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A novel rare earth coordination catalyst for polymerization of biodegradable aliphatic lactones and lactides
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1998
Year
EngineeringRing-opening PolymerizationOrganic ChemistryChemistryPolymersChemical EngineeringMacromolecular EngineeringPolymerization YieldsPolymer ChemistryMaterials ScienceSynthetic MacromoleculeCatalysisCatalytic SynthesisPolymer ScienceBiodegradable Aliphatic LactonesPolymerization KineticsMolecular WeightPolymer ReactionPolymer Synthesis
A novel rare earth coordination system composed of lanthanide trifluoroacetates Ln(CF3COO)3 (Ln=Y, Yb, Nd, Tm, Ho, La, Pr) and tri-isobutylaluminium Al(i-Bu)3 was used as catalyst for the polymerization of ε-caprolactone (CL), D,L-lactide (DLLA) and their copolymerization. The influence of temperature, time and catalyst concentration on polymerization yields and molecular weights of the polyesters have been studied. It was shown that the ring-opening polymerization of cyclic esters catalysed by Ln(CF3COO)3/Al(i-Bu)3 has some living character and the molecular weight of the polyester could be controlled by adjusting the molar ratio of monomer to catalyst. The DLLA/CL copolymer was synthesized by sequential addition of monomers and the structure of the copolyester was characterized by GPC, NMR and DSC. © 1998 SCI.