Non-aqueous PVAc dispersions prepared in a reactive epoxy functionalized PDMS liquid medium

The system vinyl acetate (VAc)/poly(dimethylsiloxane) diglycidylether (PDMS-DGE) is a typical example of two monomers where both components are polymerizable in a “one-pot” procedure by two distinct reaction mechanisms. Non-aqueous dispersions (NAD) are obtained in a first step by free-radical polymerization of the dispersed VAc-PVAc phase. The study of the reaction kinetics has shown that the polymerization rate is mainly influenced by the partition coefficient of VAc between both phases in presence. The colloidal characteristics of the NAD, such as particle size, stability and viscosity were examined in function of monomer and initiator concentrations. Preliminary UV curing tests of the PDMS-DGE phase in the presence of a cationic photoinitiator have shown that PVAc/PDMS two-phase coatings can be obtained, without any solvent emission.