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11.
Semi-interpenetrating polymer networks (semi-IPN) of linear polyurethane (LPU) and heterocyclic polymer network (HPN) were characterized by IR spectroscopy, small-angle X-ray scattering, differential calorimetry with diathermal shells (temperature interval 130-500 K), and dynamic mechanical analysis (temperature interval 150-500 K and frequency range 0.3-30 Hz). The main results obtained may be summarized as follows: (1) The affinity of HPN towards the soft LPU microphase is responsible for the absence of large-scale heterogeneity of semi-IPNs on their base (at least, at low HPN/LPU ratios). (2) Phenomenological analysis of small-scale, Arrhenius-like subglass relaxations (γ1 and γ2 in LPU and in HPN, respectively) revealed little interference of HPN with relaxation centers (RCs) of LPU in semi-IPNs, while the local environment of RCs in HPN, on the contrary, strongly depended on semi-IPN composition.  相似文献   
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Thermoplastic apparent interpenetrating polymer networks (thermoplastic‐AIPNs) were prepared at several compositions by melting and pressing of crystallizable polyurethane (CPU), based on butylene adipate glycol (BAG), and styrene/acrylic acid random copolymer (S/AA). Structure‐property relationships in the thermoplastic‐AIPNs were investigated by means of wide‐angle and small‐angle X‐ray scattering (WAXS, SAXS), differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA), thermally stimulated depolarization currents (TSDC) techniques, dielectric relaxation spectroscopy (DRS) and several physico‐mechanical characterization techniques. The results obtained by the various techniques were critically compared to each other. They suggest that the two components show weak affinity to each other and that the thermoplastic‐AIPNs can be classified into two groups with high and low contents of CPU, showing essentially the behavior of CPU and S/AA, respectively. However, deviations from additivity and significant changes for several properties on addition of small amounts of either of the components suggest partial miscibility. Most of the results are explained by physical interactions of COOH‐groups of AA in S/AA with the ester groups of the flexible CPU blocks, which promote microphase separation in both the CPU and the S/AA components.  相似文献   
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Structure–property relationships in thermoplastic‐apparent interpenetrating polymer networks (t‐AIPNs), prepared by mechanical blending in a common solvent 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), thermally stimulated depolarization currents (TSDC) techniques, dielectric relaxation spectroscopy (DRS), and density, water uptake, deformation, and strength characteristics measurements. Several mechanical and dielectric relaxations of the pure components were characterized, and the effects thereupon induced by blending were followed. 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 behavior 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. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 385–397, 1999  相似文献   
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Pseudo-thermoplastic interpenetrating polymer networks (p-TIPNs) prepared by mechanical mixing of a crystallizable polyurethane (CPU) and styrene/acrylic acid random copolymer (S/AA) were characterized by specific heat capacity measurements in the temperature interval 133-433 K, as well as by wide-angle and small-angle X-ray scattering. It was established that:

1. Crystallizability of BAG is the main cause of microphase-separated morphology of CPU.

2. Limited miscibility of CPU with S/AA significantly affects the phase morphology of p-TIPNs on their base. Mixed microphase of fixed composition [CPU/(S/AA) = 90/10] and essentially pure microphase of S/AA are the main structural entities in as-quenched samples of p-TIPNs of whatever nominal composition. More complex phase morphology (that is, coexistence of essentially pure microphases of crystallized BAG and of S/AA, and of the mixed CPU/(S/AA) microphase enriched with S/AA) is expected for initial samples.  相似文献   
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