Polymers polyhydroxyalkanoates

Akhtar, S. Pouton, C. W Notarianni, L. J. Crystallization behaviour and drug release from bacterial polyhydroxyalkanoates. Polym. 1992, 33(1), 117-126. 

Keywords Bio-based Biodegradable Microorganism Palm oil PHA Plastics Polyhydroxyalkanoate Polymer... 

Bordes, R, Hablot, E., Pollet, E., Averous, L, Effect of clay organomodifiers on degradation of polyhydroxyalkanoates. Polymer Degradation and 5, 789-796 (2009), DOl http //dx.doi.0rg/lO.lOl6/j.polym degradstab.2009.01.027. 

Renard, E., Walls, M., Gu6rin, P., Langlois, V. Hydrolytic degradation of blends of polyhydroxyalkanoates and functionalized polyhydroxyalkanoates. Polym. Degrad. stab. 85(2), 779-787 (2004)... 

Singh AK, Mallick N (2008) Enhanced production of SCL-LCL-PHA co-polymer by sludge-isolated Pseudomonas aeruginosa MTCC 7925. Lett Appl Microbiol 46 350-357 Snell KD, Peoples OP (2002) Polyhydroxyalkanoate polymers and their production in transgenic plants. Metab Eng 4 29 0... 

Renard E, Temat C, Langlois V, Guerin P (2(X)3b) Synthesis of graft bacterial polyesters for nanoparticles preparation. Macromol Biosci 3 248-252 Renard E, Walls M, Guerin P, Langlois V (2004) Hydrolytic degradation of blends of poly hydroxyalkanoates and functionalized polyhydroxyalkanoates. Polym Degrad Stab 85 779-787... 

S.F. Williams, D.P. Martin, F.A. Skraly, Medical devices and applications of polyhydroxyalkanoate polymers, US7553923... 

Table 111. Comparison of physical properties of selected polyhydroxyalkanoate polymers and petroleum-based plastics.

Snell, K.D., Peoples, O. P. "Polyhydroxyalkanoate Polymers and Their Production in Transgenic Plants Metabolic Engineering, 4, 29-40, 2002... 

Snell KD, Peoples OP. 2002. Polyhydroxyalkanoate Polymers and Their Production in Transgenic Pltuits. 

Table 9.1 Physical characteristics of polyhydroxyalkanoate polymers and petroleum-based plastics, including melting temperature (T ,), glass transition temperature (Tg), and degree of crystallinity (% crystall.)...

Other blends such as polyhydroxyalkanoates (PHA) with cellulose acetate (208), PHA with polycaprolactone (209), poly(lactic acid) with poly(ethylene glycol) (210), chitosan and cellulose (211), poly(lactic acid) with inorganic fillers (212), and PHA and aUphatic polyesters with inorganics (213) are receiving attention. The different blending compositions seem to be limited only by the number of polymers available and the compatibiUty of the components. The latter blends, with all natural or biodegradable components, appear to afford the best approach for future research as property balance and biodegradabihty is attempted. Starch and additives have been evaluated ia detail from the perspective of stmcture and compatibiUty with starch (214). 

Polyesters offer multiple options to meet the complex world of degradable polymers. All polyesters degrade eventually, with hydrolysis being the dominant mechanism. Degradation rates range from weeks for aliphatic polyesters (e.g. polyhydroxyalkanoates) to decades for aromatic polyesters (e.g. PET). Specific local environmental factors such as humidity, pH and temperature significantly influence the rate of degradation. 

The exhaustible nature of the oil reserves and the pollution that oil-based technological polymers can have on the environment has rekindled an interest in polymers of natural origin, in particular the biotechnological polymers. Until now, however, the polyhydroxyalkanoates are the only biotechnological polymers that have been developed industrially, occupying a notable position as biodegradable and biocompatible biomaterials for temporary use [1, 2]. 

Sudesh K, Doi Y (2005) Polyhydroxyalkanoates. In Bastioli C (ed) Handbook of biodegradable polymers. Rapra Technology Ltd, Shrewsbury... 

Kessler, B. Ren, Q. de Roo, G. Prieto, M.A. Withok, B. (2001) Engineering of biological systans for the synthesis of tailor-made polyhydroxyalkanoates, a class of versatile polymers. Chimia, 55, 119-22. 

Various procaryotic microorganisms can produce polyhydroxyalkanoates using regenerable carbon sources. This polymer is a storage material and can make up to 90 % of the dried cell weight. The most widely researched material in this group up till now is the poly-D(-)-3-hydroxybutyric acid (PHB). 

It has already been pointed out that it is not only PolyPs but other anionic polymers, such as [X)I y-ft -hy< I rox ybutyrate, which may form metachromatic granules in the cells of prokaryotes. However, recently a number of methods for differential staining of PolyPs and polyhydroxyalkanoate-containing granules in cells have been developed (see the review of Serafim et al, 2002). 

---