Polyhydroxyalkanoates thermal stability

Biodegradable carboxy aromatic polyhydroxyalkanoate resins, (II), having high thermal stability were prepared by Fukui et al. (4) and used as toners in electrophotographic processes. 

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. 

Carrasco E, Dionisi D., MartineUi A., Majone M. Thermal stability of polyhydroxyalkanoates, J.Appl. Polym. Sci. 100(2006)2111. 

In air, the thermooxidative degradation and stability of commercial and laboratory made polyhydroxyalkanoates such as the homopolymer poly(3-hydroxybutyrate) and the copolymer poly(3-hydroxybutyrate-co-3-hydroxyvalerate) was investigated by Carraso et al. [20]. It was indicated that the presence of hydroxyvalerate within the copolymer led to a thermally more stable material (with an increase of 14°C). 

---