Epoxidized High-Oleic Vegetable Oils Applied to Composites

Abstract

Vegetable oils are a renewable source for the production of oleochemicals. Oils with high oleic and low saturate content may be an excellent source for producing epoxy resins because of the uniform distribution of cross-linking sites. Bio-based epoxy resins can be used as matrix components for composite materials. Vegetable oils with oleic acid content varying from 22% to 86% were epoxidized in situ with peracetic acid and a heterogeneous catalyst. Contents of 30%, 35%, and 40% (% wt of total matrix) of bio-based epoxy resins were blended with a synthetic epoxy resin and an anhydride curing agent to be applied as the matrix in the preparation of composites using E-glass as the structural fiber. A control was also prepared with a 100% synthetic epoxy resin. Mechanical properties (flexural properties, interlaminar shear strength, and dynamic mechanical analysis) of the produced composite materials were evaluated. More flexible but less resistant composites were obtained as the content of oleic acid in the initial vegetable oil and the content of bio-based resin increased. Toughness increased at lower levels of oleic acid content. Interlaminar shear strength showed low adhesion of the matrix-fiber at a bio-based epoxy resin content of 40%. High homogeneity and slightly reduced glass transition temperatures were shown in composites with high-oleic bio-based resins when compared with the control. The application of bio-based epoxy resins in the production of composites materials helps decrease the dependence on petroleum-based resins and may lead to a high added-value product from vegetable oils. However, future studies are needed to increase the adhesion of matrices containing bio-based resin with synthetic and natural fibers, which will improve the mechanical performance of the composites.