Thermal stability and miscibility of poly(hydroxybutyrate) and soda lignin blends

Industrial Crops and Products (Impact Factor: 2.84). 11/2010; 32(3):656-661. DOI: 10.1016/j.indcrop.2010.08.001


The thermal properties and miscibility of poly(hydroxybutyrate) (PHB) and soda lignin blends were investigated by thermogravimetry analysis (TGA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and Fourier transform infra-red spectroscopy (FTIR) over the entire range of composition. Although the addition of soda lignin shifts the onset of PHB decomposition to lower temperatures, the PHB/lignin blends are thermally more stable than PHB over a wider temperature range. The thermal behaviour of these blends as measured by TGA suggests compatibility for the blends containing up to 40 wt% soda lignin. These results correlate well with the glass transition temperature (Tg) data where a single Tg was obtained for these blends. At higher lignin to PHB ratios, two Tgs depicting immiscibility were obtained. The infra-red data show that the miscibility of the blends containing up to 40 wt% soda lignin is associated with specific hydrogen bonding interactions between the reactive functional groups in lignin with the carbonyl groups of PHB.Research highlights▶ PHB/soda lignin blends are miscible up to 40 wt% lignin so that the Gordon–Taylor and Kwei equations are obeyed. ▶ The miscibility of PHB/soda lignin blends are due to the association between the OH groups of lignin and the carbonyl groups of PHB. ▶ Soda lignin reduces the initial PHB decomposition temperature though it stabilises PHB decomposition.


Available from: William Doherty, Aug 05, 2014

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Article: Thermal stability and miscibility of poly(hydroxybutyrate) and soda lignin blends

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    • "Depending on the source and extraction method used, the physico-chemical characteristics are different and influence the properties of materials in which are embedded. The effective use of lignin in composites with various biopolymers like PHB [12] [13], starch [14], cellulose [15], chitosan [16] has been also reported in literature. Sahoo et al. [17] achieved the incorporation of up to 65 wt% lignin in polybutylene succinate (PBS) matrix and proved the reinforcing effect of lignin. "
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    • "The problem of PHB stability can be solved (or at least limited) by making use of stabilizers, such as anti-oxidants, plasticizers, thermal stabilizers, processing aids [16] [17] [18] [19] [20] [21] [22] [23] [24] [25]. The choice of the proper stabilizing system for PHB is a relevant issue. "
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    • "Infrared spectroscopy can provide information on the development of weak bonds and interactions such as hydrogen bonding between matrix and filler. Mousavioun et al. [25] observed a shift in the carbonyl absorption for melt extruded blends of PHB and soda lignin, which was ascribed to hydrogen bonding interactions of the reactive functional groups of lignin with the carbonyl oxygen in PHB. FTIR-ATR experiments were carried out on cross-sections cut from plate sample in order to investigate on the interactions between PHB and LRR. "
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