小角X射线散射法测定高密度聚乙烯微观结构随温度的变化  

Small Angle X-Ray Scattering Measurements of HDPE Microstructure Evolution with Temperature

作　　者：海洋[1,2] 柳义[1] 陈西良[3] 黄灿[1,2] 刘崎[1] 林俊[1] 朱智勇[1] 

机构地区：[1]中国科学院上海应用物理研究所,上海201800 [2]中国科学院大学,北京100049 [3]黄河水利职业技术学院,河南开封475004

出　　处：《高分子材料科学与工程》2015年第9期117-121,126,共6页Polymer Materials Science & Engineering

基　　金：国家自然科学基金资助项目(11175235);国家基础研究计划项目(子课题2010CB832903)

摘　　要：利用同步辐射装置在不同温度下对高密度聚乙烯(HDPE)进行小角X射线散射测量,并通过对散射数据的洛伦兹(Lorentz)变换、一维相关函数和积分不变量的分析,研究HDPE的片晶结构随温度的变化规律。研究结果表明,在100℃以下时,HDPE的长周期结构不随温度发生变化,但片晶内部非晶区厚度略有增加而晶区厚度略有减小,相应的线性结晶度由30℃的79%减小到100℃时的74%。当温度升至110℃以上时,随着温度的升高,晶区、非晶区和片晶的尺寸均明显增大。当温度升至110℃以上时,随着片晶的熔化,片晶份额的减小导致散射强度降低。实验确定120℃时的片晶份额是原有的95%左右,而在130℃时,片晶份额仅剩余61%。Microstructure variation of high density polyethylene （HDPE） in the temperature range from room temperature to 150 ℃ was investigated in situ by small angle X-ray scattering （SAXS） technique at Shanghai synchrotron radiation facility. SAXS curves and their Lorentz corrections show that below 120 ℃, the scattering intensity increases with increase of temperature and the scattering peak shifts slightly towards smaller scatter vector direction. At temperatures above 130 ℃, the scattering intensity decreases drastically and the character scattering peak that is related to long period structure of HDPE reduces in intensity and disappears completely above 140 ℃. One-dimensional correlation function of the measurements reveal that at temperatures below 100 ℃ the long period of HDPE shows no change with temperature while the thicknesses of crystalline and amorphous layers show slight decreasing and increasing, respectively, with increase of temperature. Above 110℃ the long period, the thickness of crystalline layer as well as the thickness of amorphous layer increase strongly with increase of temperature. The corresponding linear crystallinity decreases gradually from about 79% at 30 ℃ to about 69% at 130 ℃. Integral invariant analysis through correction of contributions from crystallinity and thermal expansion reveals that the fraction of lamellar stacks is close to 100 % at room temperature and shows no change with temperatures up to 110 ℃. With further increase of temperature, the lamellar stack fraction decreases sharply from about 95 % at 120℃ to about 61% at 130 ℃.

关 键 词：小角X射线散射 高密度聚乙烯 片晶结构 一维相关函数 积分不变量 

分 类 号：TQ325.12[化学工程—合成树脂塑料工业]