Small-angle neutron scattering study of nanophase separated epoxy hydrogels
Small-angle neutron scattering study of nanophase separated epoxy hydrogels
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DOI：
10.1016/j.jnoncrysol.2009.11.037
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发表时间：
2010-03
影响因子：
3.5
通讯作者：
I. Krakovský;N. Székely
中科院分区：
文献类型：
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作者：
I. Krakovský;N. Székely
以平均摩尔质量约为600gmol−1的α，ω-二氨基端部聚氧丙烯-嵌段聚氧乙烯-嵌段聚氧丙烯与双酚A丙氧酸酯二缩水甘油醚在不同氨基与环氧基的化学计量比r值下进行端连接反应，制备了一系列亲水性环氧网络。环氧水凝胶是通过环氧网络在氘化水中膨胀得到的。用小角中子散射揭示了所有水凝胶的纳米相分离结构。该结构比先前研究的类似体系精细得多，该体系是用更长的二胺（摩尔质量约为2000gmol−1）制备的。与以前的体系不同，本体系的散射数据不能用percuss - yevick模型拟合，但基于聚合物网络拓扑结构守恒所决定的纳米相局部层状顺序的Teubner-Strey模型在拟合中表现良好。确定并详细分析了纳米相分离结构参数的两个特征长度：局部层序的周期性和持续长度及其与网络组成的依赖关系。
A series of hydrophilic epoxy networks was prepared by end-linking reaction of α,ω-diamino terminated poly(oxypropylene)-block-poly(oxyethylene)-block-poly(oxypropylene) of average molar mass ca. 600gmol−1and diglycidyl ether of Bisphenol A propoxylate at various values of stoichiometric ratio, r, of amino to epoxy groups. Epoxy hydrogels were obtained by swelling of the epoxy networks in deuterated water. Nanophase separated structure of all hydrogels has been revealed by small-angle neutron scattering. The structure is much finer than that found in the similar system investigated previously which was prepared using much longer diamine (molar mass ca. 2000gmol−1). Unlike the previous system, the scattering data from the present system cannot be fitted properly by Percus–Yevick model but Teubner–Strey model based on the locally lamellar order of nanophases dictated by conservation of polymer network topology proves well in the fitting. The values of parameters of the nanophase separated structure – two characteristic lengths: periodicity and persistence length of the locally lamellar order and their dependence on the network composition are determined and analyzed in detail.