相反转技术制备环氧树脂水基体系——相反转过程的流变行为研究

PREPARATION OF WATER BASED DISPERSIONS OF EPOXY RESIN BY PHASE INVERSION EMULSIFICATION TECHNIQUE——STUDY ON RHEOLOGICAL BEHAVIOR OF PHASE INVERSION

对高乳化剂浓度下的相反转发展过程的流变行为进行了应力扫描、动态频率扫描实验表征．结果表明，乳化剂浓度较高时，体系发生完全相反转；体系在相反转点前为Ｗ／Ｏ结构，其粘度几乎不随剪切应力的改变而改变，表现为牛顿流体行为；体系在相反转点后为Ｏ／Ｗ结构，具有很高的粘弹性，并且在较高剪切应力下表现为典型的假塑性．这是由于高分子水基微粒间通过其表面覆盖的表面活性剂与水形成氢键而产生了一种静态结构，此结构在较高剪切应力作用下破坏而导致假塑性．

The tests including steady stress sweep and dynamic frequency sweep were performed to characterize the rheological behavior of phase inversion evolution at high concentration of the emulsifier (e.g.10.9%). It is shown that the phase inversion is complete, which means that all water molecules in the system are transformed to be continuous phase at the phase inversion point. The viscosity of the system before the phase inversion point is almost constant independent on stress, which is the characteristics of Newtonian fluid. The systems after the phase inversion point exhibit high viscoelasticity and strong pseudoplasticity at relatively high stress. This is attributed to the formation of a new static structure among waterborne particles through hydrogen bond between the emulsifier and water molecules, and the static structure is broken at high stress.