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

Industrial Crops and Products (Impact Factor: 3.21). 11/2010; 32(3):656-661. DOI: 10.1016/j.indcrop.2010.08.001

ABSTRACT 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.

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    International Conference Agriculture for Life, Life for Agriculture; 06/2014
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    ABSTRACT: The thermal and rheological properties of poly(hydroxybutyrate) (PHB) and lignin blends were investigated by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and rheological analysis over the entire range of composition. The drop in the apparent energy of activation of decomposition, E-a from 112 kJ mol(-1) for pure PHB to half that value with PHB/lignin blends, suggests that the addition lignin reduces the thermal stability of PHB. The rheology results show that for <= 30 wt% lignin, lignin behaved like a plasticizer forming a single phase with PHB (as shown by glass transition data and scanning electron micrographs), and reduced the elasticity and viscosity relative to pure PHB. Further additions of lignin (e.g., 60 wt% lignin) result in phase separation and thus decreased the ability of the blends to dissipate energy and increased the viscosities of the blends.
    Industrial Crops and Products 10/2013; 50:270-275. DOI:10.1016/j.indcrop.2013.07.026 · 3.21 Impact Factor
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    ABSTRACT: Isolated and purified organosolv eucalyptus wood lignin was depolymerized at different temperatures with and without mesostructured silica catalysts (i.e., SBA-15, MCM-41, ZrO2-SBA-15 and ZrO2-MCM-41). It was found that at 300 °C for 1 h with a solid/liquid ratio of 0.0175/1 (w/v), the SBA-15 catalyst with high acidity gave the highest syringol yield of 23.0% in a methanol/water mixture (50/50, wt/wt). Doping with ZrO2 over these catalysts did not increase syringol yield, but increased the total amount of solid residue. Gas chromatography–mass spectrometry (GC–MS) also identified other main phenolic compounds such as 1-(4-hydroxy-3,5-dimethoxyphenyl)-ethanone, 1,2-benzenediol, and 4-hydroxy-3,5-dimethoxy-benzaldehyde. Analysis of the lignin residues with Fourier transform-infrared spectroscopy (FT-IR) indicated decreases in the absorption bands intensities of OH group, CO stretching of syringyl ring and aromatic CH deformation of syringol unit, and an increase in band intensities associated with the guaiacyl ring, confirming the type of products formed.
    Bioresource Technology 03/2015; 180. DOI:10.1016/j.biortech.2014.12.098 · 5.04 Impact Factor

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