γ-辐射对聚丙烯及聚丙烯/聚乙烯共混物结晶熔融行为的影响

<正> 近年人们对于聚丙烯(PP)辐射效应的研究与日俱增,主要目的在于寻求增强PP辐射稳定性的有效途径。迄今为止文献报道的方法有:添加小分子游动剂(mobilizing addi-tives)、抗氧剂、多官能团单体等,笔者曾研究过不同晶型和含少量聚乙烯(PE)链

RADIATION EFFE CT ON THE MELTING BEHAVIOURS OF POLYPROPYLENE/POLYETHYLENE BLENDS

In the present work, the crystalline morphology of polypropylene/high density polyethylene (PP/HDPE) was observed by the method of polarized light micrography(PLM),and the melting behaviour was in vestigated by differential scanning calorimetry. It has been shown that the incorporation of HOPE resulted in decreasing the regularity degree of PP spherulites and forming some defection in the crystalline region. It was also found that Y-irradiation strongly affected the crystallinity of PP/HDPE blends. The melting point and crystallinity of PP and /or HDPE in the blends decreased with radiation dose. The crystallinity of pure PP wasn't noticeable changed and that of pure HDPE increased with radiation dose. The more the blends contained HDPE, the faster the melting point and crystallinity of PP decreased, but pure PP showed a relatively faster decreased in the melting point than in the PP/HDPE blends. The results might reveal that radiation induced chain scission mainly took place in PP crystalline regions, especially in the imperfect regions.