Preparation And Performance Study Of SiO₂/PI Composite Insulating Paper

Oil-paper insulation structure is a commonly used insulation structure for large power transformers,among which the common solid insulation material is wood insulating paper and Nomex insulating paper.However,the heat resistance rating of wood insulation paper is 105?,and easy to aging under the influence of water and oxygen,and Nomex insulating paper production technology has been monopolized and expensive;although some domestic enterprises have also developed alternative products of Nomex insulating paper,there is still in some performance gap and high production cost.The purpose of this study is to develop a high-performance and low-cost insulation paper for domestic transformer,to achieve new breakthroughs in the field of electrical insulation,and to provide new materials and new ideas for the development of a new high-voltage-resistant transformer.In this paper,nano SiO₂ was introduced into polyamide acid(PAA)by in situ polymerization,SiO₂/polyimide(PI)porous fiber membrane was prepared by electrospinning technology,and verify the performance of various parameters used as insulating paper,and analyze the key factors and rules affecting the performance of SiO₂/PI composite insulating paper.It is found that the insulation energy,mechanical performance and thermal performance of PI composite insulating paper are improved.With the increase of doping of SiO₂particles,the improvement performance of PI composite insulating paper is the first increased and then reduced.Surface treatment of nanoparticles using the conjugates KH550 and KH560 creates a"molecular bridge"between nanoparticles and PI,enabling optimization of insulating paper performance.According to the experimental results,the performance of KH550-SiO₂/PI composite insulating paper is the best.When the KH550-SiO₂content is 3 wt%,the breakdown field strength of KH550-SiO₂/PI composite insulating paper can reach 89 k V/mm,dielectric constant is 1.28,dielectric loss is 6.28×10^-4,and longitudinal tensile strength can reach 263.9 MPa with potential applications.