聚丙烯/聚乙烯共混物的辐射凝胶生成动力学研究

本文研究辐照PP/HDPE共混物的溶胶生成分数s与辐照剂量R的关系,结果表明适用于某些纯聚合物辐射交联规律的Charlesby-Pinner关系式和陈-刘-唐关系式皆不适用于PP/HDPE共混体系。张万喜等人曾研究过许多纯聚合物的辐射交联,提出裂解度正比于R~β的假定,β是与高分子结构相关的参数,这个假定可与大多数聚合物的辐射交联实验数据符合。同样的假定被应用于本文的共混体系,不同的是根据共混物结构特点对R~β项进行了必要的修正,即共混物的R~β=∑f_iR~(βI),其中f_i,β_i分别为共混物第i组分的重量分数及β值。用修正后的R~β处理辐照PP/HDPE共混物的实验数据,R(s+√s)～R~β,有很好的线性关系。

A STUDY ON KINETICS OF GEL FORMATION OF POLYPROPYLENE/POLYETHYLENE BLENDS BY GAMMA RADIATION

In the present work, the relationship between sol fraction (s) and radiation dose (R) in radiation crosslinking of PP/HDPE blends was studied. The results indicate that both Charles-by-pinner expression and Chen-Liu-Tang expression, which were well applicable with radiation crosslinking of some polymers, do not well fit to the case of PP/HDPE blends.According to Zhang's assumption, which deals with relationship between structure and radiation crosslinking of pure polymers and applies to most cases, fracture density of polymer is proportional to Rβ,whereβ is a parameter depending on the structure of a polymer. In this paper, we extended their assumption to polymer blends, but the Rβ value of blends were modified by equation Rβ = fjRβi, where fi and βi are weight fraction and β value of i component in blend, respectively. Using the modified Rβ, good linear relation between R(s+s) and Rβ of PP/HDPE blends was obtained.