Fig. 2From: Reflectance FT-IR spectroscopy as a viable option for textile fiber identificationIndividual example spectra of polypropylene (PP) samples recorded in the r-FT-IR mode. The vertical axis represents absorbance. First two spectra (PP1 an PP2) are from the same sample—showing differences within a sample. Spectra PP3 and PP4 are from a different sampleBack to article page