Changes in molecular dynamics during bulk polymerization of an epoxide-amine system as studied by dielectric relaxation spectroscopy
Changes in molecular dynamics during bulk polymerization of an epoxide-amine system as studied by dielectric relaxation spectroscopy
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DOI：
10.1021/ma9517862
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发表时间：
1996-10-21
期刊：
影响因子：
5.5
通讯作者：
Aldridge, GA
中科院分区：
文献类型：
--
作者：
Fournier, J;Williams, G;Aldridge, GA
本文同时用介电弛豫谱（DRS）和差示扫描量热法（DSC）研究了双酚A二缩水甘油醚与4，4 ′-二氨基二环己基甲烷在290-353 K温度范围内的等温固化过程。在10（1.2）~ 10（5）Hz频率范围内，测量了热固性混合物的介电常数和介电损耗随反应时间的变化。的介电性能的演变进行了研究，作为固化温度降低到接近样品的固化值。还用量热法测定了四个反应温度下的固化动力学，在整个转化范围内，直到体系玻璃化和反应变为扩散控制的点。并且已经开发了一个理论工作模型，该模型允许DRS预测玻璃化范围内的反应过程。以前的解释介电事件在这个玻璃化区域，实验动力学和介电结果的基础上，重新审视。
Dielectric relaxation spectroscopy (DRS) and differential scanning calorimetry (DSC) have been used simultaneously as a means of following the isothermal cure of the diglycidyl ether of Bisphenol A with 4,4'-diaminodicyclohexylmethane in the temperature range 290-353 K. The dielectric permittivity and dielectric loss of the thermosetting mixture have been measured as a function of reaction time over the frequency range 10(1.2)-10(5) HZ. The evolution of the dielectric properties was studied as the curing temperature was lowered to values close to the solidification of a sample. The kinetics of the cure have also been determined, using calorimetry, for four reaction temperatures over the whole range of conversion up to the point where the system vitrifies and the reaction becomes diffusion-controlled Correlations between the changes in molecular dynamics and the chemical kinetics occurring during the thermosetting process have been made in some detail, and a theoretical working model has been developed that allows DRS to predict the course of the reaction in the vitrification range. Previous interpretations of dielectric events in this vitrification region, based on experimental kinetic and dielectric results, are reexamined.