熔体温度对HDPE微制品结构及性能的影响

Effect of Melt Temperature on the Structure and Property of HDPE Microparts

采用微注塑成型技术,在不同熔体温度下制备高密度聚乙烯(HDPE)微制品。通过拉伸测试考察了熔体温度对力学性能的影响,并利用差示扫描量热法(DSC)、广角X射线衍射(WAXD)、小角X射线散射(SAXS)和扫描电子显微镜(SEM)对制品的微结构变化进行系统研究。结果表明:随着熔体温度的升高,shish结构和shish-kebab晶体的数量增加,制品的结晶度增加,分子链和片晶取向程度增大;取向度和结晶度的增加是HDPE制品拉伸强度和模量随熔体温度升高而增加的主要原因。

The high density polyethylene（HDPE） microparts were prepared by micro-injection molding under different melt temperature. Dependence of mechanical properties of samples on melt temperature was examined by tensile test. The microstructure characterizations, including differential scanning calorimetry（DSC）, wide-angle X-ray diffraction（WAXD）, small-angle X-ray scattering（SAXS） and scanning electronic microscope（SEM） were performed to systematically investigate the variations of microstructure. The main results are as follows： more shish and shish-kebab structure are formed with increasing of melt temperature; the crystallinity as well as molecular and crystalline orientation increases with increase of melt temperature, which are beneficial to the the improvement of strength and modulus.