New synthesis of polyurethane nanocomposites based on Maghnite used both as a catalyst and as an inorganic improver of thermal, mechanical and textural properties

Abstract

For the first time, polyurethane-based nanocomposites (PU-Magx) were synthesized using Maghnite as an inorganic reinforcement. Maghnite is a laminar clay, characterized by a relatively higher SiO2/Al2O3 ratio compared to other world clays. The interfacial cations of Maghnite can be active sites during the reaction, which gives it a catalytic aspect. The X-ray diffraction (XRD) study showed that the organophilic Maghnite (Mag-CTAB); treated with cetyl trimethylammonium bromide, exhibits a large interlayer distance compared to sodium and raw Maghnite. Different PU-Magx formulations were prepared by introducing 1, 3, 5, 7 and 10% of Mag-CTAB. The chemical structure of pure PU and PU-Magx has been confirmed by infra-red and Solid State 1H MAS NMR spectroscopy. The crystallographic structure and the dispersion of the sheets in the PU matrix were studied by XRD and transmission electron microscopy. The thermogravimetric analysis and its differential recorded a gain of up to 111 °C in the thermal stability. The Young's modulus and the yield strength were calculated to evaluate the mechanical behavior. PU loaded with 5% of Maghnite has better mechanical properties; this is due to the state of dispersion of the Mag-CTAB in the PU matrix. The textural study of nanocomposites has also been done by measuring the adsorption capacity.