO

http://creativecommons.org/licenses/by-nc-nd/4.0/