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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Influence of the Synthesis Conditions on the Structural and Thermal Properties of Poly( L- lactide)- b- Poly( ethylene glycol)- b- Poly( L- lactide)

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Author(s):
Trinca, Rafael Bergamo [1] ; Felisberti, Maria Isabel [1]
Total Authors: 2
Affiliation:
[1] Univ Estadual Campinas, Inst Chem, BR-13083970 Sao Paulo - Brazil
Total Affiliations: 1
Document type: Journal article
Source: Journal of Applied Polymer Science; v. 131, n. 13 JUL 5 2014.
Web of Science Citations: 8
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. (AU)

FAPESP's process: 10/17804-7 - Polymeric composites
Grantee:Maria Isabel Felisberti
Support Opportunities: Research Projects - Thematic Grants
FAPESP's process: 08/07157-4 - Synthesis and characterization of amphiphilic copolymers based on poly(ethylene glycol)/PEG, poly(L-lactide)/PLLA and poly(trimethylene carbonate)/PTMC
Grantee:Rafael Bergamo Trinca
Support Opportunities: Scholarships in Brazil - Master
FAPESP's process: 10/02098-0 - Multicomponent polymeric materials
Grantee:Maria Isabel Felisberti
Support Opportunities: Regular Research Grants
FAPESP's process: 11/09479-1 - Multicomponent segmented polyurethanes
Grantee:Rafael Bergamo Trinca
Support Opportunities: Scholarships in Brazil - Doctorate