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Poly‐β‐hydroxybutyric acid—a naturally occurring thermoplastic material
Author(s) -
Werber F. X.,
Baptist J. N.
Publication year - 1964
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760040403
Subject(s) - materials science , crystallinity , polyester , polymer , polypropylene , thermoplastic , brittleness , composite material , rheology , hydrolysis , chemical engineering , polymer chemistry , organic chemistry , chemistry , engineering
Poly‐β‐hydroxybutyric acid has been isolated in quantities sufficient for characterization and evaluation of mechanical properties from both Bacillus megaterium and a special strain of Rhizobium. Its presence in a larger variety of bacteria than previously suspected has been demonstrated by a screening method based on density‐gradient centrifugation. The intrinsic viscosity of the isolated polymer has been shown to depend on the technique of isolation; basic solvents facilitate hydrolytic cleavage of the polyester. Mechanical properties of the polymer are based on the high crystallinity and polarity of the material; in a highly crystallized state, it is quite brittle, but its rigidity exceeds that of polypropylene. Thermal degradation of molecular weight, due to beta‐eliminatin of the carboxyl group from the polyester structure, severely limits processing of the polymer in the melt.