Thermal Softening and Degradation of UHMWPE Composites: Effect of Melting Process

• Published in: Journal of applied polymer science 2025-01
• Main Authors: Zhang, Run, Niu, Kai, Tian, Jing, Liu, Mingfei, Hua, Zetian, Jiang, Lin, Fu, Chenchao
• Format: Article
• Language: English
• ISSN: 0021-8995; 1097-4628
• DOI: 10.1002/app.56688

This study investigates the effect of gradual melting process for crystallization zone on the thermal softening and degradation properties of ultra‐high molecular weight polyethylene (UHMWPE) composites. The results of the differential scanning calorimetry test indicate that UHMWPE composites exhibit an initial melting endotherm at low temperatures. UHMWPE composites show significant differences in storage and loss modulus at room temperature, but both values decline sharply with increasing temperature. The data reveals that the discrepancy in temperature values at a specified melting percentage is negligible (≤ 4°C). Thus, thermal softening is more significantly influenced by percentage of crystalline melting than by crystallinity. Most samples' vicat softening temperature (VST) values align with the melted temperature of about 50% crystalline regions. Furthermore, the VST curves show a notable displacement increase at 120°C, corresponding to a melting percentage of about 20%. The heat deflection temperature (HDT) values for UHMWPE composites range from 61°C to 67°C, aligning with the initial melting temperature with no significant variation. Moreover, the melting of crystalline regions does not influence thermal degradation, due to the significant gap between melt and degradation temperatures. This study reveals new understanding of thermal softening and degradation in semicrystalline composites.