The effects of short-chain branches (SCBs) in the high-molecular-weight (MW) chains on the solid-state tensile properties of polyethylene (PE) have been investigated using blend samples of linear PE with a polydisperse MW distribution and PE with very narrow MW distribution and SCBs with four carbons. The introduction of SCBs in the high-MW chains had almost no effect on the crystalline structure, but relaxation of the interlamellar amorphous chains was only activated by blending the high-MW chains with a large fraction of SCBs (2.0 wt%). The blends of PE with 0.4 wt% SCBs resulted in significant increases in the strain-hardening modulus and strength without greatly decreasing the strain at break. The improvement in the strain-hardening modulus and strength by adding a small amount of SCBs (0.4 wt%) was significant compared with the improvement by adding linear PE or branched PE with a large amount of SCBs (2.0 wt%). For a small amount of SCBs, the SCBs will be incorporated into the crystalline structure, which enhances the fragmentation and subsequent orientation of the crystalline structure under yielding deformation. Consequently, blending the branched PE with a small amount of SCBs in the high-MW chains leads to significant improvement of the tensile properties.

中文翻译：

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高分子量组分中短支链对聚乙烯固体拉伸性能的影响

使用具有多分散 MW 分布的线性 PE 和具有多分散 MW 分布的 PE 的共混物样品，研究了高分子量 (MW) 链中的短支链 (SCB) 对聚乙烯 (PE) 固态拉伸性能的影响。非常窄的分子量分布和具有四个碳的 SCB。在高分子量链中引入 SCB 对晶体结构几乎没有影响，但只有通过将高分子量链与大量 SCB（2.0 wt%）混合才能激活层间无定形链的松弛。 PE 与 0.4 wt% SCB 的共混物导致应变硬化模量和强度显着增加，而断裂应变没有大幅降低。与添加大量SCB(2.0wt%)的线性PE或支化PE相比，添加少量SCB(0.4wt%)对应变硬化模量和强度的改善是显着的。对于少量的SCBs，SCBs将被纳入晶体结构中，这增强了晶体结构在屈服变形下的破碎和随后的取向。因此，在高分子量链中将支化 PE 与少量 SCB 共混可显着改善拉伸性能。