Mechanism of formation of monodisperse polystyrene hollow particles prepared by membrane emulsification technique. Effect of hexadecane amount on the formation of hollow particles |
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Authors: | Guang-Hui Ma Shinzo Omi |
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Institution: | National Key Laboratory of Bio-Chemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, No. 1 Bei-Er-Tiao, Zhong-Guan-Cun, Beijing 100080, China |
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Abstract: | In a previous study, it was found that monodisperse polystyrene (PSt) hollow particles can be prepared under special conditions by combining a Shirasu Porous Glass (SPG) emulsification technique and subsequent suspension polymerization process. The dispersed phase mainly containing St, hexadecane (HD), and initiator, was pressed through the uniform pores of a SPG membrane into the continuous phase to form uniform droplets. Then, the droplets were polymerized at 70°C. It was proposed that rapid phase separation between PSt and HD was a main reason responsible for the formation of hollow particle. Rapid phase separation confined the HD inside the droplets, it belonged to a non-equilibrium morphology. In this study, HD/St ratio was increased to a high value to confirm the above proposition by promoting rapid phase separation further between HD and PSt, to prevent monomer diffusion into aqueous phase, and to obtain hollow particle with a large hole. |
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