ABSTRACT
Abstract ................................................................................................... 18 2.1 Introduction .................................................................................... 18 2.2 X-ray and DSC Studies .................................................................. 20 2.3 Dynamics of ESR Probe Mobility and H-D Exchange Kinetics in
D2O ................................................................................................ 22 2.4 Conclusions .................................................................................... 24 Keywords ................................................................................................ 24 References ............................................................................................... 25
ABSTRACT
The specific features of novel blends on the basis of copolymers 3-hydroxybutyrate with hydroxyl valerate (95:5 mol %) (PHBV) and segmented polyetherurethane (SPEU) have been investigated. The samples with different content (100/0, 60/40, 40/60, 50/50, and 0/100 wt.%) are explored by structural (WAXS, FTIR), thermo physical (DSC) and dynamic (probe ESR nano analysis, H-D isotopic exchange) methods at about physiological (40 °C) and elevated (70 °C) temperatures after treatment by water or heavy water. It was shown that for the first 5 h during water exposition at 40 °C the individual polymers (PHB and SPEU) and the blends kept structural stability that was confirmed by ESR time correlation data for the probe TEMPO and stable crystallinity (WAXS, DSC). Dependence of H-D exchange rate on the blend content has minimum at PHB/SPEU ratio 60/40. At 70 °C the water-temperature effect leads to enhanced molecular mobility of TEMPO in all systems besides the individual PHB. In accordance with DSC data in this case the crystallinity and melting points of PHBV are decreased. The descriptions of PHBV-SPEU system using a combination of structural and dynamic features gives a more complete assessment of its structural evolution at relatively short-term times, which precede its hydrolytic decomposition.
