Preparation of Uniform Size-Poly(styrene-co-butyl acrylate) Particles by Dispersion Polymerization
Seo HJ, Ahn JH, Lee KC
분산중합에 의한 단분산의 Poly(styrene-co-butyl acrylate) 미립자 제조
서형주, 안주현, 이기창
Abstract
Dispersion copolymerization of styrene(St) and butyl acrylate(BA) (100/0 ~ 0/100 wt%) in isopropanol/water medium was carried out at 70 ~ 80 ℃ in the presence of poly (vinyl pyrrolidone) and 2,2''-azobis (isobutyronitrile) as steric stabilizer and initiator, respectively. The resulting poly(St/BA) latexes, containing 100/0 ~ 50/50 wt% in St/BA monomer compositions, were found to be monodisperse particle diameter of 1.28 ~ 2.12 ㎛. But, the poly(St/BA) latex, containing 25/75 wt% in St/BA monomer composition, was found to have a broad size distribution with average particle diameter of 2.72 ㎛. Particle size of the poly(St /BA) latexes was in general increased and molecular weight of the latex particles was decreased with increasing BA wt%. Dispersion polymerization of St/BA (50/50 in wt%) was also carried out to investigate the effect of concentration of monomer, molecular weight of PVP stabilizers and its concentration, initiator types and its concentration, polymerization temperatures, agitation types, and isopropanol/water ratios on particle size and size distribution of the resulting latexes.
Isopropanol/water 분산매 하에서 styrene(St)/butyl acrylate(BA) (100/0~0/100 wt%)의 분산중합을 poly(vinyl pyrrolidone)과 2,2''-azobis(isobutyronitrile)을 각각 안정제와 개시제로 하여 70~80℃에서 행하였다. St/BA 단량체 조성이 100/0~50/50 wt% 범위에 걸쳐, 제조한 라텍스는 평균입자경이 1.28~2.12 ㎛
의 단분산성을 보이는 반면, BA 단량체 75 wt%에서는 2.72 ㎛
의 다분산 분포를 보였다. 일반적으로 BA 함량이 증가할수록 라텍스의 평균입자경은 증가하였고 고분자 미립자의 분자량은 감소하였다. 또한, St/BA (50/50 in wt%)의 분산중합을 행하여 단량체 농도, 안정제의 분자량 및 농도, 개시제의 종류 및 농도, 중합온도, 가교단량체의 농도, 교반기의 종류, isopropanol/water의 중합분산매 조성 등의 중합 조건에 따르는 poly(St/BA, 50/50 wt%)라텍스의 입자경 및 입자경 분포를 조사하였다.
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