Comparative Study of Different Protocols for the Preparation of Anionic Clay-Polymer Nanocomposite (Hydrotalcite-Cellulose) and their Structural Properties

Abstract

In this study, different synthesis methods of nanocomposites, based on microcrystalline cellulose MCC and Hydrotalcite (family of layered double hydroxide LDH), were developed. The Hydrotalcite was previously prepared by a coprecipitation method. Four processes have been explored for synthesis of cellulose-Hydrotalcite nanocomposite: (I) Activation by microwave to the mixture of LDH dispersed in the cellulose solution (cellulose dissolved in 7%wt NaOH/12%wt urea aqueous solution). (II) The second method enables the synthesis of nancomposite by the coprecipitation method which comprises adding drop wise a solution of magnesium-aluminium salts and carbonates solution to cellulose solution. (III) The third process consists in swelling the LDH and cellulose with distilled water and activating the mixture by microwave. (IV) The fourth protocol consists of the dispersion of cellulose in LDH-solution which was homogenized by ultrasonic radiation. The influence of the reaction parameters including the synthesis methods and the structure of the composite obtained were discussed by X-ray diffraction (XRD), transmission electron microscopy (TEM) and Fourier Transform Infrared (FTIR) spectrometry. X-Ray diffraction (XRD) analysis and transmission electron microscopy (TEM) revealed the existence of partially exfoliated structure or mixed phase clay-cellulose. Analysis of Fourier Transform Infrared (FTIR) showed functional groups of cellulose and LDH with some differences. Methods and conditions of processing were thoroughly investigated to obtain exfoliated and/or dispersed cellulose/LDH nanocomposites.