Enhancement of mechanical properties of ultra-high molecular weight polyethylene nanocomposites without losing thermal stability

摘要

This study involves the development of individual and hybrid nanocomposites and their structural, thermal, and mechanical characterization, using wear-resistant fillers like aluminum oxide (Al2O3) and boron carbide (B4C) in a high-performance polymer, namely, ultra-high molecular weight polyethylene (UHMWPE). Nanocomposites were produced by ball milling followed by hot-pressing molding, using vitamin E as an antioxidant agent. Fourier transform infrared spectroscopy and x-ray diffractometry revealed no interaction at the molecular level between the phases. Optical microscopy evidenced a network formed by the nanoparticles surrounding the polymeric grains in the nanocomposites structure. Field emission scanning electron microscopy and confocal Raman spectroscopy helped understand this morphology. The mixing process results in a polymeric powder covered by the nanometric particles with a superficial interaction. Thermogravimetric analysis and differential scanning calorimetry were able to show the stability of the polymeric matrix, even with the presence of the nanofillers, which is possible due to the nanocomposites' structure. The produced nanocomposites present enhancement of their mechanical properties as compared to the pure polymer, evidenced by indentation tests. This work shows that UHMWPE can be manipulated to suit industrial applications that demand good mechanical reinforcement without losing thermal stability.