Degradable Polyester Applications

TABLE 2.3 Names, Composition, and Applications of Some Commercial Degradable Polyesters... 

The next step in developing controlled degradation polyester is to understand expectations for specific product applications. Some questions to be answered include the following ... 

For recycling uses, degradable polyesters are desirable for relatively small mass applications, such as glues, thin coatings or labels, in order to facilitate the rapid cleaning of the primary structure for recycling. These applications may be rigid structures such as plastic containers or modifiers for paper products. 

Copolyesters (such as BIOMAX ) which combine aromatic esters with aliphatic esters or other polymer units (e.g. ethers and amides) provide the opportunity to adjust and control the degradation rates. These added degrees of freedom on polymer composition provide the opportunity to rebalance the polymer to more specifically match application performance in physical properties, while still maintaining the ability to adjust the copolyesters to complement the degradation of natural products for the production of methane or humic substances. Since application performance requirements and application specific environmental factors and degradation expectations vary broadly, copolyesters are, and will continue to be, an important class of degradable polyesters. 

Several review articles on biodegradable polymers and polyesters have appeared in the literature [12-22]. Extensive studies have been carried out by Al-bertsson and coworkers developing biodegradable polymers such as polyesters, polyanhydrides, polycarbonates, etc., and relating the structure and properties of aliphatic polyesters prepared by ROP and polycondensation techniques. In the present paper, the current status of aliphatic polyesters and copolyesters (block, random, and star-shaped), their synthesis and characterization, properties, degradation, and applications are described. Emphasis is placed primarily on aliphatic polyesters derived by condensation of diols with dicarboxylic acids (or their derivatives) or by the ROP of cyclic monoesters. Polyesters derived from cyclic diesters or microbial polyesters are beyond the scope of this review. 

Seppala, J. V.,Helminen, A. O., and Korhonen, H. (2004), Degradable polyesters through chain linking for packaging and biomedical applications, Macromol. Biosci., 4(3), 208-217. 

As non-degradable polyesters are quite common as textile materials, it comes as no surprise that their degradable counterparts are also readily processable into fibres. Polymer fibres are particularly interesting for biomedical applications, including wound dressings, controlled-release formulations and tissue engineering. Several spinning techniques result in the formation of polymer fibres. 

Another use of degradable polyesters in agriculture lies in bacterial inoculants which can enhance nitrogen fixation in plants. The bacterial cultures used in this application have to withstand harsh conditions prior to their application, making the use of a suitable carrier material crucial. To improve the survival rates within these carriers, nutrients can be added, although the type of bacteria applied may play a more important role in this regard. 

P3HB as a natural thermoplastic polyester has mechanical properties comparable with those of synthetically produced degradable polyesters such as the polylactides [61]. The relatively high brittleness of the crystalHne natural isotactic P3HB is of disadvantage in tissue engineering applications but can be overcome by copolymerization and incorporation of PHA components such as 3-hydroxyvalerate (3HV) [60], 4-hydroxybutyrate (4HB) [62], or... 

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