Structure-property relationships in thermoplastic-apparent interpenetrating polymer networks based on crystallizable polyurethane and styrene-acrylicacid copolymer

Structure-property relationships in thermoplastic-apparent interpenetrating polymer networks (t-AIPNs), prepared by mechanical blending in a common so lvent of crystallizable polyurethane (CPU) and styrene/acrylic acid random copolymer (S/AA), were investigated by means of wide-angle and small-angle X-ray scattering (WAXS and SAXS), dynamic mechanical analysis (DMA), therma lly stimulated depolarization currents (TSDC) techniques, dielectric relaxa tion spectroscopy (DRS), and density, water uptake, deformation, and streng th characteristics measurements. Several mechanical and dielectric relaxati ons of the pure components were characterized, and the effects thereupon in duced by blending were followed. The two components show weak affinity to e ach other. The t-AIPNs can be classified into two groups with high and low contents of CPU, showing essentially the behavior of CPU and of S/AA, respe ctively. On the other hand, deviations from additivity in several propertie s indicate interactions between the two components, caused by the formation of H-bonds between their functional groups, and resulting in partial misci bility. In addition, significant changes are observed on some properties of the t-AIPNs on addition of small amounts of either of the components. (C) 1999 John Wiley & Sons, Inc.