Polyhydroxyalkanoates thermal properties

Hassan MA, Nawata O, Shirai Y, Rahman NAA, Yee PL, Ariff AB, Ismail M, Karim A (2002) A proposal for zero emission from palm oil industry incorporating the production of polyhydroxyalkanoates from pahn oil mill effluent. J Chem Eng Jpn 35 9-14 Hu SG, Jou CH, Yang MC (2003) Protein adsorption, fibroblast activity and antibacterial properties of poly(3-hydroxybutyric acid-co-3-hydroxyvaleric acid) grafted with chitosan and chitooUgo-saccharide after immobihzed with hyaluronic acid. Biomater 24 2685-2693 Ishida K, Wang Y, Inoue Y (2001) Comonomer unit composition and thermal properties of poly (3-hydroxybutyrate-co-4-hydroxybutyrate)s biosynthesized by Ralstonia eutropha. Biomacromol 2 1285-1293... 

CeccomUi G, PizzoU M, Scandola M (1993) Effect of a low-molecular-weight plasticizer on the thermal and viscoelastic properties of miscible blends of bacterial poly(3-hydroxybutyrate) with cellulose acetate butyrate. Macromolecules 26 6722-6726 Chanprateep S, Kikuya K, Shimizu H, Shioya S (2(X)2) Model predictive controller for biodegradable polyhydroxyalkanoate production in fed-batch culture. J Bacterid 95 157-169 Chen GQ, Wu Q (2005) The application of polyhydroxyalkanoates as tissue engineering materials. Biomaterials 26 6565-6578... 

Polyhydroxyalkanoates, Polyhydroxybutyrate, History, Bacterial synthesis. Chemical synthesis. Genetic engineering. Mechanical properties. Thermal transitions. Crystallization, Plasticizers, Thermal degradation. Processing, Applications... 

Many workers have used PyMS to study the structures of polymers, both natural and artificial. Understanding the performance of polymers in terms of cohesion and substrate adhesion is of immense commercial significance in the paint and adhesive industries. Similarly, the behavior of polymers under stress and when exposed to external factors such as ultraviolet light has been extensively studied by PyMS and is useful in the development of novel materials that have desirable properties, e.g., fire-retardant coatings and biodegradable fibers. There is much interest in polyhydroxyalkanoates as potentially biodegradable plastics, and PyMS has been a principal method used to study thermal degradation profiles of this material. Similarly, in forensic science, PyMS has been used to analyze fibers and to help match samples of automotive finishes to paint chips found at crime scenes. 

Biodegradable polymers can be mainly classified as agro-polymers (starch, protein, etc.) and biodegradable polyesters (polyhydroxyalkanoates, poly(lactic acid), etc.). These latter, also called biopolyesters, can be synthesized from fossil resources but main productions can be obtained from renewable resources (Bordes et al. 2009). However for certain applications, biopolyesters cannot be fully competitive with conventional thermoplastics since some of their properties are too weak. Therefore, to extend their applications, these biopolymers have been formulated and associated with nano-sized fillers, which could bring a large range of improved properties (stiffness, permeability, crystallinity, thermal stability). The resulting nano-biocomposites have been the subject of many recent publications. Bordes etal. (2009) analyzed this novel class of materials based on clays, which are nowadays the main nanoflllers used in nanocomposite systems. 

Although the long sidechain polyhydroxyalkanoates show some interesting properties, they do not currently have commercial applications. This may be attributed to difficult fermentation requirements with rather low yields. Additionally, very slow crystallization rates mean that they are difficult to process by conventional thermal routes. 

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