Characterization of thermoplastic interpenetrating polymer networks by various thermal analysis techniques

Thermoplastic interpenetrating polymer networks (t-IPNs), prepared by melti ng and pressing of crystallizable polyurethane (CPU) and styrene/acrylic ac id random copolymer (S/AA) in wide ranges of composition, were investigated by the combination of various thermal analysis techniques: differential sc anning calorimetry (DSC), thermomechanical analysis (TMA), thermally stimul ated depolarization currents (TSDC) and thermally stimulated conductivity ( TSC) measurements, as well as broadband dielectric relaxation spectroscopy (DRS), The results show that the t-IPNs under investigation are microhetero geneous systems with contributions to microheterogeneity from both the hete rogeneity of the individual polymers and the thermodynamic incompatibility of the components. (C) 2001 Elsevier Science B.V. All rights reserved.