Biodegradable polyesters products

As mentioned before, there are a few biodegradable polyesters which were historically obtained from renewable sources as their production concerns fermentation or microbial processes from vegetable raw material (i.e., PLA, PHA and more recently polyhydroxyfattyacid). Moreover, in the last 5 years an increasing interest in renewable raw material for polymer synthesis has been developed, not only for biodegradable polyester production but also for nonbiodegradable polymers such as polyethylene or PET. 

With regards to biodegradable polyester production, the use of renewable monomers can be of particular interest as not only can the final products be biodegraded, hence avoiding plastic accumulation in landfills, but also the biodegradation products (usually CO2 and water) are used by plants to produce the renewable monomers. As can be deduced, this cradle-to-grave cycle can significantly reduce the carbon footprint due to plastic production. 

The main monomers for the most common biodegradable polyester production, which can now be obtained from renewable resources are succinic acid, 1,4-butanediol, 1,2-ethanediol, sebacic acid and azelaic acid. 

In vitro polyester syntheses using an isolated enzyme as catalyst via non-bio-synthetic pathways is reviewed. These enzymatic routes for production of biodegradable polyesters possess several advances in comparison with fermentation and chemical processes ... 

The ring-expansion carbonylation of epoxides is the most widely studied field in the epoxide carbonylation chemistry since the product lactones are highly attractive targets particularly, /1-lactones are useful compounds due to their versatility in organic synthesis [ 14,15] as well as their utilization as monomers to produce poly(3-hydroxyalkanoate)s, naturally occurring biodegradable polyesters [16-19]. 

Carothers and colleagues were the first to explore the ROP of lactones. Many research laboratories have now been involved in this research area. The ROP of lactones is the method of choice for the production of biocompatible and biodegradable polyesters. Lactones are ambidentate and the polymerization may proceed by either alkyl-oxygen or acyl-oxygen scission. Evidence in favor of both types of scission is reported in the literature. 

Several synthetic procedures have been developed for the production of biodegradable polyester-based materials from 1,3-propanediol and succinic acid obtainable from renewable resources. 

One of the anticipated growth areas for industrial uses of plants is in development of non-brittle, durable polymers from renewable plant feedstocks (in both biodegradable and non-biodegradable forms). Starch and sugars are currently used commercially as feedstocks for polyester production utilising microbial monomer and polymer fermentation systems (see Chapter 5 for more information). 

During the same period, commercialization of thermoplastic starch polymer blends was pursued by Novamont, a division of the Ferruzzi Group of Italy.162-172 Their products, marketed under the trade name Mater-Bi, are typically comprised of at least 60% starch or natural additive and hydrophilic, biodegradable synthetic polymers.64,165 It is stated that these blends form interpenetrated or semi-interpenetrated structures at the molecular level. Properties of typical commercial formulations have properties similar to those in the range of low- and high-density PE. Blends of Mater-Bi products with biodegradable polyesters have been claimed for use as water impervious films.173... 

Polyhydroxybutyrate Biodegradable polyester used in degradable plastic products. 

The most advanced and ecologically friendly method of disposal of inhibited refuse is considered to be the use of self-destructive inhibited plastics with regulated lifetime. For example, Cortec Corp. has developed biodegradable resin products that are inhibited by VCI consisting essentially of a polymeric resin of PE, starch and polyesters, such as polylactic acid or other suitable polyesters [32]. 

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