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首页> 外文期刊>Journal of Applied Polymer Science >New aspects of aging in epoxy networks. II. Hydrothermal aging
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New aspects of aging in epoxy networks. II. Hydrothermal aging

机译：环氧网络老化的新方面。二。水热老化

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An amine cured epoxy is prepared in two different network states for hydrothermal aging. The "low-crosslinked" network has a considerable amount of residual reactive groups and a relatively high-molecular mobility. The low-crosslinked matrix contains high-crosslinked regions. In contrast, the "highly crosslinked" epoxy system has little reactive groups and a lower molecular mobility. Here, low-crosslinked regions are found in a high-crosslinked matrix. Hydrothermal loading for both networks is performed in demineralized water at temperatures below their glass transition. The water plasticizes both kinds of networks which remain in the glassy state, however. As a consequence, in the low-crosslinked epoxy, the increased molecular mobility promotes an ongoing curing reaction leading to the consumption of epoxy groups until an almost complete network has formed. As a new aging process, phase separation occurs in the highly crosslinked epoxy. The new phase is more mobile than the matrix because it has its own glass transition at a lower temperature. In addition, thermooxidative degradation is observed for both network states. Certainly, these chemical and structural changes in the epoxy networks should influence the performance of an adhesive joint, a coating, or a fiber-reinforced composite. (C) 2003 Wiley Periodicals, Inc. [References: 20]
机译：制备了两种不同网络状态的胺固化环氧树脂，以进行水热老化。 “低交联的”网络具有大量的残余反应基团和相对较高的分子迁移率。低交联的基质包含高交联的区域。相反，“高度交联的”环氧体系具有很少的反应性基团和较低的分子迁移率。在此，在高交联的基质中发现了低交联的区域。两个网络的水热负荷均在软化水中，低于其玻璃化转变温度的温度下进行。但是水会塑化两种保持玻璃态的网络。结果，在低交联的环氧中，增加的分子迁移率促进正在进行的固化反应，导致环氧基的消耗，直到形成几乎完整的网络。作为一种新的老化过程，在高度交联的环氧树脂中会发生相分离。新相比基质具有更高的移动性，因为它在较低的温度下具有自己的玻璃化转变温度。另外，对于两种网络状态都观察到热氧化降解。当然，环氧网络中的这些化学和结构变化会影响粘合接头，涂料或纤维增强复合材料的性能。 （C）2003 Wiley Periodicals，Inc. [参考：20]

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