Polycaprolactone synthetic polymers

In the case of polymer particles for life-science applications, it is obvious that only a few kinds of polymers were suitable, those able to be degraded upon hydrolysis in water or upon the action of enzymes were a priori appropriate. This explains the interest of polyesters such as polylactic acid, polyglycolic acid (and their copolymers) and polycaprolactone. Synthetic polymers of low molecular weight and which are non-toxic, that is, being bioresorbable, such as polycyanoalkylacrylates and polyacryhc acids, are also used. 

Selection of a tissue engineering substrate includes a choice between absorbable and nonabsorbable material, as well as a choice between synthetic and naturally derived materials. The most common synthetic polymers used for fibrous meshes and porous scaffolds include polyesters such as polylactide and polyglycolide and their copolymers, polycaprolactone, and polyethylene glycol. Synthetic polymers have advantages over natural polymers in select instances, such as the following i... 

Endodontic points based on synthetic polymers are also available. One relatively new material is supplied as Resilon, manufactured by the Penton Clinical company, USA [15], and comprises a blend of polycaprolactone polymer with small amounts... 

Cell-culture studies have indicated that such structures promote cellular infiltration into the fibrillar network and can become densely populated in a reasonably short time. A number of natural and synthetic polymers have been successfully electrospun into fibrous scaffolds for the purpose collagen, elastin, gelatin, fibrinogen, polyglycolic acid, polylactic acid, polycaprolactone, polylactide-co-glycolide and polylactide-co-caprolac-tone. Recently published work indicates that an electrospun web formed... 

The most common strategy to decrease the price or improve the properties of polylactide to fulfill the requirements of different applications is blending. Polylactide has been blended with degradable and inert polymers, natural and synthetic polymers, plasticizers, natural fibers and inorganic fillers. The most common blends include blends with other polyesters such as polycaprolactone or PLA/starch blends. Usually the compatibility between the two components has to be improved by addition of compatibilizers such as polylactide grafted with starch or acrylic acid (114,115). Recently a lot of focus was concentrated on the development of polylactide biocomposites, nanocomposites and stereocomplex materials. In addition various approaches have been evaluated for toughening of polylactide. 

In mid-1970, due to the petroleum crisis, the production of plastics from renewable resources became economically attractive (Lenz and Marchessault 2005). The price of an oil barrel increased at very high values, and the same occurred to all petroleum products. So, at that time, an extensive search of materials that could replace synthetic polymers took place. Many polymers were proposed and investigated regarding to its biodegradability and its possibility of industrial application, such as cellulose, starch, polycaprolactone, poly(lactic acid), and PHA. Among these polymers, PHA are of particular interest due to their biodegradability, biocompatibility, and mainly because of their similarity to conventional thermoplastics (Zinn et al. 2001). 

Figure 2.1 Basic structures for some groups of synthetic polymers commonly employed as degradable materials in medical applications a) polylactide-co-polyglycolides (also commonly used as their homopolymers (i.e., n/m = 0), b) polycaprolactones, c) polydioxanones, d) polyorthoesters, e) polyanhydrides, f) polyalkylcyanoacrylates, g) poly(organo)phosphazenes and h) polyphosphoesters...

Synthetic polymers. Polylactic acid (PLA), polyglycolic acid (PGA), polycaprolactone (PCA), polyamino acids, polyethylene (PE) and high molecular weight derivatives, polysulfone, polyhydroxybutyrate. 

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