The effect of bio-based content in resin blends on tensile properties of FRP wet layup systems

Abstract

This study explores three partially bio-based resin blends, in comparison to a conventional epoxy (E), to develop alternative sustainable Fiber Reinforced Polymers (FRPs). Ninety tension coupons and sixty lap splice specimens were fabricated using wet lay up of glass and carbon FRPs. The first bio-based resin was a two-part system that has 41% of its total content derived from by-products of the wood and vegetable industries, referred to as (WV). The second is a mix of conventional epoxy (E) and cashew nut shell liquid that varied to obtain a total bio content ranging from 20 to 40%, referred to as (CN). The third is a mix of (E) and epoxidized linseed oil that varied to obtain a total bio content ranging between 10 and 40%, referred to as (ELO). WV-FRP provided the best performance, in terms of similar tensile strength (fu), within 9%, to carbon and glass E-FRPs, at the highest bio content of 41%. CN-carbon-FRP reached a peak fu similar to E-FRP at 30% bio content, while CN-glass-FRP reached a maximum fu, 15% lower than E-FRP, at 40% bio. ELO-carbon-FRP reached a fu similar to E-FRP at 20% bio, but at 10% bio, it showed 16% higher fu. ELO-glass-FRP showed a maximum fu, 13% higher than E-FRP, at 30% bio. E-carbon and WV-carbon 102 mm lap splices reached 75 and 77%, respectively, of their respective full tensile strengths. E-glass and WV-glass 102 mm splices reached 94 and 79%, respectively, of their respective full tensile strengths.