High Performance and Thermal Processable Dicarboxylic Acid Cured Epoxidized Plant Oil Resins through Dynamic Vulcanization with Poly(lactic acid)

Abstract

Dicarboxylic acid (DA) cured expoxidized soybean oil (ESO) resins are nonprocessable and usually exhibit low mechanical performance, which significantly restrict the application of these sustainable materials. In this study, we report a facile and efficient way of endowing these thermosetting ESO resins with high performance and thermoplasticity via dynamic vulcanization of ESO with sebacic acid (SA) and poly(lactic acid) (PLA). A phase-separated morphology with vulcanized ESO resin (VESO) dispersed in PLA matrix was formed for the dynamically vulcanized blends even with the content of VESO as high as 80 wt %. Rheological analysis indicated that the obtained VESO/PLA blends showed good melt processability as evidenced by the low complex viscosity at high frequency range. The blend contained 80 wt % cross-linked VESO could also be injection molded. The tensile strength and Young’s modulus of VESO were improved by ∼11 and ∼16 times after incorporation of only 20 wt % PLA and could be further increased by ∼39 and ∼103 times with increasing PLA’s content to 50 wt %. Furthermore, the VESO/PLA blends showed high toughness with large tensile strains although both VESO and PLA showed brittle characters. With excellent mechanical properties and thermal processability, the dynamically vulcanized ESO resins would find wider potential applications than the low performance and thermosetting ESO resins.