Thermomechanical and hygroelastic properties of an epoxy system under humid and cold-warm cycling conditions

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• 作者：Jalal El Yagoubi ; Gilles Lubineau ; Shahid Saghir ; Jacques Verdu ; Abe Askari
• 关键词：Epoxy ; Hygrothermal aging ; Hydrolysis ; Sorption
• 刊名：Polymer Degradation and Stability
• 出版年：January, 2014
• 年：2014
• 卷：99
• 期：Complete
• 页码：146-155
• 全文大小：1699 K

文摘

In this paper, we study the hygrothermal aging of an anhydride-cured epoxy under temperature and hygrometry conditions simulating those experienced by an aircraft in wet tropical or subtropical regions. Gravimetric and dimensional measurements were performed and they indicate that there are three stages in this aging process: the first one, corresponding to the early cycles can be called the 鈥渋nduction stage鈥? The second stage of about 1000 cycles duration, could be named the 鈥渟welling stage鈥? during which the volume increase is almost equal to the volume of the (liquid) water absorbed. Both the first and second stages are accompanied by modifications of the mechanical properties and the glass transition temperature. During the third (鈥渆quilibrium鈥? stage, up to 3000 cycles, there is no significant change in the physical properties despite the continuous increase of water uptake. This can be explained by the fact that only physically sorbed water can influence physical properties.