ABSTRACT The present study aims at developing crosslinked polyvinyl alcohol (PVA) membranes using boric acid as the crosslinker. The physico‐chemical changes in the structure of the PVA membranes as a function of the boric acid were investigated. The membrane hydrophilicity was determined using water contact angle measurements, which showed a significant increase from 49.3° for pristine PVA membrane to 83.0° for crosslinked PVA‐BA membrane, due to a reduction in the available hydroxyl groups of PVA. A characteristic peak in the FTIR spectrum at 1274 cm −1 attributed to B─O─C stretching vibrations, provided strong evidence of the crosslinking reaction between PVA and BA. The mechanical strength and the modulus of the crosslinked membranes were found to increase with an increase in the BA content. Differential scanning calorimetry (DSC) and XRD demonstrated decrease in crystallinity with the increase in the BA concentration. The nature of water in the PVA‐BA membranes was investigated using low‐temperature DSC studies in the range of −40°C to 20 ° C. Water management in membranes showed that a fraction of water behaves in a different manner and does not show any freezing transition. The optimized membranes can be further used in combination with bioactive agents for water disinfection.
Mehta et al. (Fri,) studied this question.