Preparation of cross-linked poly(methyl methacrylate) microspheres using an asymmetric cross-linker via dispersion polymerization and its application in light diffusers

Cross-linked poly(methyl methacrylate) (PMMA) microspheres have been successfully prepared by using the asymmetric cross-linker allyl methacrylate (AMA) via dispersion polymerization. The influence of the AMA amount and polymerization process on the PMMA particle size and morphology has been studied thoroughly. It was found that micron-sized, cross-linked PMMA particles with narrow size distributions could be obtained by a semi-continuous process with the asymmetric cross-linker AMA. The obtained micron-sized, cross-linked PMMA particles could be further used as a light diffusion agent in a polycarbonate matrix, and their light diffusion properties were significantly enhanced by increasing the gel content in the cross-linked particles. Moreover, the influence of the polymerization process, cross-linker content in PMMA and PMMA content in the polycarbonate matrix on light diffusion was carefully investigated. The results showed that the PMMA particles containing 5.0 wt% AMA, obtained by semi-continuous polymerization, had a higher haze and gel content and exhibited a better light diffusion effect than did the other particles. We prepared cross-linked PMMA microspheres by dispersion polymerization with asymmetric cross-linker AMA and obtained light diffusers by blending cross-linked PMMA microspheres with matrix PC.