Synthesis and Characterization of a Pharmaceutical Polyacrylate Emulsion

Using dibutyl itaconate (DBI), ethyl acrylate (EA), methacrylate (MMA) and acrylic acid (AA) as raw monomer materials, sodium lauryl alkyl sulfate (SDS) and OP-10 as complex emulsifier system and potassium peroxy-sulfate (KPS) as initiator, the EA/MMA/AA/DBI copolymer emulsion with solid content of 31.48% was prepared by seed emulsion polymerization. Effects of reaction factors on monomer conversion and mean diameter of the emulsion were studied, and the prepared copolymer was tested and characterized by Infra-red spectrum (IR), Differential Scanning Calorimetry (DSC), Gel Permeation Chromatography (GPC), Transmission Electron Microscope (TEM), and ZataSizer for particle size distribution. The DSC pattern of the prepared copolymer emulsion shows that its vitrification temperature (Tg) is 6.27℃.The GPC chromatogram of the copolymer shows that its weight-average molecular weight is equal to 7.8428×105, number-average molecular weight is 3.3373×105, and poly dispersion is 2.35. Particle morphology of the prepared copolymer emulsion was examined by TEM, and spherical emulsion particles with mean diameter of about 100 nm were observed. The most optimum reaction conditions of EA/MMA/AA/DBI copolymer emulsion preparation were found as follows: emulsifier dosage is 4.5%~5.5%, initiator dosage is 0.45%~0.55%, AA content is 1.0% and DBI content is 0.5%. Using above reaction conditions, the synthetic latex prepared has narrow particle size distribution and excellent properties. Experimental results also show that the water absorption of the copolymer membrane formed by the emulsion prepared can be evidently reduced by adding very little amount of DBI.