| Abstract: | Crosslinked polymer seed latexes of butyl acrylate, methyl methacrylate and methacrylic acid were synthesized with ethylene glycol dimethacrylate as a crosslinking agent in a first step. Three different processes of seeded emulsion polymerization were used to prepare an outlayer of polysiloxane on the above seed latex particles: (A) direct anionic polymerization of D4 (octamethyl tetracyclosiloxane) catalyzed by potassium hydroxide; (B) direct cationic polymerization of D4 onto the seed catalyzed by dodecylbenzene sulfonic acid; (C) a vinyl-containing polysiloxane prepared by copolymerization of D4 and vinyl septamethyl tetracyclosiloxane was added before the D4 cationic polymerization. Characterization by transmission electron microscopy showed that only process C provided satisfactory results. Film hardness was measured, and the latex film from process C demonstrated the lowest hardness of all the films. The mechanism of polymerization is discussed. |
