Good dispersion of poly(δ-gluconolactone)-grafted graphene in poly(vinyl alcohol) for significantly enhanced mechanical strength

Abstract

Here, we presented a straight forward and new approach for designing the interfacial compatibility between polyvinyl alcohol (PVA) and graphene sheets. The synthesis of poly(delta-gluconolactone) grafted from reduced graphene oxide (PGL-g-rGO) has been primarily developed by the ring-opening polymerization (ROP) of the green delta-gluconolactone monomer. The structure of PGL-g-rGO was fully confirmed using 1HNMR, XRD, FTIR, UV/Vis spectroscopy, TGA, and SEM. Poly(delta-gluconolactone) was expected to have a dual function of an efficacious modifier and a reducing agent for graphene oxide. Hence, the addition of PGL-g-rGO as a filler into PVA polymer was done into different mass ratios to obtain high-performance polymer nanocomposites. The dispersion and interfacial interaction of PGL-g-rGO sheets with the PVA matrix were studied. The thermal behavior, mechanical properties, and surface wettability of the final PVA nanocomposites were also evaluated. It can be observed that the char yield and the initial decomposition temperature of PVA were considerably enhanced after the addition of PGL-g-rGO to the polymer besides, the mechanical properties were totally improved. The use of PGL-g-rGO with only a mass ratio of 1.5% results in increasing the tensile strength and Young's modulus of PVA polymer by 124 and 121%, respectively. The elongation at break was uncommonly increased from 93 to 251% because of the formed strong hydrogen bonding between the filler and the polymer which can't only work on the efficacious convey of stress from PVA to reduced graphene sheets but also facilitate the polymer crystallization.