Determination of multiple thermal degradation mechanisms of poly(3-hydroxybutyrate)

Ariffin, Hidayah; Nishida, Haruo; Shirai, Yoshihito; Hassan, Mohd Ali

doi:10.1016/j.polymdegradstab.2008.05.020

Cited by 103 publications

(97 citation statements)

References 34 publications

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“…For the plain PHB, mostly statistical intramolecular decomposition with formation of crotonate end groups takes place during thermal but PHB thermal decomposition could be easily decreased by carboxylate end groups due to E1cB mechanism. So, PHBg-AA had a lower IDT value than PHB [41,42]. As compared with the neat PHB or the PHB-g-AA copolymer, the PHB/MWNTs or PHB-g-AA/MWNTs-OH hybrids had a positive effect on the value of IDT and gave the higher amount of residual ash ( Figure 5).…”

Section: Thermal Properties Of Blendsmentioning

confidence: 96%

Poly(3-hydroxybutyrate)/multi-walled carbon nanotubes nanocomposites: preparation and characterizations

Liao

2012

Designed Monomers and Polymers

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In this study, the poly(3-hydroxybutyrate)/multi-walled carbon nanotubes (PHB/MWNTs) nanocomposite was prepared by means of a melt blending method. To improve the compatibility/dispersability of MWNTs within the PHB matrix, the acrylic acid grafted poly(3-hydroxybutyrate) (PHB-g-AA) and the multihydroxyl functionalized MWNTs (MWNTs-OH) were used as alternatives. Based on the results of TEM micrographs, FTIR spectra, 13 C solid-state NMR spectra, XRD patterns, and thermal and mechanical characterizations, the PHB-g-AA/MWNTs-OH blend demonstrated dramatic enhancement in thermal and mechanical properties of PHB due to the formation of ester carbonyl groups through the reaction between carboxylic acid groups of PHB-g-AA and hydroxyl groups of MWNTs-OH. For example, with an addition of 1 wt.% MWNTs-OH, the increases in the initial decomposition temperature and the tensile strength at break were 75°C and 15.1 MPa, respectively. Finally, the optimal amount of MWNTs-OH was 1 wt.% because excess MWNTs-OH caused separation of the organic and inorganic phases and reduced their compatibility.

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Section: Thermal Properties Of Blendsmentioning

confidence: 96%

Poly(3-hydroxybutyrate)/multi-walled carbon nanotubes nanocomposites: preparation and characterizations

Liao

2012

Designed Monomers and Polymers

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“…The precipitated polymer was filtered using 0.45 µm PTFE membrane filter and dried overnight at room temperature. The extracted pure polymer was then characterized for its chemical structure and molecular weight, by proton nuclear magnetic resonance (1HNMR, 500 MHz JEOL JNM-ECP500 FT NMR) and sizeexclusion chromatography (SEC, TOSOH HLC-8120), respectively [29].…”

Section: Extraction and Purification Of Polymer From Cellmentioning

confidence: 99%

Polyhydroxyalkanoate Synthesis by Recombinant Escherichia coli JM109 Expressing PHA Biosynthesis Genes from Comamonas sp. EB172

Yee¹,

Mumtaz²,

Mohammadi³

et al. 2012

J Microb Biochem Technol

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Recombinant Escherichia coli JM109 harbouring the polyhydroxyalkanoate (PHA) biosynthesis gene (phaCABco) of Comamonas sp. EB172, an acid tolerant microbe, was examined for the production of PHAs from various carbon sources. The study demonstrated that the recombinant E. coli JM109 had the potential to utilize both sugar-and acid-based carbon sources, for the biosynthesis of both poly(3-hydroxybutyrate) P(3HB) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) P(3HB-co-3HV) copolymers. In the shake flask experiments, the strain was capable of producing P (3HB-co-3HV) copolymer from mixed organic acids, and higher productivities were obtained using glucose compared to mixed acids. However, PHA accumulation was found to be similar, regardless of the carbon source used. Nitrogen supplementation in the medium was found to improve the cell dry weight, but negatively affected the 3HV formation in copolymer production. Maximum 3HV monomer (3 mol%) was obtained with C/N 42.1, using mixed acids as the carbon source. In the 2L bioreactor, the productivity and yield based on substrate utilization coefficient were found to be 0.16 g PHA/(L.h) and 0.41 g PHA/g substrate under C/N around 75, using 20 g/L glucose and 0.5 g/L ammonium sulphate, respectively. The polymer produced by the recombinant strain had molecular weight in the range of 8.5 x 105 to 1.4 x 106 Da. Overall, the ability of the recombinant E. coli JM109 to utilize both glucose and mixed acids, has widened its substrate selection for fermentation, including the opportunity to use renewable biomass.

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“…This resulted in findings of mixed mechanisms comprising a thermal random degradation with subsequent auto-accelerated trans-esterification and a kinetically favored chain reaction from crotonate chain ends, and so on. 111,112 The chain reaction was kinetically analyzed as a 0th-order weight loss process, which was assumed to be an unzipping b-elimination reaction, occurring repeatedly at an ester group neighboring the crotonate end group.…”

Section: Materials and Technologies For Polymer Recycling H Nishidamentioning

confidence: 99%

Development of materials and technologies for control of polymer recycling

Nishida

2011

Polym J

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The movement toward a recycling-based society through the essential development of recyclable materials alongside technologies for controlling recycling is reviewed. Recently, there has been progress in producing various polymers and technologies with the aim of achieving circulative utilization. For example, the upgrade recycling of commodity plastics, selective transformation of engineering plastics, selective depolymerization of various polymers in supercritical fluids, crosslinking-decrosslinking control using reversible reactions and developments in biomass-based recyclable polymers. Despite great strides taken in the effectiveness, efficiency and precision of these polymers and technologies, further improvements will be required to meet the practical requirements of a responsible sustainable system for the recycling of containers, packages, electric household appliances and end-of-life vehicles all of which are operated in compliance with the recycling laws of Japan.

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Determination of multiple thermal degradation mechanisms of poly(3-hydroxybutyrate)

Cited by 103 publications

References 34 publications

Poly(3-hydroxybutyrate)/multi-walled carbon nanotubes nanocomposites: preparation and characterizations

Poly(3-hydroxybutyrate)/multi-walled carbon nanotubes nanocomposites: preparation and characterizations

Polyhydroxyalkanoate Synthesis by Recombinant Escherichia coli JM109 Expressing PHA Biosynthesis Genes from Comamonas sp. EB172

Development of materials and technologies for control of polymer recycling

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