Small-angle neutron scattering study on specific polymerization loci induced by a copolymerization of polymerizable surfactant and styrene during miniemulsion polymerization
ミニエマルション重合において重合性界面活性剤が誘発する特異的重合反応場の中性子小角散乱による研究
元川 竜平 ; 谷口 竜王*; 佐々木 祐亮*; 榎本 勇人*; 村上 史泰*; 春谷 昌克*; 桑折 道済*; 中平 隆幸*
Motokawa, Ryuhei; Taniguchi, Tatsuo*; Sasaki, Yusuke*; Enomoto, Yuto*; Murakami, Fumiyasu*; Kasuya, Masakatsu*; Kori, Michinari*; Nakahira, Takayuki*
We have investigated the origin of a specific polymerization locus that yielded copolymer particles with a bimodal gel permeation chromatographic profile in the early stage of miniemulsion polymerization of styrene (St) with CDMAEMA. The formation of particles by miniemulsion polymerization using CDMAEMA was investigated as a function of the polymerization time (), and was compared with that using the non-polymerizable surfactant CTAB. GPC and elemental analysis indirectly predicted two different polymerization loci in the St/CDMAEMA/V50 polymerization system. Time-resolved SANS was used to directly observe and examine the specific polymerization loci in the miniemulsion polymerization solutions. The droplets formed in St/CDMAEMA/V50/PSt hydrophobe at the initial stage of the polymerization were not fully stabilized by CDMAEMA and poly(CDMAEMA-ran-St), and were found to build up the large aggregates. The spherical droplets were stabilized later in tp 20 min by forming a homogeneous dispersion in the water phase. Porod analysis of the power law scattering observed by SANS provided direct evidence for the specific polymerization loci, which appeared in the early stage of the polymerization system of St/CDMAEMA/V50/PSt hydrophobe on the surface of the droplet, and was the origin of the bimodal peaks in the GPC chromatogram.