口模拉伸共聚高密度聚乙烯的动态力学分析

DYNAMIC MECHANICAL BEHAVIOR OF COPOLYMERIZED HDPE BY DIE DRAWING PROCESS

共聚 HDPE的 DMA结果表明 ,β松弛峰是以往均聚 HDPE所没有的 ,它应归属于共聚 HDPE中丁基的运动。随着拉伸比的增大 ,γ峰的强度变弱 ,非晶区的有序化程度提高。α松弛则是一个多重转变过程 ,代表球晶结构中的颗粒疆界或层状片晶之间滑移运动 α3的退化 ,以及代表纤维结构微原纤或原纤之间折叠区运动的 α1的强化 ,从分子运动的角度反映了共聚 HDPE经口模拉伸后由球晶结构向纤维结构的转变。

The result of DMA for HDPE copolymer after drawing in the die showed that there was a β-relaxation peak present in the drawn filament. This was not observed on the normal HDPE homopolymer. Thus, it should belong to the motion of butyl in the HDPE copolymer. The intensity of γ-relaxation peak weakened and the ordering degree of the noncrystalline region rose with the increase of the draw ratio. α-relaxation was a multiple transition process, while the strengthening of α 1 which represented the motion of the folded regions between microfibrillars or fibrillars in the fibre structure and the weakening of α 3 which represented the slip motions between microspherulite boundary layers or lamellas of laver shape in the spherulite structure, reflected the transformation of HDPE copolymer from spherulite to fibre structure after the drawing from the point of view of molecular motion.