PRS (R) paraffin wax was encapsulated by means of suspension-like copolymerization of methyl methacrylate (MMA) with butyl acrylate (BA). The effects of the polymeric shell dry glass transition temperature (T-g) and the reaction temperature (T-r) were then studied. Additionally, the evolution of particle diameter, molecular weight, conversion, and T-g during polymerization was also researched. The chemical properties of the shell material (acrylic polymer), together with those found in the core material (PRS (R) paraffin wax), for instance: polarity and interfacial tensions, largely determine whether the morphology of the microcapsules will be thermodynamically favored or not. The high polarity of MMA ((0) = 18 mN m(-1)) and BA ((0) = 24 mN m(-1)) should provide a thermodynamic driving force to cover the paraffin wax droplet which would result in a core/shell thermodynamically favored structure. However, most systems are defined by kinetics rather than thermodynamics such as the monomers dry T-g and T-r. It was observed that penetration of polymer radical chains was severely limited when the dry T-g was 10 degrees C above the reaction temperature, resulting in irregular and undifferentiated particles. However, penetration did occur when the copolymeric shell dry T-g was approximate to 10 degrees C below the reaction temperature which led to uniform and spherical particles being synthesized. POLYM. ENG. SCI., 54:208-214, 2014. (c) 2013 Society of Plastics Engineers