Remote Determination of Composite Chemical Characterization

The capability of using fiber optics to monitor cure in polymer matrix composite materials has received continued attention since the concept of using fiber optics and spectroscopy methods to identify molecular moieties was first demonstrated in 1983. In the past 10 years, many advancements have been made using spectroscopic methods and other techniques which have the potential of making in-situ cure monitoring of composite structures a reality. Properly fabricated optical sensors may even provide continued use a senors in smart structures, providing useful feedback on part temperature, mechanical strain or vibration, and chemical attack. Embedded sensors can even provide a vehicle for assessing structural damage by directly detecting crack propagation or delamination, or by providing an avenue for internal investigation of part integrity using various non-destructive inspection methods. Under the proposed program, a technical evaluation will be made of the techniques in which Fourier Transform Near-Infrared (FTIR) spectroscopy methods (Raman or otherwise) are used to remotely monitor cure kinetics in composite structures via embedded fiber optics. In addition, the experimental portion of the proposed effort will clearly demonstrate the feasibility of using FTIR spectroscopy methods and embedded fiber optics for in-situ measurement of the cure kinetics of an aerospace grade epoxy matrix, glass reinforced composite structure.