Cellulose nanofiber-incorporated high-solid siloxane acrylic latex by mini-emulsion polymerization for hydrophobic coating and wood adhesive

Abstract

In order to contribute to the thriving research on bio nanocomposites for sustainable future, here we developed a cellulose nanofiber (CNF)-based siloxane acrylic nanocomposite aiming to the application as hydrophobic coating and wood adhesive. CNF was incorporated in a copolymer matrix of poly (methyl methacrylate-co-butyl acrylate) [P(MMA-co-BA)] cross-linked with methacrylate-terminated siloxane (MTS). The copolymer was prepared by mini-emulsion polymerization at a high solid content of about 57 wt%, where CNF was incorporated to the latex both by in-situ polymerization and ex-situ mixing process. The impact of the process of CNF incorporation and its content in the copolymer matrix were evaluated by measuring the thermal, mechanical, water repelling and adhesion properties. All the nanocomposites showed improved mechanical properties (tensile strength: upto 3.9 MPa) and wood adhesion strength (upto 1178 N) compared to the pristine copolymer. In addition, they showed significantly high water-repelling properties on spray-coated cotton (water contact angle: 110°–124°). Such siloxane acrylic/CNF nanocomposite has the potential as a sustainable material in the application area of hydrophobic coatings and adhesives.