Emulsion polymerization process: effects of particle nucleation mechanism on properties of acrylic-styrene latex

The properties of acrylic-styrene latex (ASL) were investigated  using two different nucleation methods by changing the sequence of addition of components, without changing the overall composition of the systems. In the first method, the semi-batch method was used and in the second method, the seeded semi-batch method was used and these were named ASL-1 and ASL-2, respectively. The latexes were characterized by dynamic light scattering, differential scanning calorimetry, tensiometer, gel permeation chromatography, viscometer, scanning electron microscopy, and transmission electron microscopy. The results showed that despite having the constant compositions, the two latexes have significant differences in different parameters studied. Sample ASL-1 showed higher zeta potential, glass transition temperature, surface tension, number average molecular weight and viscosity compared to sample ASL-2, but showed lower particle size. The two synthesized ASLs were also evaluated for their potential for pigment wetting and dispersion, as measured by the color development, by incorporation of three pigment pastes (red, green and blue). The study showed interesting findings that for each color pigment paste, ASL-1 produced deeper color tone than ASL-2. Also, color differences (L, a, b scale), contrast ratios, and gloss of ASL-1 and ASL-2 latexes-based pigment pastes were compared.