Preparation of functionally gradient composite polymer particles by suspension polymerization

采用悬浮聚合法制备了功能梯度复合聚合物粒子。采用两种不同物理性能的粉体对复合聚合物粒子进行均匀包覆。作为固体粉末，采用磁铁矿和碳化硅。用硅烷偶联剂对粉体进行表面处理，以改变粉体对液-液体系的亲合力。在悬浮聚合前，先将一种粉体加入到连续水相中，然后在聚合过程中再加入另一种粉体，通过两种粉体同时加入且加入量不同，在聚合物粒子表面形成功能梯度结构。粉体对液-液体系的亲和程度决定了复合聚合物颗粒的形成和功能梯度结构的形成。

Functionally gradient composite polymer particles were prepared by suspension polymerization. Composite polymer particles were coated uniformly by two kinds of powders, which have different physical properties respectively. As solid Powders magnetite and silicon carbite were adoeted. These powders were treated by silane coupling agent in order to change the affinity for the liquid-liquid system. Before suspension polymerization, one powder was added into the continuous water phase and then, another powder was added during the polymerization process.Functionally gradient structure on the surface of polymer particle was made up by simultaneous addition of two kinds of powders and different amounts. A degree of affinity of powders for the liquid-liquid system was found to strongly decide the formation of composite polymer particles and the functionally gradient structure.