Mid and Far Fourier‐Transform Infrared Authentication Analysis for Polymeric Paints and Their Raw Materials

Inorganic and metallic compounds are often added in the paint formulation to improve the performance of protective coatings. Since some of these materials are infrared (IR) inactive in the mid‐IR region, the applicability of far‐IR as an additional quality assurance or quality control (QA/QC) tool to ensure the batch‐to‐batch consistency or fingerprinting/authentication of inorganic raw materials or paints with inorganic component(s) supplied to the job sites is instigated. Results suggest that the degree of similarity (r) in the far‐IR region can be used to differentiate the inorganic polymorph mixtures of rutile and anatase TiO2, which are attested by desummation of the superimposed absorbance bands for the same purpose. However, far‐IR region for authentication of inorganic compounds is challenging for paints with small amount of inorganic component(s). Mid‐IR spectroscopy is still practical to be used as the QA/QC tool for the batch‐to‐batch consistency or authentication of polymeric wet paints with or without inorganic component(s) coupled with other physical analyses.