SiO2-covered graphene oxide nanohybrids for in situ preparation of UHMWPE/GO(SiO2) nanocomposites with superior mechanical and tribological properties

The modified Hummer technique was used in the preparation of graphene oxide (GO) nanosheets, and then SiO2 decorated GO [GO(SiO2)] nanosheets were synthesized via the sol-gel method. Then, ultrahigh-molecular-weight polyethylene (UHMWPE) nanocomposites loaded with 0.5, 1, 1.5, and 2wt % of GO(SiO2) were prepared using magnesium ethoxide/GO(SiO2)-supported Ziegler-Natta catalysts via the in situ polymerization. Morphological study of the prepared polymer powders was assessed using field-emission scanning electron microscopy, which showed that GO(SiO2) nanohybrids have been uniformly dispersed and distributed into the UHMWPE matrix. Also, the neat UHMWPE and its nanocomposites were evaluated with different analyses, including viscosity-average molecular weight measurement, differential scanning calorimetry, thermogravimetric analysis, tensile test, scratch hardness, and pin-on-disk test. The characterization of the UHMWPE nanocomposites indicated that many characterizations, including the mechanical, thermal, and tribological properties of UHMWPE, were significantly improved by incorporation of these new nanosheets in spite of the molecular weight reduction of the polymeric matrix and the improved flowability and processability of the produced nanocomposite. (c) 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47796.