The Effect of Pressure-Induced Flow (PIF) Processing on the Thermal Stability and Mechanical Properties of Ultra-High Molecular Weight Polyethylene (UHMWPE) Gel

A new method using gel-swelling state and pressure-induced flow (PIF) will be presented for obtaining high-performance materials of ultra high molecular weight polyethylene (UHMWPE), which is available for the production of high-strength and high-modulus materials. The effect of PIF on the thermal stability and mechanical properties UHMWPE gel state has been investigated using four kinds of gel formed from 4, 6, 8 and 10% of UHMWPE. The microstructures of UHMWPE gel were studied by using scanning electron microscope (SEM). The thermal and mechanical properties of the UHMWPE gel were investigated by thermogravimetric analysis (TGA), diffraction scanning calorimetry (DSC), dynamic mechanical analysis (DMA) and the universal test machine (UTM). The images obtained by SEM present a gel-like layers structure of UHMWPE gel sheet as a result of the deformation and re-arrangement of the gel sheets during PIF process. From the DSC, DMA and TGA results, we found that the thermal stability of the UHMWPE gel increased as the UHMWPE content increased. The thermal stability and the increase of strength are discussed with respect to the effect of PIF deformation.