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4250340 
Journal Article 
Effect of external influences on the structural and dynamic parameters of polyhydroxybutyrate-hydroxyvalerate-based biocomposites 
Karpova, SG; Iordanskii, AL; Popov, AA; Shilkina, NG; Lomakin, SM; Shcherbin, MA; Chvalun, SN; Berlin, AA 
2012 
1 
Russian Journal of Physical Chemistry B, Focus on Physics
ISSN: 1990-7931
EISSN: 1990-7923 
6 
1 
72-80 
WOS:000301570000013 
The EPR probe, DSC, and WARDX methods are applied to study the molecular dynamics and structure of 3-hydroxybutyrate-3-hydroxyvalerate copolymer (PHBHV, 5 mol %) and its mixtures with segmented polyester urethane (SPEU) upon ozone oxidation and hydrothermal treatment. It is shown that time-limited (3 and 5 h) treatment of the mixed compositions with water at 40A degrees C has no noticeable effect on the dynamics of rotation of the probe (EPR) and the crystallinity of PHBHV (DSC). However, hydrothermal treatment at 70A degrees C causes an increase in the molecular mobility of the probe in the system, accompanied, according to XRD and DSC analyses, by increases in the degree of crystallinity and density of PHBHV crystallites. The temperature of fusion of mixed compositions also increases. During ozonation, the mobility of the probe slows gradually in PHBHV all the time, whereas in mixed compositions, a slowdown is observed only up to 3 h of oxidation time, after which, up to 5 h of ozonation, the mobility increases, along with decreases in the fraction of the amorphous phase and in the density of the crystallites. 
biodegradable composition; crystallinity; probe EPR; DSC; X-ray analysis; ozone; water