Environmental Effects on Composite Matrix Resins Used in Construction.
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.
Building and Fire Research Laboratory
National Institute of Standards and Technology
Gaithersburg, MD 20899