Compositional heterogeneity and properties of the blends of methacrylic acid copolymers with methacrylic esters

The mechanical behavior of blends of butyl acrylate and butyl methacrylate copolymers containing 27-33 mol % methacrylic acid and the viscosity of their solutions are shown to be markedly controlled by the compositional heterogeneity of the components. The blends containing a compositionally homogeneous butyl methacrylate-methacrylic acid copolymer and 10-50 wt % compositionally heterogeneous butyl acrylate-methacrylic acid copolymer were characterized by the maximum strength, transparency, and specific rheological properties. This behavior is likely related to a better compatibility between the components as compared with that in other blends. The compatibility of the copolymers was assessed by studying the optical density of solutions, light transmittance, and density of films and by measuring the specific surface area of the densely packed Langmuir monolayers in the blends.