Abstract Two main issues are essential nowadays for practitioners in the field of polymeric materials: how a polymer will behave under dynamic loading conditions and for how long a polymer is reliable. In this sense, the time-temperature superposition principle was applied to the main viscoelastic properties (E′, E″ and tan δ) of a series of polyurethane coatings (PU-DEG-TMP) tested for mechatronic devices. Polyurethanes are derived from an ester glycol (poly(ethylene adipate) glycol), an aromatic diisocyanate (4,4′-dibenzyldiisocyanate) and di/trifunctional chain extenders - diethylene glycol (DEG) and trimethylol propane (TMP). Despite polyurethane intrinsic rheologic complexity, the moduli/loss factor curves superimpose well over several decades of reduced frequency at the glass transition temperature (Tg), 0 °C and 15 °C, the last temperature being considered the midpoint of the practical testing range. Three criteria were for checking the applicability of the time-temperature superposition: the Cole-Cole plot, the similarity between the aT calculated from both moduli (E′, E″) and the visual appearance of the final master curve. The presence of both hydrogen bonding and chemical joint points, along with some dangling chains put in a broader context the discussion of the microstructural features resulted from the application of the William-Landell-Ferry (WLF) equation.

中文翻译：

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通过时间-温度叠加预测聚氨酯行为：意义和局限性

摘要 目前，聚合物材料领域的从业人员面临两个主要问题：聚合物在动态负载条件下的行为方式以及聚合物的可靠性。从这个意义上说，时间-温度叠加原理被应用于一系列用于机电设备测试的聚氨酯涂层 (PU-DEG-TMP) 的主要粘弹性特性（E'、E'' 和 tanδ）。聚氨酯衍生自酯二醇（聚（己二酸乙二醇酯）二醇）、芳族二异氰酸酯（4,4'-二苄基二异氰酸酯）和双/三官能扩链剂 - 二甘醇 (DEG) 和三羟甲基丙烷 (TMP)。尽管聚氨酯固有的流变复杂性，模量/损耗因子曲线在玻璃化转变温度 (Tg)、0°C 和 15°C 下几十年的频率降低中很好地叠加，最后一个温度被认为是实际测试范围的中点。三个标准用于检查时间-温度叠加的适用性：Cole-Cole 图、从两个模量（E'、E”）计算的 aT 之间的相似性和最终主曲线的视觉外观。氢键和化学连接点的存在，以及一些悬空链的存在，使得对威廉-兰德尔-费里 (WLF) 方程应用产生的微观结构特征的讨论在更广泛的背景下进行。