Improved compatibilization and shape memory properties of poly(3-hydroxybutyrate-co-3-hydroxyvalerate)/poly(ethylene-co-vinyl acetate) blends by incorporation of modified reduced graphene oxide

Reduced graphene oxide modified with vinyl laurate (rGO-VL) was incorporated to extruded blends of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and poly(ethylene-co-vinyl acetate) (EVA) at different compositions. X-ray diffraction analyses showed decrease in crystallinity for the PHBV/EVA/rGO-VL hybrids in relation to the neat blends. Scanning electron microscopy images and dynamic mechanical analyses (DMA) indicated that well-dispersed rGO-VL sheets contributed to the blends compatibilization. DMA results revealed improved flexibility as the rGO-VL content was increased. Differential scanning calorimetry showed that EVA and rGO-VL acted synergistically to reduce PHBV crystal size. Tensile tests showed increased flexibility for PHBV/EVA/rGO-VL hybrids. Cyclic shape memory tests and folding-unfolding shape recovery tests revealed enhanced shape memory properties. For the PHBV/EVA blends at 50:50 and 25:75 compositions, the recovery rate (Rr) values were (83.1 ± 7.4)% and (70.3 ± 6.2)%, respectively. With the addition of rGO-VL at 1.0 mass%, Rr values higher than 97.0% and a shorter recovery time of ~ (3.8 ± 1.7) s were achieved. [Display omitted] •Vinyl laurate-modified GO was synthesized and characterized for the first time.•The product (rGO-VL) was proved to be suitable to compatibilize PHBV and EVA.•New shape memory materials, based on PHBV, EVA and rGO-VL, were developed by melt extrusion.•PHBV/EVA blend composition and rGO-VL dispersion were correlated with shape memory properties.•PHBV/EVA/rGO-VL hybrids presented improved shape memory properties.