The Stability of Emulsion Polymerization for Organosiloxane Modified Acrylate Nanolatex

Organosiloxane modified acrylate nanolatex was synthesized by different emulsion polymerization processes with methylmethacrylate (MMA) and butylacrylate (BA) as main monomers. The effects of polymerization methods, reaction temperatures, amounts of initiator, emulsifier, vinyltriethoxysilane (A151), 2-hydroxyethl methacrylate (HEMA), methyl acrylic acid (MAA) contents and pH on polymerization stability were investigated by measuring coagulation rate and monomer conversion. The results showed that with semi-continuous emulsion polymerization, organosiloxane modified acrylate nanolatex with particle size of about 80 nm and with low coagulation rate of 0.5% as well as solid content of 40 wt% was obtained under the condition of the better reaction stability when temperature at 80˚C - 85˚C, the mass fraction of initiator, emulsifier, A151, HEMA, MAA at 0.5%, 3%, 4%, 2%, 2% respectively. The increase of emulsifier contents can improve the stability of the polymerization process; but the temperature increase and the more dosage of A-151 are not conducive to the reaction stability. The optimal values for the stirring speed, pH and dosage of initiator exist for the stable state in emulsion polymerization.