Biodegradable polyesters examples

Biodegradable polyester-based nanoparticles have also been studied, especially in the biomedical domain. Like microelectronics, biomedical research follows the rule smaller is better . A typical example of nanoparticles based on the aliphatic polyester engineering by living ROP is provided by the poly(CL-h-GA) copolymers which form stable colloidal dispersions in organic solvents such as toluene and THF without the need of any additional surfactant [27]. The poly(CL-h-GA) particles form a new class of stable non-aqueous dispersions in... 

Several biodegradable polyesters have now been developed. For example, the polyhydroxyal-kanoates (PHAs) are polymers of 3-hydroxy carboxylic acids, such as 3-hydroxybutyric acid or 3-hydroxyvaleric acid. 

In recent years, the enzymatic synthesis of biodegradable polyesters was focused on the polycondensation method (22,23). Among the very few successful example of enzymatic ring-opening polymerization for polyesters synthesis, Novozyme-435 (immobilized lipase B from Candida antartica) has been proved an effective catalyst for polycaprolactone (PCL) synthesis in toluene (24). Considering the low cost and high recyclablity of IPPL, we also... 

Aliphatic polyesters are the most representative examples of biodegradable polymeric materials. Poly(3-hydroxyalkanoate)s, PHA, are well known biocompatible and biodegradable polyesters that are produced by various microorganisms as carbon and energy reserves. The physical properties of PHAs vary from crystalline-brittle to soft-sticky materials depending on the length of the side aliphatic chain on p carbon ... 

Still another starch-polyester graft copolymer and a chemically modified starch-polyester graft copolymer composition has been described. The starch-polyester graft copol5mers are synthesized by the reaction of starch with biodegradable polyester polymers in the presence of maleic acid and glycerol as plasticizer. Examples of biodegradable polyesters are summarized in Table 7.6. 

Aliphatic poly(alkylene dicarboxylate) polyesters (APDs) are among the biodegradable polyesters of maximum interest and they can be prepared by biomass-derived monomers (renewable resources), petroleum-derived monomers (nonrenewable resources), or a mixture of both. Examples of APDs... 

The feasibihty of the Diels-Alder coupling was shown on the example of biodegradable polyester by Ninh and Bettinger [47]. In this case, hyperbranched poly(glycerol-co-sebacate) with pendant furan groups was coupled with a bifunctional maleimide cross-linker to produce an elastomeric material. POSS moieties may serve as cross-linking sites, as well. Ishida et al. [48] have shown how a... 

Biodegradable polyester-based composites have been extensively studied for use in medical applications owing to their biocompatible and degradable properties in the human body. The major reported examples in biomedical products are fracture-fixation devices, such as sutures, screws, micro titration plates, and delivery systems [77]. Cellulosic nanofiber reinforced PLA composite materials... 

Synthetic biodegradable polyesters are general made by the pofycondensation method and raw materials are obtained from petrochemical feed stocks. Aliphatic polyesters such as pofy(butylene succinate) and poly( -caprolactone) are cormnercially produced. Besides these ahphatic pofyesters, various types of synthethic biodegradable polymers have been designed [33]. They are, for example, poly(ester amide)s, pofy(ester carbonate)s, pofy(ester urethane)s, etc. Most of them are still at a premature stage. 

Chemically synthesized biodegradable polyesters are obtained by synthesis from monomers obtained from biomass. Their best example is polylactic acid (PLA) derived from corn. PLA shares some similarities with commodity polymers such as polyethylene terephthalate (PET). It has many good characteristics like good transparency, glossy appearance, high rigidity, and ability to tolerate various types of processing conditions. 

Besides PCT and its copolymers, other examples of biodegradable polyesters which can be used in the presence of destructurised starch are those obtained by the polycondensation of glycols such as 1,4-BDO with succinic acid, sebacic acid, adipic acid, azelaic acid, dodecandioic acid, or brassylic acid and PBTA [85, 86]. 

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