Thermal degradation of poly(3‐hydroxybutyrate) and poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) as studied by TG, TG–FTIR, and Py–GC/MS

Abstract

ABSTRACT:The thermal degradation kinetics of poly(3-hydroxybutyrate) (PHB) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [poly(HB-HV)] under nitrogen was studied by thermogravimetry (TG). The results show that the thermal degradation temperatures (T o , T p , and T f ) increased with an increasing heating rate (B). Poly(HB-HV) was thermally more stable than PHB because its thermal degradation temperatures, T o (0), T p (0), and T f (0)-determined by extrapolation to B ϭ 0°C/min-increased by 13°C-15°C over those of PHB. The thermal degradation mechanism of PHB and poly(HB-HV) under nitrogen were investigated with TG-FTIR and Py-GC/MS. The results show that the degradation products of PHB are mainly propene, 2-butenoic acid, propenyl-2-butenoate and butyric-2-butenoate; whereas, those of poly(HB-HV) are mainly propene, 2-butenoic acid, 2-pentenoic acid, propenyl-2-butenoate, propenyl-2-pentenoate, butyric-2-butenoate, pentanoic-2-pentenoate, and CO 2 . The degradation is probably initiated from the chain scission of the ester linkage.

Precise Depolymerization of Poly(3-hydoxybutyrate) by Pyrolysis

“…Several thermoanalytical procedures have been used to investigate the thermal degradation behavior of PHB, including thermogravimetry (TG) for the analysis of weight loss behavior (Kopinke et al, 1999;Galego & Rozsa, 1999;Li et al, 2001;He et al, 2001;Lee et al, 2001;Aoyagi et al, 2002;Carrasco et al, 2006;Kim et al, 2006;Kawalec et al, 2007;Liu et al, 2009;Ariffin et al, 2008Ariffin et al, , 2010, differential scanning calorimetry (DSC) for monitoring the heat of reaction (Kopinke et al, 1996), fast atom bombardment mass spectrometry (FAB-MS) (Ballistreri et al, 1989), electrospray ionization mass spectrometry (ESI-MS) (Kawalec et al, 2007), pyrolysis-mass spectrometry (Py-MS) (Abate, 1994;Kopinke et al, 1996), pyrolysisgas chromatography (Py-GC) (Lehrle, 1994), pyrolysis-GC/mass spectrometry (Py-GC/MS) (Kopinke et al, 1996(Kopinke et al, , 1997Aoyagi et al, 2002;Ariffin et al, 2008Ariffin et al, , 2010, TG/Fourier transform infrared spectroscopy (TG/FTIR) (Li et al, 2003), NMR (Melchiors et al, 1996;Kopinke et al, 1996;Ariffin et al, 2009), and pyrolysis-GC/FTIR (Li et al, 2003;Gonzalez et al, 2005), for the analysis of volatile products, and size exclusion chromatography (SEC) (Grassie et al, 1984;Kunioka & Doi, 1990;Nguyen et al, 2002;Kim et al, 2006) for the analysis of changes in molecular weight of residual PHB. (Kopinke et al, 1996;Galego & Rozsa, 1999;Li et al, 2001;…”

Compositional analysis of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) by pyrolysis-gas chromatography in the presence of organic alkali

“…0.1 mg or less) of the samples [7]. So far, thermal degradation mechanisms of biodegradable aliphatic polyesters such as PHB [8][9][10][11][12][13], poly(lactic acid) [12,14,15], and poly(e-caprolactone) (PCL) [12] have been investigated by Py-GC. In addition, biodegradation behaviors of the polyesters have been also studied by Py-GC [16,17].…”

Caseinate–gelatin and caseinate‐hydrolyzed gelatin composites formed via transglutaminase: chemical and functional properties

“…Fourier transform–infrared (FT‐IR) analysis as a classic physical technique has been widely used to show chemical characteristics of organic molecules, for instance, to evidence those typical chemical groups and bonds in the molecules. The combination of TG and FT‐IR analysis can be used to investigate the thermal degradation mechanism of polymers or to detect the gaseous species eliminated by thermal degradation of casein . Confocal laser scanning microscopy (CLSM) analysis is a more intuitive analysis for some microstructural characteristics, and can be used to investigate the targets clearly and directly.…”