双向应力场对HDPE1158分子取向结晶效果的影响

Effect of Two-Dimensional Compound Stress Field on the Molecule′s Orientation and Crystallization of HDPE1158

利用自行设计制造的剪切拉伸双向复合应力场挤管装置生产出了双向自增强的高密度聚乙烯(HDPE)管材。采用差示扫描量热法(DSC)和大角X射线衍射法(WAXD)研究分析了该双向应力场对HDPE1158分子的结晶效果和取向行为的影响。结果表明,剪切拉伸双向复合应力场能改善管材的结晶度、耐热性和分子的取向效果。结晶度从68.37%提高到81.86%,比常规管材提高了13.51%;结晶熔融潜热从200.3J/g提高到239.9J/g,比常规管材提高了39.6J/g;熔融峰向高温漂移了约1.5℃;熔程变窄了1.36℃;自增强管材轴周向上的分子取向效果都更好。

By shearing-drawing two-dimensional compound stress field die developed by the authors, two-dimensions self-reinforced high-density polyethylene（HDPE）1158 pipes were extruded. The effect of two-dimensional compound stress field on the molecule crystallization and orientation of these pipes was studied by differential scanning calorimetry（DSC） and wide-angle X-ray diffraction（WAXD） in this paper. The results show that the shearing-drawing two-dimensional compound stress field can improve the molecule crystallinity, heat-durability and orientation of these pipes. The crystallinity is increased by 13.51%, the enthalpy of melting（ΔHf ） is increased by 39.6 J/g , the melting point is increased by 1.5 ℃, the melting rang is narrowed by 1.36 ℃. Moreover, the axial and circular molecule orientation of these pipes is improved too.