pH Induced Fabrication of Kaolinite-Chitosan Biocomposite

Abstract

Functionalization of indigenous materials improves inherent physicochemical properties that depend mainly on their fabrication techniques. Here, pH triggered biocomposites using different proportions of kaolinite and chitosan were fabricated. It was revealed that the biocomposites were formed in 1M acetic acid and stabilized after dropwise addition of the mixture of kaolinite and chitosan solution in 3M NaOH. Binding of kaolinite and chitosan at their interface through functional groups was studied using Fourier transform infrared (FT-IR) spectroscopy and dynamic light scattering (DLS). The average particle size of the biocomposite in aqueous system having 80% w/w kaolinite and 20% w/w chitosan was determined to be 400.8 nm. Crystallinity disappearance of chitosan in the biocomposite, as shown in x-ray diffraction (XRD) spectrum, supports the wrapping of kaolinite with soft and flexible chitosan. Differential scanning calorimetry (DSC) showed the thermal stability of the biocomposites and it was found that the biocomposite fabricated from 50% w/w kaolinite and 50% w/w chitosan was stabled up to 318°C. Morphological studies were carried out using scanning electron microscopy (SEM), where a progressive tendency towards granular morphology was evidenced with increase in kaolinite content. These functionalized materials in bionanocomposite structure would play a vital role in advanced research in analytical and environmental science.