Improvement of poly(propylidene carbonate) mechanical properties by using stereocomplex crystals of polylactide to anchor graphene oxide at the interface of poly(propylidene carbonate)/poly(L-lactide) blends

Abstract

To improve the weak strength of biodegradable poly(propylidene carbonate), blending with the both biodegradable polylactide is very effective if they can form good interfaces. Nanoparticles can impart their superior properties on the matrix as well as enhance the interface of the blends. However, anchoring nanoparticles at the interface and avoidance of nanoparticles transferring into the continuous phase or dispersed phase during varied processing are still a challenge. Poly(D-lactide) (PDLA) was grafted onto GO and added into poly(propylidene carbonate)/polylactide (70/30) blend to solve this problem. By investigating the structures of solution cast film samples and melt processing samples, it was demonstrated that GO was anchored at the interface of the blends, which decreased the sizes of dispersed phase. Atomic force microscope investigations found that the interfacial width increased with the increase in PDLA-g-GO contents. Consequently, the mechanical properties were significantly improved. In particular, the tensile strength and Young’s modulus of the solution cast film samples with loading 10 wt% PDLA-g-GO increased by 310% and 226%, respectively. According to the shifting glass transition temperature (Tg) of PPC and PLLA phase, it was deduced that the rigid interfacial phase of PDLA-g-GO linked both PPC and PLLA and played compatibilizer. Therefore, it is expected to deepen the understanding of the compatibilization mechanism of nanoparticles and promote the usages of biodegradable materials.