Characterisation and morphology of biodegradable chitosan/synthetic polymer blends

Chitosan has been used to form miscible, biodegradable blends with hydrophi lic synthetic polymers as PVA and PEG. Characterisation of the blends by DS C, JR and microscopy analysis was made giving much attention to possible in teractions of molecular polar group in the polymer chains. PVA/chitosan are found to be amorphous in the whole range of composition having one glass t ransition temperature. Molecular interactions in the pair of polymers are c onnected with amide group of chitosan and hydroxyl groups of PVA. PEO/chito san blends stay amorphous up to 0.2 weight fraction of PEG. For a higher am ount of PEO that polymer crystallises forming a spherulite crystalline stru cture. We correlate the overall kinetics of crystallisation and melting beh aviour of solid, semicrystalline blends PEO/chitosan in the form of thin fi lms for a set of PEO species of different blend composition with a morpholo gical structure of the blends. Negative values of the Flory-Huggins interac tion parameter due to specific interactions by hydrogen bonding through eth er group of PEO and hydroxyl group of chitosan were evaluated. Amide groups do not participate in the molecular interaction between PEO and chitosan m olecules. Avrami equation was applied to describe kinetics of crystallisati on of pure PEO and PEO/chitosan blends of various compositions.