Abstract：
The isothermal melting behaviors of ultra-high molecular weight polyethylene (UHMWPE) with different entangled states (i.e., nascent and melt-crystallized samples) are studied. For two kinds of UHMWPE samples, the result shows that the relative content of survived crystals (Xs) exponentially decreases with time and reaches a constant value. It is suggested that such a melting behavior is related to the observed nonlinear growth of crystals induced by the kinetically rejected entanglements accumulated at the growth front. Additionally, the exponential decay of Xs with time provides a characteristic melting time (τ) for the melting process. Compared to the melt-crystallized UHMWPE, the τ value of nascent UHMWPE is generally longer even in a higher temperature range, which is mainly because the former has a larger entanglement density difference. Furthermore, these observations demonstrate that UHMWPEs with different entangled states have an analogous melting mechanism since they exhibit a similar melting activation energy (≈1300 kJ mol-1).
摘要：
具有不同纠缠态的超高分子量聚乙烯（UHMWPE）的等温熔融行为（即，新生和熔融结晶样品）已被研究。对于两种UHMWPE样品，我们的结果表明，存活晶体（Xs）的相对含量随时间呈指数下降，并达到恒定值。我们建议这种熔化行为与观察到的晶体非线性生长有关，该晶体是由在生长前沿积累的动力学排斥缠结引起的。此外,Xs随时间的指数衰减为熔化过程提供了特征熔化时间(τ)。与熔融结晶UHMWPE相比，即使在较高的温度范围内，新生UHMWPE的τ值通常也更长，这主要是因为前者具有较大的纠缠密度差。此外，我们的观察结果表明，具有不同纠缠态的UHMWPE具有类似的熔化机制，因为它们表现出相似的熔化活化能（〜1300kJ/mol）。本文受版权保护。保留所有权利。
