Polycaprolactone PCL

PCL is a bioresorbable and biocompatible aliphatic polyester that is generally used in pharmaceutical products and wound dressings. In addition, PCL nanofibrous matrices coated with collagen support cell growth or make the three-dimensional structured multilayer of PCL nanofibers and collagen nanofibers suitable for blood 

Since PCL is compatible with a range of other materials, it can be mixed with starch to lower its cost and increase biodegradability or it can be added as a polymeric plasticizer to PVC. 

The degradation of PCL in vivo is lower than that of PGA and PLA. Therefore, its use in long-term implantable devices has been studied. 

The Solvay company produces PCL under the name of CAPA, and Union Carbide under the name of TONE. 

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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. 

Polycaprolactone (PCL) Poly-cis-2-butene adipate Poly-cis-2-butene sebacate Poly-trans-2-butene sebacate Poly-2-butyne sebacate Polyhexamethylene fumarate Poly-cis-2-butene fumarate Poly t e t r ame t hy Icy c lobut ane succinate... 

The inhibitory effects of PVA can also be found in degradation studies of polycaprolactones (PCLs). These polyesters can be readily split by lipase enzymes binding to hydrophobic domains of that linear substrate. PVA/PCL films in contrast are not biodegradable by PCL-degrading microorganisms. It can be assumed that the surface properties of PCL change upon interaction with PVA in a manner that enzymatic accessibility of the hydrolysable PCL backbone motifs is decreased. 

Figure 7.7 SAXS profiles for two hydroxyl-terminated oligomers crosslinked by alkoxysilane sol-gel chemistry. First, 1 mole of macrodiol, SS (hydrogenated polybutadiene, HPBD or polycaprolactone, PCL, Mn= 2 kg mol-1), was reacted at 80°C with 2 mole of dicyclohexylmethane diisocyanate, H12 MDI. After complete reaction, the prepolymer was dissolved in tetrahydro-furan and the y-aminosilane, yAPS was added dropwise at room temperature. After 1 h of reaction, the solvent was removed under pressure. The final network was obtained in the absence of a solvent by hydrolysis and condensation of the ethoxysilane groups by the addition of 0.1 mol% TFA, trifluor-oacetic acid. After stirring at room temperature, the mixture was cast into a mold and cured for 24 h at 100°C under pressure, and then postcured at 150°C for 12 h. (Cuney et al., 1997 - Copyright 2001, Reprinted by permission of John Wiley Sons, Inc.)...

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. 

Starch can be destructured in the presence of more hydrophobic polymers such as aliphatic polyesters. Aliphatic polyesters with low melting points are difficult to process by conventional techniques such as film blowing and blow moulding. Films such as polycaprolactones (PCL) are tacky as extruded and have a low melt strength (over 130 °C). Also, the slow crystallisation of the polymer causes the properties to change with time. Blending starch with aliphatic polyesters improves processability and biodegradability. 

Beside the natural polyesters a number of synthetic aliphatic polyesters have also been shown to be biodegradable. From a commercial point of view the most important synthetic biodegradable aliphatic polyester was traditionally polycaprolactone (PCL). 

Aliphatic polyesters like polycaprolactone (PCL) or polybutylene adipate (PBA) are readily biodegradable, but because of their melting points of 60 °C are unsuitable for many applications. On the other hand, aromatic polyesters like polyethylene terephthalate (PET) or polybutylene terephthalate (PBT) have high melting points above 200 °C and very good material properties, but are not biodegradable. 

A mixture of the 50 50 polycaprolactone (PCL) matrix and the appropriate weight nicotine drug load were placed in an oil bath at 150°C. A Teflon stirrer slowly mixed the viscous material in a polypropylene cup for thirty minutes. After visually inspecting for homogeneity, the PCL/drug mixture was allowed to cool in the freezer until it hardened and could be removed from the cup with ease. It was then stored at room temperature until ready for pressing. To create... 

Solid-state carbon NMR with MAS has been used to study the structure and dynamics of semicrystalline polycaprolactone (PCL) and its inclusion complexes formed with a- and y-cyclodextrins (a- and y-CDs), which are shown to have channel structures occupied by single and two parallel, side-by-side chains, respectively. ... 

Those nanoparticles (3LNPs) were fabricated via a pH-controlled hierarchical self-assembly of a tercopolymer brush (Schemes 10.2 and 10.3), which contained hydrophilic polycaprolactone (PCL) chains, water-soluble PEG chains, and pH-responsive poly[2-(iV,iV-diethylamino)ethyl methacrylate] (PDEA) chains. PDEA is a polybase that is soluble at low pH but insoluble at neutral pH [167-169]. The brush polymer was initially dispersed in a pH 5.0 solution where the PDEA chains were protonated and hence water-soluble. The hydrophobic PCL chains and drug molecules associated to form the hydrophobic core. The PEG and protonated PDEA chains formed a hydrophilic corona surrounding the core. After the solution pH was raised to 7.4, the PDEA chains were deprotonated and became hydrophobic, collapsing on the PCL core as a hydrophobic middle layer with only the PEG chains forming the hydrophilic corona (Scheme 10.3). 

Fig. 10.16 Tumor pacUtaxel concentrations upon intravenous administration to SKOV-3 human ovarian adenocarcinoma bearing nude mice. Paclitaxel was administered intravenously in aqueous solution, poly(ethylene oxide)-modified polycaprolactone (PCL) nanoparticles, or poly(ethylene oxide)-modified poly(P-amino ester) (PbAE) nanoparticles, (reproduced from [212], with permission from Springer)...

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