A novel polymerization method based on pressure drop for monomodal high solid content low viscosity latexes of poly(ethylene-co-vinyl acetate)

A novel polymerization route to synthesize monomodal high solid content latexes of poly(ethylene-co-vinyl acetate) with low viscosity based on pressure drop was designed. This route consists of a semi-continuous polymerization step (step I) and a pressure drop step (step II). An investigation of the effect of pressure drop on the polymerization showed that pressure drop led to a secondary reaction. Secondary nucleation of a large number of particles followed by limited flocculation was caused by the pressure drop, which further led to an optimization of the particle size distribution (PSD) of latex. The effect of pressure drop on formation and growth of new particles was investigated and a possible mechanism was inferred. Latex with solid content of 70.1 wt% and a viscosity of 640 mPa s at a constant shear rate of 20 s−1 was obtained through this method.