Effect of Color and Shape on Discrimination of Plastic by a Portable Near-Infrared Spectrometer

Abstract

NIR spectra of plastic wastes with different color, thickness, and particle size of polymer materials were measured by using a portable NIR spectrometer to investigate their effects for the discrimination of plastic materials.
NIR and UV/vis spectra for 80 pieces of wastes plastic were measured and analyzed by principal component analysis (PCA) after standardization. The NIR spectra for different color samples had a little difference in the shape and the intensity. These differences could be brought by the difference of pigment additives and its particle size in each sample. And the results for PCA indicated that the color and form of the plastic samples were not affected to the discrimination of the plastics. It was also found that the types of waste plastic were discriminated by PCA with barcode NIR spectra effectively.