Abstract
A major hindrance to the acceptance of polymer composites in civil engineering applications is the susceptibility of the polymeric matrix to weathering. The polymer matrix is prone to degradation initiated by ultraviolet (UV) radiation, moisture, temperature, and high pH environments. The objective of this study was to characterize chemical and physical changes in polymeric matrix resins following exposure to these environments. The ultimate goal is to identify factors that contribute to matrix resin degradation under environmental and mechanical stresses.
Resin systems studied included vinylester and isophthalic polyester, both of which are commonly used in construction applications. Neat polymer films were exposed to UV radiation, moisture, alkaline, and saline environments. Diffusion of water, alkali, and saline solution into the polymers was calculated from gravimetric measurements. Changes in strength, viscoelastic response, and thermal properties were evaluated through tensile testing, dynamic mechanical thermal analysis (DMTA), and differential scanning calorimetry (DSC). Atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) were also used for detecting changes in the polymer surface following UV exposure.
