Macromolecular engineering of cyclic aliphatic polyesters by ring-opening polymerization

Conference (2006, September 24)

New prospects for the grafting of functional groups onto aliphatic polyesters. Ring-opening polymerization of alpha- or gamma-substituted epsilon-caprolactone followed by chemical derivatization of the substituents

in Macromolecular Symposia (2006), 240

Recent progress in the synthesis of aliphatic polyesters, substituted by pendent functional groups, has been reviewed. Two main strategies have to be distinguished. The first route consists of the ring ... [more ▼]

Recent progress in the synthesis of aliphatic polyesters, substituted by pendent functional groups, has been reviewed. Two main strategies have to be distinguished. The first route consists of the ring-opening polymerization of F,caprolactone substituted by various functional groups, protected if needed, in alpha- or gamma-position. In a second strategy, the functional groups are grafted onto preformed polyesters chains in alpha-position of the carbonyl groups. alpha-chloro-epsilon-caprolactone is quite an interesting monomer because, after polymerization, the activated chloride can be easily derivatized by atom transfer radical addition and "click" chemistry, respectively. Similarly, gamma-acrylic-epsilon-caprolactone is precursor of (co)polyesters wellsuited to derivatization of the pendent double bonds by Michael addition. [less ▲]

Combination of ring-opening polymerization and "click" chemistry towards functionalization of aliphatic polyesters

in Chemical Communications (2005), (42), 5334-5336

Azide pendent groups of aliphatic polyesters have been derivatized into tertiary amines, ammonium salts and poly(ethylene oxide) grafts. The experimental conditions have been optimized (organic solvent ... [more ▼]

Azide pendent groups of aliphatic polyesters have been derivatized into tertiary amines, ammonium salts and poly(ethylene oxide) grafts. The experimental conditions have been optimized (organic solvent, 35 degrees C), such that the aliphatic polyesters are not degraded, including even poly(lactide) which is very sensitive to attack by weak nucleophiles. [less ▲]

Functionalization of poly(epsilon-caprolactone) by pendant hydroxyl, carboxylic acid and epoxide groups by atom transfer radical addition

in Polymer (2005), 46(19), 8511-8518

A straightforward strategy is proposed for grafting hydroxyl, carboxylic acid and epoxide groups along poly (epsilon-caprolactone) chains. Statistical copolymerization of epsilon-caprolactone (epsilon-CL ... [more ▼]

A straightforward strategy is proposed for grafting hydroxyl, carboxylic acid and epoxide groups along poly (epsilon-caprolactone) chains. Statistical copolymerization of epsilon-caprolactone (epsilon-CL) with alpha-chloro-epsilon-caprolactone (alpha-Cl-epsilon-CL) has been initiated by 2,2-dibutyl-2-stanna-1,3-dioxepane (DSDOP), followed by the atom transfer radical addition (ATRA) of but-3-en-1-ol, vinylacetic acid and 1,2-epoxyhex-5-ene, respectively, onto the alpha-chloro units of a poly(alpha-Cl-epsilon-CL-co-epsilon-CL) copolymer. alpha-Cl-epsilon-CL is easily prepared by the Baeyer-Villiger oxidation of 2-chlorocyclohexanone. The influence of the experimental conditions, i.e. temperature, solvent, catalyst, on the grafting yield has been discussed. Because ATRA is tolerant of the investigated functional groups, no protection/deprotection reaction is required, which is a major advantage of the method. [less ▲]

Synthesis of new substituted poly(ε-caprolactone)s by comination of ring-opening polymerization, atom transfer radical addition and click reaction

Poster (2005, May 19)

During the last few years, a great research effort has been devoted to the synthesis of aliphatic polyesters, e.g. poly(ε-caprolactone) and polylactides. Indeed, their remarkable properties of ... [more ▼]

During the last few years, a great research effort has been devoted to the synthesis of aliphatic polyesters, e.g. poly(ε-caprolactone) and polylactides. Indeed, their remarkable properties of biodegradability and biocompatibility pave the way to many new applications in the biomedical field and as substitutes for non degradable polymers. In order to tailor the polyester properties, the grafting of functional groups along the polymer backbone is highly desirable. For the last few years, CERM has reported on the synthesis and the (co)polymerization of novel ε-caprolactones γ-substituted by various functional groups, e.g., ketal, ketone, olefin, protected alcohol and carboxylic acid. Nevertheless, the grafting of a specific functional group onto the aliphatic polyester backbone requires the synthesis of the parent substituted ε-caprolactone. There is accordingly a need for a strategy that would use a unique substituted ε-caprolactone, followed by derivatization by well-established reactions, so making available a wide range of pendent functional groups, polymeric or not. The derivatization reactions have however to be quantitative under mild conditions to prevent the aliphatic polyester from degrading. Moreover, these reactions must be compatible with the functional groups of interest, e.g., hydroxyl and carboxylic acid, in order to avoid the use of cumbersome protection/deprotection reactions. This communication aims at reporting that a-chloro-e caprolactone (αCLεCL) can be easily copolymerized with εCL into poly(αCLεCL-co-εCL) copolymers, which are precursors for various aliphatic polyesters, by using either Atom Transfer Radical Addition (ATRA) or Click reactions. The number of steps is limited whatever the "Click" or the "ATRA" strategy under consideration. In both cases, mild conditions have been found, such that degradation is minimized. Pendent hydroxyl, carboxylic acid and epoxide groups have been attached without using any protection/deprotection reaction. This strategy has been implemented for the synthesis of amphiphilic poly(εCL-g-ethylene oxide) graft copolymers, that have been used to prepare poly(D,L-lactide) nanoparticles for drug delivery applications. [less ▲]

Ring-opening polymerization of alpha-chloro-epsilon-caprolactone and chemical modification of poly(alpha-chloro-epsilon-caprolactone) by atom transfer radical processes

in Macromolecules (2004), 37(11), 4055-4061

A highly versatile strategy was implemented in order to attach a range of polymer grafts and functional groups along the backbone of poly(epsilon-caprolactone). alpha-Chloro-epsilon-caprolactone ... [more ▼]

A highly versatile strategy was implemented in order to attach a range of polymer grafts and functional groups along the backbone of poly(epsilon-caprolactone). alpha-Chloro-epsilon-caprolactone (alphaClepsilonCL) was first prepared by the Baeyer-Villiger oxidation of alpha-chlorocyclohexanone. This monomer (alpha-Cl-epsilon-CL) was then copolymerized with epsilon-caprolactone in the presence of 2,2-dibutyl-2-stanna-1,3-dioxepane. Finally, the pendant activated chlorides of the copolymer were used to initiate (i) the "grafting from" of poly(methyl methacrylate) by atom transfer radical polymerization and (ii) the grafting of benzoate groups by atom transfer radical addition of 3-butenyl benzoate. [less ▲]

Poly(α-chloro-ε-caprolactone), a new precursor for functionalized and graft polyesters

Poster (2003, May 16)