Transition behavior, surface characteristics and film formation of functionalized poly(methyl methacrylate-co-butyl acrylate) particles

Carboxylic functionalized poly(methyl methacrylate-co-butyl acrylate) particles were synthesized by soap free emulsion polymerization using sodium salts of itaconic acid and acrylic acid. Transition behaviors of these latexes in terms of glass transition of matrix and cluster were found to be completely different from those synthesized by solution polymerization. This disparity was attributed to the difference between co-monomers sequence distribution along the chains. Distribution of functional groups in the latexes was determined by conductometric titration. Film formation process of the latexes was also examined and interpreted based on the density of surface functional groups, transition behaviors, and particle size. AFM images revealed that, as the amount of these ionic co-monomers increases, more ordered films are obtained, while the particle inter-diffusion is greatly retarded. A dimensionless parameter indicating relative roughness of the films further supported the aforementioned findings.