Asymmetric bismaleimide containing 1, 3, 4-oxadiazole structure and preparation method thereof

Abstract

The invention discloses a novel asymmetric bismaleimide containing a 1, 3, 4-oxadiazole structure and a preparation method thereof, and mainly solves the problem of fused process difficulty caused by large rigidity, high melting point and poor solubility property of the bismaleimide. Substituents R1 and R2 in the bismaleimide structure are -H and C1-C6 saturated fatty alkyl. Asymmetric aromatic diamine containing the 1, 3, 4-oxadiazole structure reacts with maleic anhydride to generate bismaleamic acid, and imide cyclization reaction is performed in the present of catalysts and dehydrating agents to obtain the bismaleimide. According to the bismaleimide, the structure is asymmetric, double bonds at two ends are in different chemical environments, and the reactivity and the curing temperature are different, so that curing is more stable; the 1, 3, 4-oxadiazole structure is introduced, cured products are provided with superior heat resistance and mechanical properties and suitable for being used as matrices of high-performance polymer matrix composites.

Description

technical field

[0001] The invention belongs to the technical field of polymer materials, and in particular relates to a class of asymmetric bismaleimide containing 1,3,4-oxadiazole structure and a preparation method thereof. Background technique

[0002] Bismaleimide is an important thermosetting resin with excellent properties such as easy processability, excellent chemical resistance, high strength, high modulus and high temperature resistance. However, the disadvantages of bismaleimide resin, such as insolubility in common solvents, high melting point and brittleness after curing, limit its application. There are many ways to improve the toughness of bismaleimide resins. Designing and synthesizing new bismaleimide monomers containing flexible chains and heterocyclic structures in the main chain is one of the effective methods to improve their performance.

[0003] Because the polymer containing the 1,3,4-oxadiazole structure has a high glass transition temperature, exce...

Examples

Embodiment 1

[0023] (A) Dissolve maleic anhydride (0.22mol) in 20ml of N,N-dimethylformamide and stir to dissolve. Dissolve 2-p-aminophenyl-5-(4-p-aminophenoxy)phenyl-1,3,4-oxadiazole (0.1 mol) in 50 ml N,N-dimethylformamide, Slowly drop into the reaction kettle, react at room temperature for 8 hours, after the reaction, pour the reaction solution into deionized water, precipitate a yellow solid, filter with suction, and dry the filter cake under vacuum to obtain 2-bismaleamic acid benzene Base-5-(4-bismaleamidophenoxy)phenyl-1,3,4-oxadiazole. The yield was 93.3%, the purity determined by HPLC was 99.6%, and the melting point was 208°C. FT-I R (KBr, cm -1 ): 3288, 1541 (-NH), 1720, 1631 (C=O).

[0024] (B) Add 2-p-bismaleamic acid phenyl-5-(4-p-bismaleamic acid phenoxy)phenyl-1,3,4-oxadiazole (0.05mol) to the reaction In the kettle, add 300ml of acetone, add 0.2g of sodium acetate, heat to 50°C, add dropwise 8ml of triethylamine and 20ml of acetic anhydride, and react at constant tempe...

Embodiment 2

[0026] (A) Dissolve maleic anhydride (0.24mol) in 30ml N,N-dimethylformamide and stir to dissolve. Dissolve 2-p-aminophenyl-5-(3-p-aminophenoxy)phenyl-1,3,4-oxadiazole (0.1 mol) in 40 ml N,N-dimethylformamide, Slowly add it dropwise into the reaction kettle, and react at room temperature for 10 hours. After the reaction, pour the reaction solution into deionized water to precipitate a yellow solid, filter it with suction, and dry the filter cake in vacuum to obtain 2-bismaleamic acid benzene Base-5-(3-bismaleamidophenoxy)phenyl-1,3,4-oxadiazole. The yield was 91.3%, the purity determined by HPLC was 99.0%, and the melting point was 184°C. FT-IR (KBr, cm -1 ): 3288, 1551 (-NH), 1719, 1626 (C=O).

[0027] (B) Add 2-p-bismaleamic acid phenyl-5-(3-p-bismaleamic acid phenoxy)phenyl-1,3,4-oxadiazole (0.05mol) In the reaction kettle, add 200ml of acetone, add 0.18g of cobalt acetate, heat to 60°C, add 10ml of triethylamine and 25ml of acetic anhydride dropwise, and react at const...

technical field

[0001] The invention belongs to the technical field of polymer materials, and in particular relates to a class of asymmetric bismaleimide containing 1,3,4-oxadiazole structure and a preparation method thereof. Background technique

[0002] Bismaleimide is an important thermosetting resin with excellent properties such as easy processability, excellent chemical resistance, high strength, high modulus and high temperature resistance. However, the disadvantages of bismaleimide resin, such as insolubility in common solvents, high melting point and brittleness after curing, limit its application. There are many ways to improve the toughness of bismaleimide resins. Designing and synthesizing new bismaleimide monomers containing flexible chains and heterocyclic structures in the main chain is one of the effective methods to improve their performance.

[0003] Because the polymer containing the 1,3,4-oxadiazole structure has a high glass transition temperature, exce...

Examples

Embodiment 1

[0023] (A) Dissolve maleic anhydride (0.22mol) in 20ml of N,N-dimethylformamide and stir to dissolve. Dissolve 2-p-aminophenyl-5-(4-p-aminophenoxy)phenyl-1,3,4-oxadiazole (0.1 mol) in 50 ml N,N-dimethylformamide, Slowly drop into the reaction kettle, react at room temperature for 8 hours, after the reaction, pour the reaction solution into deionized water, precipitate a yellow solid, filter with suction, and dry the filter cake under vacuum to obtain 2-bismaleamic acid benzene Base-5-(4-bismaleamidophenoxy)phenyl-1,3,4-oxadiazole. The yield was 93.3%, the purity determined by HPLC was 99.6%, and the melting point was 208°C. FT-I R (KBr, cm -1 ): 3288, 1541 (-NH), 1720, 1631 (C=O).

[0024] (B) Add 2-p-bismaleamic acid phenyl-5-(4-p-bismaleamic acid phenoxy)phenyl-1,3,4-oxadiazole (0.05mol) to the reaction In the kettle, add 300ml of acetone, add 0.2g of sodium acetate, heat to 50°C, add dropwise 8ml of triethylamine and 20ml of acetic anhydride, and react at constant tempe...

Embodiment 2

[0026] (A) Dissolve maleic anhydride (0.24mol) in 30ml N,N-dimethylformamide and stir to dissolve. Dissolve 2-p-aminophenyl-5-(3-p-aminophenoxy)phenyl-1,3,4-oxadiazole (0.1 mol) in 40 ml N,N-dimethylformamide, Slowly add it dropwise into the reaction kettle, and react at room temperature for 10 hours. After the reaction, pour the reaction solution into deionized water to precipitate a yellow solid, filter it with suction, and dry the filter cake in vacuum to obtain 2-bismaleamic acid benzene Base-5-(3-bismaleamidophenoxy)phenyl-1,3,4-oxadiazole. The yield was 91.3%, the purity determined by HPLC was 99.0%, and the melting point was 184°C. FT-IR (KBr, cm -1 ): 3288, 1551 (-NH), 1719, 1626 (C=O).

[0027] (B) Add 2-p-bismaleamic acid phenyl-5-(3-p-bismaleamic acid phenoxy)phenyl-1,3,4-oxadiazole (0.05mol) In the reaction kettle, add 200ml of acetone, add 0.18g of cobalt acetate, heat to 60°C, add 10ml of triethylamine and 25ml of acetic anhydride dropwise, and react at const...

Images