title: Synthesis and rheological properties of polylactide/poly(ethylene glycol) multiblock copolymers.
abstract: Ring-opening polymerization of D,L-lactide was carried out in the presence of poly(ethylene glycol), using Zn powder as catalyst. The hydroxyl-capped PLA-PEG-PLA triblock copolymers were coupled with adipoyl chloride at different molar ratios under mild conditions. N-Dimethylaminopyridine (DMAP) was used as catalyst of the coupling reaction. The resulting PLA/PEG multiblock copolymers were characterized by various analytical techniques such as IR, 1H NMR, SEC, and DSC. Sol-gel transition properties of the multiblock copolymers were investigated by mechanical rheology. The data showed that the sol-gel transition temperature and the transition modulus increased with increasing molecular weight and the solution concentration of the multiblock copolymers. [Graph: see text] Variation of storage modulus (G') and loss modulus (G'') as a function of temperature for a 20% sample of MB3.
authors.affiliation: Centre de Recherche sur les biopolymères Artificiels, Faculté de Pharmachie, 15 Avenue Charles Flahault, 34060 Montpellier, France.
authors.forename: Feng
authors.initials: F
authors.lastname: Li
authors.forename: Suming
authors.initials: S
authors.lastname: Li
authors.forename: Michel
authors.initials: M
authors.lastname: Vert
mesh_terms: D000272:Adipates / Q000737:chemistry; D001672:Biocompatible Materials / Q000138:chemical synthesis / Q000737:chemistry*; D044367:Phase Transition; D011091:Polyesters / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry*; D011108:Polymers / Q000138:chemical synthesis / Q000737:chemistry; D011725:Pyridines / Q000737:chemistry; D012212:Rheology; D013057:Spectrum Analysis; D044366:Transition Temperature
chemical_list: C417980:4-(dimethylamine)pyridine; D000272:Adipates; D001672:Biocompatible Materials; D011091:Polyesters; D011108:Polymers; D011725:Pyridines; C503083:adipoyl chloride; C507889:polylactide-polyethylene glycol-polylactide; D011092:Polyethylene Glycols