聚甲醛/热塑性聚氨酯弹性体在双螺杆挤出机共混中相形态的形成机理

Formation Mechanism of Thermoplastic Polyurethane(TPU) Morphology in Polyoxymethylene(POM) Matrix Blended in Twin-screw Extruder

聚甲醛(POM)和热塑性聚氨酯弹性体(TPU)于不同温度下在双螺杆挤出机中共混,用扫描电镜(SEM)考察了共混试样的相形态,并对试样分散相粒径进行了统计,研究了分散相粒径随加工温度的变化。发现摩擦剪切机理可以很好地解释双螺杆挤出机共混中TPU分散相粒径的形成过程,利用该机理可有效控制POM/TPU共混物相形态,得到了比母料法还好的共混效果,进一步提高了POM/TPU体系的冲击性能。

Polyoxymethylene （POM） and thermoplastic polyurethane elastomer （TPU） were blended in twin-screw extruder. The morphologies of the specimens blended at different processing temperature were investigated using scanning electron microscopy （SEM）. To study the influence of processing temperature on the morphology, the size of dispersed phase was compared by means; of statistical method. It was found that the formation of the TPU morphology in POM matrix bended in twin-screw extruder can be explained by the abrasion mechanism, according to which the morphology of TPU in POM matrix can be effectively controlled and the toughening effect of TPU on POM can be farther improved. When POM and TPU were blended in extruder at 175℃, the blending effect was better than master batch method, and the notched impact strength of POM/TPU blends was further enhanced.