Methyl methacrylate (MMA), styrene (St), ethly acrylate (EA) 등의 단량체를 수용성 개시제와 음이온계 유화제를 이용하여 한 입자 내에 복합물성을 나타내는 core (내부)와 shell(외부)의 폴리머 성분이 다른 organic/organic core-shell 폴리머를 합성하고 각 core-shell 폴리머에 대한 구조를 연구하였다. Organic/organic core-shell 폴리머 합성에서 최소량의 유화제를 사용하여 많은 양의 유화제를 사용한 효과를 나타내기 위해 pre-emulsion화 하는 방법을 사용하여, 무유화제 중합시와 달리 전환율 향상과 shell 중합 시에 생성되는 새로운 입자의 생성이 적은 안정한 core-shell 폴리머를 합성할 수 있었다. 그래서 PMMA/PS, PS/PMMA 그리고 PS/PEA core-shell latex 입자들을 유화제로 sodium dodecly benzene sulfonate (SDBS)를 사용하여 pre-emulsion화하고 Seed 중합을 한 후 두번째 단계에서 개시제로서 ammonium persulfate (APS)를 사용하여 중합하였다. 합성한 core-shell polymer들을 입도분석기(Particle Size Analyzer) 및 투과전자현미경(Transmission Electron Microscope, TEM)을 이용하여 실제 입자측정과 입자형태를 확인하였으며 시차주사열량계(Differential Scanning Calorimeter, DSC)를 이용하여 유리전이온도(T_g)의 측정, 필름 조막성, NaOH 첨가에 의한 가수 분해에 따르는 pH를 측정하여 core-shell 구조를 확인하였다.

Core-shell polymers of organic/organic pair that has two different properties within a particle were prepared by a sequential emulsion polymerization of methyl methacrylate (MMA), styrene (ST), and ethyl acrylate (EA) by using an water-soluble initiator in the presence of an anionic surfactant. The characteristics and structures of these core-shell polymers were evaluated. In organic/organic core-shell polymerization, the pre-emulsion method, which minimized required quantity of surfactant, has been 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. Therefore, PMMA/PS, PS/PMMA and PS/PEA core-shell latex paticles were prepared by a monomer pre-emulsion using sodium dodecyl benzene sulfonate (SDBS), which proceeded by a two-stage emulsion polymerization with ammonium persulfate as an initiator after the seed emulsion polymerization. We used several methods to observe the core-shell structure. The core-shell structure was studied by measuring pH changes during hydrolysis by NaOH: glass transition temperature by Differential Scanning Calorimeter (DSC); morphology of latex by Transmission Electron Microscope (TEM); and change of particle size and distribution by a particle analyzer.