Fatty acid – functionalized cellulose nanocomposites for vat photopolymerization

Abstract

In recent years, nanocellulose, also called cellulose nanocrystals (CNCs), arose as one of the most interesting bio-based material for the incorporation as additive in polymers, due to its ability to increase the mechanical properties of the derived nanocomposites. Unfortunately, the natural hydrophilicity of CNCs strongly limited the mutual dispersion of cellulose crystals into the polymeric lipophilic chains, posing huge limitations both in cellulose loadings and efficacy. Herein we have synthesized a series of nanocomposites for vat photopolymerization, based on a commercial resin and CNCs modified with fatty acids obtained from safflower oil (SOFA), which allows hydrophobization of CNCs and their proper dispersion in the polymeric resin. The combination of these compounds allows manufacturing solid and complex objects without any defects in their structure from bio-based nanocomposites with CNCs-SOFA concentrations up to 5 wt%. The analyses of their mechanical and optical properties were also studied revealing that nanocomposites with CNCs-SOFA possess increased stiffness and strength without experiencing a significant loss in their transparency, when compared to the pristine resin.