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Accelerated aging versus realistic aging in aerospace composite materials. V. The effects of hot/wet aging in a structural epoxy composite
Author(s) -
Dao B.,
Hodgkin J.,
Krstina J.,
Mardel J.,
Tian W.
Publication year - 2009
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.31029
Subject(s) - composite number , epoxy , materials science , composite material , fourier transform infrared spectroscopy , accelerated aging , gravimetric analysis , humidity , glass transition , thermogravimetric analysis , polymer , chemical engineering , chemistry , organic chemistry , thermodynamics , physics , engineering
Samples of an aerospace‐grade, carbon‐fiber epoxy composite (Hexcell 8552/IM7) were subject to long‐term (≈ 1 year) hot/wet aging and thermal spiking under different humidity levels and temperature conditions related to the “in‐service” conditions seen in military aircraft. Changes to the chemical and physico‐chemical structure of the composite were analyzed by a range of experimental techniques including gravimetric analysis, FTIR, and DMA, to compare the effects of the various aging conditions. The results indicated that, while the chemical changes (as seen by FTIR) in this well cured composite appeared to be only significant at the surface, they did appear to have a deeper influence on some of the major physical property changes observed, such as microcracking, glass‐transition‐temperature ( T g ) variations, and Tan δ curves. These physical changes could not be fully explained by standard water‐absorption effects alone but could also be influenced by chemical changes similar to those seen at the surface. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010