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首页> 外文期刊>Journal of Applied Polymer Science >Condition monitoring of a by H-1-NMR T-2 relaxation solvent-swelled samples thermally aged elastomer measurements of
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Condition monitoring of a by H-1-NMR T-2 relaxation solvent-swelled samples thermally aged elastomer measurements of

机译：通过H-1-NMR T-2弛豫溶剂溶胀样品的热老化弹性体测量的状态监测

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The aging of polymers is often monitored by mechanical property measurements such as those of Young's modulus or tensile elongation at break; new methods are required, however, in situations where traditional mechanical methods cannot be employed. A hydroxy-terminated polybutadiene/isophorone diisocyanate elastomer is commonly used as a propellant binder. The thermal degradation of the binder is believed to be an important parameter governing the performance of the propellant. Classical mechanical methods cannot be used to monitor the condition of this material when it has been aged in situ as a highly dispersed binder. In this study, the H-1-NMR spin-spin relaxation times, T-2, of solvent-swelled samples decreased substantially as thermally induced oxidation led to additional crosslinking. A time-temperature superposition analysis of the relaxation times was performed on samples that had been aged at temperatures ranging from 50 to 125degreesC. The acceleration factors derived from the relaxation measurements agreed with those reported earlier for tensile elongation at break and oxygen consumption. The dependence of T-2 on tensile elongation at break was independent of the temperature at which the sample was aged. A shortened version of the experiment, requiring only two spin-echo delay times, is presented. (C) 2002 Wiley Periodicals, Inc. [References: 14]
机译：聚合物的老化通常通过机械性能测量来监测，例如杨氏模量或断裂拉伸伸长率;但是，在无法采用传统机械方法的情况下，需要使用新方法。羟基封端的聚丁二烯/异佛尔酮二异氰酸酯弹性体通常用作推进剂粘合剂。据信粘合剂的热降解是控制推进剂性能的重要参数。当该材料作为高度分散的粘合剂就地老化时，经典的机械方法不能用于监视该材料的状况。在这项研究中，由于热引发的氧化导致额外的交联，溶剂溶胀样品的H-1-NMR自旋自旋弛豫时间T-2大大减少。对在50至125℃的温度下老化的样品进行了弛豫时间的时温叠加分析。从弛豫测量得出的加速因子与先前报道的断裂拉伸伸长和耗氧量一致。 T-2对断裂拉伸伸长率的依赖性与样品老化的温度无关。提出了实验的简化版本，仅需要两个自旋回波延迟时间。 （C）2002 Wiley Periodicals，Inc. [参考：14]

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