Low melt viscosity, thermosetting polyimide precursor suitable for rtm molding and preparation method

A polyimide precursor and melt viscosity technology, applied in organic chemistry and other fields, can solve the problems of narrowing temperature processing window, unfavorable RTM molding, narrow processing window, etc., and achieve the effect of outstanding thermal stability

Active Publication Date: 2022-06-07
NORTHWESTERN POLYTECHNICAL UNIV
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  • Abstract
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Problems solved by technology

Even if the content of these polymers with higher molecular weight is not high, the melt viscosity will be significantly increased due to their larger molecular weight, while the low molecular weight polymers tend to greatly narrow the temperature processing window due to the rapid crosslinking reaction. This is very unfavorable for RTM molding
Therefore, it is urgent to develop a new synthesis scheme to guide the precise synthesis of the molecular structure and degree of polymerization of thermosetting polyimide precursors, and avoid excessive melt viscosity and excessive processing window caused by different degrees of polymerization of precursors. narrow question

Method used

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  • Low melt viscosity, thermosetting polyimide precursor suitable for rtm molding and preparation method
  • Low melt viscosity, thermosetting polyimide precursor suitable for rtm molding and preparation method
  • Low melt viscosity, thermosetting polyimide precursor suitable for rtm molding and preparation method

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preparation example Construction

[0054] A. Preparation of Nitro-Substituted Monoamino Compounds

[0055] The present invention prepares the nitro-substituted monoamino compound through the nucleophilic reaction between the phenolic compound and the halogenated nitrobenzene, and the specific reaction scheme is as follows:

[0056]

[0057] B. Preparation of Bisnitrobisimide Monomers

[0058] The present invention reacts the nitro-substituted monoamino compound and dibasic acid anhydride in a carboxylic acid solution, and adopts cyclohexane to azeotrope with water to obtain a bisnitrobisimide monomer, and the specific reaction scheme is as follows:

[0059]

[0060] C. Preparation of Bisaminobisimide Monomers

[0061] The present invention adopts the reduction technology of palladium-carbon catalytic hydrogenation to reduce the bisnitrobisimide monomer to obtain the bisaminobisimide monomer, and the specific reaction scheme is as follows:

[0062]

[0063] D. Preparation of Thermosetting Polyimide Pr...

Embodiment 1

[0066] 12.72 g of sodium carbonate, 16.37 g of p-aminophenol, 98 g of N,N-dimethylformamide, 15.75 g of o-nitrochlorobenzene and 1.5 mL of triphenyl phosphite were sequentially added to the reactor equipped with mechanical stirring. Under argon, stirring was started and the system was warmed. When the temperature rose to 90°C, the stirring was continued for 16h. When the system was cooled to 25°C, the reaction system was poured into deionized water, and a brown precipitate was precipitated. After suction filtration, the filter cake was washed three times with deionized water to obtain a crude product. The crude product was recrystallized, and the filter cake was collected after filtration and dried in a vacuum oven at 80° C. for 24 h to obtain 30.60 g of product E with a yield of 88.6%. 22.21g of 6FDA was added to a three-necked flask equipped with a water separator and a condensing reflux device at one time, 725g of acetic acid was added under argon atmosphere and mechanica...

Embodiment 2

[0068] In the reactor equipped with mechanical stirring, 16.59g potassium carbonate, 18.47g 2-methyl-3-aminophenol, 103g N,N-dimethylacetamide, 15.75g p-nitrochlorobenzene and 1.6mL trimethylacetamide were added successively. Phenyl phosphite. Under argon, stirring was started and the system was warmed. When the temperature rose to 100°C, the stirring was continued for 18h. When the system was cooled to 25°C, the reaction system was poured into deionized water, and a brown precipitate was precipitated. After suction filtration, the filter cake was washed twice with deionized water to obtain a crude product. The crude product was recrystallized, and the filter cake was collected after filtration and dried in a vacuum oven at 80° C. for 24 h to obtain 33.04 g of product E with a yield of 90.2%. 11.21g of a-BPDA was added to the three-necked flask equipped with a water separator and a condensing reflux device at one time, 700g of acetic acid was added under argon atmosphere an...

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Abstract

The invention relates to a thermosetting polyimide precursor with low melt viscosity and suitable for RTM molding and its preparation method. It uses commercial dibasic acid anhydride as the basic monomer unit and prepares bisamino The bisimide macromonomer is used as a diamine to react with a monoanhydride compound containing a carbon-carbon unsaturated bond. After imidization, a low melt viscosity, a degree of polymerization, and a molecular weight distribution index of 1 are obtained. imide oligomers. The thermal decomposition temperature of the thermosetting polyimide precursor prepared by the invention is higher than 500°C, the melt viscosity is 0.3-0.6Pa·s, and the temperature range of the resin processing window is 80-160°C, which can meet the requirements of the RTM molding process. The design idea proposed by the invention can provide technical support for the mass production of polyimide resin composite materials for aerospace, and provides the possibility of further deepening the wide application of thermosetting polyimide in the field of aerospace.

Description

technical field [0001] The invention belongs to the technical field of thermosetting polyimide, and relates to a thermosetting polyimide precursor with low melt viscosity and suitable for RTM molding and a preparation method thereof, in particular to a molecular chain end group whose end group is an unsaturated carbon bond (carbon A method for preparing an imide oligomer with carbon double bond, carbon-carbon triple bond) and a molecular main chain consisting of a bisimide structure, low melt viscosity, and suitable for RTM molding. Background technique [0002] In the middle of the last century, with the rapid development of aerospace technology and the urgent demand for heat-resistant, high-strength and light-weight polymer materials in various industries, at this time, a class of main chains with aromatic rings and imide rings as the main structural units Polymer - polyimide came into being. According to whether the molecular chain structure is highly cross-linked, polyi...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D487/04C07D487/08C07D405/14C07D471/08
CPCC07D487/04C07D487/08C07D405/14C07D471/08
Inventor 雷星锋张秋禹薛书宇连如贺
Owner NORTHWESTERN POLYTECHNICAL UNIV
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