Elaboration and characterization of a natural bentonite-poly(ethylene glycol) composite: Development of an exact theoretical study in function of the polymer-density

Abstract

The first aim of this work was a systematic experimental and theoretical study of the basal-spacing and characteristics of X-rays diffraction-peaks (positions, intensities, crystallites size...), versus the polymer-density, for a natural bentonite-poly(ethylene glycol) composite. The natural bentonite was extracted from a deposit located in Eastern Rif chain of Morocco (near Nador-city). The basal distance and diffraction-peaks characteristics were measured using X-Rays Diffraction (XRD) method, first, for raw bentonite, and second, for bentonite-poly(ethylene glycol) composites. In particular, measurements reveal the existence of a series of montmorillonite-phases (crystallites) of different sizes within the composites. Afterwards, we have developed a powerful theoretical approach based on Renormalization Theory, and obtain exact scaling relations for the physical quantities of interest. We have compared our theoretical predictions with our experimental data dealt with the considered natural bentonite-poly(ethylene glycol) composites, and found that theory and experiment are in good agreement. Also, as a complementary experimental study, we achieved a detailed analysis of pure PEG, natural bentonite and Bentonite-PEG composites using the so-called Fourier Transform Infrared Spectroscopy (FTIR) tool. A comparison between these complexes show that the polymer-density affects drastically the stretching and bending vibration modes.