Hygrothermal aging of a pultruded unidirectional carbon fiber reinforced epoxy composite

PMSE 296

Guijun Xian, gxian@ucsd.edu, Department of Structure Engineering and Materials Science and Engineering Program, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0085 and Vistasp M Karbhari, vkarbhari@ucsd.edu, Department of Structural Engineering and Materials Science and Engineering Program, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0085.
A pultruded unidirectional carbon fiber (CF) reinforced epoxy composite was hygrothermally aged in deionized water at 23, 37.8 and 60 C for three years. Water uptake is successfully described by Fickian law, and the diffusivity along fiber direction is about five times higher than that transverse fiber direction. Dynamic mechanical thermal analysis was performed to clarify the effect of hygrothermal ageing on the variation of viscoelastic response. It is found that water uptake causes the Tan delta peak to widen and to shift to lower temperatures, due to plasticization and swelling effects. Annealed samples show similar viscoelastic behavior as compared to unaged samples. This indicates that no significant irreversible damage occurred under the present hygrothermal ageing conditions. The glass transition temperature and the glassy storage modulus of dried samples are lower than those of annealed samples, indicating the extent of swelling effect due to water uptake.
 

Joint PMSE/POLY Poster Session
6:00 PM-8:00 PM, Tuesday, 12 September 2006 Moscone Center -- Hall D, Poster

Division of Polymeric Materials: Science & Engineering

The 232nd ACS National Meeting, San Francisco, CA, September 10-14, 2006