The evolution of particle size and the ratio of particle number (Np) and droplet number (Nd) of the mini-emulsion copolymerization of γ-methacryloxy propyl trimethoxysilane (MPS) and styrene (St) were investigated.The droplet and particle size were measured by dynamic light scattering (DLS).The individual conversion of St was followed by gas chromatography

and the overall conversion was measured by gravimetry.The surface tension of the mini-emulsion was measured with the plate method using Krüss processor tensiometer.With the increase of the ratio of MPS to St

the size of mini-droplets decreased gradually due to the decrease of the interfacial tension between oil and aqueous phase.The evolution of particle size and Np/Nd were tightly dependent on the nature of initiators.The particle size of the system initiated by KPS increased and Np/Nd decreased in the process of polymerization which could be ascribed to the increase of the formation of hydrogen bonding between particles due to the existence of the extending polymer chain with silanol groups on the interface of the latexBecause the radicals were mainly produced in the latex

the particle size of the system initiated by AIBN nearly kept constant in the process of polymerization.With the increase of the MPS/St [JP+3]ratio

the particle size increased

but Np/Nd decreased

which could be attributed to the decrease of adsorption ability of the surfactant on the latex and the increase of the formation of hydrogen bonding between particles as a result of the increase of hydrolysis resultants.The value of Np/Nd was independent of the amount of surfactant and HD.The sizes of initial mini-emulsion in acidic and basic conditions were much lower than that in neutral condition.However

as the polymerization proceeded

the particle size under acidic and basic conditions increased and the particle number decreased rapidly.It was worthwhile to note that the final products in acidic and basic conditions were still emulsion.