无规立构聚丙烯对全同立构聚丙烯流延基膜取向片晶结构及拉伸成孔性的影响  

Influence of a-PP on Oriented Lamellar Structure of PP Casting Film and Its Performance of Micropore Formation by Uniaxially Stretching

作　　者：杨兴成[1] 沈鹏[1] 俞强[1] 

机构地区：[1]常州大学材料科学与工程学院江苏省太阳能电池材料与技术重点实验室,江苏常州213164

出　　处：《高分子材料科学与工程》2015年第6期60-65,共6页Polymer Materials Science & Engineering

基　　金：江苏省太阳能电池材料与技术重点实验室资助项目

摘　　要：将无规立构聚丙烯(a-PP)与全同立构聚丙烯(i-PP)共混改性树脂在一定流延工艺条件下制备流延基膜,经过热处理后施加单向拉伸作用使流延基膜转变为微孔膜;通过差示扫描量热分析、红外光谱、原子力显微镜及力学性能、孔隙率和透气率测试来表征流延基膜的取向片晶结构和微孔膜的孔结构。研究了添加无规立构聚丙烯对全同立构聚丙烯流延基膜取向片晶结构及拉伸成孔性的影响。结果表明,流延基膜中含有少量a-PP可以增强i-PP链段的运动能力,促进分子链沿牵伸方向取向,从而使流延基膜冷却结晶过程中形成的取向片晶结构比较完善。但是当流延基膜中含有较多aPP时,其稀释作用和对链段松弛的促进作用使结晶度以及晶区和非晶区取向程度下降。热处理后流延基膜的取向片晶结构进一步改善,相对于未改性流延基膜,含少量a-PP流延基膜在120℃热处理可以取得未改性流延基膜在145℃热处理的效果。含少量a-PP流延基膜拉伸制备的微孔膜具有较大的孔隙率和透气率,但是随着流延基膜中a-PP含量增加,拉伸后制备的微孔膜孔隙率和透气率均下降。PP precursor films with different contents of atactic polypropylene were prepared through casting process.After annealed under certain conditions,the precursor films were stretched uniaxially to develop micropores membranes.The oriented lamellar structure of the precursor was characterized by DSC,FT-IR,AFM and mechanical properties.The pore structure of the microporous membrane was characterized by porosity and permeability.The results show that small amount of a-PP in the precursor film could enhance moving ability of PP segment,and promote chain orientation along the drawing direction,giving rise to a more perfect oriented lamellar structure in the precursor films.However,more a-PP in the precursor will dilute the crystalline molecules,and promote segment relaxation,leading to decreased crystallinity and lamellar orientation in both crystalline and amorphous regions.Oriented lamellar structure of precursor films is further improved after annealing.The oriented lamellar structure in the precursor film that m(a-PP)/m(i-PP)=2/98 and is annealed at 120℃is almost same perfect as in the precursor film that is without a-PP and is annealed at 145 ℃.The microporous membrane obtained by stretching precursor film with small amount of a-PP has a higher porosity and permeability.However,as a-PP content is increased in the precursor film,the porosity and permeability are decreased.

关 键 词：聚丙烯流延基膜 无规立构聚丙烯 取向片晶结构 硬弹性 拉伸成孔性 

分 类 号：TQ325.14[化学工程—合成树脂塑料工业]