Studies On Characterization Methods And Properties Of Ultra-high Molecular Weight Polyethylene

The application of UHMWPE molding technology was studied to establish the influence factors and experimental models with proper UHMWPE raw materials selected by their viscosity average molecular weights. The crystallization of UHMWPE after molding was analyzed through differential scanning calorimetry (DSC), simple double notched impact tests and mortar abrasion tests were also used to study the mechanical properties of molded UHMWPE; as well as the morphologies of UHMWPE fracture surfaces were observed by scanning electron microscopy (SEM) after charpy impact tests, and wear surface after the mortar abrasion tests.The molding mechanism of UHMWPE was verified in this topic to determined that temperature was the main influence factors of molding, such as at about210℃the declines of impact properties and crystallization properties of the molding materials decreased by oxidative degradation. Under the same experimental process, the narrower molecular weight distribution was, the higher crystallinity of UHMWPE was; the higher molecular weight and the more regular structures of UHMWPE were, the higher crystallinity but the worse impact performances were.After researching the wear properties of the mortar abrasion influenced by the runoff directions of cooling water, quartz sand type and test speed, the results showed that the cooling water in parallel improved the stability of mortar abrasion experiments, quartz sands with high hardness could improve abrasion efficiency, and the test speed of1300r/min could avoid the fretting wear and reach desired wear quantities. The narrower molecular weight distribution of UHMWPE was, the more stable the wear resistance was under constant experimental conditions; as well as the higher molecular weight and higher entanglement degrees of UHMWPE were, the better wear resistance was. Cooling water of low temperature could effectively reduce the UHWMPE surface thermal softening and degradation by speeding up the transfer of the energy to inhibit the formation of lubrication layer in wearied surface, and to improve the wear rate of materials.