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

Industrial Crops and Products (Impact Factor: 3.21). 01/2010; 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.

  • [Show abstract] [Hide abstract]
    ABSTRACT: The author proposes a control design method based on a coprime factorization of the plant. The design method includes the synthesis of low-order H <sub>∞</sub> controllers and the generation of a robustness margin which is less conservative than a gap-metric bound. For a set of linear models the choice of nominal model is discussed. The developed control design method is used to design a robust linear low-order controller for a nonlinear flexible wind turbine model under full load conditions. The controller will have to stabilize a set of linear models representing the nonlinear wind turbine under various operating conditions. It is shown that using the new robustness test this controller stabilizes the whole set with the desired performance
    Decision and Control, 1992., Proceedings of the 31st IEEE Conference on; 02/1992
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: A Lignin Rich Residue (LRR) obtained as a by-product from the fermentative bioethanol production process, and commercial alkali lignin (AL), were used as fillers for the preparation of bio-based blends and composites with poly(3-hydrobutyrate) (PHB). Chemical characterization of LRR demonstrated that the filler contained sugar residues. Rheological and thermal characterization of the blends demonstrated that LRR did not affect thermal stability of PHB, while AL had a strong pro-degrading effect. Addition of suitable amounts of LRR dramatically affected the rheological behavior of the polymer melt, suggesting that the additive can modify polymer processability. LRR was also a heterogeneous nucleating agent, potentially able to control the physical aging of PHB. Lower resilience and elongation at break values were found for the biocomposites, due to the poor interfacial adhesion between filler and matrix. Biodegradation behavior of the composites was qualitatively assessed by analyzing the surface of soil buried films. Significant surface degradation was observed for PHB, while the process was retarded at high filler concentration, as LRR inhibited hydrolytic and biotic polymer degradation. The reported results demonstrated the feasibility of the conversion of an agro-industrial by-product into a bio-resource in an environmentally friendly and cost-effective way.
    International journal of biological macromolecules. 07/2014;
  • [Show abstract] [Hide abstract]
    ABSTRACT: The authors investigate some geometrical properties of the domain of (generalized) stability in the coefficient space for a monic n th-order polynomial. Regions of root location such that the convex hull of the corresponding domain of stability is a polyhedron are investigated, and specific regions for which the convex hull is an n +1 vertex polyhedron are derived. The discrete-time stability domain falls in the latter class of regions. These results are exploited in the design of filters solving the robust strict positive realness problem for families of rational functions with uncertainty in the numerator

Full-text (2 Sources)

Available from
Aug 6, 2014