Enhancement of thermal stability and insulation properties of cellulose composites insulating paper by the first introduction of polyimide fiber

Traditional inefficient "tentative" trial and error experiments are difficult to rapidly and efficiently prepare synthetic fiber/cellulose composites with high thermal stability and strong insulation properties because the direct scientific theory or simulation guidance is insufficient. In this paper, PI fiber is the first time introduced to cellulose insulating paper. The mechanical, thermal stability, and dielectric properties of PI/cellulose composite insulating paper are predicted by molecular dynamics (MD) simulation. The composite insulating papers with the corresponding content of PI fiber were prepared and their thermal stability, mechanical properties, and electrical properties were investigated. Relative to the pure cellulose insulating paper, the 6% PI/cellulose insulating paper is the most representative, its tensile strength increased by 26.24%, the glass transition temperature increased from 113.4 to 124.7 K, permittivity decreased from 4.22 to 3.25, the dielectric loss decreased by 58.33% at 50 Hz, and the breakdown strength increased by 30.35%. This work confirms the effectiveness of MD simulation to rapidly guide the preparation of the new composite insulating paper, which can provide a reference for the future expansion and development of synthetic fiber in the preparation of cellulose insulating paper, and proves that PI fiber can enhance the thermal stability and insulation properties of cellulose insulating paper.