Influence of compositions and polymerization processes on morphologies, molar mass distributions, and phase structures of n-Butyl acrylate–methyl methacrylate copolymers

The target of the research is to examine influence of a polymerization process and monomer ratio on structures and compositions of phases in an emulsion copolymerization of n-butyl acrylate (BA) and methyl methacrylate (MMA). Emulsion copolymerizations are performed using three different BA/MMA weight ratios (60%/40%, 50%/50%, and 40%/60%) and two different processes, statistical batch and seeded emulsion polymerizations. Phase structures, monomer compositions, and morphological stabilities of copolymers are investigated by differential scanning calorimetry, 1H-NMR, and scanning electron microscopy. Gel permeation chromatography is used to follow the changes in the molar mass distribution during syntheses. The gel content and backbiting level of end products are measured by extraction and 13C-NMR, respectively. Copolymerizations give products with a bimodal molar mass distribution and three or two separate phases having different BA/MMA compositions. The morphological stability of particles decreases with the increasing BA fraction in the feed. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41467.