Polymer and Materials Science
Wiley InterScience Backfile Collection 1832-2000
Chemistry and Pharmacology
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
The embrittlement of poly(hydroxybutyrate), and its copolymers with hydroxyvalerate, on storage at room temperature has been considered in the light of the relaxation of the interlamellar glassy regions and also the development of secondary crystallisation. From a study of the kinetics of the two processes, the first mechanism has been eliminated particularly since the glass transition, as measured by dielectric thermal analysis (DETA), was below room temperature.Control of the primary crystallisation of PHB was observed to reduce the extent of the development of secondary crystallisation and to eliminate the embrittlement on storage. DMTA and DETA were found to be useful techniques for measuring the mobility of the amorphous regions in partially crystalline samples, under conditions where DSC was unable to detect any glass transition.
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