SMART STRUCTURE FOR CORROSION MONITORING OF ANTICORROSION FRP

摘要

Polymeric materials including FRP are used in chemical plants under acidic or alkaline condition for anti corrosion purpose. These materials also degradate under severe condition, then they show obvious change in chemical structures due to hydrolysis or other reactions. Sometimes chemical degradation results in fracture of chemical equipments. Therefore, the developments of the on-line health monitoring system of equipment materials are required. In this study, possibility of new on-line monitoring system realized by smart structures was examined. In order to detect the chemical structure changes, some smart materials with embedded sensors, were investigated. Evanescent wave spectroscopy with chalcogenide glass fiber was used. The chalcogenide glass fiber which can transmit infrared spectral region (3 μm ～ 8μm) was used as evanescent wave sensor. If the clad of an optical fiber is removed or thinned and replaced with an analyte, the evanescent wave formed at the core surface can interact with the analyte. If the analyte is absorbing energy at the evanescent field, there will be a loss in the overall energy transmitted by the optical fiber. Therefore, the spectrum gives a information of the sample in this wavelength. Sensors were prepared by stripping the clad from chalcogenide fibers. Transmitted infrared light detects the sample contacted to-the exposed fiber core at the evanescent field. In our past research, it showed that chalcogenide fiber sensor was available for sensing chemical structures of liquid samples. In this study, this technique was improved and expanded, and the application to the corrosion monitoring of FRP was examined.