The preparation of nano—CaCO_3 emulsion for the in—site polymerization modification of PVC and its properties

The emulsifying effects of poly(vinyl alcohol),sodium dodecyl benzene sulfonate, polyacrylamide and emulsifying agent TY-01 on nano-CaCO_3 were compared.The optimum using amounts of emulsifying agent TY-01 were determined as well as the working parameters of agitation and ultrasonic oscillation.Influences of solid contents in emulsion on viscosity and pH value were studied.The dispersion of nano-CaCO_3 was observed by SEM.The results showed that: (1)amoung the four kinds of emulsifying agent,the emulsifying effect of emulsifying agent TY-01 was the best,and the optimum mass ratio of emulsifying agent TY-01 to nano-CaCO_3 was 1: 20;(2)during the preparation of emulsion,the stirring speed would be more than 800 r/min,and the stirring time could be shortened if the stirring speed was increased or ultrasonic oscillation was adopted; (3)with the increase of solid contents in emulsion,the pH value of emulsion was kept essentially constant and its viscosity was increased sharply;(4)nano-CaCO_3 treated by emulsifying agent could homogeneously disperse in water and had uniform granularity with even particle size 50 nm.