Characterization of thermoplastic apparent interpenetrating polymer networks CPU-S/AA by WAXS, SAXS, TSDC, DRS and DMA

Thermoplastic apparent interpenetrating polymer networks (t-AIPNs), prepared by mechanical blending in a common solvent of crystallisable polyurethane (CPU) and styrene/acrylic acid random copolymer (S/IAA), were investigated by means of wide-angle and small-angle X-ray scattering (WAXS and SAXS), thermally stimulated depolarization currents (TSDC) measurements in the temperature range 77-420 K, dielectric relaxation spectroscopy (DRS) measurements in the frequency range 10^-2-10⁶ Hz and dynamic mechanical analysis (DMA) measurements in the frequency range 10^-1-10 ² Hz and the temperature range 180-500 K. Several mechanical and dielectric relaxations were observed and analysed. The two components show weak affinity to each other. The t-AIPNs can be classified into two groups with high and low contents of CPU, showing essentially the behaviour of CPU and of S/AA, respectively. On the other hand, deviations from additivity in several properties indicate interactions between the two components, caused by the formation of H-bonds between their functional groups, and resulting in partial miscibility. In addition, significant changes are observed on some properties of the t-AIPNs on addition of small amounts of either of the components