Influence of Glyoxal on Preparation of Poly(Vinyl Alcohol)/Poly(Acrylic Acid) Blend Film

The preparation of a poly(vinyl alcohol)/poly(acrylic acid)/glyoxal film (PVA = poly(vinyl alcohol); PAA = poly(acrylic acid)) with high tensile strength and hydrophobic properties by using the crosslinking reaction for OH group removal is reported herein. PAA was selected as a crosslinking agent because the functional carboxyl group in each monomer unit facilitates reaction with PVA. The OH groups on unreacted PVA were removed by the addition of glyoxal to the PVA/PAA solution. The chemical properties of the PVA/PAA films were investigated using Fourier transformation infrared spectroscopy and the thermal properties of the PVA/PAA/glyoxal films were investigated by means of differential scanning calorimetry and thermogravimetric analysis. A tensile strength of 48.6 N/mm(2) was achieved at a PVA/PAA ratio of 85/15 for the PVA/PAA film. The tensile strength of the crosslinked PVA/PAA/glyoxal film (10 wt% glyoxal) was increased by 55% relative to the pure PVA/PAA (85/15) film. The degree of swelling (DS) and solubility