阅读说明：本技术 一种环磷腈基聚亚胺vitrimer的制备方法及其用于制备环氧树脂和聚氨酯材料 (Preparation method of cyclophosphazenil polyimine vitrimer and application of cyclophosphazenil polyimine vitrimer in preparation of epoxy resin and polyurethane material ) 是由 吴战鹏 张新芳 刘伟 张双琨 马翰林 林红吉 于 2021-08-02 设计创作，主要内容包括：一种环磷腈基聚亚胺vitrimer的制备方法及其用于制备环氧树脂和聚氨酯材料,属于vitrimer制备领域。包括：(1)制备含醛基的醇/酚的钠盐Ⅰ和不含醛基的醇/酚的钠盐Ⅱ。(2)将钠盐Ⅱ和钠盐Ⅰ分步与六氯环三磷腈反应,制备得到CP-3A。(3)将CP-3A、二醛基化合物、二氨基化合物进行醛基和氨基的缩合反应,制备得到环磷腈基聚亚胺vitrimer。(4)将CP-3A和氨基醇/酚反应,制备得到CP-3OH。(5)CP-3OH与环氧树脂或二异氰酸酯固化,制备得到环氧树脂或聚氨酯vitrimer。本发明的vitrimer,在循环利用后仍能保持较高的力学性能和循环效率,拥有优异的热稳定性和阻燃性能。(A preparation method of cyclophosphazenitrile polyimine vitrimer and application of the same in preparing epoxy resin and polyurethane materials belong to the field of vitrimer preparation. The method comprises the following steps: (1) preparing sodium salt I of alcohol/phenol containing aldehyde group and sodium salt II of alcohol/phenol containing no aldehyde group. (2) And (3) reacting the sodium salt II and the sodium salt I with hexachlorocyclotriphosphazene step by step to obtain the CP-3A. (3) And (3) carrying out condensation reaction of aldehyde group and amino group on the CP-3A, the dialdehyde compound and the diamino compound to prepare the cyclophosphazene based polyimine vitrimer. (4) CP-3OH is prepared by reacting CP-3A with amino alcohol/phenol. (5) And solidifying the CP-3OH and epoxy resin or diisocyanate to prepare the epoxy resin or polyurethane vitrimer. The vitrimer disclosed by the invention can still keep higher mechanical property and cycle efficiency after being recycled, and has excellent thermal stability and flame retardant property.)

1. A preparation method of cyclophosphazenitrile polyimine vitrimer is characterized by comprising the following specific steps:

(1) dropwise adding 1-2 molar equivalents of hydroxyl-containing aldehyde compound containing solvent into 1 molar equivalent of Na/NaH containing solvent to obtain sodium salt I; in the same way, preparing the sodium salt II of the alcohol/phenol without aldehyde group;

(2) adding 3 molar equivalents of the solution of the sodium salt II into 1 molar equivalent of a solution of Hexachlorocyclotriphosphazene (HCCP) containing a solvent, and reacting at room temperature for 1-120 hours; then, 3 to 12 molar equivalents of the above sodium salt I containing a solvent is added thereto, and the reaction is further carried out at 40 to 70 ℃ for 1 to 120 hours. Finally washing the product for several times by using deionized water and ethanol to obtain the cyclic phosphazene derivative containing aldehyde groups and no aldehyde groups, which is abbreviated as CP-3A;

(3) CP-3A, a dialdehyde compound and a diamino compound are added according to the ratio of total aldehyde groups to total amino groups 1: dissolving the materials into a solvent according to the proportion of 1 molar equivalent, uniformly mixing, volatilizing the solvent, and finally performing hot-pressing solidification to obtain the cyclic phosphazene based polyimine vitrimer; the hot pressing temperature is 30-250 ℃, the hot pressing pressure is 0-50MPa, and the hot pressing time is within 150 hours.

2. The method for preparing a cyclophosphazenil polyimine vitrimer according to claim 1, wherein the aldehyde compound containing hydroxyl groups is one or a combination of several of the following substances: p-hydroxybenzaldehyde, m-hydroxybenzaldehyde, p-hydroxybenzaldehyde, vanillin, ethyl vanillin, 4-hydroxy-3-methylbenzaldehyde, 3-hydroxy-4-fluorobenzaldehyde, 4 '-hydroxy (1, 1' -biphenyl) -4-formaldehyde;

the alcohol/phenol without aldehyde group is one or a combination of several of the following substances: phenol, p-ethylphenol, m-ethylphenol, 4-fluorophenol, naphthol, ethanol, propanol, butanol, trifluoroethanol, octafluoropentanol;

the dialdehyde compound is one or more of the following substances (optionally not added): terephthalaldehyde, bis (4-formylphenyl) ether, biphenyldicarboxaldehyde, anthracene-9, 10-dicarboxaldehyde.

3. The method of claim 1, wherein the diamino compound is one or a combination of the following: ethylenediamine, hexamethylenediamine, 1, 4-cyclohexanediamine, p-phenylenediamine, m-xylylenediamine, benzidine, 4,4' -diaminodiphenylmethane, 2, 2-bis (4-aminophenyl) propane, 4,4' -diaminodiphenyl ether, 4,4' -diaminodiphenyl sulfone.

4. A preparation method of epoxy resin or polyurethane vitrrime is characterized by comprising the following steps:

(A) the method comprises the following steps CP-3A and amino alcohol/phenol react in a solvent, the molar amount of amino is not less than that of aldehyde group in CP-3A, and finally CP-3OH is obtained by precipitation in petroleum ether or n-heptane or n-hexane; the reaction time is not more than 36 hours, and the reaction temperature is within 100 ℃;

(B) the method comprises the following steps And (2) carrying out curing reaction with epoxy resin or diisocyanate to prepare the flame-retardant recyclable epoxy resin or polyurethane vitrimer, wherein the curing reaction temperature is not more than 250 ℃, the total curing reaction time is not more than 48 hours, and the molar ratio of hydroxyl in CP-3OH to epoxy groups in the epoxy resin or isocyanate in the diisocyanate is 1: 1, carrying out proportioning reaction.

5. The method of claim 4, wherein the amino alcohol/phenol is one or a combination of: p-aminophenol, m-aminophenol, o-aminophenol, 4-hydroxyphenylethylamine, ethanolamine, isopropanolamine, 3-aminopropanol, 2-amino-1-butanol, 1-amino-2-methyl-2-propanol, 2-amino-2-methyl-1-propanol;

6. the method of claim 4, wherein the epoxy resin is selected from the group consisting of: epoxy resin E42, epoxy resin E44, epoxy resin E51, triglycidyl meta-aminophenol, N, N, N, N, -tetracyclooxypropyl-4, 4-diaminodiphenylmethane, 1, 4-butanediol diglycidyl ether, EP-12, EP-13, EP-16 and EP-20;

the diisocyanate used is one or a combination of several of the following: p-phenylene diisocyanate, toluene 2, 6-diisocyanate, 1, 3-phenylene diisocyanate, toluene 2, 4-diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, 1, 5-diisocyanatonaphthalene, m-xylylene diisocyanate, 4,4' -methylenebis (phenylisocyanate), 4, 4-diisocyanate dicyclohexylmethane, 3,3' -dichloro-4, 4' -diisocyanate biphenyl.

7. The method of claim 1 or 4, wherein the solvent is one of the following: dichloromethane, trichloromethane, chlorobenzene, dichlorobenzene, tetrahydrofuran, acetone, 1-4-dioxane, dimethylformamide, ethanol, petroleum ether, n-heptane, n-hexane and/or dimethyl sulfoxide.

8. Covalently cross-linked polymers obtainable by the process for the preparation of a vitrrime according to any one of claims 1 to 7.

9. Method for recycling of covalently cross-linked polymers obtained by the process for the preparation of vitrrimes according to any one of claims 1 to 7, characterized in that all the fragments or powders of vitrrimers are recycled by obtaining a second sample of the recycle under a pressure of 0 to 50MPa, at a temperature of 30 to 250 ℃ and with a hot pressing time of 150 hours.

Technical Field

The invention belongs to the field of preparation of polyimine type vitrimmers, and particularly relates to a preparation method for constructing a vitrimmer by covalently connecting imine bonds of an aldehyde-containing cyclic phosphazene derivative (CP-3A) and a dialdehyde compound and a diamino compound, and application of the method to preparation of epoxy resin and polyurethane materials. The finally obtained material has high mechanical property, high cycle efficiency, high glass transition temperature, excellent thermal stability and flame retardant property.

Background

Thermosetting resins are widely used in various fields such as printed circuit boards, aerospace composites, automobile parts, electric appliances, and the like, due to excellent three-dimensional stability and mechanical strength. Due to the permanent cross-linking of the covalent bonds of thermosetting resins, such resins often cannot be used further when subjected to aging, damage or service life, and disposal of waste materials becomes a troublesome problem. At present, thermosetting resins are almost treated by in-situ burial or incineration, which causes great resource waste and serious environmental pollution. Finding a way to recycle thermosetting resins has become a priority for countless scientists.

The reversible or exchangeable covalent bond is introduced into the cross-linked polymer structure, so that the material can be recycled through the exchange reaction between chemical bonds. Virimer is a covalent cross-linked polymer, has the advantages of stable cross-linking density, three-dimensional stable structure, solvent resistance and the like of the traditional thermosetting resin, and can be repeatedly processed and recycled like thermoplastic resin. The cross-linked network recombination can be realized by the exchange reaction between covalent bonds of the vitrimer, so that the material can be repeatedly processed and utilized.

The polyimine-type vitrimmers are widely used for recycling materials because they can recombine cross-linked structures only by condensation reaction between amino and aldehyde groups and amino exchange reaction without the need of catalysts or other additional stimuli. However, most polyimine vitrimers are not sufficiently thermally stable and also present a potential flammability risk, which greatly limits their use. The phosphazene compound has excellent thermal stability and flame retardant property, so that the phosphazene compound is widely applied to the field of flame retardance. Therefore, it is expected that the preparation of a phosphazene-based polyimine-type vitrimer will solve the above-mentioned problems. On the basis, a cyclic phosphazene compound containing imine bond reversible bonds and hydroxyl at the end group is prepared, and the cyclic phosphazene compound is reacted with epoxy resin and diisocyanate to prepare epoxy resin and polyurethane vitrimer, so that the cyclic phosphazene compound can be conveniently applied to the repeated utilization of the epoxy resin and the polyurethane, and the problem of flame retardance of the cyclic phosphazene compound is solved.

Disclosure of Invention

The invention aims to provide a preparation method of a polyimine vitrimer material with excellent thermal stability and flame retardant property, and the polyimine vitrimer material is applied to preparation of recyclable flame retardant epoxy resin and polyurethane materials. The introduction of the cyclic phosphazene base prepolymer solves the problems of poor thermal stability and combustibility of the polyimine type vitrimer. In order to prevent the defects that the crosslinking degree is too high and the subsequent vitrimer is not easy to recycle and the mechanical property is poor due to too low crosslinking degree, the invention firstly designs the cyclophosphazene derivative containing three aldehyde groups, then adjusts the functionality degree by optimizing the proportion of the derivative and a dialdehyde compound, and carries out condensation reaction with a diamino compound to finally prepare the cyclophosphazene polyimine vitrimer. On the basis, amino alcohol/phenol is reacted with CP-3A to prepare another kind of cyclic phosphazene compound CP-3OH containing imine reversible bonds and blocked by hydroxyl, and the cyclic phosphazene compound CP-3OH is reacted with epoxy resin and diisocyanate to prepare the flame-retardant recyclable epoxy resin and polyurethane material.

A preparation method of cyclophosphazenitrile polyimine vitrimer is characterized by comprising the following specific steps:

(1) dropwise adding 1-2 molar equivalents of hydroxyl-containing aldehyde compound containing solvent into 1 molar equivalent of Na/NaH containing solvent to obtain sodium salt I; in the same way, preparing the sodium salt II of the alcohol/phenol without aldehyde group;

(2) adding 3 molar equivalents of the solution of the sodium salt II into 1 molar equivalent of a solution of Hexachlorocyclotriphosphazene (HCCP) containing a solvent, and reacting at room temperature for 1-120 hours; then, 3 to 12 molar equivalents of the above sodium salt I containing a solvent is added thereto, and the reaction is further carried out at 40 to 70 ℃ for 1 to 120 hours. Finally washing the product for several times by using deionized water and ethanol to obtain the cyclic phosphazene derivative containing aldehyde groups and no aldehyde groups, which is abbreviated as CP-3A;

(3) CP-3A, a dialdehyde compound and a diamino compound are added according to the ratio of total aldehyde groups to total amino groups 1: dissolving the materials into a solvent according to the proportion of 1 molar equivalent, uniformly mixing, volatilizing the solvent, and finally performing hot-pressing solidification to obtain the cyclic phosphazene based polyimine vitrimer; the hot pressing temperature is 30-250 ℃, the hot pressing pressure is 0-50MPa, and the hot pressing time is within 150 hours.

The relation between the amounts of CP-3A and the dialdehyde compound in the step (3) is not limited and can be adjusted as required.

A preparation method of epoxy resin or polyurethane vitrimer is characterized by comprising the following steps:

(A) the method comprises the following steps CP-3A and amino alcohol/phenol react in a solvent, the molar amount of amino is not less than that of aldehyde group in CP-3A, and finally CP-3OH is obtained by precipitation in petroleum ether or n-heptane or n-hexane; the reaction time is not more than 36 hours, and the reaction temperature is within 100 ℃;

(B) the method comprises the following steps And (2) carrying out curing reaction with epoxy resin or diisocyanate to prepare the flame-retardant recyclable epoxy resin or polyurethane vitrimer, wherein the curing reaction temperature is not more than 250 ℃, the total curing reaction time is not more than 48 hours, and the molar ratio of hydroxyl in CP-3OH to epoxy groups in the epoxy resin or isocyanate in the diisocyanate is 1: 1, carrying out proportioning reaction.

And cutting all vitrimers into pieces or grinding into powder, and hot-pressing under the pressure of 0-50MPa and at the temperature of 30-250 ℃ for 150 hours to obtain a secondary circulating sample for recycling.

The aldehyde compound containing hydroxyl is one or a combination of several of the following substances: p-hydroxybenzaldehyde, m-hydroxybenzaldehyde, p-hydroxybenzaldehyde, vanillin, ethyl vanillin, 4-hydroxy-3-methylbenzaldehyde, 3-hydroxy-4-fluorobenzaldehyde, 4 '-hydroxy (1, 1' -biphenyl) -4-formaldehyde.

The alcohol/phenol without aldehyde group is one or a combination of several of the following substances: phenol, p-ethylphenol, m-ethylphenol, 4-fluorophenol, naphthol, ethanol, propanol, butanol, trifluoroethanol, octafluoropentanol.

The dialdehyde compound is one or more of the following substances (optionally not added): terephthalaldehyde, bis (4-formylphenyl) ether, biphenyldicarboxaldehyde, anthracene-9, 10-dicarboxaldehyde.

The diamino compound is one or a combination of the following substances: ethylenediamine, hexamethylenediamine, 1, 4-cyclohexanediamine, p-phenylenediamine, m-xylylenediamine, benzidine, 4,4' -diaminodiphenylmethane, 2, 2-bis (4-aminophenyl) propane, 4,4' -diaminodiphenyl ether, 4,4' -diaminodiphenyl sulfone.

The amino alcohol/phenol is one or a combination of more of the following: p-aminophenol, m-aminophenol, o-aminophenol, 4-hydroxyphenylethylamine, ethanolamine, isopropanolamine, 3-aminopropanol, 2-amino-1-butanol, 1-amino-2-methyl-2-propanol, 2-amino-2-methyl-1-propanol.

The epoxy resin is one or a combination of more of the following: epoxy resin E42, epoxy resin E44, epoxy resin E51, triglycidyl meta-aminophenol, N, N, N, N, -tetracyclooxypropyl-4, 4-diaminodiphenylmethane, 1, 4-butanediol diglycidyl ether, EP-12, EP-13, EP-16 and EP-20.

The diisocyanate used is one or a combination of several of the following: p-phenylene diisocyanate, toluene 2, 6-diisocyanate, 1, 3-phenylene diisocyanate, toluene 2, 4-diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, 1, 5-diisocyanatonaphthalene, m-xylylene diisocyanate, 4,4' -methylenebis (phenylisocyanate), 4, 4-diisocyanate dicyclohexylmethane, 3,3' -dichloro-4, 4' -diisocyanate biphenyl.

The solvent is one of the following substances: dichloromethane, trichloromethane, chlorobenzene, dichlorobenzene, tetrahydrofuran, acetone, 1-4-dioxane, dimethylformamide, ethanol, petroleum ether, n-heptane, n-hexane and/or dimethyl sulfoxide.

Detailed Description

The present invention will be further described with reference to some examples, but the present invention is not limited to only the following examples.

Example 1

1.8 molar equivalents of vanillin were gradually added to 1 molar equivalent of sodium hydride containing tetrahydrofuran until all the sodium hydride was consumed to obtain sodium salt i. And in the same way, reacting the p-ethylphenol with metallic sodium to prepare the sodium salt II of the p-ethylphenol.

3 molar equivalents of sodium salt II were added to 1 molar equivalent of HCCP and reacted at 40 ℃ for 48 hours. Then 9 molar equivalents of sodium salt I were added thereto and reacted at 50-65 ℃ for 120 hours. And finally, washing the mixture for four times by using deionized water and ethanol to obtain the CP-3A.

Dissolving 2 mol equivalent of CP-3A, 3 mol equivalent of terephthalaldehyde and 6 mol equivalent of m-xylylenediamine in chloroform, pouring into a mold, volatilizing the solvent, and then carrying out hot pressing at 60-120 ℃ for 24 hours and at 150-190 ℃ for 1 hour to obtain the vitrimer. After the mechanics is measured, the vitrimer is cut into fragments, and the fragments are hot-pressed for 20 to 50 minutes at the temperature of 30MPa,160 ℃ and 190 ℃ to obtain a secondary circulating sample.

The prepared vitrimer has the mechanical property of 67MPa, the thermal decomposition temperature of 420 ℃, the residual carbon content of 70 percent at 800 ℃, the Limiting Oxygen Index (LOI) of 35 percent and the UL-94 of V-0 grade. The secondary cycle sample mechanics can still reach 65 MPa.

Example 2

0.9 molar equivalent of p-hydroxybenzaldehyde and 0.9 molar equivalent of vanillin were gradually added to 1 molar equivalent of sodium hydride containing tetrahydrofuran until all the sodium hydride was consumed to obtain sodium salt i. And preparing the mixed sodium salt II of the p-ethylphenol and the phenol in the same way.

3 molar equivalents of the mixed sodium salt II were added to 1 molar equivalent of HCCP, and the reaction was carried out at room temperature for 60 hours. Then, 6 molar equivalents of the mixed sodium salt I was added thereto, and reacted at 50 to 65 ℃ for 120 hours. And finally, washing the mixture for four times by using deionized water and ethanol to obtain the CP-3A.

Dissolving 2 molar equivalents of CP-3A, 1 molar equivalent of terephthalaldehyde, 2 molar equivalents of biphenyldicarboxaldehyde, 3 molar equivalents of m-xylylenediamine and 3 molar equivalents of 4,4' -diaminodiphenylmethane in chloroform, pouring into a mold, volatilizing the solvent, hot-pressing at 60-120 ℃ for 24 hours, and hot-pressing at 150-190 ℃ for 1 hour to obtain the vitrrimer. After the mechanics is measured, the vitrimer is cut into fragments, and the fragments are hot-pressed for 20 to 50 minutes at the temperature of 30MPa,160 ℃ and 190 ℃ to obtain a secondary circulating sample.

The prepared vitrimer has the mechanical property up to 63MPa, the thermal decomposition temperature of 410 ℃, the residual carbon content of 67 percent at 800 ℃, the Limiting Oxygen Index (LOI) of 33 percent and the UL-94 of V-0 grade. The secondary cycle sample mechanics can still reach 62 MPa.

Example 3

1.5 molar equivalents of p-hydroxybenzaldehyde were gradually added to 1 molar equivalent of sodium hydride containing dichlorobenzene until all the sodium hydride was consumed to obtain sodium salt I. And similarly, reacting phenol with metallic sodium to prepare phenol sodium salt II.

3 molar equivalents of sodium salt II were added to 1 molar equivalent of HCCP and reacted at 40 ℃ for 48 hours. Then, 12 molar equivalents of sodium salt I was added thereto, and reacted at 50 to 65 ℃ for 120 hours. And finally, washing the mixture for four times by using deionized water and ethanol to obtain the CP-3A.

Dissolving 2 mol equivalent of CP-3A and 3 mol equivalent of benzidine into dichloromethane, pouring into a mold, volatilizing the solvent, and then carrying out hot pressing at 60-120 ℃ for 24 hours and at 150-190 ℃ for 1 hour to obtain the vitrimer. After the mechanics is measured, the vitrimer is cut into fragments, and the fragments are hot-pressed for 20 to 50 minutes at the temperature of 30MPa,160 ℃ and 190 ℃ to obtain a secondary circulating sample.

The prepared vitrimer has the mechanical property up to 77MPa, the thermal decomposition temperature of 430 ℃, the residual carbon content of 75 percent at 800 ℃, the Limiting Oxygen Index (LOI) of 39 percent and UL-94 of V-0 grade. The secondary cycle sample mechanics can still reach 73 MPa.

Example 4

0.9 molar equivalent of 4-hydroxy-3-fluorobenzaldehyde and 0.9 molar equivalent of vanillin are gradually added to 1 molar equivalent of sodium hydride containing tetrahydrofuran until all the sodium hydride is consumed, thus obtaining the mixed sodium salt I. And preparing the mixed sodium salt II of the trifluoroethanol and the phenol by the same method.

3 molar equivalents of the mixed sodium salt II were added to 1 molar equivalent of HCCP, and the reaction was carried out at room temperature for 60 hours. Then, 6 molar equivalents of the mixed sodium salt I was added thereto, and reacted at 50 to 65 ℃ for 120 hours. And finally, washing the mixture for four times by using deionized water and ethanol to obtain the CP-3A.

Dissolving 2 molar equivalents of CP-3A, 1 molar equivalent of terephthalaldehyde, 2 molar equivalents of anthracene-9, 10-dicarboxaldehyde, and 3 molar equivalents of 2, 2-bis (4-aminophenyl) propane and 3 molar equivalents of 4,4' -diaminodiphenylmethane in chloroform, pouring into a mold, volatilizing the solvent, and then hot-pressing at 60-120 ℃ for 24 hours and at 150-190 ℃ for 1 hour to obtain the vitrrimer. After the mechanics is measured, the vitrimer is cut into fragments, and the fragments are hot-pressed for 20 to 50 minutes at the temperature of 30MPa,160 ℃ and 190 ℃ to obtain a secondary circulating sample.

The prepared vitrimer has the mechanical property of 66MPa, the thermal decomposition temperature of 350 ℃, the residual carbon content of 62 percent at 800 ℃, the Limiting Oxygen Index (LOI) of 46 percent and UL-94 of V-0 grade. The secondary cycle sample mechanics can still reach 64 MPa.

Example 5

1.5 molar equivalents of ethyl vanillin were gradually added to 1 molar equivalent of sodium hydride containing 1-4-dioxane until all the sodium hydride was consumed to obtain sodium salt i. And similarly, reacting the ethanol with the metal sodium to prepare the phenol sodium salt II.

3 molar equivalents of sodium salt II were added to 1 molar equivalent of HCCP, and the reaction was carried out at room temperature for 24 hours. 9 molar equivalents of sodium salt I were subsequently added thereto and reacted at 50-65 ℃ for 90 hours. And finally, washing the mixture for four times by using deionized water and ethanol to obtain the CP-3A.

Dissolving 2 molar equivalents of CP-3A and 3 molar equivalents of ethylenediamine in dimethylformamide, pouring into a mold, volatilizing the solvent, and then hot-pressing at 60-120 ℃ for 24 hours and at 150-190 ℃ for 2 hours to obtain the vitrimer. After the mechanics is measured, the vitrimer is cut into fragments, and the fragments are hot-pressed for 20 to 50 minutes at the temperature of 30MPa,160 ℃ and 190 ℃ to obtain a secondary circulating sample.

The prepared vitrimer has the mechanical property of 53MPa, the thermal decomposition temperature of 330 ℃, the residual carbon content of 56 percent at 800 ℃, the Limiting Oxygen Index (LOI) of 31 percent and the UL-94 of V-0 grade. The secondary cycle sample mechanics can still reach 53 MPa.

Example 6

0.9 molar equivalent of 4-hydroxy-3-fluorobenzaldehyde and 0.9 molar equivalent of vanillin are gradually added to 1 molar equivalent of sodium hydride containing tetrahydrofuran until all the sodium hydride is consumed, thus obtaining the mixed sodium salt I. And preparing the mixed sodium salt II of the trifluoroethanol and the phenol by the same method.

3 molar equivalents of the mixed sodium salt II were added to 1 molar equivalent of HCCP, and the reaction was carried out at room temperature for 60 hours. Then, 6 molar equivalents of the mixed sodium salt I was added thereto, and reacted at 50 to 65 ℃ for 120 hours. And finally, washing the mixture for four times by using deionized water and ethanol to obtain the CP-3A.

4 molar equivalents of p-aminophenol were reacted with 1 molar equivalent of CP-3A in tetrahydrofuran at 50 ℃ for 12 hours, and precipitated in petroleum ether to obtain CP-3 OH.

Reacting CP-3OH with epoxy resin E44 according to the ratio of hydroxyl to epoxy group 1: 1, reacting according to the following process: 120 ℃/3 hours, 150 ℃/3 hours, 180 ℃/3 hours. And preparing the flame-retardant recyclable epoxy resin vitrimer. After the mechanics is measured, the epoxy resin vitrimer is cut into fragments, and the fragments are hot-pressed for 20 to 50 minutes at the temperature of 150 ℃ and 190 ℃ under the pressure of 30MPa to obtain a secondary cycle sample.

The obtained epoxy resin vitrimer has the mechanical property of 67MPa, the thermal decomposition temperature of 350 ℃, the carbon residue of 52 percent at 800 ℃, the Limiting Oxygen Index (LOI) of 28 percent and the UL-94 of V-0 grade. The secondary cycle sample mechanics can still reach 59 MPa.

Example 7

0.9 molar equivalent of p-hydroxybenzaldehyde and 0.9 molar equivalent of vanillin were gradually added to 1 molar equivalent of sodium hydride containing tetrahydrofuran until all the sodium hydride was consumed to obtain sodium salt i. And preparing the mixed sodium salt II of the p-ethylphenol and the phenol in the same way.

3 molar equivalents of the mixed sodium salt II were added to 1 molar equivalent of HCCP, and the reaction was carried out at room temperature for 60 hours. Then, 6 molar equivalents of the mixed sodium salt I was added thereto, and reacted at 50 to 65 ℃ for 120 hours. And finally, washing the mixture for four times by using deionized water and ethanol to obtain the CP-3A.

6 molar equivalents of ethanolamine are reacted with 1 molar equivalent of CP-3A in ethanol at 60 ℃ for 9 hours, and the resulting product is precipitated in petroleum ether to obtain CP-3 OH.

Reacting CP-3OH with isophorone diisocyanate according to the ratio of hydroxyl to isocyanate group 1: 1, reacting according to the following process: 60 ℃/3 hours, 90 ℃/6 hours, 150 ℃/3 hours. After the mechanics is measured, the epoxy resin vitrimer is cut into fragments, and the fragments are hot-pressed for 10 to 120 minutes at the temperature of 120-180 ℃ under the pressure of 20MPa to obtain a secondary cycle sample.

The prepared flame-retardant recyclable polyurethane has the mechanical property of 34MPa, the thermal decomposition temperature of 330 ℃, the residual carbon content of 48 percent at 800 ℃, the Limiting Oxygen Index (LOI) of 29 percent and the UL-94 grade of V-0. The secondary cycle sample mechanics can still reach 28 MPa.

Example 8

Dissolving 1 molar equivalent of terephthalaldehyde and 1 molar equivalent of m-xylylenediamine in chloroform, pouring into a mold, volatilizing the solvent, and then carrying out hot pressing at 60-120 ℃ for 24 hours and at 150-190 ℃ for 1 hour to obtain the vitrier. After the mechanics is measured, the vitrimer is cut into fragments, and the fragments are hot-pressed for 20 to 60 minutes at the temperature of 40MPa,160 ℃ and 190 ℃ to obtain a secondary circulating sample.

The prepared vitrimer has the mechanical property of 69MPa, the thermal decomposition temperature of 440 ℃, the residual carbon content of 54 percent at 800 ℃, the Limiting Oxygen Index (LOI) of 29 percent and the UL-94 grade of V-0. The secondary cycle sample mechanics can still reach 61 MPa.

Example 9

1.8 molar equivalents of vanillin were gradually added to 1 molar equivalent of sodium hydride containing tetrahydrofuran until all the sodium hydride was consumed to obtain sodium salt i. And in the same way, reacting phenol with metallic sodium to prepare the sodium salt II of the p-ethylphenol.

3 molar equivalents of sodium salt II were added to 1 molar equivalent of HCCP and reacted at 40 ℃ for 24 hours. 9 molar equivalents of sodium salt I were subsequently added thereto and reacted at 50-65 ℃ for 90 hours. And finally, washing the mixture for four times by using deionized water and ethanol to obtain the CP-3A.

Dissolving 2 mol equivalent of CP-3A and 3 mol equivalent of m-xylylenediamine in chloroform, pouring into a mold, volatilizing the solvent, and then carrying out hot pressing at 60-120 ℃ for 24 hours and at 150-190 ℃ for 1 hour to obtain the vitrimer. After the mechanics is measured, the vitrimer is cut into fragments, and the fragments are hot-pressed for 20 to 50 minutes at the temperature of 30MPa,160 ℃ and 190 ℃ to obtain a secondary circulating sample.

The prepared vitrimer has the mechanical property of 71MPa, the thermal decomposition temperature of 420 ℃, the residual carbon content of 76 percent at 800 ℃, the Limiting Oxygen Index (LOI) of 43 percent and the UL-94 of V-0 grade. The secondary cycle sample mechanics can still reach 67 MPa.