Polyimide-Modified Cellulose Insulating Paper With Improved Thermal Stability and Insulation Properties

Abstract

As the voltage level continues to rise, an imperative demand arises for novel insulating papers characterized by superior electrical insulation strength and heightened thermal stability, to align with the transformative advancements in high-voltage power transformers. Nevertheless, conventional approaches relying on “trial-and-error” approaches encounter significant challenges in expeditiously developing alternative materials. Therefore, the mechanical, thermal stability and dielectric attributes of polyimide (PI)/cellulose insulating paper have been predicted through molecular dynamics (MD) simulations. Subsequently, insulating papers of the composite variety, featuring varying PI fiber content, have been fabricated and subjected to comprehensive investigations of their thermal stability and electrical characteristics. In comparison to pure cellulose insulating paper, the 6% PI/cellulose composite proves (P6) to be the most representative, exhibiting a notable 26.24% increase in tensile strength, a rise in glass transition temperature from 113.4 to 124.7 K, a reduction in permittivity from 4.22 to 3.25, a substantial 58.33% decrease in dielectric loss, and a 30.35% enhancement in breakdown strength. This study unequivocally confirms the efficacy of MD simulations in expediting the development of insulating material and establishes PI/cellulose insulating paper as an avant-garde alternative for high-voltage transformers, ushering in a new era for insulation materials.