Manipulation of mechanical and thermal properties of graphene oxide/nanoclay/unsaturated polyester hybrid nanocomposites by the surface chemistry and nanofiller composition

Dispersion of platelet-like nanominerals in low-viscous resins is a serious challenge; which arises from the strong interactions among the large surface area of the layers. Herein, we improved the dispersion of graphene oxide (GO) within unsaturated polyester (UP) resin and synergistically enhanced the mechanical and thermal prop-erties of the resulting nanocomposites. In a multi-stage manner, GO was incorporated into a novel hybrid structure before adding to the polymer matrix alongside with benefited from the advantage of surface func-tionalization. Functional hybrid nanofiller skeletons comprising GO and nanoclay (NC) were designed and prepared at different composition ratios (25:75, 50:50 and 75:25) and different surface chemistries via modifi-cation with two thermal-resistant silane coupling agents, namely (3-Aminopropyl) triethoxysilane (APTES) and 3-(trimethoxysilyl) propyl methacrylate (MPS). The optimal loading of different hybrid structures into UP has been examined by applying three loading levels (0.25, 0.50 and 1.00 wt%). The results indicated the synergistic effects of GO and NC on the mechanical properties of UP, where the composition ratio of the hybrid constituents played a key role. Moreover, it was demonstrated that the range of composition ratio for the realization of synergistic reinforcement is strongly affected by the surface chemistry of the GO and NC. For UP matrix rein-forced with APTES-modified hybrid nanofillers of GD:CD at 50:50 w/w composition, a higher tensile modulus compared to blank UP (approximate to+21.5%) was obtained due to boosted dispersion of nanoplatelets in UP matrix. The results of DMTA and TGA analyses suggested that there are two different UP/GO and UP/NC interfacial in-teractions in the composites containing unmodified hybrid nanofillers. However, after modification of hybrid nanofillers, the homogeneous dispersion of nanoplatelets boosted the interfacial interactions between nanofillers and polymer, such that higher properties were obtained.

Automated summary

Improving the dispersion of graphene oxide (GO) in unsaturated polyester (UP) resin enhances the mechanical and thermal properties of the resulting nanocomposites. Functional hybrid nanofillers comprising GO and nanoclay (NC) were designed and prepared with different composition ratios and surface chemistries. The modified hybrid nanofillers achieved better dispersion and interfacial interactions, leading to improved properties of the nanocomposites.