Key Laboratory of Carbon Fiber and Functional Polymers, Ministry of Education, Beijing University of Chemical Technology, Beijing 100029, P. R. China.
Soft Matter. 2018 Nov 7;14(43):8740-8749. doi: 10.1039/c8sm01516c.
Moisture corrosion of cured epoxy resins seriously affects the durability of epoxy products and has been a serious issue in scientific and engineering fields. In this study, a series of cured epoxy resins with different structures were prepared by tuning their curing conversion in both experimental and simulation methods. In experiments, the equilibrium water content and the diffusion coefficient of amine-cured epoxy resins were measured by gravimetric measurement. The interaction between water molecules and epoxy network was investigated by time-resolved FTIR, difference spectroscopy and 2D correlation spectroscopy. In simulation, the hydrogen bonds, the mobility of hydroxypropyl ether groups and water molecules, and the free volume with its distributions were analyzed. Five types of water molecules were intuitively observed in this study; free volume had a stronger influence on equilibrium water content than polarity in the bifunctional epoxy/amine system, and the increase in the diffusion coefficient was considered as the result of reduction in motion resistance and an increase in channels for the motion of water molecules.
固化环氧树脂的吸湿腐蚀严重影响环氧树脂制品的耐久性，一直是科学和工程领域的一个严重问题。在本研究中，通过实验和模拟方法调节固化转化率，制备了一系列具有不同结构的固化环氧树脂。在实验中，通过重量法测量了胺固化环氧树脂的平衡含水量和扩散系数。通过时间分辨傅里叶变换红外光谱、差谱和二维相关光谱研究了水分子与环氧网络的相互作用。在模拟中，分析了氢键、羟丙基醚基团和水分子的迁移率以及自由体积及其分布。在本研究中直观地观察到了五种类型的水分子；在双官能环氧树脂/胺体系中，自由体积对平衡含水量的影响强于极性，扩散系数的增加被认为是由于运动阻力的降低和水分子运动通道的增加所致。
