The Cellulose Loading and Silylation Effects on Mechanical Properties of Epoxy Composite: Insights from Reactive Molecular Dynamics Simulations

This study investigates the effect of silylation and cellulose loading on the tensile properties of epoxy composites. We use the hydrolyzed (3-aminopropyl)triethoxysilane (APTES) as a crosslinker for epoxy and as a coupling agent for cellulose. The cellulose chains are silylated to enhance the interfacial adhesion between epoxy and cellulose through the covalent bonds formed at the interface by silane and amine parts of the APTES. The effect of non-covalent bonds, such as hydrogen bonds, on the interfacial adhesion at the epoxy/cellulose interface is considered by using APTES as a crosslinker for epoxy and then implementing raw cellulose as a reinforcement for the resulting composite. The tensile properties of the epoxy composites are evaluated using the molecular dynamics simulations. The silylated cellulose at 28.1 wt.% enhances the tensile modulus, shear modulus, and strength of the epoxy composite by 14.55%, 15.65%, and 17.11%, respectively, compared to the properties of the epoxy/raw cellulose composite. Using the silylation treatment on cellulose that reinforces epoxy at 43.9 wt.% improves the elastic modulus, shear modulus, and tensile strength of the epoxy/cellulose composite by 4.23%, 4.64%, and 16.50%, respectively. The silylation treatment can effectively increase the tensile strength of epoxy/cellulose composites even at high cellulose contents.