Use of Raman Spectroscopy to Identify Automotive Polymers in Recycling Operations 2000-01-0739
To support its recycling efforts, Ford Motor Company is using a Raman based instrument, the RP-1, co-developed with SpectraCode Inc. to identify unknown polymeric parts. Our recycling initiative involves detailed dismantling of our vehicles into individual parts, calculating the percentage recyclability and making recommendations for the future use of recycled polymers. While Ford has voluntarily adopted the SAE J1344 marking protocol for identifying part material composition, a large number of unmarked parts still exist and require identification. This identification is being done with the help of RP-1. To facilitate this identification, we have generated an accurate reference library of Raman spectra for comparison to those of unknown materials. This paper will describe the techniques that were used to develop and refine the RP-1 reference library to identify automotive polymers, especially black/dark plastics. The specific techniques under study include strategies for grouping polymer types, characterization of the effect of higher laser power, as well as that of laser exposure, the binning of the scattered light on the detector and the use of masking techniques for the controlling the spectral region used for identification. The Raman based RP-1 is not affected by surface roughness, which is a previously noted shortcoming of specular reflectance infrared devices. Future work will concentrate on identifying and quantifying fillers, and determining the percentage of each polymer in a blend using this nondestructive technique.