成型温度对脉振模压成型自增强UHMWPE结构与性能的影响

Influence of Molding Temperature on Structure and Property of Self-Enhancement UHMWPE Molded by Pulse Vibration Molding

在远低于普通模压(CM)成型温度的温度下,采用脉振模压(PVM)成型实现了自增强超高分子量聚乙烯(UHM-WPE)制品的低温高效成型。通过拉伸性能、耐磨性能、流变性能、差示扫描量热分析、扫描电镜、原子力显微镜、红外光谱等测试表征,分析了成型温度对PVM成型UHMWPE(PVM-UHMWPE)样品宏观性能和微观结构的影响规律。结果表明,PVM的低温成型能保留UHMWPE部分初生相特征结构,提高了整体结晶度和晶片厚度,赋予了PVM-UHMWPE样品更高的力学强度和抵抗磨损能力;随着成型温度的提高,分子链在颗粒界面处的扩散程度增加,并形成垂直于颗粒界面的“纤维状”晶相提高了PVM-UHMWPE样品的界面固结质量,但当成型温度达到180℃时,对初生相结构的破坏加剧,致使整体结晶度和晶片厚度降低,反而弱化了样品力学强度和耐磨性能。因此,成型温度为170℃的PVM-170℃-3Hz样品具有最好的力学性能和耐磨性能。

Low-temperature efficient molding of self-enhancement UHMWPE products was achieved by pulse vibration molding(PVM)at temperature far lower than that of compression molding(CM).The influence rule of molding temperature on the macroscopic properties and microstructure of UHMWPE samples molded by PVM(PVM-UHMWPE)were analyzed and clarified by tensile properties,wear resistance,rheological properties,DSC,SEM,AFM and FT-IR.The results show that with the structural characteristics of UHMWPE nascent phase retained by low-temperature molding of PVM,the overall crystallinity and lamellae thickness were increased,and the mechanical strength and wear resistance of PVM-UHMWPE samples were enhanced.With the increase of molding temperature,the diffusion degree of molecular chains at particles interface increases,and the formation of fibrous crystal structure perpendicular to the interfaces at particle interfaces can effectively promote the interfaces fusion and improve the quality of consolidation for PVM-UHMWPE samples.However at the molding temperature of 180℃,the structure characteristics of UHMWPE nascent phase can be seriously damaged,which reduces the crystallinity and lamellae thickness,and makes the mechanical strength and wear resistance of PVM-UHMWPE samples decline.Therefore,PVM-170℃-3 Hz samples with the molding temperature of 170℃have the best mechanical properties and wear resistance.