Studies on adsorptive dehydration of pasteurised milk by filled polymeric IPN hydrogel

Abstract

ABSTRACT Adsorptive dehydration utilising polymeric hydrogels presents an effective technique for removing excess water from pasteurised milk. This study investigated three Interpenetrating Polymeric Network (IPN) hydrogels comprising Polyvinyl Alcohol (PVOH) and Hydroxyethyl Cellulose (HEC) at mass ratios of 90:10, 70:30 and 50:50, respectively, with Maleic Anhydride (MAn) as a cross-linker at concentrations of 2% 4%, and 8% based on total polymer weight. It was observed that the rate of dehydration increased with higher HEC content in the hydrogels. However, the stability decreased due to changes in the structural alignment of polymer chains and weak cross-linking. Among the tested hydrogels, the one with a composition of 70:30 for PVOH and HEC, respectively, cross-linked with 8% MAn (0.096gm), exhibited the best adsorption (569% Swelling) with minimal changes in pH (<10%) and conductivity (<10%) and was, therefore, selected for further study. This selected hydrogel composition was further enhanced by incorporating a hydrophilic nanofiller (Bentonite) at proportions of 2%, 4% and 6% based on total polymer weight during hydrogel synthesis. The hydrogel with 4% nanofiller (0.081 gm) showed the best results in terms of swelling and stability although the 6% filled hydrogel exhibited superior swelling but lower stability. Finally, the dehydration process was optimised using Type 1 fuzzy logic (T1FL), achieving an R2 value of 95.13%.