Quality Control Tests and Matching Fourier-Transform Infrared Spectra for Raw and Intermediate Materials of 2-Pack Epoxy Paints

摘要

The local users of the oil and gas companies suffering from high cost of repainting the steel structures and pipelines when the coatings fail prematurely, where one of the attributing factors may be the adulterated polymeric coatings supplied to the job sites. This posted the needs to fingerprint the polymeric coatings supplied, which shall not deviate from the submitted specifications for prequalification and tender purpose of projects. The first part of the study shows that the coatings formula remains trade secret, even though spectra of Fourier- transform infrared spectroscopy (FTIR) are submitted along with the delivery of the polymeric coatings. Characterizations of the raw materials (viscosity and density) as well as final products (adhesion and dry film thickness) can hardly be differentiated for different grades of materials with exception on the salt spray test. The salt spray test is usually performed before the paint manufacturer submits its product for qualification and tender purpose. Infrared component searching of various raw and intermediate paint materials ranging from organic color pigments, epoxy resins to epoxy hardeners for 2-pack epoxy paints was attempted. The materials were analyzed with FTIR. It appears that the component search gives several possible (chemical) compounds according to extensive FTIR library search. Although some of these components are known to exist within the material (color pigments, epoxy resins and epoxy hardeners), it does not reveal further detailed formulation. Reproducibility of the estimation of correlation (r) or the matching ratio of the reference spectrum to that of the sample spectrum is noted when the FTIR analysis was carried out. The statistical examination utilizing two-sample paired t-test shows that there is no statistically difference at 95% confidence level for the results of r estimated between Softwares A and B, or between Softwares A and C when the samples were analyzed using Nicolet FTIR spectrometer.