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Type: Artigo
Title: Influence of the synthesis conditions on the structural and thermal properties of poly(l‐lactide)‐b‐poly(ethylene glycol)‐b‐poly(l‐lactide)
Author: Trinca, Rafael Bergamo
Felisberti, Maria Isabel
Abstract: The poly(l-lactide)-b-poly(ethylene glycol)-b-poly(l-lactide) block copolymers (PLLA-b-PEG-b-PLLA) were synthesized in a toluene solution by the ring-opening polymerization of 3,6-dimethyl-1,4-dioxan-2,5-dione (LLA) with PEG as a macroinitiator or by transterification from the homopolymers [polylactide and PEG]. Two polymerization conditions were adopted: method A, which used an equimolar catalyst/initiator molar ratio (1-5 wt %), and method B, which used a catalyst content commonly reported in the literature (<0.05 wt %). Method A was more efficient in producing copolymers with a higher yield and monomer conversion, whereas method B resulted in a mixture of the copolymer and homopolymers. The copolymers achieved high molar masses and even presenting similar global compositions, the molar mass distribution and thermal properties depends on the polymerization method. For instance, the suppression of the PEG block crystallization was more noticeable for copolymer A. An experimental design was used to qualify the influence of the catalyst and homopolymer amounts on the transreactions. The catalyst concentration was shown to be the most important factor. Therefore, the effectiveness of method A to produce copolymers was partly due to the transreactions. (c) 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40419.
The poly(l‐lactide)‐b‐poly(ethylene glycol)‐b‐poly(l‐lactide) block copolymers (PLLA‐b‐PEG‐b‐PLLA) were synthesized in a toluene solution by the ring‐opening polymerization of 3,6‐dimethyl‐1,4‐dioxan‐2,5‐dione (LLA) with PEG as a macroinitiator or by tran
Subject: Copolímeros
Polimerização por abertura de anel
Country: Estados Unidos
Editor: John Wiley & Sons
Citation: Journal Of Applied Polymer Science. Wiley-blackwell, v. 131, n. 13, 2014.
Rights: fechado
Identifier DOI: 10.1002/app.40419
Date Issue: 2014
Appears in Collections:IQ - Artigos e Outros Documentos

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