ISSN:
0032-3888
Keywords:
Chemistry
;
Chemical Engineering
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
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.
Additional Material:
3 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pen.760040403
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