Acrylate-Styrene core/shell polymer의 제조와 물성에 관한 연구
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The core/shell composite latexes were prepared by sequential emulsion polymerization of methyl methacrylate(MMA), ethyl methacrylate(EMA), buthyl methacrylate(BMA) and styrene(ST) by using an water-soluble initiator after preparing monomer pre-emulsion in the presence of an anionic surfactant. We prepared monomer pre-emulsion by sodium do- decyl benzene sulfonate(SDBS) and composite latex polymer by using ammonium persulfate(APS). In organic(core)/organic(shell) polymerization, the pre-emulsion method, which minimized quantity of required sulfactant, used to increase the conversion rate and the stability of core/shell polymer particle as well as to reduce the formation of secondary particle that cause problems of soap-free emulsion during shell polymerization. We used several methods to observe the core/shell structure. The core/shell structure was studied by measuring pH changes with time during hydrolysis by NaOH, glass transition temperature(T_g) using differential scanning calorimeter(DSC), FT-IR spectrum, morphology of latex using transmission electron microscope(TEM), and chang of particle size and distribution using a particle analyzer. We obtained the results as follows. In emulsion polymerization with APS as initiator, the rate of polymerization was increased and particle size was decreased with increasing concentration of sulfactant. In the case of core polymerization, lower conversion was obtained from low glass transition temperature by using BMA than by using MMA and EMA. We confirmed that the stable core/shell polymer particles were prepared from the results of DSC curve with two T_g, pH changes with time during hydrolysis by NaOH, FT-IR spectrum, TEM photographs, and particle size distribution.