Method for preparing polyimide foam by polyether couple precursor process

A polyimide and precursor technology, applied in the field of preparation of polymer foam materials, can solve the problems of poor stability, high shrinkage, and high content of open-cell structure, and achieve good stability, improved uniformity, and good stability. and structural regularity

Inactive Publication Date: 2005-08-17
ZHEJIANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] In the above-mentioned method for preparing polyimide foam, polyimide foam in a wide density range cannot be provided, and the density and pore size distribution uniformity of the obtained foam are not easy to control
The foam obtained by using the precursor of isocyanate has poor stability, is easy to hydrolyze and decompose; the content of open-cell structure in the foam is high, which is easy to cause the infiltration of water vapor to reduce its heat insulation performance, and has a high shrinkage rate when encountering fire and high temperature.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] 1) Preparation of precursors

[0033] 21.8 grams (0.1 moles) of 1,2,4,5-pyromellitic dianhydride were added to a 250-milliliter reactor equipped with a stirrer, a temperature controller, and a condenser tube, and 4.5 grams of The mixture of monohydroxypolypropylene oxide with a molecular weight of 1200 and 100 grams of methanol is heated to reflux at 70-75 °C, and the reaction is continued for 4 hours after the solution becomes clear, and then 20 grams of tetrahydrofuran is added to the solution. Stir for 1 hour. Cool the solution to below 50°C, add 20.1 grams (0.1 mole) of 4,4'-diaminodiphenyl ether, stir and react at 55-60°C for 4 hours, then add 1.5 grams of polysiloxane to the reaction mixture, After stirring at room temperature for 2 hours, a homogeneous polyimide salt-like precursor solution was obtained. The solution was heated at 70°C to remove excess small molecule alcohol and small molecule ether, cooled to room temperature, and ground into fine powder to ob...

Embodiment 2

[0038] 1) Preparation of precursors

[0039] Same as Example 1

[0040] 2) Foaming and hardening

[0041] Mold: cuboid, the cavity size is 8.0 cm x 8.0 cm x 5.0 cm, and the material is breathable ceramics.

[0042]Put 0.3 gram of the obtained polyimide salt-like precursor powder into the above-mentioned ceramic mold after grinding. The mold is put into a negative pressure environment with a pressure of 25 centimeters of mercury, heated at 1 kilowatt for 30 minutes with a microwave oven, and then heated at 2 kilowatts for 50 minutes. After cooling, the mold is opened to obtain polyimide microspheres.

Embodiment 3

[0044] 1) Preparation of precursors

[0045] 29.4 grams (0.1 moles) of 3,3 ', 4,4'-biphenyltetralic acid dianhydride are added to 250 milliliters of reactors with stirrer, temperature controller, condenser tube, and in this reactor, add The mixture of 5 grams of monohydroxypolyethylene oxide with a molecular weight of 2000 and 110 grams of methanol was heated to reflux at 70-75 ° C, and the reaction was continued for 4 hours after the solution became clear, and then 20 grams of tetrahydrofuran was added to the solution. Stir at -70°C for 1 hour.

[0046] Cool the solution to below 50°C, add 20.1 grams (0.1 mole) of 4,4'-diaminodiphenyl ether, react at 55-60°C for 3 hours, then add 1.5 grams of polysiloxane to the reaction mixture, at room temperature After stirring for 1 hour, a homogeneous polyimide salt-like precursor solution was obtained. The solution was spray-dried at 60° C. to remove excess small molecule alcohol and small molecule ether to obtain polyimide salt-like ...

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Abstract

The invention discloses a method to prepare polyimide foam in the course that polyether is coupled with precursor. It makes aromatic dianhydride react with monohydroxy polyether and small molecular alcohol at 60-90 deg.C, to obtain aromatic diacid diester solution, then adds in aromatic diamine and small molecular ether to fully react at 50-80 deg.C, adds in foam stabilizer and strengthener; eliminates superfluous alcohol and small molecular ether to obtain polyether-coupled monomer precursor powder; places the powder in mould, preheats and foams at 70-180 deg.C, and solidifies at high temperature of 200-450 deg.C to obtain the polyimide foam which has closed cell structure and density 0.01-0.5g / cu cm.

Description

technical field [0001] The invention relates to a method for preparing polymer foam materials, in particular to a method for preparing polyimide foam through a polyether coupling precursor process. Background technique [0002] Due to its low density and light weight, polymer foam is often used in thermal insulation, sound insulation, shock absorption and other fields. Commonly used are the first-generation and second-generation polymer foams made of polyolefin, polyurethane and phenolic formaldehyde, but the strength, temperature resistance, physical and chemical stability, and flame resistance of these materials cannot meet the needs of some special fields. requirements. Typical polyimides are polymers containing aromatic rings and heterocyclic structures. They are recognized as materials with the best comprehensive properties in terms of strength, high temperature / low temperature resistance, insulation, chemical stability, and radiation resist...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08G73/10C08J9/02
Inventor 朱宝库楚晖娟徐又一徐志康
Owner ZHEJIANG UNIV
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