Method for preparing and curing hydroxyl-terminated liquid fluoropolymer

A curing method and technology of liquid fluorine, which is applied in the field of preparation and curing of hydroxyl-terminated liquid fluoropolymers, can solve the problems of affecting the service life of the product and prone to degradation, and achieve good mechanical properties, low cost, and simple and easy process Effect

Inactive Publication Date: 2014-08-13
BEIJING UNIV OF CHEM TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Carboxyl-terminated liquid fluoropolymers are prone to degradation

Method used

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  • Method for preparing and curing hydroxyl-terminated liquid fluoropolymer
  • Method for preparing and curing hydroxyl-terminated liquid fluoropolymer
  • Method for preparing and curing hydroxyl-terminated liquid fluoropolymer

Examples

Experimental program
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Effect test

Embodiment 1

[0018] With 5.02g carboxyl-terminated liquid fluoropolymer (vinylidene fluoride-hexafluoropropylene copolymer, the carboxyl mass percentage content is 1.16%, the number average molecular weight is 3058, and the weight average molecular weight is 3752, and the following examples are all of this material if there is no description. ) was dissolved in 50ml tetrahydrofuran, added to a 250ml there-necked flask, added sodium borohydride (0.0490g, 1.29mmol), stirred for 45 minutes, added iodine (0.1641g, 0.65mmol) in tetrahydrofuran (10ml), stirred at 70°C React for 2 hours. Add 10ml of hydrochloric acid to quench the reaction, the system will have a white precipitate, which is removed by filtration. After washing with a saturated aqueous solution of sodium sulfite, and then repeatedly washing with deionized water, the product was vacuum-dried at 70° C. to constant weight to obtain a white viscous liquid with a yield of 94%. The number average molecular weight of the product is 5155...

Embodiment 2

[0020] 10.07g of carboxyl-terminated liquid fluoropolymer (vinylidene fluoride-hexafluoropropylene copolymer, carboxyl mass percentage content is 1.16%, number average molecular weight is 3058, weight average molecular weight is 3752, and the following examples are all this material if there is no description. ) was dissolved in 150ml tetrahydrofuran, added to a 500ml there-necked flask, added sodium borohydride (0.1473g, 3.90mmol), stirred for 45 minutes, added iodine (0.3294g, 1.30mmol) in tetrahydrofuran (50ml), stirred at 50°C React for 5 hours. Add 30ml of hydrochloric acid to quench the reaction, the system will have a white precipitate, which is removed by filtration. After washing with a saturated aqueous solution of sodium sulfite, and then repeatedly washing with deionized water, the product was vacuum-dried at 70° C. to constant weight to obtain a white viscous liquid with a yield of 97%. The number average molecular weight of the product is 3948g / mol, the molecula...

Embodiment 3

[0022] 20.10g of carboxyl-terminated liquid fluoropolymer (vinylidene fluoride-hexafluoropropylene copolymer, carboxyl mass percentage content is 1.16%, number-average molecular weight is 3058, weight-average molecular weight is 3752, and the following examples are all this material if there is no description. ) was dissolved in 300ml tetrahydrofuran, added to a 1000ml there-necked flask, added sodium borohydride (0.3900g, 10.31mmol), stirred for 45 minutes, added iodine (0.6575g, 2.60mmol) in tetrahydrofuran (80ml), stirred at 25°C React for 12 hours. Add 50ml of hydrochloric acid to quench the reaction, the system will have a white precipitate, which is removed by filtration. After washing with a saturated aqueous solution of sodium sulfite, and then repeatedly washing with deionized water, the product was vacuum-dried at 70° C. to constant weight to obtain a white viscous liquid with a yield of 98%. The number average molecular weight of the product is 4876g / mol, the molec...

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Abstract

The invention discloses a method for preparing a hydroxyl-terminated liquid fluoropolymer. The hydroxyl-terminated liquid fluoropolymer is prepared from a carboxyl-terminated liquid fluoropolymer as a raw material in the presence of sodium borohydride/iodine and the like as reducing agents. The prepared hydroxyl-terminated liquid fluoropolymer has the characteristics of excellent heat resistance, oil resistance, mechanical performance and the like. The invention also discloses a method for curing the hydroxyl-terminated liquid fluoropolymer, and the hydroxyl-terminated liquid fluoropolymer is reacted with isocyanate and cured. The cured product has the characteristics of excellent heat resistance, solvent resistance, mechanical properties and the like. The hydroxyl-terminated liquid fluoropolymer can be prepared into a sealing agent, an adhesive, a coating and the like, and can be applied in harsh environments.

Description

technical field [0001] The invention relates to a preparation and curing method of a hydroxyl-terminated liquid fluoropolymer Background technique [0002] Traditional fluororubber basically appears in solid form, and is prepared into parts by molding or extrusion. Due to the limitation of mold size and shape, traditional solid fluororubber cannot meet all application requirements, and its processing performance is poor. Liquid fluoropolymer has excellent heat resistance, oxidation resistance and chemical resistance, and can be cured into any desired shape at a lower temperature as required, especially suitable for bonding, surface protection and porosity under harsh conditions It is an ideal sealing material, adhesive and coating for the aviation industry. [0003] For low molecular weight polymers, the end groups can significantly affect its properties, especially curing properties. Currently, the existing liquid fluoropolymers are mainly carboxyl-terminated liquid fluor...

Claims

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Application Information

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IPC IPC(8): C08F214/22C08F8/04C08G18/62
Inventor 齐士成吴佳佳李晓军李玉婵张孝阿齐僖
Owner BEIJING UNIV OF CHEM TECH
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