阅读说明：本技术 一种聚乙烯基硅硼氮烷及其制备方法 (Polyvinyl silaborazine and preparation method thereof ) 是由 王国辉 张兵 陈红波 付继伟 刘金峰 廖锡广 岳勇 赵继亮 于 2020-05-07 设计创作，主要内容包括：本发明涉及一种聚乙烯基硅硼氮烷及其制备方法,属于硅橡胶制造技术领域,也属于高温热防护技术领域。本发明相对于乙烯基硅橡胶,聚乙烯基硅硼氮烷的拉伸强度和撕裂强度分别提高了35％和47％,硅硼氮橡胶的抗老化性能提高了29％,高温防热性能,乙烯基硅橡胶辐照后背面温升为480℃,聚乙烯基硅硼氮烷辐照后背面温升为87℃,这说明本发明的聚乙烯基硅硼氮烷防热性能显著提高。(The invention relates to polyvinyl silaborazine and a preparation method thereof, belonging to the technical field of silicon rubber manufacture and the technical field of high-temperature thermal protection. Compared with vinyl silicone rubber, the tensile strength and the tear strength of the polyvinyl borosilazane are respectively improved by 35% and 47%, the ageing resistance of the silicon borosilazane is improved by 29%, the high-temperature heat-proof performance is achieved, the back surface temperature rise after the irradiation of the vinyl silicone rubber is 480 ℃, and the back surface temperature rise after the irradiation of the polyvinyl borosilazane is 87 ℃, which shows that the heat-proof performance of the polyvinyl borosilazane is obviously improved.)

1. A polyvinylsilaborazane, characterized by: the monomer structural formula of the polyvinylborazine is as follows:

2. a method for preparing polyvinyl silaborazane, characterized in that the method comprises the steps of:

step one, adding tetrahydrofuran and a metal sodium block into a reaction bottle, wherein the atmosphere in the reaction bottle is protected by nitrogen, the temperature of the reaction bottle is 0 ℃, then adding dimethyldivinylsilane into the reaction bottle, stirring, and then dropwise adding dimethylchloroethylborane under the condition of continuous nitrogen protection, wherein the molar ratio of the dimethyldivinylsilane to the dimethylchloroethylborane is 1: 1; the ratio of tetrahydrofuran to dimethyl chloroborane is 2-3L: 1 mol; the ratio of the metal sodium blocks to the tetrahydrofuran is 1-2 g: 100 ml;

step two, reducing the temperature of a reaction bottle to be 20 ℃ below zero to 30 ℃ below zero, then adding pentamethyl vinyl disilazane into the reaction bottle, and stirring to obtain a light yellow viscoelastic body; the molar ratio of dimethyl chloroethylborane to pentamethylvinyldisilazane is 1: 1;

thirdly, removing the metal sodium blocks, cleaning the faint yellow viscoelastic body by tetrahydrofuran, and filtering to obtain a filter cake of silazane;

and fourthly, mixing the silicon boron nitrogen alkane and the dibutyltin dilaurate catalyst, stirring and heating to obtain the polyvinyl silicon boron nitrogen alkane, wherein the polyvinyl silicon boron nitrogen alkane is the silicon boron nitrogen rubber, and the molar ratio of the dibutyltin dilaurate catalyst to the silicon boron nitrogen alkane is 0.01-0.1: 1; the heating temperature is 80-120 ℃.

3. The method of claim 2, wherein the method comprises the steps of: in the first step, the nitrogen is introduced at a speed of 1-10L/min.

4. The method of claim 2, wherein the method comprises the steps of: in the first step, the time for dripping the dimethyl chloroethylborane is 240-360 minutes.

5. The method of claim 2, wherein the method comprises the steps of: in the first step, the stirring speed is 120-200 r/min.

6. The method of claim 2, wherein the method comprises the steps of: in the second step, the dropping time of the pentamethyl vinyl disilazane is 500-700 minutes.

7. The method of claim 2, wherein the method comprises the steps of: in the second step, the stirring speed is 50-100 r/min.

8. The method of claim 2, wherein the method comprises the steps of: in the fourth step, the stirring speed is 80-100 revolutions per minute.

9. The method of claim 2, wherein the method comprises the steps of: in the fourth step, the stirring time is 5-10 minutes.

10. The method of claim 2, wherein the method comprises the steps of: in the fourth step, the heating time is 20-50 minutes.

Technical Field

The invention relates to polyvinyl silaborazine and a preparation method thereof, belonging to the technical field of silicon rubber manufacture and the technical field of high-temperature thermal protection.

Background

Since the advent of organosilane macromolecules, the organosilane macromolecules have the characteristics of high and low temperature resistance, ultraviolet resistance, irradiation resistance, good weather resistance, electrical insulation, moisture resistance and the like, and gradually become an irreplaceable novel material, and the organosilane macromolecules are widely applied to the fields of aviation, aerospace, electronics, textile, building and the like. Theoretically, it is confirmed that: the introduction of heteroatoms into silanes significantly improves the overall performance of silicone rubber and has been gaining increasing attention in recent years. Since they develop rapidly, either theoretically or practically, and are widely used. With the deepening of theoretical research, if boron atoms are introduced into the main chain of the silicon rubber, the heat resistance, the weather resistance, the mechanical property and other properties of the obtained silicon-boron rubber are obviously improved, in addition, the theory proves that the nitrogen atoms are introduced into the main chain of the silicon-boron rubber, the comprehensive properties of the silicon-boron rubber are further replaced, the introduction of the boron atoms and the nitrogen atoms can obviously improve the high-temperature resistance of the silicon rubber, and the application range of the silicon rubber is obviously expanded.

At present, there are few reports on silazanes and silaboranes, which are very complicated in preparation and expensive in preparation, and most importantly, there is no report on organic polymers containing silicon atoms, nitrogen atoms and boron atoms in the main chain, so-called silaborazane is generally reported to contain boron or nitrogen in the side chain, and the influence of the boron atom or nitrogen atom in the side chain on the overall performance of the polymer is weak.

In the present invention, a novel first-addition and second-condensation step method is adopted to prepare an organic compound containing silicon, boron and nitrogen atoms on the main chain under the condition of isolating air and water, and most importantly, vinyl groups are arranged at two ends of the organic compound, so that the organic compound can be easily polymerized into a high polymer, namely, the silicon-boron-nitrogen rubber.

The present invention provides a novel and simple method to synthesize organic compound containing silicon, boron and nitrogen atoms on the main chain, and two ends of the organic compound are vinyl groups, the silicon boron nitrogen alkane can be easily polymerized into silicon boron nitrogen rubber, and the mechanical properties, heat resistance and other properties of the silicon boron nitrogen rubber are tested.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the defects of the prior art are overcome, and the polyvinyl borazine and the preparation method thereof are provided.

The technical solution of the invention is as follows:

a polyvinylborazine having the following monomeric formula:

a method for preparing polyvinylsilazanes, the method comprising the steps of:

step one, adding tetrahydrofuran and a metal sodium block into a reaction bottle, wherein the atmosphere in the reaction bottle is protected by nitrogen, the temperature of the reaction bottle is 0 ℃, then adding dimethyldivinylsilane into the reaction bottle, stirring, and then dropwise adding dimethylchloroethylborane under the condition of continuous nitrogen protection, wherein the molar ratio of the dimethyldivinylsilane to the dimethylchloroethylborane is 1: 1; the nitrogen is introduced at a speed of 1-10L/min, the time for dripping the dimethyl chloroethyl borane is 240-360 minutes, and the stirring speed is 120-200 r/min; the ratio of tetrahydrofuran to dimethyl chloroborane is 2-3L: 1 mol; the ratio of the metal sodium blocks to the tetrahydrofuran is 1-2 g: 100 ml;

secondly, reducing the temperature of a reaction bottle to be-20 ℃ to-30 ℃, then adding pentamethyl vinyl disilazane into the reaction bottle, and stirring, wherein the dropwise adding time of the pentamethyl vinyl disilazane is 500-700 minutes, and the stirring speed is 50-100 revolutions per minute, so as to obtain a faint yellow viscoelastic body; the molar ratio of dimethyl chloroethylborane to pentamethylvinyldisilazane is 1: 1;

thirdly, after removing the metal sodium block, repeatedly dissolving and cleaning the faint yellow viscoelastic body by using tetrahydrofuran, and filtering to obtain a filter cake of silazane;

and fourthly, mixing, stirring and heating the silicon boron nitrogen alkane and the dibutyltin dilaurate catalyst to obtain the polyvinyl silicon boron nitrogen alkane, wherein the polyvinyl silicon boron nitrogen alkane is the silicon boron nitrogen rubber, the stirring speed is 80-100 r/min, the stirring time is 5-10 minutes, and the molar ratio of the dibutyltin dilaurate catalyst to the silicon boron nitrogen alkane is 0.01-0.1: 1; the heating temperature is 80-120 ℃, and the heating time is 20-50 minutes.

Mixing silaborazane and dibutyltin dilaurate catalyst, stirring, coating in a mold, putting in a baking oven to obtain a flexible rubber sheet with the thickness of 2mm, wherein the temperature of the baking oven is 80-120 ℃, and the heating time is 20-50 minutes;

testing the mechanical property, the ageing resistance and the high-temperature heat-proof property of the obtained flexible rubber sheet with the thickness of 2mm, wherein the testing of the mechanical property adopts the measurement of the tensile stress strain property of GB/T528-1998 vulcanized rubber or thermoplastic rubber, the testing of the ageing resistance adopts GB/T3512-2001 vulcanized rubber or thermoplastic rubber hot air accelerated ageing and heat-proof tests, and the testing of the high-temperature heat-proof property adopts 600kw/m²The heat flow of (2) mm thick rubber sheet was irradiated for 60s, and the temperature rise at the back of the rubber sheet was measured.

The reaction process is as follows:

wherein the structural formula of the divinyl dimethylsilane is as follows:

the structural formula of the dimethyl chloroethyl borane is as follows:

pentamethylvinyldisilazane:

advantageous effects

Compared with vinyl silicone rubber, the tensile strength and the tear strength of the polyvinyl borosilazane are respectively improved by 35% and 47%, the ageing resistance of the silicon borosilazane is improved by 29%, the high-temperature heat-proof performance is achieved, the back surface temperature rise after the irradiation of the vinyl silicone rubber is 480 ℃, and the back surface temperature rise after the irradiation of the polyvinyl borosilazane is 87 ℃, which shows that the heat-proof performance of the polyvinyl borosilazane is obviously improved.

Detailed Description

The invention is further illustrated by the following examples, without restricting its application to the examples given.