LCST over UCST Phase Behavior of a Nanocomposite Determined by Differential Scanning Calorimetry and Rheomechanical Analysis

Phase behavior of butylacrylate-rich and methyl methacrylate-rich copolymers of an emulsion copolymerized 30/70 methyl methacrylate/butyl acrylate (MBC30) copolymer and its nanocomposite containing 5 wt. % mono-size soft nanoparticles of 70/30 styrene/acrylonitrile copolymer (SAN70) were characterized using time-sweep rheomechanical analysis. The test was conducted at 150 °C, the near-critical temperature determined by differential scanning calorimetry, and depicted matrix enhanced storage modulus, G’, followed by a plateau implying criticality. The latex blended and dried nanocomposite, however, represented three orders of magnitude lower G’ with a maximum-crossing evolution