Optoelectronic refractive index measurements: application for smart polymer processing

In the last decade, polymeric based composites, in the light of their low weight/mechanical strength ratio, have been widely used in many industrial areas such as, automotive, aeronautic and aerospace. Because of the dependence of their properties on the manufacturing stage, real time monitoring of the processing stage has been indicated as the key point for improving the quality and reducing manufacturing process costs through an intelligent control of the manufacture itself. To this aim, optimal monitoring systems should be non-intrusive, real time and able to measure a physical property changing during the process development. Refractive index is a suitable state parameter being directly correlated to the material density. In this work, a fiber optic sensor has been used to monitor the cure kinetics and measure glassy transition temperature by refractive index measurements. Experimental results are presented, demonstrating the potentiality of refractive index measurements for smart polymer processing.