Molecular simulation of the influence of TiO₂ particle size on the strength and thermal stability of cellulose

The main component of transformer insulating paper is cellulose. In order to improve the strength and thermal stability of insulating paper, cellulose doped with Nano-TiO₂ was used to study the strength and thermal stability of cellulose doped with different Nano-TiO₂ particle sizes by molecular simulation. Studies have shown that Nano-TiO₂ increases cellulose strength, tensile modulus, deformation resistance, ratio of volume modulus to shear modulus (K/G), and cellulose toughness. The formation of a new hydrogen bond network between hydroxyl and cellulose on the surface of Nano-TiO₂ increases the peak value of radial distribution function, makes the composite system more stable and its thermal stability enhanced. With the same doping ratio, as the particle size of Nano-TiO₂ decreases, the tensile modulus and Cauchy pressure increase, poisson's ratio decreases, and the anti-deformation ability of cellulose increases. The higher the hydroxyl group share on the surface of Nano-TiO₂, the easier it is for Nano-TiO₂ to form hydrogen bonds with cellulose to inhibit the cellulose chain movement. Nano-TiO₂ also reduces the free volume of the composite system, making the composite structure more stable and thermal stability stronger. Therefore, the particle size of doped TiO₂ is an effective method to enhance the strength and thermal stability of cellulose. (authors)