共聚聚丙烯(cPP)/线型低密度聚乙烯(LLDPE)共混体系的流变与结晶形为

Rheological Behavior and Crystallization Morphology Of cPP/LLDPE Blend

用毛细管流变仪研究了共聚聚丙烯(cPP)与线型低密度聚乙烯(LLDPE)共混物熔体的流变行为。讨论了共混物的组成、切应力和剪切速率对熔体流变行为和熔体粘度的影响。测定了不同配比共混物熔体的非牛顿指数。结果表明:共混物熔体属假塑性流体,但共混体系粘度随LLDPE加入量的增加变化不大。DSC结晶曲线及扫描电镜(SEM)照片表明,LLDPE的加入使cPP的结晶温度变化不大,但对晶体形态有一定影响。LLDPE对cPP有一定的增韧改性作用,当LLDPE质量分数为1 5%时,共混物的冲击强度增幅在4 0 %左右,而拉伸强度保持率为80 %。

s: The melt rheological behavior of cPP/LLDPE blend were studied by means of capillary rheometer. The influences of the composition of the blends, shear stress and shearing rate on melt rheological behavior and melt viscosity were discussed. The non-Newtonian index of the melt was measured.Results showed that cPP/LLDPE blends were pseudoplastic fluid, the melt viscosity of the blend changed little with the increase of LLDPE content. DSC and SEM experiments showed that the addition of LLDPE made the crystallization temperature of cPP changed little, but had effect on the crystalline morphology. LLDPE had toughening effect on cPP, when the mass fraction of LLDPE was 15%, the notched impact strength increased about 40%, while the tensile strength of cPP remained over 80%.