Preparation of cross-linked poly (methyl methacrylate) microspheres by post-crosslinking method and its application in light diffusers

Cross-linked polymer microspheres are widely used in biomedicine, flat panel display, analytical testing, in vitro diagnostics, semiconductor chips, and light diffusion. However, the process of preparing micron-sized cross-linked polymer microspheres is complicated, and it is difficult to obtain a high crosslinking degree conveniently. In this work, we applied post-crosslinking strategy to prepare poly (methyl methacrylate) (PMMA) microspheres having a high crosslinking degree by dispersion polymerization, while the method separated the polymerization process and cross-linking process of microspheres. In the method, the silane coupling agents containing double bonds were used as the comonomer in polymerization and hydrolyzed to form Si-O-Si cross-linked structure at the later stage. The obtained microspheres are not only highly cross-linked but also have uniform particle size distribution and good thermal stability. The produced cross-linked PMMA microspheres exhibit great light diffusion properties and might be employed as a light diffusion agent in a polycarbonate matrix.