NIST Time|NIST Home|About NIST|Contact NIST

HomeAll Years:AuthorKeywordTitle2005-2010:AuthorKeywordTitle

Environmental Effects on Composite Matrix Resins Used in Construction.


pdf icon Environmental Effects on Composite Matrix Resins Used in Construction. (673 K)
Chin, J. W.; Haight, M. R.; Hughes, W. L.; Nguyen, T.

Durability of Fibre Reinforced Polymer (FRP) Composites for Construction (CDCC'98), 1st International Conference. Proceedings. 1998, Canada, Benmokrane, B.; Rahman, H., Editor(s)(s), 229-241 pp, 1998.

Keywords:

construction; environmental effects; building technology; alkaline conditions; composite materials; durability; polyester; salt water; vinyl ester; water

Abstract:

One of the obstacles hindering the acceptance of polymer composites in civil engineering applications is the susceptibility of the polymeric matrix to degradation initiated by moisture, temperature, and corrosive chemical environments. The objective of this study was to characterize chemical and physical changes in polymeric matrix resins following exposure to these environments. Resin systems studied were vinyl ester and isophthalic polyester, both of which are suitable for use in construction applications. Unreinforced free films were exposed to water, alkaline and saline environments at ambient and elevated temperatures for extended periods of time. Changes in strength and thermophysical properties were evaluated through tensile testing, dynamic mechanical thermal analysis (DMTA) and thermogravimetric analysis (TGA). Chemical degradation of the polymers was characterized using Fourier Transform Infrared Spectroscopy (FTIR). Energy dispersive x-ray (EDX) analysis of specimens following exposure was carried out to determine if ion diffusion into the bulk polymer occurred. Changes in the glass transition temperatures and tensile strengths of the polymers were observed after prolonged exposure at elevated temperature, particularly in the case of the isophthalic polyester. Examination of the polymers following immersion in salt water and alkaline solution showed essentially no ionic penetration into the bulk. Spectroscopic analysis of chemical structure prior to and following exposure revealved varying degrees of ester hydrolysis.