Preparation And Properties Of The Photocrosslinked Natural Macromolecule Membrane

Chitosan(CS)is a kind of natural macromoleculule and chitosan based material are expected to be environment-friendly, biodegradable and reproducible products. Polyvinylacohol (PVA) bearing styrylpyridinium group (PVA-SbQ) is a new photosensitive polymer, styrylpyridinium group on side of PVA main chain can be cross-linked under UV radiation to form network. We focused on Photocrosslinked chitosan-(PVA-SbQ) blend membrane, Photocross-linked chitosan-(PVA-SbQ) two layer composite membrane and chitosan-SbQ resin in this paper.In part 1, Photocross-linked chitosan-(PVA-SbQ) blend membrane was made by mixing the solutions of chitosan and PVA-SbQ. Its structure was examined by means of SEM, XRD and FTIR. The properties of membrane, such as mechanical property, light transmittance, hygroscopicity, surface contact angle, water uptake, degree of swelling had been studied. The results showed that membrane with interesting surface structure, there was some hydrogen bonding interaction between chitosan and PVA-SbQ in the blend membrane, Exposed membrane had network, which improved properties of the membrane such as mechanical property, hygroscopicity and UV screen property.In part 2, Photocross-linked chitosan-(PVA-SbQ) two layer composite membrane was made by the solvent casting method.we use SEM to study its structure, the properties of membrane, such as mechanical property, light transmittance, hygroscopicity, water uptake, degree of swelling had been studied. The results showed that membrane with smooth side-face structure. Exposed membrane had network, which improved the membrane's properties such as hygroscopicity, water uptake ability, but degree of swelling was falled. In the range of visible light, the light transmittance of membrane exceeded 70%, but when the wavelength less than 400nm, the light transmittance of membrane was 0%, Photocross-linked chitosan-(PVA-SbQ) two layer composite membrane had better UV screen property.In part 3, we synthesized chitosan-SbQ resin by shifft reaction. Its structure was examined by means of XRD and FTIR, and the adsorption propertier of the resin on Cu2+, Co2+ had been studied. The results showed that the reaction was successful, but graft rate was low, Chitosan-SbQ resin improved the stability of chitosan in acid medium, which had better selectivity of absorption on metal ions in wide pH range. chitosan-SbQ resin expanded the application scope of chitosan.