Changes in the Shape of the CH Absorption Band in the IR Spectra of the Chemicaly Dehydrofluorinated Poly(Vinylidene Fluoride) Film During Aging

Abstract

Abstract—The stability of the atomic structure and physical and chemical properties of new materials is of crucial importance for their practical use. Long-term (more than 5 × 105 min) and regular monitoring of the molecular structure of a poly(vinylidene fluoride) film sample after its chemical dehydrofluorination and rinsing with ethanol is performed by the infrared (IR) spectroscopy technique. Changes in the absorption spectra of stretching oscillations of CH and OH bonds in the wave-number range 2500–3700 cm–1 are analyzed. The results of the study indicate the initial attachment of ethoxy groups to carbonized fragments of carbon chains and their subsequent detachment, accompanied by sample oxidation. A feature with a center near 3090–3100 cm–1 is found to be in all spectra, the origin of which cannot be unambiguously identified at present. A previously unknown effect of a steady, but different-rate decrease in the contribution to the infrared absorption of stretching vibrations of four molecular complexes of ethoxy groups is revealed. The oscillation frequencies of three of them steadily increase also at different rates.