退火与非退火测定聚乙烯密度的研究

Determination of Density of Polyethylene by Annealing and Non-annealing Methods

采用密度梯度柱法,对不同牌号的高密度聚乙烯颗粒和同一牌号的颗粒和粉末分别进行了退火和非退火实验的密度测定,并对得到的密度数据进行了处理和分析。结果表明,退火后测定的密度与非退火测定的密度存在密切关系,非退火密度偏小,两者之间的差值在0.002~0.003之间。同时对比了不同牌号颗粒及同一牌号颗粒与粉末的结晶度,退火后比退火前结晶度约增加3%。

The annealing and unannealing experiments were taken for different types of linear light densitypolyethylene and the same type of the polyethylene＇s particle and powder by using the density gradient column method,and the data of density was analyzed. The results indicated that the difference of density between annealing andunannealing experiments was in the range of 0. 002 to 0. 003, non-annealing density was smaller. At the same time,compared the different grades of particles and the same grade particles and powder crystallinity, after annealing, thedegree of crystallinity increased about 3 %.