Ultraviolet-Initiated Curing of Natural Fiber-Reinforced Acrylated Epoxidized Soybean Oil Composites 05-14-04-0027

Sustainable practices are taking precedence across many industries, as evident from their shift towards the use of environmentally responsible materials, such as natural fiber-reinforced acrylated epoxidized soybean oil (NF-AESO). However, due to the lower reactivity of AESO, the curing reaction usually requires higher temperatures and longer curing time (e.g., 150°C for 6-12 h), thus making the entire process unsustainable. In this study, we demonstrate the potential power of photons towards manufacturing NF-AESO composites in a sustainable manner at room temperature (RT) within 10 min. Two photoinitiators, i.e., the 2,2-dimethoxy phenylacetophenone (DMPA) and 1-hydroxycyclohexyl phenyl ketone (HCPK), were evaluated and compared with the thermal initiator, i.e., tert-butyl perbenzoate (TBPB). Based on the mechanical performance of the AESOs, the photoinitiation system for NF-AESO was optimized. Further, NF-AESO was processed by incorporating three types of natural fibers, i.e., flax, areca, and coir, of different chemical compositions (e.g., the contents of cellulose and lignin). Our results suggest that the photoinitiation for NF-AESO favors natural fibers of low lignin content, which suppressed the photo-curability of the composite due to the photon-absorbing nature of lignin chromophores. Photo-cured NF-AESO typically exhibited superior tensile strength over their thermally cured counterparts.