PE/PP共混物热氧老化产物结构及老化过程研究

Study of products structure and process of thermal oxidative aging of PE/PP blends

乙丙共混物的热氧老化过程是一个复杂的过程,对于材料的应用有重要的影响。本文首先制备乙丙共混物,并对其进行了表征;通过逐步老化和快速老化2种老化方式研究共混物的变化规律和影响因素。结果表明,1)逐步老化过程首先产生羰基类化合物,生成的羰基化合物再进一步氧化转化为醚类;2)快速升温老化,聚合物容易分解成小分子挥发而产生较少积炭;而逐步升温老化,聚合物在缓慢分解同时可能继续交联碳化而产生较多积炭;3)乙丙共混物的老化变黑主要是由PE产生。

The thermal aging process of PE/PP blends is very complicated, which affects the use performance of material deeply. The PE/PP blends were prepared and then characterized by FT-IR spectra, at first. Secondly, their thermal oxidative aging processes and related influencing factors were discussed by using two aging methods--gradual aging and accelerated aging. The main results are as follows： 1.the carbonyl compounds are produced and then get further oxidized to ethers during the gradual aging process; 2. the polymers easily decomposed into the small molecular volatiles and produce a little carbon deposit during the accelerated aging, while during the gradual aging process the slow decomposition and crosslinking-carbonization reactions for the polymers might occur simultaneously, so the amount of produced carbon deposit is more; 3.the aging-blackening of the PE/PP blends is caused by the aging products of PE.