In order to discover the bonding mechanism of self-adhesive silicone rubber tape, we prepared a self-adhesive silicone rubber tape through the reaction of boric acid and methyl-vinyl silicone rubber. The variation of bonding force at interface of self-adhesive silicone rubber tape with temperature and soaking time was traced by tensile tests, and the self-fusion effect was verified. A physical model of self-fusion effect was proposed with the help of infrared spectrum test. The results show that when the content of boric acid in the reaction system is 2.5%, the self-adhesive tape has the highest initial bonding force. When silicone rubber has the molecular structure of short chain boron-containing siloxanes imbedded in long chain siloxane network, the well contacted silicone rubber interfaces can bond through complexation between boron and oxygen atoms in the boron-containing siloxanes, and the bonding force is stronger than the cohesion among polysiloxane molecules. The complexation can not complete instantly, and the higher the temperature of interface, the shorter the time of complexation. Under 60℃, the complexation strength can reach the optimum value within 12 hours.

In view of the burning loss and fire risk of T-type cable plug used in high voltage devices when the conductor is overheating, we built an experimental platform for the pyrolysis of rubber material for T-type cable plug , and the pyrolysis behavior of T-type cable plug was studied based on FTIR method. The results show that in the temperature range of 80-260℃, the pyrolysis characteristic components of T-type cable plug are silicone grease, CO₂, and H₂O. The escape temperature of CO₂ and H₂O is 80℃, and their concentration reaches the maximum value at 200℃, while the escape temperature of silicone grease is above 200℃, and the escape temperature increases with the increase of temperature. The results of non-isothermal thermogravimetric analysis show that the weight loss rate at 305℃ is 2.50%.

The high thermal conductive insulation structure applied in H-class AC high voltage motor was studied. The coil samples with the insulation structure were conducted turn-to-turn impulse, withstand voltage to ground, dielectric loss factor, breakdown voltage, voltage durability (electrical ageing), thermal evaluation and classification (thermal ageing) experiments, and the thermal conductivity of several dry mica tapes were tested and analysed. The results show that the application of dry mica tape with high thermal conductivity could improve the thermal conductivity of insulation structure for motor, and the temperature rise reduces effectively. The insulation structure also show good electrical performance, and the temperature index reaches 181℃, which can meet the requirements of the insulation structure for H-class motor.

With the miniaturization and lightweight of electronic equipment, graphite film materials with high thermal conductivity were widely concerned recently. In this paper, the preparation of polyimide (PI) based graphite film was reviewed, and the influence factors of their performance, which included molecular structure, molecular orientation, and the inducement of other materials, were introduced in detail. The research and patent situation of graphite film composite materials were summarized, and the future research and development direction were suggested and prospected.

The thermal conductive and insulating composite material with polymer matrix and high thermal conductive filler is an ideal solution to settle insulation protection of live working equipment and heat dissipation problem of electrical and electronic equipment. In this study, micron alumina (Al₂O₃), surface modified by silane coupling agent KH550, mixed with high thermal conductive carbon nanotubes (CNT) as thermal conductive filler, silicone rubber (SR) with wide temperature range resistant and corrosion resistant was selected as polymer matrix, an SR composite material was prepared, and its performance was tested. The results show that when the total content of Al₂O₃/CNT mixed filler is 10%, the proportion of carbon nanotubes is 0.2%, the thermal conductivity of the SR composite is as high as 0.268 W/(m·K), which is improved by 103.1% compared with SR, the resistivity is 10.5×10¹² Ω·cm, the relative dielectric constant is almost unchanged, and the Shore hardness A and Young’s modulus increase slightly .

A silicon carbide/organic montmorillonite/epoxy resin micro-nano non-linear corona resistant composite material was prepared. The influence of silicon carbide and organic montmorillonite content on the dielectric properties of the corona resistant material was studied. Bars were prepared using the corona resistant material, and their corona resistance and surface temperature were tested. The results show that the addition of a certain amount of nano organic montmorillonite could effectively improve the non-linear characteristic of the corona resistant composite, reduce the surface temperature of anti-corona area, and improve the corona resistance of bars.

Polymer materials such as epoxy resin have hidden dangers of thermal failure and insulation failure during long-term service since its low thermal conductivity. In this study, a high thermal conductive composite insulating material was prepared by filling micron boron nitride and nano alumina with high thermal conductivity and high insulation properties to epoxy resin, and the effect of filling amount and ratio of fillers on the thermal conductivity and insulation properties of composite materials were studied. The results show that when the total filling content is 30% and the mass ratio of micron boron nitride to nano alumina is 3∶1, the thermal conductivity, breakdown time, and imaginary part of complex permittivity (ε″) of the composite materials is 1.182 0 W/(m·K), 31.9 s, and 0.034, respectively, which is improved by 697%, 21.7%, and 406% compared with epoxy resin, respectively. The composite material has good resistance performance under high frequency and high electric field.

In order to improve the thermal conductivity and environmental resistance of motor insulation system, we analyzed the conventional properties, heat resistance, thermal conductivity, and environmental resistance of a high thermal conductive and high temperature resistant epoxy encapsulating resin. A prototype was made, and the application performance of the epoxy encapsulating resin in low voltage motor was tested. The results show that the epoxy encapsulating resin has excellent mechanical and electrical properties, excellent low temperature and thermal shock resistance, and good compatibility with enameled wire, and the thermal conductivity and temperature index reach 1.18 W/(m·K) and 187.5℃, respectively. The application of high thermal conductive insulating resin could effectively improve the thermal conductivity of the motor insulation system, under the same conditions, the temperature rise of motor decreases by 20.7℃ compared to the motor with ordinary high temperature resistant insulating varnish. At the same time, compared with the vacuum pressure impregnation process, the insulation system of the motor made by the vacuum encapsulation process has better integrity, electrical properties, and humidity resistance, and the disadvantage of low paint hanging at the groove is avoided.

A polyacrylonitrile (PAN)/styrene-isoprene-styrene (SIS) composite fiber membrane was prepared by electrospinning method. The effects of different PAN/SIS ratios on its porosity, liquid absorption, thermal stability, mechanical properties were studied. The results show that when the ratio of PAN to SIS is 8∶2, the SIS/PAN composite membrane fiber prepared has the most cross-linked structures, uniform size, and the best mechanical properties. The tensile strength is 20.29 MPa, the porosity and absorption rate reach 47.8% and 310.7%, respectively, and the ionic conductivity is 2.03×10^-4 mS/cm. Under the condition of 0.2 C multiplier, the initial discharge specific capacity of Li-ion battery assembled by the composite fiber membrane is 146.4 mAh/g, the discharge specific capacity fluctuates little after 50 cycles, and the capacity retention rate is as high as 98.02%, showing good cycle stability.

In order to develop a high thermal conductive epoxy potting adhesive for dry-type transformer, we prepared a potting adhesive by adding self-made modified silica to epoxy anhydride system. The thermal conductivity and electrical insulation performance were tested, and the suitable pouring temperature and best curing process of the potting adhesive were studied. The results show that when the filling content is 75%, the potting adhesive has high thermal conductivity and excellent electrical insulation performance, the thermal conductivity is 1.494 W/(m·K), the dielectric loss factor is only 0.41%. When the pouring temperature is 70℃, the potting adhesive has good pouring process, the viscosity is low than 2 800 MPa·s within 2 h. The best pouring process for potting adhesive is 80℃ vacuum/0.5 h + 80℃/4 h + 90℃/3 h + 110℃/2 h + 140℃/5 h. Under the condition, the deposition of powder in potting adhesive is small, and the cured product has the best comprehensive performance.