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Journal ArticleDOI

Crystallization and morphology of a bacterial thermoplastic: poly-3-hydroxybutyrate

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TLDR
In this paper, a number of interesting results on the physical properties of poly-3-hydroxybutyrate (PHB) were presented on crystallization kinetics, morphology of melt-and solution-crystallized PHB, the variation of lamellar thickness with crystallization temperature, and the assessment of some thermodynamic quantities.
Abstract
This paper presents a number of interesting results on the physical properties of poly-3-hydroxybutyrate (PHB). Data are presented on crystallization kinetics, morphology of melt- and solution-crystallized PHB, the variation of lamellar thickness with crystallization temperature, and the assessment of some thermodynamic quantities. These properties include surface free energies, heat of fusion and melting, and glass transition temperatures. It is shown that the special properties of PHB such as the large spherulite size, which is probably due to its exceptional purity, make it an ideal material for model studies of polymer crystallization and morphology. For example, we show that the variation of growth rate with crystallization temperature is consistent with the very latest theories; and that the single crystal morphology has important implications for the understanding of crystal growth in other polymer systems.

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Journal ArticleDOI

Occurrence, metabolism, metabolic role, and industrial uses of bacterial polyhydroxyalkanoates.

TL;DR: The physiological functions of PHB as a reserve material and in symbiotic nitrogen fixation and its presence in bacterial plasma membranes and putative role in transformability and calcium signaling are also considered.
Journal ArticleDOI

Synthesis, structure and properties of polyhydroxyalkanoates: biological polyesters

TL;DR: This review attempts to bring together the biochemical and physicochemical aspects of PHA along with new perspectives on its potential therapeutic applications to show that the polymer's physical properties can be regulated to a great extent.
Journal ArticleDOI

Physico-mechanical properties of degradable polymers used in medical applications: A comparative study

TL;DR: The physico-mechanical properties of degradable polymers used for medical applications have been characterized and flexural storage modulus as a function of temperature was determined by dynamic mechanical analysis.
Journal ArticleDOI

Tissue response and in vivo degradation of selected polyhydroxyacids: Polylactides (PLA), poly(3-hydroxybutyrate) (PHB), and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHB/VA)†

TL;DR: Several samples showed pronounced bimodal molecular weight distributions (MWD), which may be due to differences in degradation rate, resulting from variability in distribution of crystalline and amorphous regions within the samples, i.e., nonenzymatic and enzymatic, which are involved in the degradation process.
Journal ArticleDOI

The chemomechanical properties of microbial polyhydroxyalkanoates

TL;DR: In this article, a review comprehensively covers current understanding with respect to PHA biosynthesis and crystallinity, and the effect of composition, microstructure and supramacromolecular structures on chemomechanical properties.
References
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Polymer single crystals

Journal ArticleDOI

Regime III crystallization in melt-crystallized polymers: The variable cluster model of chain folding

TL;DR: In this article, the authors extended the kinetic nucleation theory of chain folding, including the effects of reptation, to predict the increase in crystal growth rate G that is implied by measurements on PE and POM at moderately large undercoolings.
Journal ArticleDOI

Structural studies of polyesters: 5. Molecular and crystal structures of optically active and racemic poly (β-hydroxybutyrate)

TL;DR: In this article, the molecular and crystal structure of naturally occurring optically active poly(β-hydroxy-butyrate) was analyzed by X-ray diffraction and it was shown that the racemic polymer has an isotactic configuration and consists of two kinds of crystallites.
Journal ArticleDOI

Physical properties of poly-β-hydroxybutyrate

TL;DR: Comparison of the crystalline conformation of poly-β-hydroxybutyrate with that proposed for polypivalolactone suggests that these two molecules are isoconformational.
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