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首页> 外文期刊>Journal of Applied Polymer Science >Characterization of the Relaxation Transitions in Toluene Diisocyanate-Based Polyurethanes with Poly (propylene glycol) as the Soft Segment by Thermally Stimulated Current Depolarization with Relaxation Mapping Analysis
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Characterization of the Relaxation Transitions in Toluene Diisocyanate-Based Polyurethanes with Poly (propylene glycol) as the Soft Segment by Thermally Stimulated Current Depolarization with Relaxation Mapping Analysis

机译：弛豫映射分析法通过热刺激电流去极化表征以聚丙二醇为软链段的甲苯二异氰酸酯基聚氨酯的弛豫转变

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摘要

Thermal relaxation transisions of toluene diisocyanate (TDI)-based polyurethanes (PU) were characterized by the thermally stimulated current (TSC) technique with verification data from the relaxation mapping analysis (RMA) measurement. TDI-based PU elastomers with poly (propylene glycols) (PPG) as the soft segment and methylene-bis-orthochloroaniline (MOCA) as the hardener, showed three relaxations, (1) a subglass transition (T_g) of the terminal groups occurred near -135 deg C; (2) the T_g; and (3) a global transition occurred above the T_g (assigned as T_globaltransition). The temperature of T_g of PU as expected was varied by the chain length and attributed by the motion of an urethanic chain dominated by the soft segment and may also associate in the cooperative movement with the hard segment. The T_global transition appearing above the T_g was identified and attributed to the global transition in the macromolecule scale and was supported by the tangent plot of the dynamic mechanical analyzer (DMA) measurement. The TSC measurement on thermal characteristic transitions of TDI-based PU provided a whole range of thermal transitions including a sub-T_g, the T_g (observed by DSC) to a global transistion (may be observed by DMA) with the ease of sample preparation in one measurement.
机译：甲苯二异氰酸酯（TDI）基聚氨酯（PU）的热弛豫转换通过热激电流（TSC）技术进行了表征，并具有弛豫映射分析（RMA）测量的验证数据。基于TDI的PU弹性体，其中以聚丙二醇（PPG）为软链段，以亚甲基双邻氯苯胺（MOCA）为硬化剂，显示出三个弛豫：（1）末端基团的亚玻璃化转变（T_g）在附近发生-135℃; （2）T_g; （3）在T_g上方发生全局过渡（分配为T_globaltransition）。如所期望的，PU的T_g的温度随链长而变化，并且归因于由软链段支配的尿烷链的运动，并且还可能与硬链段协同运动。确定了出现在T_g上方的T_global过渡，并将其归因于大分子尺度的全局过渡，并由动态力学分析仪（DMA）测量的切线图支持。基于TDI的PU的热特性转变的TSC测量提供了一个完整的热转变范围，包括一个子T_g，T_g（由DSC观察到）到一个整体晶体管（可以通过DMA观察到），并且样品制备简便。一种测量。

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