Rheological Study on Crosslinking and Gelation of Amidated Carboxymethylcellulose Solutions

Viscosupplementation is an intra-articular symptomatic treatment of mild osteoarthritis in synovial joints. It normally consists of single or repeated injections of hyaluronan- based fluids, aimed to restore desirable viscoelastic behavior of the synovial fluid and thus recreate the intra-articular joint homeostasis. Recently, a novel viscosupplement based on amidated carboxymethylcellulose has been developed by blending the soluble polymer (CMCAp) with its crosslinked derivative (CMCAg) in appropriate proportions and concentrations in order to ensure an optimal combination of flow behavior and viscoelastic properties. The present work is concerned with the rheological monitoring of the crosslinking reaction performed at 25 °C by starting from aqueous CMCAp solutions in order to describe the time evolution of the linear viscoelastic moduli occurring along the whole gelation process and to individuate how the polymer concentration affects the mechanical response at the sol-gel transition and the fractal dimension of the incipient polymeric network.