Studies on the preparation and characterization of poly(4‐vinylpyridine) microgel. I. Preparation with polymer emulsifier

Poly(4‐vinylpyridine) (P4VP) microgels with a narrow size distribution have been prepared by a special emulsion polymerization method. This is to say that P4VP, to which cation and double‐bond were introduced with iodomethane and chloromethylstyrene, by quarternization reaction was used as a polymer emulsifier. Divinylbenzene was used as a crosslinking agent. It was found that the microgel became larger with the increase in monomer concentration, and became smaller and softer with the enhancing emulsifer/monomer ratio. Microgels, with the diameter of between 70–700 nm, were obtained by varying the monomer concentration from 1.0 wt % to 5.0 wt %, and by varying the emulsifier/monomer (unit/unit) ratio from 0–10.0 mol %. Compared with conventional emulsion polymerization with surfactant or hydrophilic monomer, this method provides an advantage in that monoingredient microgels can be obtained.