Epoxy resin blends and composites from waste vegetable oil

Abstract

Thermosets and composites were prepared from blends of epoxidized waste vegetable oils and diglycidylether of bisphenol-A to investigate this material as an alternative triglyceride source for oleochemistry. Purifications were developed to remove impurities derived from thermal degradation in the frying process and different epoxidation methodologies were investigated.Effects of epoxidized vegetable oil content (up to 30 wt %) and origin on the tensile properties were studied and revealed that purified waste oils performed similarly to neat oil in contents up to 10 wt %, proving that this strategy does not compromise tensile properties when waste oils are used in suitable proportions. Furthermore, a more prominent plasticizing effect was observed when more than 15 wt% of bio-based resin was used as confirmed by DMA.Composites were prepared with recycled carbon fibres (up to 30 wt %) and thermosets with 10 wt% of bio-based epoxy resins, significantly improving the mechanical properties.

Sustainable Alternative Composites Using Waste Vegetable Oil Based Resins

“…Flax fibres (Biotex Flax Fiber 2/2 Twill 200 GSM) and Glass fibres (Woven Glass 2/2 Twill 280 GSM) were supplied by Easy Composites Ltd, UK. Bio-based epoxy resins were synthesised from purified waste vegetable oil (epoxidized purified vegetable oil-EPVO) and neat vegetable oil (epoxidized neat vegetable oil-ENVO) according to previous reported methodologies [33]. Super Sap CLR ® Part A was used as the epoxy part A (DGEBA, Entropy Resins, United States) and a part B of hardener (mixture of isophorone diamine and 1,3-benzenedimethanamine, Entropy Resins, United States) as the benchmark epoxy.…”

“…Characterization of the bio-based epoxy resins (EPVO and ENVO) was performed by Infrared spectra (ATR-FTIR) and 1 H Nuclear Magnetic Resonance ( 1 H NMR) according to the methodologies previously described in literature [33]. Weight-loss curves were obtained by thermogravimetric analysis (TGA) using a Mettler Toledo TGA 1 STARe programmed to heat the sample from 25 to 600 °C, with heating rate of 10 °C min −1 , under N 2 flow of 100 mL min −1 .…”

“…Bio-based epoxy resins used in this study were synthesised according to procedures previously developed in our group, Fig. 1 [33]. Although WVO presents a number of impurities and by-products deriving from hydrolysis and thermal oxidation during the frying process, the development of purification methodologies based on liquid-liquid (L-L) extraction was capable of producing a clean source of triglycerides [43].…”

“…The exploration of this post-use material (which can be collected from food outlets, households etc.) is aligned with sustainable principles [33][34][35]. Since WVO becomes a non-edible feedstock after the frying process, its use alleviates potential pressures on the commodity food price caused by the exploration of vegetable oils in engineering applications [36,37].…”

“…The incorporation of WVO-derived triglycerides into epoxy-based polymer networks has been recently demonstrated in the literature [33]. Partially bio-based matrices enabled the production of composites with recycled carbon fibres by resin casting with maximum of Young's Modulus of 3.2 GPa and a tensile strength of 53 MPa.…”