Thermoplastics biocompatibility

Poly(lactide) (PLA) is a thermoplastic, biocompatible and capable of biological and hydrolitical degradation polymer. A few years ago, production of PLA was very expensive and only recently, after the costs of its production came down, it has become widely applicable in many aspects of everyday life. As a result, PLA is the most technically advanced, biodegradable polymer. On an industrial scale, it is produced from lactic acid that is obtained in process of glucose fermentation [48]. 

Both polyesters exhibit outstanding properties thermoplastic, biocompatible and biodegradable. The latter (composting) needs some weeks or months, in aerobic waste water six to sixty days. They can be processed on standard equipment for thermoplastic processing. Handling and properties are similar to polypropylene. 

El Fray, M., Prowans, P., Puskas, J.E., and Altstadt, V. Biocompatibility and fatigue properties of polystyrene-polyisobutylene-polystyrene, an emerging thermoplastic elastomeric biomaterial. Biomacromolecules, 7, 844-850, 2006. 

Polyhydroxyalkanoate (PHA) is a biodegradable and biocompatible thermoplastic that can be synthesized in many microoiganisms from almost all genera of the microbial kingdom. Many microoiganisms synthesize polyhydroxyalkanoates (PHAs) as intracellular carbon and energy reserve materials [1]. These microbial polyesters materials are thermoplastics with biodegradable properties [2]. PHAs are usually accumulated... 

PPC has become an emerging material in the landscape of thermoplastic polymers. Most of its essential properties are known. It is biocompatible and biodegradable, which makes it attractive for packaging purposes. PPC is a material with unusual... 

PHA has been attracting much attention because it is a biodegradable, biocompatible, microbial thermoplastic that is regarded as a potentially useful polyester to replace petroleum-derived thermoplastics (3). 

Ethylene-norbornene copolymers, which have thermoplastic properties when heated above their glass transition temperatures of ca. 200-250°C, have been commercialized by Ticona GmbH under the trade name TOPAS (Tliermoplas-tic Olefin Polymer of Amorphous Structure). Their properties - exceptional transparency, low double refraction, high stiffnes and hardness, low permeability for moisture and excellent biocompatibility - make these ethylene-norbornene copolymers particularly valuable as engineering polymers, for optical applications and as materials for food and medical packaging. 

At the low concentrations 5-10 % silicone, the blend is reported to retain much of its thermoplasticity and processability. This silicone semi-IPN reportedly improves the lubricity, wear and biocompatibility of polyamide as well as reducing the shrinkage and warpage although... 

Poly(butylene succinate) (PBS) is an important member of biodegradable aliphatic polyester family. PBS and related copolymers have shown considerable promise for uses as environmentally biodegradable thermoplastics, as well as bioabsorbable/biocompatible medical materials (/). In both cases, practical applications require that the polymer possess a high molecular weight (M >20,000) so that it can have useful mechanical properties. 

However, in addition to their thermoplasticity, representatives of PHAs have optical activity, increase induction period of oxidation, exhibit the piezoelectric effect and, what is most important, they are characterized as being biodegradable and biocompatible. At the same time, the PHAs have disadvantages (high cost, brittleness), which can be partially or completely compensated by using composite materials based on blends with other polymers, with dispersed fillers or plasticizers. Taking into account all the above, we have suggested to create a mixed polymer composite based on poly-3-hydroxybutyrate (PHB) and polyisobutylene (PIB). 

Commercial IPNs have been developed to combine useful properties of two or more polymer systems. For example, high levels of silicone have been combined with the thermoplastic elastomer (TPE) based on Shells Kraton styrene-ethylene/butadiene-styrene TPE and Monsantos Santoprene olefin TPE. These IPN TPEs are said to provide the biocompatibility and release properties of silicone with tear and tensile strength up to five times greater than medical-grade silicone. Thermal and electronic properties and elastic recovery are also improved. 

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