Bio-additive chitosan for surface functionalization and antioxidant compounding of value-added commodity polymer

Abstract

The present disssertation proposes two approaches to develop bio-additive of chitosan, i.e. (i) chitosan bio additive for surface functionalization onto polymer, and (ii) chitosan bio-additive based antioxidant for commodity polymer. In the case of (i), surface functionalization of polyethylene with chitosan is successful via chitosan aqueous solution prepared by chitosan-HOBt. Chtiosan grafted onto polyethylene film is achieved by y-ray irradiation. Copper ion adsorption on polyethylene-graft-chitosan clarifies the specific property of chitosan in chelating of copper ion resulting in new product manifesting the properties of both polyethylene and chitosan. For (ii), bio-additive based antioxidant chitosan is successfully prepared by conjugating gallic acid onto chitosan to achieve chitosan-based antioxidant (chitosan-GA) in water based system. The development of bio-additive chitosan-based antioxidant for compounding with commodity polymer is also prepared by conjugating chitosan with both gallic acid and deoxycholic acid. The electorn paramagnetic resonance (EPR) is used to clarify the antioxidant ability of chitosan derivatives. The derivative obtained shows the specific antioxidant ability via galloylate group.