The Evaluation of Performance Properties of CMC-Based Copolymer Hydrogels Reinforced with Cellulosic Fibers Subjected to Stepwise Chemical and Mechanical Pretreatments: Moderate Alkaline Oxidation Treatment

In this study, mechanical refining and alkaline oxidation pretreatments were applied to cellulose reducing the side effect of it on hydrogel performance. In addition to moderate oxidation with hydrogen peroxide at 80°C, mechanical treatment was performed using PFI or supermasscolloider. The effectiveness of epichlorohydrin and citric acid as crosslinkers for hydrogel formation was investigated separately. The liquid absorption capacity, water uptake and swelling ratios of the produced hydrogels were measured and evaluated. The structural, morphological and thermal properties of the hydrogels were analyzed using FTIR, SEM and DSC. IR spectrum revealed that the interactions with both crosslinkers were effective. Although hydrogels with 10% cellulose ratio and cross-linked with citric acid can absorb liquid up to 50 times the initial mass, the overall performance of the samples produced with epichlorohydrin was found to be superior. SEM images showed that the porosity of the hydrogel decreased and the surface closedness increased in the samples with citric acid. These phenomena were considered as a reduction in diffusion of liquids and absorption capacity.