High Performance Polysodium Acrylate Superabsorbents Utilizing Microfibrillated Cellulose to Augment Gel Properties

Microfibrillated cellulose was utilized at low concentrations as a filler material, added prior to free radical polymerization, in cross-linked superabsorbent polysodium acrylate hydrogels. The effect of microfibrillated cellulose concentration on equilibrium swelling, shear modulus after synthesis, and shear modulus at equilibrium swelling was studied at different degree of cross-linking. For the characterization of the microfibrillated cellulose optical microscopy, atomic force microscopy, and transmittance analysis were used. The shear modulus of the samples was determined using uniaxial compression analysis. The swelling of the gels was determined using classical gravimetrical measurements. It was found that microfibrillated cellulose was highly efficient in increasing the shear modulus of the gels. Furthermore, the microfibrillated cellulose was found to have the same effect on the swelling and shear modulus at equilibrium swelling as the same mass of the conventional covalent cross-linker N,N'-methylenebisacrylamide (MBA), while in fact improving the fracture resistance of the gels. In conclusion, microfibrillated cellulose shows great potential as an additive to enhance the performance of soft materials.