论文部分内容阅读
选择了2种密度和分子量相近但共聚单体分别为1-丁烯和1-辛烯的线性低密度聚乙烯(LLDPE)为原料制膜,通过Elmendorf撕裂、直角撕裂、广角X光衍射(WAXS)及小角X光散射(SAXS)研究了薄膜的撕裂性能和结构的关系.实验表明我国现行通用的直角撕裂法表征撕裂的结果与国际通用的Elmendorf撕裂发现得到的结果相差很大。Elmendrof撕裂的形变速度接近薄膜的实际破裂速度,比直角撕裂的形变速度快很多。实验结果表明薄膜在低速和高速形变下(如500 min~(-1))的结构响应显著不同,这一差别应该是导致此二撕裂方法表征差异的原因。LLDPE薄膜的撕裂性能在很大程度上,但并非完全由其聚集态的结构来决定,反映晶体间连接强度的系带分子(tie chain)密度也是一个重要因素.共聚单体为辛烯的薄膜和共聚单体为丁烯的薄膜相比不仅撕裂强度要大很多,在相同取向的情况下,其撕裂强度的降低也小很多.
Two kinds of linear low-density polyethylene (LLDPE) with similar molecular weight and similar molecular weight but with 1-butene and 1-octene were selected as raw materials. Elmendorf tearing, right angle tearing and wide angle X-ray diffraction (WAXS) and Small Angle X-ray Scattering (SAXS) were used to study the relationship between the tearing performance and the structure of the films. The results show that the current common method of right angle tearing in China is different from the result of Elmendorf tearing Great. Elmendrof tear deformation speed close to the actual film rupture speed, right angle tearing deformation much faster. The experimental results show that the structural responses of the films at low and high-speed deformations (eg, 500 min -1) are significantly different, and this difference should be responsible for the differences in characterization of the two-tearing methods. The tear properties of LLDPE films are determined largely, but not exclusively, by the structure of their aggregated state, which is also an important factor in determining the tie chain density of the inter-crystal linkages. The comonomer is octene Not only does the film have a much greater tear strength than butene film, but its tear strength decreases much less in the same orientation.