纳米粒子的分散状态对聚丙烯结晶行为的影响

用普通熔融共混与低剪切应力场下聚合物/纳米粒子的分散共混方法制备出聚丙烯/无机纳米粒子复合材料,采用示差扫描量热法(DSC)与偏光显微镜(PFM)对试样的结晶行为进行研究发现:在填充粒子含量相同情况下,均匀分散的纳米粒子可以较大提高聚丙烯的结晶温度,结晶速率,使晶体尺寸减小,而普通熔融共混制备的试样中,纳米粒子虽然也一定程度增加了聚合物的结晶温度,却并不改变晶体的尺寸。结果表明,当制备聚合物/纳米粒子复合材料时,纳米粒子在基体中的分散程度极大地影响聚合物基体的结晶行为。

Effect of Nano-CaCO3 Particle Dispersion on the Crystallization Behavior of PP

The objectives of this paper are to study the crystallization behavior of nanometer calcium carbonate(nano-CaCO_3) particle-filled polypropylene(PP) composites prepared by different methods.Two systems are considered in the present study: the first one consists of PP/nano-CaCO_3 composite in which mild mixing is aimed at obtaining a PP matrix with particles dispersed in it at the nanometer lever.The second one is prepared by general melt blending,which should in principle result in some aggregations of nano-CaCO_3 particles in PP matrix.The nano-CaCO_3 dispersion state and crystallization behavior of composite were investigated.The results indicate that CaCO_3 nanoparticles make PP spherulite size reduced and crystallization temperature of PP enhanced when the particles are dispersed homogeneously.A smaller effect on the crystallization temperature and no effect on spherulite size of matrix can be achieved in the sample prepared by general melt blending.