Influence of glutaraldehyde on dynamic properties of poly(vinyl alcohol) polymer

Abstract

This study investigated the dynamic mechanical properties of poly(vinyl alcohol) (PVA; (CH2CH(OH))(n)) cross-linked with glutaraldehyde (GA; OHC(CH2)(3)CHO). The cross-linked polymer was prepared by using a conventional casting technique and then treated with sulfuric acid (H2SO4) for 24 h. The flexural properties during static and dynamic modes were studied using a three-point bending condition. The static flexural properties are improved with the addition of 30% GA in PVA, with higher value of strain. It was observed that the dynamic mechanical properties of PVA improved significantly with an increase in cross-linking percentage. The storage and loss moduli increased drastically with the addition of the cross-linker up to 20%, and marginal changes occurred with further addition of the cross-linker. The fracture behavior was transformed from ductile to brittle for more than 20% cross-linker. Shifting of the rubber region and liquid region with higher temperatures was observed in storage and loss modulus plots. Improvement in the adhesion factor, cross-linking density and effectiveness was observed for GA up to 25%. The test duration was estimated using the Williams-Landel-Ferry model for different temperatures. The major changes were in the modulus in the rubbery plateau region. The cross-linked polymer had much greater storage and loss moduli, indicating a closer network structure and higher stiffness.