Synthesis and Characterization of Karaya Gum/Chitosan Composite Microspheres

Composite microspheres were prepared by suspension polymerization of karaya gum and chitosan in oil-water emulsion using glutaraldehyde as a cross-linker. The composite microspheres morphology was investigated by scanning electron microscopy. It was found that the products were composed of a large quantity of microparticles with average diameters of 250-350 ىm and a few microspheres with diameters of several micrometers. The composite microspheres are spherical particles with asperous surfaces. The thermal behaviour of composite microspheres was studied using both methods of thermogravimetric analysis and differential thermal analysis, further confirming the cross-linking reaction. The results suggest that the composite microspheres show good heat resistance after cross-linking reaction. In order to obtain an insight into the karaya gum/chitosan interactions, the composite microspheres were characterized by Fourier transform infrared spectroscopy (FTIR) to confirm the formation of Schiff’s. At the same time, the infrared spectrum indicates the presence of special functional groups on the surface of the microspheres, which involve ion-carboxyl, aldehyde, amino, and hydroxyl groups. The swelling kinetics of the composite microspheres at different pH values has been investigated. The composite microspheres swell at lower pH ( 6) as well as higher pH range (pH 9), and the deswelling occurs in the pH range from 6 to 9.