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Synthesis and aqueous phase behavior of thermoresponsive biodegradable poly( D , L ‐3‐methylglycolide)‐ block ‐poly(ethylene glycol)‐ block ‐poly( D , L ‐3‐methylglycolide) triblock copolymers
Author(s) -
Zhong Zhiyuan,
Dijkstra Pieter J.,
Feijen Jan,
Kwon YoungMin,
Bae You Han,
Kim Sung Wan
Publication year - 2002
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/1521-3935(200208)203:12<1797::aid-macp1797>3.0.co;2-a
Subject(s) - copolymer , ethylene glycol , polymer chemistry , dispersity , aqueous solution , peg ratio , differential scanning calorimetry , ethylene oxide , materials science , polymerization , ring opening polymerization , chemistry , polymer , organic chemistry , physics , finance , economics , thermodynamics , composite material
Novel biodegradable thermosensitive triblock copolymers of poly( D , L ‐3‐methylglycolide)‐ block ‐poly(ethylene glycol)‐ block ‐poly( D , L ‐3‐methylglycolide) (PMG‐PEG‐PMG) have been synthesized. Ring‐opening polymerization of D , L ‐3‐methyl‐glycolide (MG) initiated with poly(ethylene glycol) (PEG) and Ca[N(SiMe 3 ) 2 ] 2 (THF) 2 provided triblock copolymers with alternating lactyl/glycolyl sequences of controlled molecular weight, low polydispersity index and uniform chain structure. At relatively low temperatures (≈ 10 °C) these copolymers formed clear solutions in water up to high concentrations (50 wt.‐%). Depending on molecular mass ratios of PMG and PEG blocks, a sol‐gel transition or an increase in viscosity without gel formation was observed upon increasing the temperature of the aqueous solutions. The temperature‐induced gelation was ascertained by rheology and dynamic differential scanning calorimetry (DDSC).Phase diagram of PMG‐PEG‐PMG 1 400‐1 450‐1 400 in an aqueous solution.