Corona-resistant polyimide/silica nano composite film and preparation method thereof

A technology of silicon dioxide and polyimide, which is applied in the field of corona-resistant polyimide/silicon dioxide nanocomposite film and its preparation, can solve the problems of two-phase compatibility and interface morphology defects, and the electric resistance of the composite film Halo performance improvement space is limited and other issues

Inactive Publication Date: 2014-02-05
FUJIAN NORMAL UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Due to the limited dispersion of inorganic nanoparticles in the polyimide/inorganic composite film, resulting in two-phase co

Method used

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  • Corona-resistant polyimide/silica nano composite film and preparation method thereof
  • Corona-resistant polyimide/silica nano composite film and preparation method thereof

Examples

Experimental program
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Effect test

Embodiment 1

[0039] 1) The first step is to purify DABA, ODA, PMDA, and DMAc. Pretreatment methods include methods such as drying, sublimation, recrystallization and vacuum distillation;

[0040] 2) 6.8582 and 5.2100 grams of purified ODA and DABA (ie their molar ratio n ODA :n DABA =1) Dissolved in DMAc to form a diamine solution, 14.9800 grams of PMDA [the molar ratio of PMDA to diamine is n PMDA :n (ODA+DABA) =1.004:1] Add the DMAc solution of the above diamine in three batches, after the PMDA is dissolved, put the reaction system in an ice-water bath and stir for 6 hours, then continue to stir overnight at room temperature to obtain a transparent mass concentration It is 13% side chain carboxyl copolyamic acid (PAA) injection solution.

Embodiment 2

[0042] Weigh 10 grams of the PAA film injection solution prepared in Example 1, cast it on a clean and dry smooth glass plate (pre-adjusted level), and then follow the following temperature program (100 ° C for 1 h, 200 ° C for 1 h and 300 ℃ for 0.5 h) heating, during which PAA undergoes thermal imidization to obtain a polyimide (PMDA / ODA-DABA) film. The resulting film had a volume resistivity of 2.9 × 10 10 Ω·m, the dielectric constant is 3.6, the breakdown field strength is 201 kV / mm, and the corona resistance time is 4.2 h.

Embodiment 3

[0044] Take by weighing 10 grams of the PAA film injection solution prepared by Example 1, and press the SiO in the composite film 2 Add tetraethyl orthosilicate (TEOS) at a mass percentage of 5%, and then add a drop of dilute hydrochloric acid with a volume concentration of 1%. After stirring and reacting for half an hour, add distilled water dropwise (the amount added is 40wt% of DMAC ), react at room temperature for 16 h; cast film on a clean and dry smooth glass plate (pre-adjusted level), and finally make PAA heat sub- Amination, namely to get SiO 2 5% polyimide / silica nanocomposite film. The volume resistivity of the obtained nanocomposite film is 3.9×10 10 Ω·m, the dielectric constant is 3.3, the breakdown field strength is 195 kV / mm, and the corona resistance time is 8.5 h.

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Abstract

The invention discloses a corona-resistant polyimide/silica nano composite film and a preparation method thereof. The method comprises the following steps: preparing polyamide acid with carboxyl on a side chain by using a diamine monomer 3,5-diaminobenzoic acid with carboxyl, diphenyl ether diamine and benzenetetracarboxylic anhydride; and adding tetraethyl orthosilicate, so as to prepare the polyimide/silica nano composite film by a sol-gel method and a hot amination method in situ. The surfaces of nanosilica particles are closely combined with polyimide by a polymer and silica in the composite film under the action of a chemical bond and a hydrogen bond; even distribution of the silica in polyimide matrix is realized; the silica does not migrate and is stably dispersed. The polyimide/silica nano composite film provided by the invention has the characteristics of high electrical resistivity, low breakdown strength, small dielectric constant, long corona-resistant time and the like. The method is simple and convenient to operate; even and stable dispersion of the silica in the polyimide also can be achieved.

Description

technical field [0001] The invention relates to a corona-resistant polyimide / silicon dioxide nano-composite film and a preparation method thereof, in particular to a corona-resistant composite film composed of a polyimide copolymer with carboxyl groups in the side chain and nano-silicon dioxide and its preparation method. Background technique [0002] In addition to its solvent resistance, corrosion resistance, high temperature resistance and high mechanical strength, polyimide (PI) has excellent electrical and dielectric properties compared to other materials, and is recognized as a polymer with excellent comprehensive properties, so it is widely used Used in aerospace, electronic and electrical and coatings and other fields. In recent years, with the vigorous development of power electronics technology, the application of frequency conversion speed regulation has been promoted. Frequency conversion speed regulation can save 1 / 4~1 / 3 of the electric power of the motor, whic...

Claims

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Application Information

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IPC IPC(8): C08J5/18C08L79/08C08K3/36C08G73/10
Inventor 关怀民童跃进罗贝贝
Owner FUJIAN NORMAL UNIV
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