聚丙烯与聚氨酯共混物结晶的研究

本文用解偏振光强度测定(DLI)、差示扫描量热(DSC)、偏光显微镜(PLM)及激光小角散射(SALS)等方法研究了聚丙烯(PP)与聚氯酯(PU)共混物的等温结晶动力学及其结晶形态。结果表明,共混物中PP的结晶过程可由Avrami方程很好地描述;Avrami指数n及全程结晶速率常数均与组成有关。部分非晶的PU作为成核剂参与PP的结晶过程;当PU含量高于20％时,由于其聚集成较大的颗粒,而对结晶起阻碍作用,PP的球晶形态也受到破坏。

CRYSTALLIZATION OF BLENDS OF POLYPROPYLENE AND POLYURETHANE

The isothermal crystallization kinetics and morphology of blends of polypropylene and polyurethane have been studied by means of depolarized light intensity, differential scanning calorimetry, polarizing light microscopy, wide angle X-ray scattering and small angle light scattering measurements. It was found that the isothermal crystallization of PP in the blends can be well described by Avrami equation and both Avrami exponent n and crystallization rate constant k were composition dependent. The non-crystalizablc PU may partly act as nucleating agent during crystallization of PP in the blends, however, the PU droplets tended to form domains duc to coalescence as the content of PU was more than 20 wt%, which inhibited the crystallization and causcd a remarkable destruction of the spherulites of PP in the blends.