聚丙烯流延膜厚度对结晶取向及力学性能的影响  

The effect of the thickness of polypropylene cast film on crystallization,orientation and mechanical properties

作　　者：姚雪容[1] 任敏巧 郑萃 贾雪飞[1] 盛建昉[1] 唐毓婧[1] Yao Xuerong;Ren Minqiao;Zheng Cui;Jia Xuefei;Sheng Jianfang;Tang Yujing(Sinopec Beijing Research Institute of Chemical Industry,Beijing 100013,China)

机构地区：[1]中国石化北京化工研究院,北京100013

出　　处：《石油化工》2020年第6期557-564,共8页Petrochemical Technology

摘　　要：通过改变进料螺杆转速得到不同厚度的聚丙烯流延膜,采用WAXD、DSC、SALS和双折射等方法研究了厚度对流延膜的结晶、取向以及力学性能的影响。实验结果表明,在辊温50℃下,厚度32~109μm流延膜的晶型以介晶为主,同时含少量α晶,且仍能形成球晶;流延膜越薄球晶尺寸越小,此时流延膜的拉伸、撕裂和穿刺强度不随厚度显著改变。当厚度减薄至11μm时,流延膜的晶型以α晶为主,结晶度略有增加,晶粒、球晶和整体的取向度均显著增大,沿流延方向的拉伸屈服强度和弹性模量,垂直流延方向的撕裂强度以及穿刺强度显著增大,但沿流延方向的断裂伸长率下降。Polypropylene(PP)cast films with different thickness were made by changing the feeding screw rate of the extruder.The effect of the thickness on crystallization,orientation and mechanical properties of the PP cast films were studied by WAXD,DSC,SALS and birefringence tests.The test results show that,at the roll temperature of 50℃,in the films with the thickness within the range of 32-109μm,most of the crystals are mesomorphic form and also a small number of crystals ofαform are present.Spherulites are still developed in these films and the average size of the spherulites decreases when the films become thinner.The tensile strength,the tear strength and the puncture strength don’t change significantly in these films.However,in the film with a thickness of 11μm,most of the crystals are monoclinicαform and the crystallinity also increases slightly.Additionally,a much higher orientation of crystal grains and also spherulites are shown in the film.As a result,the yield strength and the tensile modulus along the machine direction(MD),the tear strength along the transverse direction and also the puncture strength obviously increase,although the tensile strain at break along MD is sacrificed.

关 键 词：聚丙烯流延膜 厚度 结晶 取向 力学性能 

分 类 号：TQ325.1[化学工程—合成树脂塑料工业]