IN-SITU FIBER OPTIC SENSOR FOR FTIR MONITORING OF COMPOSITE CURE CYCLES

FOURIER TRANSFORM INFRARED SPECTROSCOPY (FTIR) DEMONSTRATED IN THE LABORATORY IS A VALUABLE TECHNIQUE FOR MONITORING THE CURE CYCLE IN ADVANCED THERMOSETTING COMPOSITE MATERIALS. NEW INFRARED TRANSMITTING OPTICAL FIBERS OFFER THE PROMISE THAT THIS LABORATORY TECHNOLOGY CAN BE MOVED INTO A PRODUCTION ENVIRONMENT TO PROVIDE AN INSITU, NON-DESTRUCTIVE EVALUATION TECHNIQUE TO DETERMINE THE STATE OF CURE IN THERMOSET COMPOSITES IN REAL TIME. THIS PROGRAM INTENDS TO THOSE OBTAINED IN THE LABORATORY IN THE CURING CYCLE OF A TYPICAL THERMOSETTING RESIN USING AN OPTICAL FIBER SENSOR TRANSMITTING LINK AND A FTIR ANALYZER. THE FIBERS USED WILL BE OF A FLUORIDE GLASS CAPABLE OF TRANSMITTING IN THE NEAR-IR WAVELENGTHS THAT WILL PRODUCE SPECTRAL INFORMATION IN THE 2,200 TO 6,600 WAVENUMER BAND. BECAUSE OF THE RELATIVELY HIGHER ATTENUATION OF LIGHT IN THE CHALCOGENIDE GLASSES, WHICH TRANSMIT IN THE800 TO 2,200 WAVENUMBER BAND, WE PROPOSE TO USE NEAR-IR SPECTRAL INFORMATION IN THE 1 TO 5 MICRO REGION USING VERY LOW ATTENUATION HEAVY METAL FLUORIDE GLASS FIBERS AND FTIR-CORRELATION TECHNIQUES. THE PHASE I PROGRAM WILL DEMONSTRATE WHETHER IR TRANSMITTING OPTICAL FIBERS ARE TECHNICALLY AND ECONOMICALLY FEASIBLE TO PROVIDE IN-SITU MEASUREMENTS OF STATE OF CURE IN A THERMOSET COMPOSITE MATERIAL.