Elevated Temperature Aging of Glass Fiber Reinforced Vinyl Ester and Isophthalic Polyester Composites in Water, Salt Water and Concrete Pore Solution

摘要

In recent years, the use of fiber-reinforced vinyl ester and isophthalic polyester (isopolyester) composites in civil infrastructure has greatly increased, due to an optimum combination of desirable properties, processability, and ease of installation associated with these materials. One obstacle hindering greater acceptance of polymer composites in civil infrastructure applications is the susceptibility of the polymer matrices to degradation initiated by moisture, temperature and corrosive chemical environments. The objective of this study was to characterize chemical and physical changes in glass-fiber reinforced vinyl ester and isopolyester materials following exposure to water, salt water and an artificial concrete pore solution. Exposures were carried out at room temperature, 40 °C, 60 °C and 80 °C; glass transition temperature and interlaminar shear strength were monitored as a function of aging time and temperature. In general, more rapid degradation in properties was observed in concrete pore solution than either water or salt solution for both polymers. A modified Arrhenius analysis was carried out on the data to determine whether any observed acceleration in degradation was valid over such a wide temperature range. Arrhenius plots for isopolyester generated by plotting ln [time to reach 70 % of original strength] vs. [temperature]-1 could be fitted with straight lines for water and salt solution, but not for concrete pore solution. Arrhenius analyses carried out on the vinyl ester data resulted in approximately straight line fits for all three environments.