Research on TiO₂ surface nanomanipulation to improve the thermal insulation performance of polypropylene films

Abstract According to the problems of poor insulation and local temperature rise of polypropylene film, a new nano-filler was studied, and the mechanism of improving insulation and thermal conductivity was analyzed. TiO 2 with high dielectric constant is combined with Al 2 O 3 with excellent thermal conductivity in the form of a core–shell structure. TiO 2 increases the dielectric constant of polypropylene films, and shell Al 2 O 3 introduces high thermal conductivity and assumes the role of dielectric buffer layer. Compared with pure PP, the breakdown voltage of PP/TiO 2 is increased by 6.05%, the thermal diffusivty coefficient is increased by 110.67%, the breakdown voltage of PP/TiO2@Al 2 O 3 is increased by 37.05%, and the thermal diffusivity coefficient is increased by 266.85%. Experimental and simulation results show that TiO 2 introduces low-density traps, TiO 2 @Al 2 O 3 introduces high-density deep traps, and Al 2 O 3 modifies the surface defects of high-dielectric nanoparticles and increases the equivalent interface region. Based on the analysis of the experimental results with different mass fractions, this paper proposes the optimal filling ratio of the new core–shell, which provides a new method for the composite dielectric to improve the insulation and thermal conductivity at the same time.