Preparation of stable poly(methacrylic acid)- b -polystyrene emulsion by emulsifier-free emulsion iodine transfer polymerization (emulsion ITP) with self-assembly nucleation
- Citation data:
Polymer, ISSN: 0032-3861, Vol: 110, Page: 124-130
- Publication Year:
- Chemistry; Materials Science
Emulsifier-free emulsion iodine transfer polymerization (emulsion ITP) of styrene with self-assembly nucleation was successfully carried out with some living features for the first time as follows. Firstly, poly(methacrylic acid) (PMAA; degree of polymerization, 37)-iodide (PMAA 37 -I) as a macro chain transfer agent was synthesized by solution reversible chain transfer catalyzed polymerization (solution RTCP) with 2,2′-azobis(4-methoxy-2,4-dimethylvaleronitrile) as an initiator, iodoform as a chain transfer agent and germanium iodide as a catalyst in dioxane at 40 °C. A dioxane solution of PMAA37-I and styrene were added stepwisely under stirring into an aqueous solution (pH∼9), and then emulsion ITP was initiated by adding 4,4′-azobis(4-cyanopentanoic acid) at 60 °C with stirring at 500 rpm. Stable polystyrene emulsion was obtained without coagulation. At 100% conversion, the number-average diameter was 223 nm. Number-average molecular weight ( M n ) increased linearly with conversion, which were well closed to theoretical M n and molecular weight distribution at 100% conversion was comparatively narrow ( M w / M n ∼2.1).