Ethylene-vinyl acetate/poly (propylene carbonate) nanocomposites: effects of graphene oxide on microstructure, shape memory, and mechanical characteristics

Abstract

The present study aims to introduce new shape memory composites containing different nanofillersincludingreduced graphene oxide nanoplatelets (rGOnp), graphene oxide nanoplatelets (GOnp), and their hybrids (rGOnp/GOnp)andbased on ethylene-vinyl acetate copolymer, polypropylene-graft-maleic anhydride, and polypropylene carbonate (EVA/PP-g-MA/PPC). The morphologies of the synthesized nanocomposites were studied by transmission electron microscopy (TEM) and scanning electron microscopy (SEM), which showed that adding GO/rGO hybrid made better uniformity in the matrix rather than GO and rGO. Thermal gravimetric analysis (TGA) indicated that by adding nanofiller into the nanocomposites, the melting temperature (Tm) increased from 68.7 °C to 70.9 °C, while the glass transition temperatures (Tg) decreased from 33.1 °C to 30.6 °C. In addition, mechanical analysis illustrated that by adding nanofiller to the matrix, the breaking stress, modulus, and elongation-at-break increased about 321%, 193%, and 145%, respectively. Moreover, in the composites containing rGOnp/GOnp, the shape recovery and shape fixity enhanced in comparison with their rGOnp and GOnp counterparts. Therefore, the results revealed that the shape memory EVA/PP-g-MA/PPC mixture, including a hybrid of GOnp and rGOnp, has a high actuation value, superior mechanical strength, and excellent shape fixity. Finally, the obtained shape fixity of 98.7% and shape recovery of 95.9% for the synthesized samples are the best shape memory characteristics for the hybrid nanocomposites.