Preparation of Chitin-g-poly(4-vinylpyridine) Beads

Abstract

Chitin was modified via grafting with poly(4-vinylpyridine) (P4VP) to form chitin-g-P4VP. The reaction was carried out under homogeneous conditions using potassium persulphate (K₂S₂O₈) (KPS) as a redox initiator. The effect of monomer concentration on the extent of grafting (%G) was studied by the gravimetric method. Grafting percentages up to 226% were obtained. The capability of chitin to form physical gels was exploited to form beads of modified chitin. Grafted chitins were coagulated from the non-solvent ethanol in the form of beads. Chitin-g-P4VP was characterized by FTIR, TGA, XRD and SEM analyses. The swelling behavior of the beads was studied in distilled water, in acid and phosphate buffers. XRD analysis showed that the P4VP grafted product had lower crystallinity when compared to chitin. Thermal analysis carried out by TGA analyses revealed that the grafted products were less stable against thermal treatment than chitin. The gel beads were tested for their cholesterol and Fe³⁺ adsorption capacities. The beads derived from chitin-g-P4VP were found to have higher adsorption capacities than chitin beads due to a microporous bead surface and chemical modification.

Keywords:

• Bioadsorbent
• chitosan
• cholesterol adsorption
• chitin gel iron

Acknowledgment

The authors are thankful to Z. Yalinca and F. Bullici for the cholesterol analyses.