The relaxation dynamics of disentangled ultrahigh molecular weight polyethylene (UHMWPE) were analyzed by means of torsional rheology in a broad frequency and temperature range. The disentangled specimens were compression-molded at two different temperatures, solid state (125 °C) and melt state (160 °C), and the latter was compared with a melt-state-processed commercial UHMWPE specimen. Three different relaxation processes were observed, namely, α_c-, β-, and γ-relaxations, as expected for polyethylene. The relaxation strengths of the α_c- and γ-relaxations were found to be dependent on the crystallinity content, verified by means of differential scanning calorimetry. The relaxation molecular dynamics of the γ-relaxation in the solid-state-compressed disentangled sample follows a Vogel–Fulcher–Tammann–Hesse trend, suggesting a dynamic glass-to-rubber transition. The same trend is not found for the γ-relaxation of both melt-state-processed samples, thus suggesting a role of crystalline polydispersity and entanglement density in the free volume of the amorphous segments.

中文翻译：

---

扭曲流变学研究超高分子量聚乙烯解缠动力学

利用扭转流变学方法，在较宽的频率和温度范围内分析了缠结的超高分子量聚乙烯（UHMWPE）的弛豫动力学。将解缠的样品在固态（125°C）和熔融态（160°C）这两个不同的温度下压缩成型，并将后者与熔融态处理的商用UHMWPE样品进行比较。观察到三个不同的弛豫过程，即，α _Ç - ，β-，和γ-松弛，如预期的聚乙烯。的α松弛优势_Ç发现-和γ-松弛取决于结晶度，通过差示扫描量热法证实。固态压缩解缠样品中γ松弛的弛豫分子动力学遵循Vogel–Fulcher–Tammann–Hesse趋势，表明玻璃向橡胶的动态转变。两种熔融状态处理的样品的γ松弛均未发现相同的趋势，因此表明了结晶多分散性和缠结密度在无定形链段的自由体积中的作用。