Preparation and Corona Resistant of Polyimide/TiO2 Nanocomposite Films

Tough Silica-Hybridized Epoxy Resin/Anhydride System with Good Corona Resistance and Thermal Stability for Permanent Magnet Synchronous Wind-Driven Generators through Vacuum Pressure Impregnation

“…With the addition of 12 wt % mSiO 2 , the corona resistant life of EA/mSiO 2 is as long as 983 min, about 19.6 times that of the EA resin (50 min), meaning that the service life and operation reliability of the product originating from EA/mSiO 2 resins are attractively good. Note that the effect of mSiO 2 on the corona resistant life is super because the corona resistance of modified polyimide film with 20 wt % nano-TiO 2 increased about 8.3 times …”

“…On the other hand, it is known that a good dispersion and orbicular structure of nanofillers are beneficial to get long corona resistant life . This is also the reason that EA/mSiO 2 resins have better corona resistant lives than previous filler/polymer systems …”

“…Note that the effect of mSiO 2 on the corona resistant life is super because the corona resistance of modified polyimide film with 20 wt % nano-TiO 2 increased about 8.3 times. 41 To reveal the reason behind these attractive corona resistant lives, the partial discharges of EA and EA/mSiO 2 resins were recorded under a high-voltage electric field (2.5 kV) and are shown in Figure 14. The EA resin has much more charge and high charge accumulation density, especially the red part which has very high density of charge aggregation, suggesting that EA resin has poor capacity of electric homogenization, and easily generates partial discharge and electric corrosion aging; in other words, EA resin has poor corona resistance.…”

“…45 This is also the reason that EA/mSiO 2 resins have better corona resistant lives than previous filler/ polymer systems. 41 3.5. Electrical Insulating Properties of Simulation Stator Coils.…”

A review on recent advances on improving polyimide matrix nanocomposites for mechanical, thermal, and tribological applications: Challenges and recommendations for future improvement

“…In recent years, various types of micro/nanoparticles, for example, alumina, silica, titanium dioxide, glass fibre, titanate nanotubes, carbon nanotubes, calcium carbonate, nano-clay, and graphite/graphene have been employed in the development of nanocomposites, such as polyimide nanocomposites, epoxy nanocomposites, polyester nanocomposites, and polypropylene composites, and so on for thermal, mechanical, tribological, and electrical applications. 9–32 Among these entire polymer based matrices, thermoplastic polyimide matrix has gained more attention as polymer matrix material in preparing composites for tribological, mechanical, and thermal application, owing to its good wear resistance, corrosion resistance, high strength to weight ratio, good interfacial bonding, better thermal stability, and had great applications in the field of aerospace and advance equipments. 33–37 As a result of this reported properties, polyimides (PIs) are widely accepted as a new generation of polymers with naturally rigid chains, which is of high commercial importance in the design of frictional components, such as soft seal, piston ring, gear, bear, and other tribological and/or constructive parts in demanding applications 38,39 as can been seen in Figure 1.…”