环氧树脂相反转乳化过程相态发展研究

以扫描电镜为主要手段,观察了环氧树脂相反转乳化过程中的相态演化过程.结果表明:在较高乳化剂浓度下,当水含量达到某一临界值时,原W/O体系中水滴间的相互吸引大于水滴间的排斥作用,导致相邻水滴同时快速地融合为连续相并得到水基微粒,水基微粒的尺寸较小,约为亚微米级,尺寸分布窄,微粒为单个粒子.在乳化剂浓度较低情况下,非相邻较大水滴在剪切场作用下随机地融合为连续相,发生不完全相反转,并得到W/O/W结构,水基微粒尺寸较大,约10微米数量级,尺寸分布宽且为一种复合多孔结构.此外,分析了相反转发展演变过程.

Morphological Evolution with Phase Inversion Process in Emulsifying Epoxy Resin

The morphological evolution with phase inversion process in emulsifying bisphenol A epoxy resin was observed by SEM. It is revealed that the phase inversion process is completely achieved at the phase inversion point(PIP) when the concentration of the emulsifier is high, and a kind of sub micro waterborne particles of narrow size distribution is prepared. When the concentration of the emulsifier is low, the phase inversion process is incompletely achieved at PIP, and a kind of porous complex big waterborne particles of wide size distribution is obtained. In the former case, the interfacial layer of W/O structure is strong enough to impede the coalescence among water droplets before PIP. When the content of water reaches a critical value, the attraction between water droplets exceeds the repulsion, the nearest water droplets coalesce simultaneously to be continuous phase, which causes the complete phase inversion. In the latter case, the coalescence among the water droplets is noticeable due to the weak interfacial layer of W/O structure. Thus, the water droplets become larger after the coalescence and randomly dispersed in the continuous phase. The larger water drops coalesce furtherly to be continuous phase promoted by strong shear field and the W/O/W structure is formed. This is the feature of incomplete phase inversion.