Tensile properties retention of aged carbon‐FRP sheets made of fully and partially bio‐based resins and conventional epoxy

This article investigates the environmental aging of two types of bio‐resin carbon fiber reinforced polymer (CFRP) through immersion in saltwater at various temperatures, and compares results to conventional epoxy (E)‐CFRP. The two types are: a fully bio‐resin, namely furfural alcohol (FA), derived from corn‐cobs and sugarcane, and the second is a partial bio‐resin, namely epoxidized pine oil blend (EP) extracted from pine tree sap. Control specimens showed that EP resin resulted in similar CFRP strength and modulus to E resin, whereas FA resin resulted in a 9% lower strength and 14% higher modulus. These were shown by the Analysis of Variance (ANOVA) to be statistically insignificant. After 240 days exposure, tensile strength retentions of EP‐CFRP at 23°C, 40°C, and 50°C were 97%, 98%, and 92%, respectively, while those of FA‐CFRP were 83%, 81%, and 82%. For reference, retentions of E‐CFRP were 101%, 90%, and 95%. ANOVA showed that the differences in retentions between EP‐ and E‐CFRP are statistically insignificant at all temperatures, while the differences between FA‐ and E‐CFRP are significant at 23°C and 50°C after 240 days only. Also, the reductions in strength over the 240 days for each resin type are insignificant, except for FA‐CFRP at 50°C. CFRP generally suffered remarkably less deterioration than glass‐FRP at elevated temperatures, for both E and FA resins. POLYM. COMPOS., 39:2081–2092, 2018. © 2016 Society of Plastics Engineers