Other Biodegradable Natural Polymers

Some other biodegradable natural polymers such as dextran, heparin, xanthan, pullulan, elastin, fibrin, pectin and hyaluronate, were also investigated as biodegradable polymers in various fields. 

Fibrin has a particular use in suture-less surgery. Reeent developments have established fibrin glue for tissue adhesives as attractive alternatives to sutures. The current available information on fibrin glue is discussed by Panda et 

Polyglycolide is a highly crystalline polymer (45-55% crystallinity) and therefore exhibits a high tensile modulus with very low solubility in organic solvents. Strong implants can be manufactured from this polymer with a self-reinforcing (SR) technique and can be used in the treatment of fractures and osteotomies.  

Copolymers of PLA and poly(ethylene glycol) (PEG) are attractive for application in drug delivery systems. Novel thymopentin (TPS) release systems prepared from bioresorbable PLA-PEG-PLA hydrogels were reported 

Recently, investigation on poly(lactide-co-glycolide) implants was carried out, aiming at assessing the feasibility of hot-melt extrusion (HME) for preparing implants based on PLGA formulations with special emphasis on protein stability, burst release and release completeness. The results demonstrated that the release from all implants reached the 100% value in 60-80 days with nearly 

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New natural polymers based on synthesis from renewable resources, improved recyclability based on retrosynthesis to reusable precursors, and molecular suicide switches to initiate biodegradation on demand are the exciting areas in polymer science. In the area of biomolecular materials, new materials for implants with improved durability and biocompatibility, light-harvesting materials based on biomimicry of photosynthetic systems, and biosensors for analysis and artificial enzymes for bioremediation will present the breakthrough opportunities. Finally, in the field of electronics and photonics, the new challenges are molecular switches, transistors, and other electronic components molecular photoad-dressable memory devices and ferroelectrics and ferromagnets based on nonmetals. 

Biodegradability - Metabolix PHA offer hydrolytic stability under normal service conditions but when exposed to microbial organisms naturally present they break down enzymatically in soil, composting, waste treatment processes, river water and marine environments. They also rapidly decompose to carbon dioxide and water and will degrade in anaerobic environments, unlike some other biodegradable polymers. 

They are made of polymeric, waxy, or other protective materials, that is, biodegradable synthetic polymers and modified natural products such as starches, gums, proteins, fats, and waxes. The natural polymers include albumin and gelatin " the synthetic polymers include polylactic acid and polyglycolic acid. ... 

Natural monomers and polymers have complex structure and properties, which with proper modifications could be a substitute for today s high-performance plastic materials. Existing biodegradable polymers can be blended with different materials with the aim to reduce cost and to tailor the product for specific applications. NR and almost all other natural resources are discussed and possible modifications and the applications of these natural polymers as well as polymers from natural monomers are analyzed in this review. Further studies are required to improve the performance of these materials so that synthetic polymeric materials can be replaced by polymers derived from these renewable materials. 

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