Multiblock copolymers containing periodically spaced side-chain carboxyl groups were obtained by a twostep synthesis involving the preparation of ABA triblock prepolymers of e-caprolactone (A blocks) and ethylene glycol (B block) followed by chain extension to ABAn multiblock copolymers by reaction with pyromellitic dianhydride (PMDA). NMR analysis demonstrated the incorporation of PMDA in polymer chain and revealed the possibility of PMDA units to exist in two isomers, cisoid and transoid forms. Chain extension resulted in the incorporation of free carboxylic groups in polymer backbone and in an almost twofold increase of molecular weight. Thermal analysis indicated that the presence of PMDA residues interferes with the formation of crystalline phases by the chain-extended polymers. The polymers were found to slowly degrade in buffer solution at 37 °C. Further, the carboxylated polymers can be processed into nanoparticulates by nanoprecipitation. Depending on the selected organic solvent, the particulate was constituted by either a monodispersed nanoparticles with average size of 150 nm or a bimodal distribution centered at about 100 nm and 7 µm.
Multiblock Copolymers of e–Caprolactone and Ethylene Glycol Containing Periodic Side-Chain Carboxyl Groups: Synthesis, Characterization, and Nanoparticle Preparation
ALTOMARE, ANGELINA;ALDERIGHI, MICHELE;CORTI, ANDREA;DESSY, ALBERTO;CHIELLINI, FEDERICA;SOLARO, ROBERTO
2013-01-01
Abstract
Multiblock copolymers containing periodically spaced side-chain carboxyl groups were obtained by a twostep synthesis involving the preparation of ABA triblock prepolymers of e-caprolactone (A blocks) and ethylene glycol (B block) followed by chain extension to ABAn multiblock copolymers by reaction with pyromellitic dianhydride (PMDA). NMR analysis demonstrated the incorporation of PMDA in polymer chain and revealed the possibility of PMDA units to exist in two isomers, cisoid and transoid forms. Chain extension resulted in the incorporation of free carboxylic groups in polymer backbone and in an almost twofold increase of molecular weight. Thermal analysis indicated that the presence of PMDA residues interferes with the formation of crystalline phases by the chain-extended polymers. The polymers were found to slowly degrade in buffer solution at 37 °C. Further, the carboxylated polymers can be processed into nanoparticulates by nanoprecipitation. Depending on the selected organic solvent, the particulate was constituted by either a monodispersed nanoparticles with average size of 150 nm or a bimodal distribution centered at about 100 nm and 7 µm.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
