TSDC studies of the effects of plasticizer and water on the Sub-Tg relaxations of an epoxy resin system

Maggana, C; Pissis, P

dc.contributor.author	Maggana, C	en
dc.contributor.author	Pissis, P	en
dc.date.accessioned	2014-03-01T01:13:29Z
dc.date.available	2014-03-01T01:13:29Z
dc.date.issued	1997	en
dc.identifier.issn	0022-2348	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/12504
dc.subject	Epoxy Resin	en
dc.subject.classification	Polymer Science	en
dc.subject.other	Activation energy	en
dc.subject.other	Aging of materials	en
dc.subject.other	Composition effects	en
dc.subject.other	Ethers	en
dc.subject.other	Glass transition	en
dc.subject.other	Molecular structure	en
dc.subject.other	Phase separation	en
dc.subject.other	Plasticizers	en
dc.subject.other	Relaxation processes	en
dc.subject.other	Saturation (materials composition)	en
dc.subject.other	Thermal effects	en
dc.subject.other	Water absorption	en
dc.subject.other	Bisphenol	en
dc.subject.other	Thermally stimulated depolarization current (TSDC) technique	en
dc.subject.other	Epoxy resins	en
dc.title	TSDC studies of the effects of plasticizer and water on the Sub-Tg relaxations of an epoxy resin system	en
heal.type	journalArticle	en
heal.identifier.primary	10.1080/00222349708212400	en
heal.identifier.secondary	http://dx.doi.org/10.1080/00222349708212400	en
heal.language	English	en
heal.publicationDate	1997	en
heal.abstract	The sub-glass-transition-temperature (sub-T-g) relaxations of an epoxy resin system based on diglycidyl ether of bisphenol-A (DGEBA) and cured with triethylenetetramine (TETA) were investigated by means of the thermally stimulated depolarization current (TSDC) technique in the temperature range 77 K to 300 K. Three relaxation regions were observed: the gamma relaxation at about 150 K, the beta relaxation at 160 K to 200 K and the omega relaxation at 240 K to 270 K. The plasticization effect on the aforementioned relaxations of a plasticizer chemically connected to the epoxy resin network was investigated. The amount of plasticizer (commercial name THIOCOL LP3) was varied between 0% and 60% by weight of the epoxy. The broad range of the beta relaxation reflects the heterogeneous structure of the material. The activation energies of the gamma and beta relaxations were calculated using the thermal sampling technique. Physical aging strongly influenced the TSDC thermogram of the omega relaxation, indicating phase separation during the aging procedure. Water effects were systematically investigated from dry samples to water-saturated samples (water content, 2.5%). In all specimens, water induced plasticization, which is expressed by the shifting of the beta relaxation toward lower temperatures. The mode of water absorption (immersion in water or exposure to humid environment) also influenced the evolution of the omega relaxation.	en
heal.publisher	MARCEL DEKKER INC	en
heal.journalName	Journal of Macromolecular Science - Physics	en
dc.identifier.doi	10.1080/00222349708212400	en
dc.identifier.isi	ISI:A1997YD45500005	en
dc.identifier.volume	36	en
dc.identifier.issue	6	en
dc.identifier.spage	749	en
dc.identifier.epage	772	en