CN-121991292-A - Macroscopic quantity preparation method of acrylonitrile grafted modified polypropylene coarsening film

CN121991292ACN 121991292 ACN121991292 ACN 121991292ACN-121991292-A

Abstract

A macro preparation method of an acrylonitrile grafted modified polypropylene coarsening film belongs to the technical field of manufacturing of electronic and electric insulating materials. The invention aims to solve the problems that a polypropylene coarsening film serving as a capacitor insulating medium has low-temperature embrittlement and high-temperature insulation degradation in extremely cold regions, and further influences the energy storage performance of the polypropylene coarsening film. The invention takes polypropylene, acrylonitrile, interface agent, deionized water and initiator as raw materials, and adopts a water phase suspension grafting method for modification, and then the acrylonitrile grafted modified polypropylene coarsening membrane is prepared through purification, blending and macro preparation methods; because the molecular structure and the aggregation state structure of the polypropylene can be changed by the acrylonitrile, a carrier trap is introduced, the free volume is reduced, the problems of low-temperature embrittlement and high-temperature insulation degradation of the polypropylene coarsening film are solved, the energy storage performance of the polypropylene coarsening film at low temperature is improved, and the application requirements of the polypropylene coarsening film in extremely cold areas are met.

Inventors

LI LIN
ZHANG TIANDONG
WU DI
CHI QINGGUO
YANG HONGDA
ZHANG JIAN
YU HAO
XING ZHAOLIANG
GUO SHAOWEI

Assignees

国网黑龙江省电力有限公司电力科学研究院
哈尔滨理工大学
国网黑龙江省电力有限公司
中国电力科学研究院有限公司

Dates

Publication Date: 20260508
Application Date: 20260319

Claims (10)

1. The macro preparation method of the acrylonitrile grafted modified polypropylene coarsening film is characterized by comprising the following steps of: 1. adding polypropylene, acrylonitrile, an interfacial agent, deionized water and an initiator into a reaction kettle, swelling for a first preset time at a first preset temperature, and performing a grafting reaction at a second preset temperature to obtain a reaction product; 2. Soaking and washing a reaction product by using a solvent, carrying out Soxhlet extraction reaction, carrying out solid-liquid separation, and drying the obtained solid substance to obtain acrylonitrile grafted modified polypropylene; 3. mixing polypropylene, acrylonitrile grafted modified polypropylene and an antioxidant solution, and drying to obtain a mixed material; 4. And preparing the mixture into a film in a large quantity by using a film preparation device to obtain the acrylonitrile grafted modified polypropylene coarsening film.
2. The macro preparation method of the acrylonitrile grafted modified polypropylene coarsening film according to claim 1, wherein the mass ratio of the acrylonitrile, the interfacial agent, the deionized water, the initiator and the polypropylene in the first step is (0.05-0.5): 0.1-0.8): 1-6): 0.0001-0.1): 1.
3. The macro preparation method of the acrylonitrile grafted modified polypropylene coarsening film according to claim 1, wherein the interfacial agent in the first step is at least one of xylene and cyclohexane, and/or the initiator in the first step is at least one of dicumyl peroxide, dibenzoyl peroxide, azobisisobutyronitrile and ammonium persulfate.
4. The macro preparation method of the acrylonitrile grafted modified polypropylene coarsening film according to claim 1, wherein the first preset temperature in the first step is 35-80 ℃, the first preset time is 30-360 min, and/or the second preset temperature in the first step is 75-98 ℃, and the grafting reaction time is 0.5-12 h.
5. The macro-preparation method of the acrylonitrile grafted modified polypropylene coarsening film according to claim 1, wherein the solvent in the second step is at least one of deionized water, absolute ethyl alcohol, acetone and ethyl acetate.
6. The macro preparation method of the acrylonitrile grafted modified polypropylene coarsening film according to claim 1 is characterized in that soaking and washing time in the second step is 0.5-48 h, and/or Soxhlet extraction reaction is carried out on a reaction product after cleaning at a temperature of 90-125 ℃ for 4-240 h, wherein a solvent used for Soxhlet extraction is at least one of absolute ethyl alcohol, acetone, cyclohexane and ethyl acetate.
7. The macro preparation method of the acrylonitrile grafted modified polypropylene coarsening film according to claim 1, wherein the drying temperature in the second step is 30-90 ℃, the drying time is 1-36 h, or the antioxidant solution in the third step is a mixture of a main antioxidant, an auxiliary antioxidant and a solvent according to the mass ratio of (0.0001-0.01) (20-100), wherein the main antioxidant is at least one of tetra [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ] pentaerythritol ester, beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate n-stearyl alcohol ester, 2' -methylenebis (4-methyl-6-tert-butylphenol), 1.1.3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane and bis (2, 4-di-tert-butylphenol) pentaerythritol diphosphite, the auxiliary antioxidant is at least one of tris (2, 4-di-tert-butylphenyl) phosphite, triphenyl phosphite, trisnonylphenyl propionate, dithio propionate, ethyl acetate, and ethyl acetate.
8. The macro preparation method of the acrylonitrile grafted modified polypropylene coarsening film according to claim 1 is characterized in that the mass ratio of the polypropylene to the acrylonitrile grafted modified polypropylene to the antioxidant solution in the step three is 1 (0.01-1) (0.01-0.1), or the drying temperature in the step three is 30-90 ℃ and the drying time is 1-12 h.
9. The macro preparation method of the acrylonitrile grafted modified polypropylene coarsening film is characterized in that the film preparation device in the fourth step is a double-screw extruder and a chilling roller, the temperatures of all areas of the double-screw extruder are 175-185 ℃, 180-200 ℃, 185-200 ℃ and 190-210 ℃ respectively, the temperature of a machine head of the double-screw extruder is 190-200 ℃, the rotating speed of a screw of the double-screw extruder is 60-150 rpm, and the temperature of the chilling roller is 110-130 ℃.
10. An acrylonitrile grafted modified polypropylene roughened film characterized by being prepared according to the preparation method of any one of claims 1-9.

Description

Macroscopic quantity preparation method of acrylonitrile grafted modified polypropylene coarsening film Technical Field The invention belongs to the technical field of electronic and electric insulating material manufacturing, and particularly relates to a macro preparation method and application of an acrylonitrile grafted modified polypropylene coarsening film. Background The electric power system is an important infrastructure for supporting national economic and social development and guaranteeing basic civilians. The new strategy of energy safety is pushed in, the potential safety hazard existing in the long-term operation of the power grid is eliminated, the sudden fault of the operation of the power system is properly dealt with, and the important position of the power safety supply in the development of the power industry is ensured. The power capacitor is one of important power equipment in power grid engineering, is usually arranged in parallel on a bus of a transformer substation, and mainly aims to realize reactive compensation of a power system and improve the power quality of the power grid. The polypropylene as a thermoplastic plastic obtained by polymerization of propylene monomers has regular structure, high crystallinity, low price, huge yield and huge development prospect and application value in the third rank of global general plastics. The polypropylene has excellent recoverability, processability, mechanical strength, good processability, chemical corrosion resistance and heat resistance, the melting point can reach more than 150 ℃, and the melting point is 40% -50% higher than that of polyethylene materials, and can continuously work in an environment of 100 ℃. Polypropylene is widely used as an energy storage medium in power capacitors by combining excellent mechanical properties, thermal properties and electrical properties. The temperature in winter is generally between-10 ℃ and-40 ℃ in the regions of Heilongjiang, xinjiang and the eastern part of inner Mongolia of China and can even reach below-55 ℃ in extreme cases. Under extremely cold (-60 ℃ to-40 ℃) environments, the temperature difference between the outdoor low-temperature environment and the running temperature of the capacitor has a great influence on the insulativity and the thermal shrinkage degree of the capacitor film material, and long-term cold-hot circulation can cause the breakdown field strength of the capacitor film to be reduced and the dielectric loss to be increased. The molecular chain movement of the polypropylene film is slow and the brittleness is increased under the low temperature condition, the breakdown field intensity is reduced, the dielectric loss is increased, and even the mechanical damage of the film occurs due to the generation of electric stress, thereby seriously affecting the insulation performance. Therefore, how to improve the performance of the polypropylene roughened film under the low-temperature condition is of great importance for the application of the oil-immersed capacitor in extremely cold areas. Disclosure of Invention The invention aims to solve the problems that a polypropylene coarsening film serving as a capacitor insulating medium has low-temperature embrittlement and high-temperature insulation degradation in extremely cold regions so as to influence the energy storage performance of the polypropylene coarsening film, and provides a macro preparation method of an acrylonitrile grafted modified polypropylene coarsening film. The macro preparation method of the acrylonitrile grafted modified polypropylene coarsening film is specifically completed by the following steps: 1. adding polypropylene, acrylonitrile, an interfacial agent, deionized water and an initiator into a reaction kettle, swelling for a first preset time at a first preset temperature, and performing a grafting reaction at a second preset temperature to obtain a reaction product; 2. Soaking and washing a reaction product by using a solvent, carrying out Soxhlet extraction reaction, carrying out solid-liquid separation, and drying the obtained solid substance to obtain acrylonitrile grafted modified polypropylene; 3. mixing polypropylene, acrylonitrile grafted modified polypropylene and an antioxidant solution, and drying to obtain a mixed material; 4. And preparing the mixture into a film in a large quantity by using a film preparation device to obtain the acrylonitrile grafted modified polypropylene coarsening film. The acrylonitrile grafted modified polypropylene coarsening film is used in extremely cold resistant capacitors. The principle of the invention is as follows: According to the invention, acrylonitrile is used as a grafting monomer to graft and modify polypropylene, so that the molecular structure of polypropylene is changed, and the usability of the polypropylene roughened film under extremely cold conditions is improved. The structure of a molecular chain is changed by grafting the polar groups, th