Thermal characterization of acrylic-based latex blend films by modulated and pulsed differential scanning calorimetry

A complete thermal characterization of acrylic-based latex blend films is presented here using thermogravimetric analysis (TGA), modulated differential scanning calorimetry (MDSC) and pulsed differential scanning calorimetry (pulsed-DSC). These blend films are prepared from aqueous-based latices of poly(methyl methacrylate-co-ethyl acrylate) and poly(methyl methacrylate-co-butyl acrylate). The copolymer compositions are controlled to yield glass transition temperatures, T-g, of 45 degrees C and -5 degrees C, respectively. The presence of two distinct glass transition temperatures at all compositions confirm the phase separated nature of these blends. There is partial miscibility at intermediate compositions arising from significant segmental inter-diffusion across the particle interface. Constant temperature pulsed-DSC experiments, as well as those through the T-g, yield a rate-independent specific heat profile for these blends. (C) 1999 Elsevier Science B.V. All rights reserved.