title: Direct observations of three nucleation/growth processes of charge-stabilized dispersion polymerizations with varying water/methanol ratios.
abstract: This article presents observations of three polymerization modes of a self-developed cation-charge-stabilized styrene/water/methanol dispersion polymerization system: (1) a water/methanol (20/80) system, corresponding to a typical dispersion polymerization mode where the particle nucleation occurred in the solution phase and growth in the particle phase; (2) a pure CH(3)OH system, including a first nucleation in the solution phase with growth by absorption of the small particles and polymers formed in this phase, and a secondary nucleation with growth in the particle phase, when high molecular weight copolymers appeared in the solution phase; and (3) a water/methanol (5/95) system, similar to the conventional dispersion polymerization mode during the first 90 min, with subsequent epitaxial growth. Interestingly, the metastable state of the nucleation stage, including minuscule 6-nm particles, their aggregates, and the aggregating process, was first observed experimentally. By quantitatively following the relationship of the deposited molecular weight and the nucleation/growth process in the three systems, it was proposed that the molecular weight of the deposited polymer had to reach a specific high value before they could absorb or capture monomer to form smooth/spherical nuclei or particles.
authors.affiliation: Key Laboratory of Carbon Fiber and Functional Polymers, Ministry of Education, College of Material Science and Engineering, Beijing University of Chemical Technology, Beijing, 100029, PR China.
authors.forename: Fen
authors.initials: F
authors.lastname: Zhang
authors.forename: Yuhong
authors.initials: Y
authors.lastname: Ma
authors.forename: Lianying
authors.initials: L
authors.lastname: Liu
authors.forename: Wantai
authors.initials: W
authors.lastname: Yang