A COMPARISON OF SPECULAR REFLECTION AND PA-FTIR TECHNIQUES IN THE ANALYSIS OF ANNEALED INJECTION-MOLDED POLYAMIDE 6,6

A comparative study between the specular reflectance and photoacoustic FTIR techniques is presented in this work. The potential and limitati ons of these two methods are investigated by following and analyzing s tructural variations that take place at the surface in annealed inject ion-molded polyamide 6,6. Both spectroscopic techniques appear to be q uite sensitive in detecting small structural changes that occur in pol yamide 6,6 when submitted to different annealing temperatures. However , the presence of distorted bands in the specular reflection spectra m akes the photoacoustic FTIR method more attractive for the IR vibratio nal analysis of difficult materials (e.g., composites, black-filled po lymers, paints, etc.) that cannot be easily characterized by conventio nal transmission FTIR. (C) 1994 John Wiley & Sons, Inc.