The confocal Raman microscope (CRM), with its ability to scan below a sample’s surface and provide full chemical information on the components present in a sample, was employed to confirm the SEM findings and determine the distribution of the two polymers. A CRM depth profile, which produced an image of a cross-section of a representative fiber confirmed the presence of a coating. A color-coded composite image (Figure 3) was generated to show the distribution of the two components. The fiber (green) is surrounded by a second material (red), and yellow is the interface of the two materials. Comparison of the Raman spectra for each component with reference libraries revealed that the fiber was polypropylene coated with polyethylene terephthalate (Figure 4).
