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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.)

Poly (ethylene terephthalate) thermo-mechanical and thermo-oxidative degradation mechanisms

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Author(s):
Romao, Wanderson [1] ; Franco, Marcos F. [1] ; Corilo, Yuri E. [2] ; Eberlin, Marcos N. [2] ; Spinace, Marcia A. S. [1] ; De Paoli, Marco-A. [1]
Total Authors: 6
Affiliation:
[1] Univ Estadual Campinas, Lab Polimeros & Reciclagem, Inst Quim, BR-13084971 Campinas, SP - Brazil
[2] Univ Estadual Campinas, Lab ThoMSom Espectrometria Massas, Inst Quim, BR-13084971 Campinas, SP - Brazil
Total Affiliations: 2
Document type: Journal article
Source: Polymer Degradation and Stability; v. 94, n. 10, p. 1849-1859, OCT 2009.
Web of Science Citations: 46
Abstract

(1)H NMR and MALDI-TOF MS measurements were used to study the thermo-mechanical and thermo-oxidative degradation mechanisms of bottle-grade PET (btg-PET). In the thermo-oxidative degradation, the concentration of low molar mass compounds increased with time and the main products were cyclic and linear di-acid oligomers. In the thermo-mechanical degradation, the main-chain scission reactions affect the stability of the cyclic oligomers. One of the most important bottle-grade PET co-monomers is diethylene glycol (DEG), which is a ``reactive site'' in the thermal degradation of btg-PET. The DEG co-monomer was shown to be the precursor to colour changes in btg-PET, owing to the attack by molecular oxygen on the methylenic protons adjacent to the ether oxygen atoms of DEG. This behaviour was observed in the thermo-oxidative degradation process in which the degradation of DEG causes the release of hydroxyl radicals in the polymeric matrix, thereby producing mono- and di-hydroxyl substituted species. This was also observed in the thermo-mechanical degradation process. (c) 2009 Elsevier Ltd. All rights reserved. (AU)

FAPESP's process: 04/15084-6 - Polymeric materials of low environmental impact
Grantee:Marco-Aurelio de Paoli
Support Opportunities: Research Projects - Thematic Grants