CN113956416A - Triazine ring-containing bio-based benzoxazine resin and preparation method thereof - Google Patents
Triazine ring-containing bio-based benzoxazine resin and preparation method thereof Download PDFInfo
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Abstract
The invention discloses a triazine ring-containing bio-based benzoxazine resin and a preparation method thereof. The preparation process of the triazine ring-containing bio-based benzoxazine resin comprises the following steps: (1) reacting melamine and formaldehyde solution at 50-70 ℃ for 0.5-1 h, adding a bio-based phenolic compound, performing reflux reaction at 80-90 ℃ for 5-8 h, cooling, separating, and performing organic phase vacuum distillation to obtain the triazine ring-containing bio-based benzoxazine. (2) Curing the triazine ring-containing bio-based benzoxazine monomer at 150-180 ℃ for 4-6 h, and then curing at 200-220 ℃ for 2-4 h to obtain the triazine ring-containing bio-based benzoxazine resin. The triazine ring-containing bio-based benzoxazine resin prepared by the invention has the advantages of low curing temperature, excellent heat resistance and flame retardance, and can be applied to the fields of adhesives, composite materials, coatings and the like.
Description
Technical Field
The invention relates to a preparation method of benzoxazine resin, in particular to triazine ring-containing biomass-based benzoxazine resin and a preparation method thereof.
Background
Benzoxazine is a compound with an oxygen-containing nitrogen heterocyclic structure synthesized by taking phenols, amine compounds and paraformaldehyde as raw materials, and is subjected to ring-opening polymerization under the action of heating or a catalyst to generate a network structure polymer which contains nitrogen and is similar to phenolic resin, so that the polymer is called as polybenzoxazine or benzoxazine resin. Benzoxazine resin has excellent mechanical property, thermal stability, corrosion resistance, electrical insulation and other characteristics, so that the benzoxazine resin is greatly concerned by domestic and foreign scholars and enterprise personnel. Currently, benzoxazine resins have been widely used in the fields of aerospace, automobile parts, resin transfer molding, electronic packaging, and the like.
Although the N atom and the benzene ring in the molecular structure of the benzoxazine resin endow the benzoxazine resin with certain flame retardant property, the benzoxazine resin still does not meet the high flame retardant requirement of special application occasions such as electronic devices, aerospace and the like. How to connect the innovative flame retardant technology to the benzoxazine industry to promote the development of the benzoxazine in the high-end material industry is also an important lesson to be urgently needed to be overcome. The melamine is a triazine nitrogen-containing heterocyclic ring organic compound, has the characteristics of no toxicity, heat resistance, flame retardance, good insulativity and the like, and is widely applied to the fields of coatings, composite materials, synthetic resins and the like. Research shows that the introduction of a melamine structure into a synthetic resin structure can significantly improve the flame retardant effect of the resin, and the melamine structure has low smoke, no corrosion, low toxicity and low price during combustion, so that the melamine structure can be widely applied to the flame retardant field of the synthetic resin. Therefore, if the melamine is introduced into a benzoxazine resin system, the flame retardant effect can be improved to different degrees, the flame retardant property of the benzoxazine resin is improved while the advantages of the benzoxazine resin are highlighted, and the application field is widened.
Traditional benzoxazine resins mainly come from petroleum resources, but fossil raw materials are not renewable and have influence on the environment, and the development of bio-based benzoxazine resins is more and more emphasized. The patent (CN201911321743.8) prepares a full-bio-based benzoxazine resin by using phloroglucinol, furfuryl amine and paraformaldehyde, and the curing temperature of the full-bio-based benzoxazine resin is low and the heat resistance of the full-bio-based benzoxazine resin is excellent. The patent (CN202011218791.7) discloses a bio-based benzoxazine resin containing a furan amide structure and a preparation method thereof, biomass such as furoic acid and derivatives thereof is used as raw materials, a condensation reaction is adopted to introduce an amide bond of a furan group into a phenol source structure of the benzoxazine resin, and then the condensation reaction is carried out with primary amine compounds such as furanmethanamine and the like which are mono-or poly-element through Mannich reaction to prepare the semi-bio-based or full bio-based benzoxazine resin containing the furan amide structure.
In view of some defects of the existing benzoxazine materials, the invention takes a series of biological phenols as phenol sources, thereby not only reducing the pollution to the environment from raw materials, but also synthesizing the triazine ring-containing benzoxazine monomer through in-situ polymerization, and the polybenzoxazine resin formed by the monomer polymerization has lower curing temperature, excellent thermal stability and flame retardance. The invention has simple synthesis process, good resin processability and lower production cost, and can be produced in large scale.
Disclosure of Invention
The invention aims to provide a triazine ring-containing biomass-based benzoxazine resin and a preparation method thereof. The invention synthesizes the triazine ring-containing biomass-based benzoxazine resin by Mannich reaction with melamine as an amine source and a biomass phenolic compound as a phenol source. The triazine ring-containing bio-based benzoxazine resin prepared by the invention has the advantages of low curing temperature, excellent heat resistance and flame retardance, and can be applied to the fields of adhesives, composite materials, coatings and the like.
The technical scheme of the invention is as follows: a triazine ring-containing bio-based benzoxazine resin has the chemical structural formula:
wherein the chemical structure of Ph-R is any one or more of the following structures:
prepared by thermal polymerization of the following triazine ring-containing bio-based benzoxazine monomers:
wherein the chemical structure of Ph-R is any one or more of the following structures:
the preparation method comprises the following specific steps: reacting the triazine ring-containing bio-based benzoxazine monomer at 150-180 ℃ for 4-6 h, and then reacting at 200-220 ℃ for 2-4 h to obtain the triazine ring-containing bio-based benzoxazine resin.
The preparation method of the triazine ring-containing bio-based benzoxazine monomer comprises the following specific steps: reacting melamine with a formaldehyde solution at 50-70 ℃ for 0.5-1 h until the reaction system becomes a clear liquid; adding a natural phenolic compound, and reacting for 5-8 h at 80-90 ℃; cooling to room temperature after the reaction is finished; and carrying out reduced pressure distillation on the organic phase to obtain the benzoxazine monomer containing triazine ring, wherein the specific synthetic route is as follows:
wherein the chemical structure of Ph-R is one or more of the following structures:
the natural phenolic compound is any one or more of eugenol, isoeugenol, guaiacol, syringol, cardanol, vanillin, ferulic acid, p-hydroxy cinnamic acid, phloroglucinol and piperitol or derivatives thereof, and the dosage of the natural phenolic compound is 2.0-3.0 times of that of the melamine substance.
Advantageous effects
1. According to the invention, the melamine structure is introduced into the benzoxazine resin structure, so that the flame retardant property of the benzoxazine resin is improved while the advantages of the benzoxazine resin are maintained, and the application range of the benzoxazine resin is expanded. The prepared triazine ring-containing bio-based benzoxazine resin has the advantages of low curing temperature, excellent thermal stability and flame retardant property.
2. The preparation process is simple and convenient, has mild reaction conditions, and is suitable for large-scale production.
Drawings
FIG. 1 shows the triazine ring-containing eugenol benzoxazine monomer prepared in example 11H NMR and13c NMR spectrum chart.
FIG. 2 shows the triazine ring guaiacol benzoxazine monomer-containing compound prepared in example 21H NMR and13c NMR spectrum chart.
FIG. 3 is a dynamic temperature-rising viscosity curve of the triazine ring-containing guaiacol benzoxazine monomer prepared in example 2.
FIG. 4 is a thermogravimetric plot of the triazine ring-containing guaiacol benzoxazine resin prepared in example 2.
Detailed Description
A preparation method of triazine ring-containing bio-based benzoxazine resin,
(1) reacting melamine with formaldehyde solution at 50-70 ℃ for 0.5-1 h until the reaction system becomes clear liquid, adding natural phenolic compounds, continuing to react at 80-90 ℃ for 5-8 h, cooling to room temperature after the reaction is finished, and distilling the organic phase under reduced pressure to obtain the triazine ring-containing bio-based benzoxazine monomer. The specific synthetic route is as follows:
wherein the structure of Ph-R is one of the following structures:
(2) the triazine ring-containing bio-based benzoxazine monomer is pre-cured for 4-6 hours at the temperature of 150-180 ℃, and then is post-cured for 2-4 hours at the temperature of 200-220 ℃, so that the triazine ring-containing bio-based benzoxazine resin is obtained. The molecular structure is as follows:
wherein the structure of Ph-R is one of the following structures:
the phenolic compound comprises any one of natural phenolic compounds or derivatives thereof, such as but not limited to eugenol, isoeugenol, guaiacol, cardanol, vanillin, ferulic acid, phloroglucinic acid, p-hydroxy cinnamic acid, piperitol and the like, and the dosage of the phenolic compound is 2.0-3.0 times of that of the melamine substance.
Example 1
(1) Adding 12.60g of melamine and 48.60g of formaldehyde solution into a 500mL four-neck round-bottom flask with a stirrer, a thermometer and a reflux condenser, heating to 60 ℃ under stirring, reacting for 0.5h, and allowing the reaction system to become a clear liquid; adding 49.26g of eugenol and 50ml of ethanol, carrying out reflux reaction for 6h, carrying out vacuum distillation on the organic phase to 80 ℃ to obtain the eugenol benzoxazine monomer containing triazine ring, wherein the yield is 82.61%.
(2) Heating the triazinyl eugenol benzoxazine monomer prepared in the step (1) from room temperature to 150 ℃ by adopting a step heating mode, and then preserving heat for 2h at 150 ℃, 180 ℃, 200 ℃ and 220 ℃ respectively to cure the triazinyl eugenol benzoxazine monomer to obtain the triazinyl eugenol benzoxazine resin with the oxygen index of 26.0 percent.
Example 2
(1) Adding 12.60g of melamine and 49.20g of formaldehyde solution into a 500mL four-neck round-bottom flask with a stirrer, a thermometer and a reflux condenser, heating to 60 ℃ under stirring, reacting for 0.5h, and allowing the reaction system to become a clear liquid; then adding 37.20g of guaiacol and 50ml of ethanol, heating to a reflux state, reacting for 6 hours, after the reaction is finished, carrying out vacuum distillation on the organic phase to 80 ℃ to obtain the triazine ring-containing guaiacol benzoxazine monomer, wherein the yield is 85.96%.
(2) Heating the triazine ring guaiacol benzoxazine monomer prepared in the step (1) from room temperature to 150 ℃ by adopting a step heating mode, and then preserving heat for 2 hours at 150 ℃, 180 ℃, 200 ℃ and 220 ℃ respectively to cure the monomer so as to obtain the triazine ring guaiacol benzoxazine resin with the oxygen index of 27.5%.
Example 3
(1) Adding 12.60g of melamine and 48.60g of formaldehyde solution into a 500mL four-neck round-bottom flask with a stirrer, a thermometer and a reflux condenser, heating to 60 ℃ under stirring, reacting for 0.5h, and allowing the reaction system to become a clear liquid; adding 49.26g of isoeugenol and 40ml of ethanol, heating to a reflux state, reacting for 6 hours, and after the reaction is finished, carrying out vacuum distillation on the organic phase to 80 ℃ to obtain the benzoxazine monomer containing the triazine ring isoeugenol, wherein the yield is 80.6%.
(2) Heating the triazine ring-containing isoeugenol benzoxazine monomer prepared in the step (1) from room temperature to 150 ℃ by adopting a step heating mode, and then preserving heat for 2 hours at 150 ℃, 170 ℃, 200 ℃ and 220 ℃ respectively to cure the monomer so as to obtain the triazine ring-containing isoeugenol benzoxazine resin, wherein the oxygen index of the resin is 26.0%.
Example 4
(1) Adding 12.60g of melamine and 50.30g of formaldehyde solution into a 500mL four-neck round-bottom flask with a stirrer, a thermometer and a reflux condenser, heating to 60 ℃ under stirring, reacting for 0.5h, and allowing the reaction system to become a clear liquid; adding 58.20g of ferulic acid and 50ml of ethanol, heating to a reflux state for reaction for 6h, and after the reaction is finished, carrying out vacuum distillation on the organic phase to 80 ℃ to obtain the benzoxazine monomer containing triazine ring ferulic acid, wherein the yield is 86.5%.
(2) Heating the triazine ring ferulic acid-containing benzoxazine monomer prepared in the step (1) from room temperature to 150 ℃ by adopting a step heating mode, and then preserving heat for 2h at 150 ℃, 180 ℃, 200 ℃ and 220 ℃ respectively to cure to obtain the triazine ring ferulic acid-containing benzoxazine resin, wherein the oxygen index of the triazine ring ferulic acid-containing benzoxazine resin is 25.5%.
Example 5
(1) Adding 12.60g of melamine and 48.60g of formaldehyde solution into a 500mL four-neck round-bottom flask with a stirrer, a thermometer and a reflux condenser, heating to 50 ℃ under stirring, reacting for 0.6h, and allowing the reaction system to become a clear liquid; adding 49.80g of phlorizin acid and 50ml of ethanol, heating to a reflux state, reacting for 6 hours, and after the reaction is finished, carrying out vacuum distillation on the organic phase to 80 ℃ to obtain the benzoxazine monomer containing the triazine ring phlorizin acid, wherein the yield is 82.56%.
(2) Heating the triazine ring phlorizin acid-containing benzoxazine monomer prepared in the step (1) from room temperature to 150 ℃ by adopting a step heating mode, and then preserving heat for 2h at 150 ℃, 180 ℃, 200 ℃ and 220 ℃ respectively to cure the monomer so as to obtain the triazine ring phlorizin acid-containing benzoxazine resin, wherein the oxygen index of the resin is 25.9%.
Example 6
(1) Adding 12.60g of melamine and 48.60g of formaldehyde solution into a 500mL four-neck round-bottom flask with a stirrer, a thermometer and a reflux condenser, heating to 60 ℃ under stirring, reacting for 0.5h, and allowing the reaction system to become a clear liquid; then adding 90.00g of cardanol and 50ml of ethanol, heating to a reflux state, reacting for 6 hours, after the reaction is finished, carrying out vacuum distillation on the organic phase to 80 ℃ to obtain the triazine ring-containing cardanol benzoxazine monomer, wherein the yield is 81.25%.
(2) Heating the triazine ring-containing cardanol benzoxazine monomer prepared in the step (1) from room temperature to 150 ℃, and then preserving heat for 2h at 150 ℃, 170 ℃, 200 ℃ and 220 ℃ respectively to cure the monomer to obtain the triazine ring-containing cardanol benzoxazine resin with an oxygen index of 24.0%.
Example 7
(1) Adding 12.60g of melamine and 48.60g of formaldehyde solution into a 500mL four-neck round-bottom flask with a stirrer, a thermometer and a reflux condenser, heating to 60 ℃ under stirring, reacting for 0.5h, and allowing the reaction system to become a clear liquid; adding 49.28g of piperonyl alcohol and 50ml of ethanol, heating to a reflux state, reacting for 6h, after the reaction is finished, carrying out vacuum distillation on the organic phase to 80 ℃ to obtain the benzoxazine monomer containing the triazine ring pepper, wherein the yield is 83.83%.
(2) Heating the triazine ring-containing pepper benzoxazine monomer prepared in the step (1) from room temperature to 150 ℃ by adopting a step heating mode, and then respectively preserving heat for 2h at 150 ℃, 180 ℃, 200 ℃ and 220 ℃ to cure the monomer to obtain the triazine ring-containing pepper benzoxazine resin, wherein the oxygen index of the resin is 27.0%.
Example 8
(1) Adding 12.60g of melamine and 48.60g of formaldehyde solution into a 500mL four-neck round-bottom flask with a stirrer, a thermometer and a reflux condenser, heating to 60 ℃ under stirring, reacting for 0.5h, and allowing the reaction system to become a clear liquid; then adding 32.84g of eugenol and 50ml of ethanol, heating to a reflux state for reaction for 6 hours, after the reaction is finished, carrying out vacuum distillation on the organic phase to 80 ℃ to obtain the eugenol benzoxazine monomer containing triazine ring, wherein the yield is 79.59%.
(2) Heating the triazine ring eugenol benzoxazine monomer prepared in the step (1) from room temperature to 140 ℃ by adopting a step heating mode, and then preserving heat for 2h at 150 ℃, 170 ℃, 200 ℃ and 220 ℃ respectively to cure the monomer so as to obtain the triazine ring eugenol benzoxazine-containing resin, wherein the oxygen index of the resin is 28.1%.
While the preferred embodiments of the present invention have been described in detail, it will be understood by those skilled in the art that the invention is not limited thereto, and that various changes and modifications may be made without departing from the spirit of the invention, and the scope of the appended claims is to be accorded the full range of equivalents.
Claims (5)
1. The triazine ring-containing bio-based benzoxazine resin is characterized in that the chemical structural formula is as follows:
wherein the chemical structure of Ph-R is any one or more of the following structures:
2. the preparation method of the triazine ring-containing bio-based benzoxazine resin according to claim 1, wherein the triazine ring-containing bio-based benzoxazine resin is prepared by thermal polymerization of the following triazine ring-containing bio-based benzoxazine monomers:
wherein the chemical structure of Ph-R is any one or more of the following structures:
3. the preparation method of the triazine ring-containing bio-based benzoxazine resin according to claim 2, which comprises the following specific preparation steps: reacting the triazine ring-containing bio-based benzoxazine monomer at 150-180 ℃ for 4-6 h, and then reacting at 200-220 ℃ for 2-4 h to obtain the triazine ring-containing bio-based benzoxazine resin.
4. The method for preparing the triazine ring-containing bio-based benzoxazine resin according to claim 2, wherein the specific preparation steps of the triazine ring-containing bio-based benzoxazine monomer are as follows: reacting melamine with a formaldehyde solution at 50-70 ℃ for 0.5-1 h until the reaction system becomes a clear liquid; adding a natural phenolic compound, and reacting for 5-8 h at 80-90 ℃; after the reaction is finished, carrying out reduced pressure distillation on an organic phase to obtain the triazine ring-containing benzoxazine monomer, wherein the specific synthetic route is as follows:
wherein the chemical structure of Ph-R is one or more of the following structures:
5. the method for preparing the triazine ring-containing bio-based benzoxazine resin according to claim 4, wherein the natural phenolic compound is any one or more of eugenol, isoeugenol, guaiacol, syringol, cardanol, vanillin, ferulic acid, p-hydroxycinnamic acid, phloroglucinol and piperitol or derivatives thereof, and the amount of the natural phenolic compound is 2.0-3.0 times of the amount of the melamine substance.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN115521427A (en) * | 2022-10-14 | 2022-12-27 | 四川金象赛瑞化工股份有限公司 | Preparation method of benzoxazine resin containing Schiff base structure based on melamine |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN115521427A (en) * | 2022-10-14 | 2022-12-27 | 四川金象赛瑞化工股份有限公司 | Preparation method of benzoxazine resin containing Schiff base structure based on melamine |
| CN115521427B (en) * | 2022-10-14 | 2024-02-06 | 四川金象赛瑞化工股份有限公司 | Preparation method of melamine-based benzoxazine resin containing Schiff base structure |
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