Thermal stability of poly(lactic acid) before and after g-radiolysis

Babanalbandi, A., Hill, D. T., Hunter, D. S. and Kettle, L. (1999) Thermal stability of poly(lactic acid) before and after g-radiolysis. Polymer International, 48 10: 980-984.


Author Babanalbandi, A.
Hill, D. T.
Hunter, D. S.
Kettle, L.
Title Thermal stability of poly(lactic acid) before and after g-radiolysis
Journal name Polymer International   Check publisher's open access policy
ISSN 0959-8103
Publication date 1999
Sub-type Article (original research)
DOI 10.1002/(SICI)1097-0126(199910)48:10<980::AID-PI257>3.0.CO;2-B
Volume 48
Issue 10
Start page 980
End page 984
Total pages 5
Place of publication Sussex, UK
Publisher John Wiley & Sons
Collection year 1999
Language eng
Subject C1
250502 Physical Chemistry of Macromolecules
780103 Chemical sciences
Abstract The thermal degradation of poly(lactic acid) has been studied using thermal gravimetric analysis over the temperature range 300-700 K, and following a sterilization dose of 50 kGy under vacuum, nitrogen or air. Isothermal weight loss studies have been found to follow complex kinetics with activation energies determined by the MacCallum method for various fractional conversions in the range 72-103 kJ mol(-1). Dynamic thermogravimetric analysis at heating rates from 10 to 25 K min(-1) showed the maximum rate of weight loss occurs in the range 550-650 K with the onset of degradation being in the range 450-500 K. The thermograms observed for the unirradiated polymer under a nitrogen atmosphere showed a very small shoulder on the low temperature side of the thermograms. The Kissinger expression, which is based on the temperature for the maximum rare of weight loss, yielded an activation energy of 109 kJ mol(-1) for thermal degradation under nitrogen and 131 kJ mol(-1) under oxygen. Compared with those of unirradiated samples, the weight-loss profiles under nitrogen for samples irradiated under vacuum or nitrogen were shifted towards higher temperatures, but the profiles for the samples irradiated in air did not change significantly. The shift to higher temperatures for the former two samples was attributed to modification of chain-end hydroxyl groups. (C) 1999 Society of Chemical industry.
Keyword Polymer Science
Q-Index Code C1

Document type: Journal Article
Sub-type: Article (original research)
Collection: Earth Systems Science Computational Centre Publications
 
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