Synthesis And Application Of ?-Methylstyrene Copolymer Nanoparticles By Emulsion Polymerization

?-Methylstyrene(AMS) is a by-product produced during the production of phenol and acetone in the chemical industry, and its output capacity is very considerable. However, due to its special chemical structure and relatively low ceiling temperature of polymerization, AMS has few useful applications and was mainly used as a fuel. Although the emulsion polymerization of AMS has been widely investigated, most of the researches are concentrated on the polymerization process and polymerization mechanism, and little attentions have been paid on the size and surface morphology of the as-prepared polymer particles. In the present work, AMS copolymer particles with an average diameter below 30nm were prepared by conventional emulsion polymerization based on the unique polymerization behavior of AMS. The influence of various reaction parameters on the emulsion polymerization process and on the size and morphology of the as-prepared copolymer particles were investigated in details. Based on the above work, surface modification of the polymer particles were achieved through copolymerization with other functional monomers, and carboxyl-and epoxy-functionalized polymer particles were successfully obtained. The thermal degradation and thermal resistance behavior of the as-prepared AMS-containing polymers were also studied.The main research work is as follows:1. AMS copolymer particles were prepared by conventional emulsion polymerization and the effects of reaction temperature, initiator concentration, emulsifier usage, monomer feed ratio and solid content on the polymerization process were discussed. The polymer particles with an average diameter below 30nm were successfully prepared.2. The emulsion polymerization mechanism in the presence of AMS was intensively studied. Based on the comparison between the polymerization kinetics and the particle size of styrene (St) and copolymerization of AMS and St, the effect of AMS during the emulsion copolymerization process was demonstrated, the emulsion polymerization mechanism in the presence of AMS was obtained. Additionally, the reason for the particle size below 30nm was also reasonably explained. Furthermore, the polymer particles with an average diameter below 10nm could be prepared with the aid of cross-linking agent.3. Surface modification of the polymer particles was achieved through copolymerization with functional monomers. Carboxyl groups and epoxy groups were successfully attached onto the surface of polymer particles to improve the hydrophilicity and dispersibility of the as-prepared polymer particles.4. Thermal properties of AMS containing copolymer were studied, and the experimental results showed that the degradation of the AMS containing copolymer backbone took place at high temperature and the molecular weight decreased accordingly. Moreover, the heat resistance of the AMS containing copolymer was also characterized, it was found that the glass transition temperature (Tg) increased gradually with increasing AMS and divinyl benzene (DVB) content, and the Tg of the copolymer reached up to 145? when DVB content was 10%.In this dissertation, conventional emulsion polymerization was used for the synthesis of polymer nanoparticles with an average diameter below 30nm. This method avoids the drawbacks of micro emulsion polymerization, such as low monomer concentration, expensive device, and complicated post-treatment procedure, and so.on. It has great significance in both scientific and technological interest.