A dielectric study of water uptake in epoxy resin systems
A dielectric study of water uptake in epoxy resin systems
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DOI：
10.1002/app.44717
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发表时间：
2017-04-20
影响因子：
3
通讯作者：
Pethrick, Richard A.
中科院分区：
文献类型：
--
作者：
Garden, Lisa;Pethrick, Richard A.
环氧树脂配方的性质和程度的水分的影响进行了研究，使用介电和重量分析的样品固化在40，50，60，和70 ℃，并在50 ℃和70 ℃老化。平衡吸湿量取决于玻璃化转变温度和老化温度之间的差异。从1到3 x 10（10）Hz测量的介电弛豫数据表明至少在两种不同的环境中存在水。高频弛豫CA。1 × 10（10）Hz与聚集在纳米空隙中的水有关，而在10（5）Hz处的弛豫是由OH侧基重取向运动与分子分散的水分子的重取向运动相结合引起的。介电常数与吸湿量之间存在相关性。最初存在于空隙中的水随着老化而重新分散到树脂基质中，从而帮助塑化并使基质致密化。发生变化的程度取决于形成基质的化学功能，致密化导致吸水量下降。在复合树脂体系中，水与胺固化剂的OH基团和聚醚两者相互作用，这在简单体系中与脂肪族二胺不可能。(C)2017 Wiley Periodicals，Inc.
The influence of epoxy resin formulation on the nature and extent of moisture is studied using dielectric and gravimetric analysis for samples cured at 40, 50, 60, and 70 degrees C and aged at 50 degrees C and 70 degrees C. The equilibrium moisture uptake depends on the difference between the glass transition and aging temperature. Dielectric relaxation data measured from 1 to 3 x 10(10) Hz indicates the presence of water in at least two different environments. The high frequency relaxation ca. 1 x 10(10) Hz is associated with water clustered in nano-voids, whereas the relaxation at 10(5) Hz arises from a combination of OH pendant group reorientation motion coupled with that of molecularly dispersed water molecules. A correlation exist between the dielectric permittivity and the amount of moisture absorbed. Water initially resident in voids is re-dispersed with aging into the resin matrix aiding plasticization and allowing densification of the matrix. The extent to which changes occur depends on the chemical functions forming the matrix and densification leads to a drop in the amount of water absorbed. In the complex resin systems, water interacts with both OH groups and polyether of the amine curing agent which is not possible with the aliphatic diamine in the simple system.] (C) 2017 Wiley Periodicals, Inc.