The effect of glycerol on properties of chitosan/poly(vinyl alcohol) films with AlCl3·6H2O aqueous solution as the solvent for chitosan

• The AlCl3·6H2O aqueous solution was used to dissolve chitosan.
• The thermal degradation of chitosan and poly(vinyl alcohol) was suppressed in AlCl3·6H2O aqueous solution.
• Glycerol had the positive effect on AlCl3·6H2O doped chitsosan/poly(vinyl alcohol) film.
• The high performance chitosan/poly(vinyl alcohol) films were obtained with AlCl3·6H2O and glycerol.

The AlCl3·6H2O aqueous solution was used to dissolve chitosan (CS) and the CS/poly(vinyl alcohol) (PVA) blend films were prepared at the absence of acetic acid. AlCl3·6H2O was retained in CS/PVA film and glycerol was added to form the complex plasticizer with AlCl3·6H2O. The effect of glycerol on the water sorption, crystalline, thermal and mechanical properties of AlCl3·6H2O doped CS/PVA film was studied by atomic force microscopy, X-ray diffraction, thermal gravity analysis and tensile testing, respectively. The experimental results showed that glycerol had a significant positive effect on the properties of AlCl3·6H2O doped CS/PVA films. With the synergism effect of AlCl3·6H2O and glycerol, the prepared CS/PVA films showed excellent mechanical properties. With the addition of 30 wt% glycerol, the AlCl3·6H2O doped CS/PVA films behave the tensile strength of 39 MPa and elongation at break of 120%, respectively.