Effects of montmorillonite on the properties of cross-linked poly(vinyl alcohol)/boric acid films

The cross-linked poly(vinyl alcohol)/boric acid(PVA/BA) films incorporated with montmorillonite (MMT) was developed via a solution blending-casting method. The effects of MMT concentrations of 0%, 1%, 3%, 5% and 7% on the structural, mechanical, barrier, water resistance, thermal stability and morphology properties of cross linked PVA/BA film was investigated. It was found that the properties of the films changed as the MMT content varied. As the MMT content increased from 0% to 3%, the tensile strength increased, while the oxygen permeability and water vapour permeability reduced. However, these properties deteriorated slightly due to partially aggregations of MMT in the PVA film structure with increasing MMT content from 5% to 7%. The results showed the films incorporated with MMT became a little darker and tendency toward yellowness, the opacity increased, the water resistance and thermal stability was improved with the increasing amount of MMT. X-ray diffraction patterns, transmission electron microscopy (TEM) and scanning electron microscope (SEM) results revealed that the MMT was well dispersed in the PVA matrix and it was predominantly exfoliated. The cross linked PVA/BA film incorporated with 3% MMT showed the best comprehensive properties among all films.