Preparation of hollow polymer particles encapsulating functional substance and its application

具有中空结构的聚合物粒子在许多工业领域得到了广泛的关注。此类颗粒用作微胶囊、减重剂或隔热剂，并且由于其高光散射能力而应用于涂料和模塑组合物中的遮盖剂或遮光剂。我们已经成功地制备了微米级，单分散，交联聚合物粒子具有一个单一的中空中心的种子聚合。以二乙烯基苯（DVB）/甲苯液滴溶解聚苯乙烯，通过悬浮聚合法制备了类似的中空聚合物粒子，尽管它们是多分散的。中空结构的形成是基于相分离聚合物在液滴界面处的自组装。为了更详细地阐明相分离聚合物自组装（SaPSeP）法制备中空粒子的机理，本文研究了PDVB在液滴中的相分离、液滴粘度和液滴尺寸对中空粒子形成的影响。相分离是中空结构形成的必要条件。由于液滴中的粘度在低转化率下低，所以PDVB可以移动并吸附在液滴的界面处。PDVB微凝胶在聚合液滴中发生相分离后的流动性是中空结构形成的重要因素。开发了SaPSeP方法以生产包封扁柏酚或磁铁矿的复合颗粒。并将该方法应用于悬浮体系中的加聚反应。该加聚反应体系满足了SaPSeP法制备空心粒子的条件。实际上，在甲苯蒸发后，成功地制备了在中心具有一个中空的固化环氧树脂颗粒。

Polymer particles with hollow structures have gotten a lot of attention in many industrial fields. Such particles are used as microcapsules, weight-saving or thermal insulation agents, and are applied to hiding or opacifying agents in coating and molding compositions because of their high light-scattering ability. We had succeeded in preparing micron-sized, monodisperse, crosslinking polymer particles having a single hollow at the center by seeded polymerization. Similar hollow polymer particles were produced by suspension polymerization for divinylbenzene (DVB)/toluene droplets dissolving polystyrene though they were polydisperse. The formation of the hollow structure is based on the self- assembling of phase separated polymer at the interface of the droplet. The method is named the Self-assembling of Phase Separated Polymer (SaPSeP) method.In this research, in order to clarify the formation mechanism of hollow particles by the SaPSeP method in more detail, the effects of phase separation of PDVB in the droplets, viscosity within the droplet and its size on the formation of the hollow structure were discussed. The phase separation in the early stage was required point for the formation of the hollow structure. Since the viscosity in the droplet is low at the low conversion, the PDVB can move and adsorb at the interface of the droplet. The mobility of PDVB microgels after the phase separation in polymerizing droplet was important factor for the formation of the hollow structure. The SaPSeP method was developed to produce composite particles encapsulating hinokitiol or magnetite. Moreover, the method was applied to the polyaddition reaction in a suspension system. The polyaddition reaction system satisfied the required conditions for the preparation of hollow particle by the SaPSeP method. In actual, cured epoxy resin particles having one hollow at the center were successfully prepared after evaporation of toluene.