Preparation and characterization of chitin/poly(vinyl alcohol) blends using aqueous acetic acid solution as a cosolvent

The partially deacetylated chitin with degree of deacetylation of similar t o 28% fully soluble in dilute acetic acid, was prepared by alkaline treatme nt under homogeneous conditions and then blended with poly(vinyl alcohol) ( PVA) using aqueous acetic acid solution as a cosolvent. The miscibility and intermolecular interaction: between chitin and PVA were investigated using differential calorimetry. When chitin was blended with PVA up to 50%, the melting temperature (T-m) and heat of fusion (DeltaH(f)) of PVA were depres sed gradually. The interaction energy density (B) and the interaction param eter (chi (12)) estimated from the depression of melting temperature were - 10.13 J/cm(3) and -0.33 (at 502 K), respectively. The negative value of chi (12) indicates that chitin and PVA are miscible. With increasing weight fr action of chitin in blends, there were large and systematic decreases in th e crystallization temperature (T-c) and the heat of crystallization (DeltaH (c)) of PVA. The glass transition temperature (T-g) of PVA tended to shift to higher temperatures, with increasing weight fraction of chitin up to 40% in the blends, There was a broadening of the width of the transition.