Microstructure Evolution of SW/EPN Composites During Hot Air Aging

作者：Xiao Hong Mei; Zhan Mao Sheng^*; Xu Wen; Ding Xiao jun

来源：Journal of Applied Polymer Science, 2014, 131(8): 40128.

DOI：10.1002/app.40128

• ageing
• degradation
• composites
• structure-property relations
• properties and characterization

In this article, the hot air aging of high strength glass fiber fabric/epoxy novolac resin (SW/EPN) composites was investigated by the aid of the aging behavior of EPN, mainly focusing on the microstructure evolvement of SW/EPN composites. The aging mechanism and thermal mechanical properties of SW/EPN composites were analyzed by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, thermo-gravimetric analyzer coupled with Fourier transform infrared spectrometry, and dynamic mechanical thermal analysis. The results showed that micro cracks initiated and propagated at the fiber-matrix interphase because of the heat and oxygen effect. After long-time aging at elevated temperatures, delamination phenomenon was discovered in SW/EPN composites. The results of weight changes showed that the degradation of EPN played a major role in SW/EPN composites. Moreover, the degradation of EPN contained post-curing, oxidation, and decomposition. The results also revealed that unaged EPN indicated two glass transition temperatures (T-g1 and T-g2). T-g1 increased for post curing while T-g2 decreased for oxidation with increasing of aging time and temperature. In the final period of aging at higher temperatures, only one T-g was observed because the formation of perfect crosslinked networks made EPN homogeneous. In addition, the relationship between T-g and chemical structure, as well as T-g and mass loss, confirmed that the variation of T-g depended on chemical changes.

• 出版日期2014-4-15
• 单位航天材料及工艺研究所; 北京航空航天大学