环氧树脂微胶囊合成及其反应动力学

Preparation and reaction kinetics of epoxy resin microcapsules

将环氧树脂E-51分散在水中形成稳定的乳液,使用三乙烯四胺固化剂,在环氧树脂液滴表面形成交联结构作为环氧树脂微胶囊囊壁,这种微胶囊为环氧树脂复合材料的科学研究和工程应用提供了无界面差异囊壁的研究模型。采用扫描电子显微镜(SEM)和光学显微镜(OM)分析了乳化剂种类及用量、反应温度和搅拌速率等工艺条件对这种微胶囊的形成过程、表面形貌、粒径大小及分布和壁厚的影响。采用红外光谱(FTIR)研究了环氧树脂微胶囊的化学结构。当合成条件为乳化剂Tween 80浓度为1%,固化剂三乙烯四胺浓度为2.5%,反应温度90℃,搅拌速度600~1000 r·min^(-1),合成的环氧树脂微胶囊形状规整,表面光滑致密,平均粒径为103μm,囊芯含量为44.65%,壁厚为5μm。研究三乙烯四胺固化剂中伯胺和仲胺的反应速率常数和活化能等反应动力学参数,定量分析环氧树脂-三乙烯四胺的化学反应中伯胺和仲胺的反应活性差异。

A series of microcapsules were prepared by interfacial polymerization,epoxy resin E-51 as core materials and the condensation of triethylenetetramine and epoxy resin E-51 to wall materials.The kind of epoxy microcapsules provide an investigation model for scientific research and engineering applications of the epoxy resin self-healing composites with no different interfaces.The microcapsule formation process,particle size and size distribution,morphology and chemical structure were analyzed by optical microscopy(OM),scanning electron microscopy(SEM)and Fourier transform infrared spectroscopy(FTIR),etc.Optimum synthetic conditions are obtained as the following:emulsifier(Tween 80)dosage is 1%,dosage of triethylenetetramine is 2.5%,reaction temperature is 90℃,and agitation rate is 600-1000 r·min-1.The reaction kinetic parameters such as reaction rate constant and activation energy of primary and secondary amines in triethylenetetramine curing agent were studied in details.Quantitative analysis was conducted for the reactive difference of primary and secondary amine groups between these amines in the chemical condesation of epoxy resin and triethylene tetramine.