Preparation And Application Of Hollow Polymer Microsphere Latex

Hollow polymer microsphere latex is widely used in many industries, such as coating, paper making and leather. Such microspheres have also potential applications as microcapsule materials in cosmetic and pharmacy area, and so on. Therefore, hollow polymer microsphere attracts many attentions and the research about hollow polymer microsphere becomes deeper and deeper along with time. In this dissertation, hollow polymer microsphere with large size and high hollowness was successfully prepared, and film-forming of the hollow polymer microsphere latex was preliminarily studied.In chapter one, the references about hollow polymer microsphere latex was reviewed. Firstly, the application industries and potential applications of hollow polymer microsphere were listed, including coating, leather, cosmetic, pharmacy, and so on. Then preparation methods including alkali (and acid) swell, suspension polymerization, SPG film emulsification technique, W/O/W emulsion polymerization and template technique were selectively introduced. At last, the film-forming of polymer latex was introduced. The film-forming process and the forces during film-forming were analyzed. The film-forming theories were introduced. The influence factors on minimum film-forming temperature were discussed. The film-forming of core-shell polymer latex was especially introduced.In chapter two, the preparation technics and characterization of hollow polymer microsphere latex in this dissertation were explained. First, P(methyl acrylic acid-methyl methacrylate-butyl acrylate) copolymer microspheres were synthesized. Then, seeded emulsion polymerization of enlarging the. sizes of the copolymer microspheres was carried out. Using the second step microspheres as core layers particles, the copolymerization of St and MAA at their surfaces formed shell layers. As the result, core-shell polymer microsphere latex of P(methyl acrylic acid-methyl methacrylate-butyl acrylate) / P(methyl acrylic acid-styrene) was synthesized. At last, the core-shell microspheres were treated by means of stepwise swell with alkali and acid solutions at an appropriate high temperature. Thus the microspheres with special hollow structure were obtained. The sizes and morphologies of polymer microspheres at every emulsion polymerization step and swell were characterized by means of DLS, TEM and FESEM. During the experiment, the effects of emulsifier, initiator, monomers proportion and the feed speed of pre-emulsification mixture on the size distributions when seed, core polymer particles and core-shell polymer particles preparation were examined. The effects of monomers proportion on glass transition temperature of core polymer and hollowness of hollow polymer microsphere were examined. The content of core-shell polymer was improved when swell with alkali and acid by adding emulsifier.In chapter three, the film-forming of the hollow polymer microsphere latex was studied. The hollow polymer microsphere latex formed film at high temperature. The mixture of the hollow polymer microsphere latex and a kind of soft latex of acrylate polymer could easily form film at 20℃. The morphologies of the hollow polymer microsphere latex film and the mixed latex film were observed by FESEM.In chapter four, the research work of this dissertation was summarized, and the conclusion was brought forward.