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

Abstract

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 2 wt % 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. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47796.

Influence of processing conditions on microstructural, mechanical and tribological properties of graphene nanoplatelet reinforced UHMWPE

“…Wear rate was calculated by summing the two contributions, M+L, and also by considering only the area M. Since the results were qualitatively the same, as we see in the next paragraph, hereinafter, we will refer to results obtained using M as the wear rates. The first finding was the difference in wear rate for the neat UHMWPE prepared by each of the blending processes: 20x10 -7 mm 3 /Nm in the case of ball milling, consistent with previous data in the literature (Haddadi et al, 2019;Puértolas et al, 2010) for the same experimental conditions and counterpart material, and 37x10 -7 mm 3 /Nm for blade mixing. This effect could be related to the powder size of the particle before the hot consolidation, since the only morphological difference observed in the analysis of the particle distribution by SEM was a small thickening of the PE particles when using the blade mixer (Figures 1g and 1i).…”

“…On the other hand, it is recognised in the field (Puértolas and Kurtz, 2014) that, in general, a low concentration of graphene fillers helps to enhance toughness, but that above a critical J o u r n a l P r e -p r o o f value, the formation of GNP aggregates decreases toughness as consequence of a stress concentration effect. This correlation between toughness and wear rate is clear in systems with a good aggregation-free dispersion due to the functionalization of the filler (Haddadi et al, 2019). As a result, all this could explain the appearance of the minimum The other processing condition investigated in this study was the use of higher temperatures (from 175 °C up to 240 °C) during the hot-compression moulding.…”

SiO2 modified graphene oxide hybrids for improving fretting wear performance of ultra-high molecular weight polyethylene

“…Therefore, the wear mechanism of G/UPE was abrasion. SiO 2 and hybrids of SiO 2 -GO could enhance both the thermal and mechanical performance of UHMWPE (Haddadi et al, 2019). The improved thermal properties alleviated the plastic deformation.…”

Thermal Degradation Kinetics and Modeling Study of Ultra High Molecular Weight Polyethylene (UHMWP)/Graphene Nanocomposite

“… Scanning electron microscope (SEM) image of the fracture surface of ( a ) neat UHMWPE [ 37 ], and ( b ) UHMWPE/graphene 2.1% nanocomposite. …”