Poly (ethyl methacrylate) composites reinforced with modified and unmodified cellulose nanocrystals and its application as a denture resin

The aim of this study was to characterize cellulose nanocrystals (CNC) used to the preparation of nanocomposites and evaluate the influence of incorporating the CNC on flexural strength of a denture rebase resin. CNC were isolated from wood pulp by acid hydrolysis. In addition, maleic anhydride was used to superficially modify the CNCs. The modified (CNCmod) and unmodified nanocrystals (CNC) were suitably characterized and used separately as a reinforcement element in situ in a denture rebase resin consisting of poly ethyl methacrylate, at 0% (control group), 0.25%, 0.5%, 0.75% and 1%. The flexural strength of the groups was measured using a 3-point bending test with EMIC DL 2000 machine. AFM images showed that CNC and CNCmod samples presented nanoparticles with typical acicular shape and similar dimensions. A significant improvement of the flexural strength was obtained, even at low load levels, especially considering the nanoparticles with chemically modified surface. The incorporation of both modified and unmodified CNCs represents an alternative that can maximize the mechanical properties of acrylic resins and their respective dental applications.