A molar mass induced transition in the yielding properties of linear polyethylene
A molar mass induced transition in the yielding properties of linear polyethylene
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DOI：
10.1016/s0032-3861(03)00036-3
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发表时间：
2003-03
期刊：
影响因子：
4.6
通讯作者：
Q. Fu;Yongfeng Men;G. Strobl
中科院分区：
文献类型：
--
作者：
Q. Fu;Yongfeng Men;G. Strobl
在半结晶聚合物如PE中的拉伸变形机制在四个临界点处变化，这四个临界点可以与（A）单个滑移过程的开始，（B）滑移转变成集体活动，（C）晶体块的解聚开始，随后是原纤维形成，以及（D）链解缠结的开始相关联。对一系列随摩尔质量增加的LPE的变形行为的研究表明，当摩尔质量为Mt = 1.5 -2 × 105 gmol −1时，临界应变εH（C）和εH（D）突然增加。如通过动态机械测试所指示的，上升源自无定形区域的流动性和顺应性的变化，其对于Mw>Mt是熔融状的，但是对于Mw<Mt是降低的。因此，在较低的应变下，晶体块解聚和链解缠结都发生。
The mechanism of tensile deformation in a semi-crystalline polymer like PE changes at four critical points which can be associated with (A) the onset of single slip-processes, (B) a turnover into a collective activity of slips, (C) the beginning of a disaggregation of the crystal blocks, followed by fibril formation, and (D) the onset of chain disentangling. Studies of the deformation behavior of series of LPEs with increasing molar mass show an abrupt rise of the critical strains εH(C) and εH(D) at a molar mass of Mt≈(1 5–2)×105gmol−1. As indicated by dynamic mechanical tests the rise originates from a change in the mobility and compliance of the amorphous regions, which are melt-like for Mw>Mt, but reduced for Mw<Mt. As a consequence, both, crystal block disaggregation and chain disentangling, set in at lower strains.