Styrene-butyl acrylate-N,N-dimethylN-butylN-methacrylamidino propyl ammonium bromide emulsifier-free emulsion copolymerization

Abstract

Emulsifier-free emulsion copolymerization of styrene (St) and butyl acrylate (BA) in the presence of cationic functional comonomer N,N-dimethyl N-butyl N-methacrylamidino propyl ammonium bromide (DBMPAB) was carried out using azobis(isobutylamidine hydrochloride) (AIBA) as initiator. The surface properties of particles were studied by testing the actual value of -N + ≡ and -C(NH 2 ) 2 + on the surface of particles and the surface charge density. The copolymer particles were characterized by transmission electron microscopy (TEM). The effects of reaction temperature, DBMPAB content, AIBA content, and ionic strength on conversion of monomer, average diameter D w ) and number (N p ) of copolymer particles were investigated. Under constant ionic strength the average diameter of copolymer particles (D W ) decreased with increasing AIBA and DBMPAB concentration, and decreased with rising reaction temperature. At constant concentration of comonomer and initiator and constant monomer composition, D w showed an increasc-decrease-increase with ionic strength plot. The polymerization rate increased with increasing DBMPAB content, AIBA content and rising temperature. The surface charge properties of particles were mainly decided by DBMPAB content, AIBA content, and ionic strength.