Special features of recording IR spectra of MFTIR of fibrous materials

We investigated the influence exerted by the conditions of preparation of specimens of fibrous materials made of polyethylene terephthalate and triacetate threads and fabrics and the conditions of recording IR spectra of modified frustrated total internal reflection (MFTIR) on the reproducibility of spectral characteristics. We found that the area of actual contact of fibrous meterials with a reflecting prism and the reproducibility of spectral characteristics can be considerably increased by applying preliminary pressing and increasing the pressure of clamping the materials to the prism. We determined the optimum values of the parameters for preparing specimens and recording MFTIR spectra that make it possible to carry out, with sufficient accuracy, spectrophotometering of fibrous specimens made of polyethylene terephthalate and triacetate fabrics and threads.