Développement et applications des biocéramiques

Examining the Features of NaCl Activated Kaolinite Nano-layers for Use in Excipients

Abstract

Siafu SI

Successful application of 1:1 layered phyllosilicates as excipients of drugs and agrochemicals depends on the efficiency and effectiveness of activation reactions carried out prior to their usage. Reluctance of kaolinite to direct reactions involving interlayer spaces created a challenge which requires a sustainable search for optimum activation agents. This study investigated the features of cyclone based wet beneficiated kaolinite with kaolinite sheets activated using solid dispersion of NaCl. Starting materials and the resulting activated counterparts were characterized for their chemistry, functionalities (as per mineral phases present), and variation of crystal sizes upon each treatment cycle along with lattice contraction and expansion in the interlayer spaces and orientation of layers (as per their morphological changes) as well as molecular vibration. It was observed that, upon successful activation with NaCl, there was a significant change in the orientation of kaolinite sheets from euhedral pseudohexagonal platelets into vermiform whose pattern offer a maximum orientation for reactions involving interlayer spaces. The formation of vermiform which may be due to packing of nano-layers was noted to be associated with the contraction of interlayer spaces of about 0.018 nm from 2θ = 12.543o to 12.552o as revealed in the x-ray diffraction trials. Therefore, the ability of NaCl activation reactions to orient kaolinite layers into well-ordered vermiform pattern makes NaCl a suitable activation agent for use when kaolinite is to be used for design of excipients for drugs and agrochemicals.