Effects of aging on the thermomechanical properties of poly(lactic acid)

Niaounakis, M; Kontou, E; Xanthis, M

dc.contributor.author	Niaounakis, M	en
dc.contributor.author	Kontou, E	en
dc.contributor.author	Xanthis, M	en
dc.date.accessioned	2014-03-01T01:35:36Z
dc.date.available	2014-03-01T01:35:36Z
dc.date.issued	2011	en
dc.identifier.issn	0021-8995	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/21118
dc.subject	ageing	en
dc.subject	biodegradable	en
dc.subject	mechanical properties	en
dc.subject.classification	Polymer Science	en
dc.subject.other	ageing	en
dc.subject.other	Aging behavior	en
dc.subject.other	Aging process	en
dc.subject.other	biodegradable	en
dc.subject.other	Consecutive heating	en
dc.subject.other	Environmental parameter	en
dc.subject.other	Glass transition temperature	en
dc.subject.other	Heating history	en
dc.subject.other	Higher temperatures	en
dc.subject.other	Overall properties	en
dc.subject.other	Physical structures	en
dc.subject.other	Poly(lactic acid)	en
dc.subject.other	Polylactic acids	en
dc.subject.other	Relative humidities	en
dc.subject.other	Tensile measurements	en
dc.subject.other	Thermal processing	en
dc.subject.other	Thermomechanical properties	en
dc.subject.other	Time interval	en
dc.subject.other	Atmospheric humidity	en
dc.subject.other	Body fluids	en
dc.subject.other	Differential scanning calorimetry	en
dc.subject.other	Dynamic analysis	en
dc.subject.other	Dynamic mechanical analysis	en
dc.subject.other	Glass transition	en
dc.subject.other	Heating	en
dc.subject.other	Lactic acid	en
dc.subject.other	Size exclusion chromatography	en
dc.subject.other	Mechanical properties	en
dc.title	Effects of aging on the thermomechanical properties of poly(lactic acid)	en
heal.type	journalArticle	en
heal.identifier.primary	10.1002/app.32644	en
heal.identifier.secondary	http://dx.doi.org/10.1002/app.32644	en
heal.language	English	en
heal.publicationDate	2011	en
heal.abstract	In this study, we examined the role of environmental parameters and physical structure in the aging process of poly(lactic acid) (PLA). The role of heating history on the aging behavior of the material was also investigated. PLA samples with a D-content of 4.25% were exposed to a relative humidity of 80% at three different temperatures, 20, 40, and 50 degrees C (below the glass-transition temperature of the material), at various aging periods of 30, 60, 80, 100, and 130 days. Selected samples were subjected to two consecutive heating runs. The stability of PLA was monitored by a number of techniques, including size exclusion chromatography, differential scanning calorimetry, dynamic mechanical analysis, and tensile measurements. The initial thermal processing (150 degrees C) of the material resulted in an overall molecular weight reduction. A substantial lowering of properties was observed for PLA samples aged at 20 degrees C for 30 days. No further loss of properties was observed for samples aged up to 40 degrees C for several time intervals. A major portion (80-90%) of the induced changes in the tensile properties could be reversed after drying. At 50 degrees C and 100 days of aging, a sharp decrease in the overall properties was noticed. The results seem to confirm the earlier finding that PLA degradation driven by hydrolysis needs a higher temperature (> 50 degrees C) in combination with ample time to take place. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 119: 472-481, 2011	en
heal.publisher	JOHN WILEY & SONS INC	en
heal.journalName	Journal of Applied Polymer Science	en
dc.identifier.doi	10.1002/app.32644	en
dc.identifier.isi	ISI:000284176000054	en
dc.identifier.volume	119	en
dc.identifier.issue	1	en
dc.identifier.spage	472	en
dc.identifier.epage	481	en