Polymers polycaprolactone

Chang, R. K., Price, J. C., and Whitworth, C. W., Enhancement of dissolution rate by incorporation into a water insoluble polymer, polycaprolactone. Drug Dev. Ind. Pharm., 13. 249-256, 1987. 

Woodruff MA, Flutmacher W (2010) The return of a forgotten polymer-polycaprolactone in the 2T century. Prog Polym Sci 35 1217-1256... 

While PHB and PHV are not considered true plastics, another biodegradable polymer polycaprolactone (PCL) is a plastic material because its monomer e-caprolactone is obtained on an industrial scale from petrochemical products (cyclohexanone and peroxyacetic acid). This synthetic plastic with its low melting point is easily extrudable and applications in the packaging area are envisioned. 

ZrPA = Zirconium phosphate amorphous, TiPA = Titanium phosphate amorphous, SnPC = Tin phosphate crystaiiine, ZrWP = Zirconium/tungsto. phosphate, MeCN = Acetonitrile, AcOH = Acetic acid, CX = Cyclohexanone, CP = Cyclopentanone, PIN = Pinacolone, AP = Acetophenone, 6-HCA = 6-Hydroxycaproic acid, e-Cap. = e-Caprolactone, Polymer = Polycaprolactone of unknown molecular weight, DVL = S-Valerolactone, t-BA = t-Butylacetate, PhA = Phenyl acetate, PhOH = Phenol,... 

Alternative polymer systems have been developed for root canal obturation. These include a degradable polymer (polycaprolactone) and a bioactive glass (Elzubair et al., 2006). Similar to gutta percha, these materials are thermoplastic and can be heated and injected into the root canal. As before, however, there appears to be no rheological information about them in the literature. 

Woodruff, M. A., Hutmacher, D.W., 2010. The return of a forgotten polymer—polycaprolactone in the 21st century. Progress in Polymer Science 35 (10), 1217—1256. 

Co-electrospinning has been applied so far for the preparation of polymer core shell fibers, hollow polymer core shell fibers, hollow fibers composed not only of polymers, but also of ceramics, as well as for the immobilization of functional objects in droplets dispersed in the core that are arranged along the fiber axis. Among the examples reported in the literature are core shell fibers spun from polystyrene and polyethylene oxide, two kinds of polyethylene oxide (one with and the other without a chromophore), and core shell fibers with the electrically conductive polymer polyhexathiophene and the insulation polymer polyethylene oxide (Fig. 20). Hollow core shell fibers in which one polymer (polycaprolactone) forms the shell onto which the core material is deposited (polyethylene oxide) as inner wall is another example for the broad spectrum of fiber architectures which can be produced by coelectrospinning. The formation of the two-layer hollow fiber is based on the... 

Other simple tests include the soil burial test used to demonstrate the biodegradabiUty of polycaprolactone (25), following its disappearance as a function of time, and the clear 2one method which indicates biodegradation by the formation of a clear 2one in an agar medium of the test polymer or plastic as it is consumed (26). The burial test is still used as a confirmatory test method in the real-world environment after quantitative laboratory methods indicate bio degradation. 

Other blends such as polyhydroxyalkanoates (PHA) with cellulose acetate (208), PHA with polycaprolactone (209), poly(lactic acid) with poly(ethylene glycol) (210), chitosan and cellulose (211), poly(lactic acid) with inorganic fillers (212), and PHA and aUphatic polyesters with inorganics (213) are receiving attention. The different blending compositions seem to be limited only by the number of polymers available and the compatibiUty of the components. The latter blends, with all natural or biodegradable components, appear to afford the best approach for future research as property balance and biodegradabihty is attempted. Starch and additives have been evaluated ia detail from the perspective of stmcture and compatibiUty with starch (214). 

Copolymers of S-caprolactone and L-lactide are elastomeric when prepared from 25% S-caprolactone and 75% L-lactide, and rigid when prepared from 10% S-caprolactone and 90% L-lactide (47). Blends of poly-DL-lactide and polycaprolactone polymers are another way to achieve unique elastomeric properties. Copolymers of S-caprolactone and glycoHde have been evaluated in fiber form as potential absorbable sutures. Strong, flexible monofilaments have been produced which maintain 11—37% of initial tensile strength after two weeks in vivo (48). 

Thermoplastic polyurethane elastomers have now been available for many years (and were described in the first edition of this book). The adipate polyester-based materials have outstanding abrasion and tear resistance as well as very good resistance to oils and oxidative degradation. The polyether-based materials are more noted for their resistance to hydrolysis and fungal attack. Rather specialised polymers based on polycaprolactone (Section 25.11) may be considered as premium grade materials with good all round properties. 

Examples shown in this chapter are for PMMA. Other polymers can be separated as well. The polymers separated so far (1,2) include polystyrene, poly(a-methylstyrene), polycaprolactone, polycarbonate, poly(hexyl isocyanate), polytetrahydrofuran, poly (vinyl methyl ether), and polyvinylpyrrolidone. 

Commercial end functional polymers have been converted to alkoxyamincs and used to prepare PKO-Worri-PS.040 The hydroxyl group of alkoxyamine 284 was used to initiate ring-opening polymerization of caprolactonc catalyzed by aluminum tris(isopropoxide) and the product subsequently was used to initiate S polymerization by NMP thus forming polycaprolactone-Wodr- P8.641 The alternate strategy of forming PS by NMP and using the hydroxyl chain end of the product to initiate polymerization of caprolactonc was also used. 

Considering the high hydrophobicity of the palmitoyl side chain and the rigidity of the polymer backbone, we assumed that poly(N-palmitoylhydroxyproline ester) would degrade somewhat more slowly than poly (lactic acid) or polycaprolactone. In order to confirm this hypothesis, a series of long-term stability and degradation studies have been performed over the last 2 years at MIT (22). 

Aliphatic polyesters based on monomers other than a-hydroxyalkanoic acids have also been developed and evaluated as drug delivery matrices. These include the polyhydroxybutyrate and polyhydroxy valerate homo- and copolymers developed by Imperial Chemical Industries (ICI) from a fermentation process and the polycaprolactones extensively studied by Pitt and Schindler (14,15). The homopolymers in these series of aliphatic polyesters are hydrophobic and crystalline in structure. Because of these properties, these polyesters normally have long degradation times in vivo of 1-2 years. However, the use of copolymers and in the case of polycaprolactone even polymer blends have led to materials with useful degradation times as a result of changes in the crystallinity and hydrophobicity of these polymers. An even larger family of polymers based upon hydroxyaliphatic acids has recently been prepared by bacteria fermentation processes, and it is anticipated that some of these materials may be evaluated for drug delivery as soon as they become commercially available. 

All liposphere formulations prepared remained stable during the 3-month period of the study, and no phase separation or appearance of aggregates were observed. The difference between polymeric lipospheres and the standard liposphere formulations is the composition of the internal core of the particles. Standard lipospheres, such as those previously described, consist of a solid hydrophobic fat core composed of neutral fats like tristearin, whereas, in the polymeric lipospheres, biodegradable polymers such as polylactide or polycaprolactone were substituted for the triglycerides. Both types of lipospheres are thought to be stabilized by one layer of phospholipid molecules embedded in their surface. 

We report here that polyethylene adipate (PEA) and polycaprolactone (PCL) were degraded by Penicillium spp., and aliphatic and alicyclic polyesters,ester type polyurethanes, copolyesters composed of aliphatic and aromatic polyester (CPE) and copolyamide-esters (CPAE) were hydrolyzed by several lipases and an esterase. Concerning these water-insoluble condensation polymers, we noted that the melting points (Tm) had a effect on biodegradability. 

There are various routes to vinyl macromonomers [Gnanou and Taton, 2002]. For example, the reaction of an HO-terminated polymer such as polysiloxane, polycaprolactone, or poly-tetrahydrofuran with acryloyl chloride... 

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