Polypropylene surface functionalization with chitosan

Abstract

Chitosan coatings on oxygen-plasma pre-treated polypropylene (PP) surfaces were formed to improve their wettability, dyeing behavior and reactivity without altering material bulk properties. XPS, electrokinetic potential and contact angle measurements as well as dye uptake tests were carried out for surface characterization of modified PP, evaluation of chitosan coatings stability, and the effects of temperature and pH on coatings formation. About 20–30% of the total amount of chitosan immobilized on PP was found to be covalently bonded to the plasma pre-treated surface through the heat induced reactions with oxygen-containing functional groups at T > 80°C that corresponded to 47% of surface coverage. Subsequent cross-linking reaction with epichlorohydrin proved to be an efficient way to reduce the susceptibility of chitosan coatings to acidic hydrolysis.