Full-bio-based flame-retardant material, and preparation method therefor and use thereof

Abstract

A full-bio-based flame-retardant material and a preparation method therefor. The composition of the full-bio-based flame-retardant material comprises a hexaldehyde bio-based phosphazene monomer, and a castor oil polyamine and / or a furyl diamine, wherein the molar ratio of the total amino groups in the castor oil polyamine and furyl diamine to the aldehyde groups in the hexaldehyde bio-based phosphazene monomer is 1 : (0.8-1.2). The full-bio-based flame-retardant material is a full-bio-based material, and the mechanical and the flame-retardant properties thereof can be adjusted and controlled by adjusting the content of the castor oil polyamine and furyl diamine to adapt to the different requirements of different products for the flame-retardant material. Moreover, the full-bio-based flame-retardant material further has self-repairing, reprocessing and degradability properties.

Description

Fully bio-based flame retardant material and its preparation method and application Technical Field

[0001] The present invention belongs to the technical field of bio-based materials and relates to a fully bio-based flame retardant material and a preparation method and application thereof. Background Art

[0002] Synthesizing high-performance and functional materials based on renewable resources such as natural products and their derivatives offers multiple benefits, including energy conservation and environmental protection. Small-molecule natural products are inexpensive and simple in structure, making them ideal alternative resources for the large-scale synthesis and preparation of bio-based polymers. However, most current bio-based materials suffer from limitations such as limited mechanical properties and limited functionality.

[0003] Phosphazenes are a class of compounds with a stable phosphorus-nitrogen skeleton. This hybrid structure, with alternating phosphorus and nitrogen, imparts excellent thermal stability and flame retardancy, and is currently used in the preparation of flame-retardant materials. For example, Chinese patent application CN114957918A discloses a flame-retardant curing accelerator, hexa[(4-(aldehyde-oximino)-2-methoxy)phenoxy]cyclotriphosphazene. Hexachlorocyclotriphosphazene, vanillin, and hydroxylamine hydrochloride are used as raw materials. The accelerator is prepared by replacing the six chlorine atoms on the hexachlorocyclotriphosphazene with vanillin and reductively aminated the aldehyde groups of vanillin with hydroxylamine hydrochloride to form an oxime. This flame-retardant curing accelerator can be used with epoxy resin and a curing agent to prepare epoxy resin flame-retardant materials, improving the ignition time, total heat release, and heat release rate of the epoxy resin. Chinese patent CN110563765B discloses a Schiff base phosphazene double-base structure flame retardant. The flame retardant is prepared by reacting hexachlorocyclotriphosphazene with a compound containing hydroxyl groups and active carbonyl groups, a strong base and weak acid salt, and a solvent to obtain a phosphazene-containing intermediate, and then reacting the phosphazene-containing intermediate with an alcoholamine compound and a solvent. The Schiff base phosphazene double-base structure flame retardant can effectively improve the flame retardancy and anti-dripping properties of a substrate and can be used in waterborne polyurethane to prepare a waterborne polyurethane flame retardant containing a terminal hydroxyl group-containing Schiff base phosphazene double-base structure.

[0004] Summary of the Invention

[0005] The object of the present invention is to provide a fully bio-based flame retardant material, which is mainly prepared by condensing hexaaldehyde bio-based phosphazene monomers and bio-based amines (castor oil polyamines and / or furanyl diamines) in an organic solvent. The mechanical and flame retardant properties of the fully bio-based flame retardant material provided by the present invention can be regulated by adjusting the content of castor oil polyamines and furanyl diamines to meet the different requirements of different products for flame retardant materials. At the same time, the fully bio-based flame retardant material provided by the present invention also has self-repairing properties, which can effectively extend the service life of the flame retardant material, and has the ability to be reprocessed and degraded and recycled, which can realize the high-value utilization of bio-based materials.

[0006] According to one aspect of the present invention, a fully bio-based flame retardant material is provided, which comprises a hexaldehyde bio-based phosphazene monomer, castor oil polyamine and / or furanyl diamine; wherein the molar ratio of the total amino groups in the castor oil polyamine and furanyl diamine to the aldehyde groups in the hexaldehyde bio-based phosphazene monomer is 1:(0.8-1.2).

[0007] In some embodiments, the molar ratio of the aldehyde group in the hexaaldehyde bio-based phosphazene monomer, the amine group in the castor oil polyamine, and the amine group in the furanyl diamine can be 10:(0-10):(0-10). The mechanical properties and flame retardancy of the flame retardant material can be controlled by controlling the ratio of the castor oil polyamine to the furanyl diamine.

[0008] In the present invention, the hexaldehyde bio-based phosphazene monomer is mainly prepared by dissolving vanillin, hexachlorocyclotriphosphazene and an acid-binding agent in an organic solvent to carry out an aromatic nucleophilic substitution reaction, and its structural formula is shown in Formula I below. The castor oil polyamine is mainly prepared by dissolving castor oil, cysteamine hydrochloride and a free radical photoinitiator in an organic solvent and carrying out a thiol-ene addition reaction under the action of ultraviolet light, and its structural formula is shown in Formula II below. The furanyl diamine is mainly prepared by mixing furfural, bio-based acetone and concentrated hydrochloric acid and carrying out a condensation reaction, and its structural formula is shown in Formula III below:

[0009] In some embodiments, the method for preparing hexaaldehyde bio-based phosphazene monomer may include the following steps:

[0010] The method comprises dissolving vanillin, hexachlorocyclotriphosphazene and an acid-binding agent in an organic solvent to carry out an aromatic nucleophilic substitution reaction, and purifying the reaction product to obtain the product.

[0011] In some embodiments, the acid binding agent can be selected from any one of potassium carbonate, sodium carbonate, cesium carbonate, triethylamine, and N,N-diisopropylethylamine; the organic solvent can be selected from at least one of tetrahydrofuran, acetonitrile, dioxane, N,N-dimethylformamide, and N,N-dimethylacetamide.

[0012] In some embodiments, the molar ratio of vanillin to hexachlorocyclotriphosphazene may be (6-10):1; and the molar ratio of the acid-binding agent to vanillin may be (1-2):1.

[0013] In some embodiments, the reaction temperature of the aromatic nucleophilic substitution reaction is 70-100° C., and the reaction time is 36-60 h.

[0014] In some embodiments, the method for preparing castor oil polyamine may include the following steps:

[0015] Castor oil, cysteamine hydrochloride and a free radical photoinitiator are dissolved in an organic solvent, reacted under ultraviolet light for 12 to 24 hours, and the reaction product is purified to obtain the product.

[0016] In some embodiments, the free radical photoinitiator may be selected from at least one of photoinitiator DMPA, photoinitiator TPO, and photoinitiator 1173; and the organic solvent may be ethanol.

[0017] In some embodiments, the molar ratio of the double bonds in castor oil, cysteamine hydrochloride, and the photoinitiator may be 1:(2.5-4):(0.05-0.2).

[0018] In some embodiments, the preparation method of furanyl diamine may include the following steps:

[0019] The furfural, acetone and concentrated hydrochloric acid are mixed to carry out condensation reaction, and the reaction product is purified to obtain the product.

[0020] In some embodiments, the molar ratio of furfural to acetone is (2-4):1; the molar ratio of furfural to hydrochloric acid is 1:(2-4).

[0021] In some embodiments, the reaction temperature of the condensation reaction may be 35 to 45° C., and the reaction time may be 3 to 6 hours.

[0022] According to another aspect of the present invention, there is also provided a method for preparing the above-mentioned all-biobased flame retardant material, comprising the following steps:

[0023] The hexaldehyde bio-based phosphazene monomer, castor oil polyamine, furanyl diamine and an organic solvent are mixed to obtain a transparent mixed liquid, and then the mixed liquid is added into a mold, and the organic solvent is removed to obtain the product.

[0024] In some embodiments, the organic solvent may be selected from at least one of dichloromethane, chloroform, dichloroethane, tetrahydrofuran, N,N-dimethylformamide, and N,N-dimethylacetamide.

[0025] In some embodiments, the amount of the organic solvent used is 3 to 10 mL / g, based on the total mass of the hexaaldehyde bio-based phosphazene monomer, the castor oil polyamine, and the furanyl diamine.

[0026] In some embodiments, the reaction temperature is room temperature to 100° C., and the reaction time is 12 to 24 hours. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] FIG1 is a schematic diagram of the synthesis route of the fully bio-based flame retardant materials of Examples 1 to 5;

[0028] FIG2 is an infrared spectrum of the fully bio-based flame retardant materials prepared in Examples 1 to 5;

[0029] FIG3 is a graph showing the thermomechanical properties of the fully bio-based flame retardant materials prepared in Examples 1 to 5;

[0030] FIG4 is a graph showing the thermal stability of the fully bio-based flame retardant materials prepared in Examples 1 to 5. DETAILED DESCRIPTION

[0031] The present invention will be further described in detail below with reference to the following embodiments. The examples are provided for illustrative purposes only and are not intended to limit the present invention in any way. Unless otherwise specified, the raw materials and reagents used in the examples are commercially available conventional products. Experimental procedures in the examples where specific conditions are not specified are generally performed in accordance with conventional conditions in the art or the conditions recommended by the manufacturer.

[0032] In the embodiment, hexaldehyde bio-based phosphazene monomer (HVP) is mainly prepared by the following method:

[0033] Vanillin (35.42 g, 0.232 mol), hexachlorocyclotriphosphazene (12.48 g, 0.036 mol), and K2CO3 (32.07 g, 0.232 mol) were dissolved in 250 mL of dry tetrahydrofuran. The mixture was then heated to 80°C and refluxed for 48 hours. After the reaction, the solvent was removed, and the solid product was washed twice with ethanol and deionized water, and then dried in a vacuum oven at 60°C for 12 hours to obtain the hexaaldehyde bio-based phosphazene monomer.

[0034] Castor oil polyamine is mainly prepared by the following method:

[0035] 46.7 g of castor oil (0.15 mol double bond), 51.2 g of cysteamine hydrochloride (0.45 mol) and 3.5 g of photoinitiator DMPA (0.015 mol) were stirred and dissolved in 250 mL of anhydrous ethanol, reacted under a 30 W ultraviolet lamp for 18 hours, and the anhydrous ethanol was removed by rotary evaporation. The product was dissolved in chloroform and extracted 5 times with 150 mL of saturated sodium carbonate aqueous solution. The organic phase was collected and the water and solvent were removed by rotary evaporation to obtain castor oil polyamine.

[0036] Furanyl diamine is mainly prepared by the following method:

[0037] In an ice-water bath, 20 mL of concentrated hydrochloric acid (0.24 mol) and 9.7 g of furfural (0.1 mol) were slowly added to the flask and stirred for 30 minutes. Subsequently, 2.9 g of acetone (0.05 mol) was added to the above solution, heated to 40°C, and the reaction was continued for 4 hours. After cooling to room temperature, the solid product was collected by filtration. The above solid was dissolved in 100 mL of aqueous solution, adjusted to pH>10 with sodium hydroxide aqueous solution, and then the above aqueous solution was extracted 3 times with chloroform (20 mL×3). The chloroform solution was collected and washed with deionized water until neutral. The above organic solution was dried over MgSO4 overnight, filtered and evaporated to obtain furanyl diamine.

[0038] Examples 1 to 5

[0039] The formulations of the all-biobased flame retardant materials of Examples 1 to 5 are shown in Table 1, and the synthesis routes are shown in FIG1 .

[0040] Hexaldehyde bio-based phosphazene monomer, castor oil polyamine, and furanyl diamine were dissolved in DMF and stirred thoroughly to obtain a transparent mixed solution. The mixed solution was then added to a polytetrafluoroethylene mold and transferred to a vacuum oven. The mixture was reacted at 80°C for 24 hours and then the solvent was evaporated to obtain a fully bio-based flame retardant material. The amount of DMF used was 5 mL / g.

[0041] Table 1 Formula of all-biobased flame retardant materials in Examples 1 to 5

[0042] The all-bio-based flame retardant materials prepared in Examples 1 to 5 were characterized by Fourier transform infrared spectroscopy and compared with the infrared spectrum of hexaaldehyde bio-based phosphazene monomer (HVP). The results are shown in FIG2 .

[0043] The results in Figure 2 show that, compared with the infrared spectra of hexaaldehyde bio-based phosphazene monomer (HVP), in the infrared spectra of the all-bio-based flame retardant materials prepared in Examples 1 to 5, the infrared peak area of ​​the aldehyde group is reduced, and the characteristic peak of Schiff base appears at the same time, indicating that the all-bio-based flame retardant materials of Examples 1 to 5 are successfully prepared.

[0044] Test Example 1 Tensile Test

[0045] The MTSE44 tensile testing machine was used at room temperature at a speed of 10 mm min -1 The stress-strain test was performed on the bio-based flame retardant materials prepared in Examples 1 to 5 at a speed of . The results are shown in Table 2.

[0046] The results in Table 2 show that the tensile strength (stress) of the all-biobased flame retardant material prepared in Example 5 can reach a maximum of 82.67 MPa, which is comparable to the tensile strength of petroleum-based epoxy resin. Furthermore, as the content of the flexible long-chain castor oil polyamine increases, the tensile strength of the all-biobased flame retardant material decreases, but the elongation at break gradually increases. This shows that the mechanical properties of the all-biobased flame retardant material can be controlled by controlling the ratio of the two bio-based polyamines, castor oil polyamine and furanyl diamine.

[0047] Table 2 Mechanical properties of all-biobased flame retardant materials in Examples 1 to 5

[0048] Test Example 2 Dynamic Mechanical Analysis (DMA) Test

[0049] The bio-based flame retardant materials prepared in Examples 1 to 5 were cut into a size of 20 mm × 6 mm × 0.5 mm and subjected to thermomechanical property testing using a German NETZSCH DMA instrument. The test results are shown in FIG3 .

[0050] As shown in Figure 3, the all-biobased flame retardant material provided by the present invention has a high storage modulus. At the same time, the higher the content of furanyl diamine, the higher the storage modulus and glass transition temperature. This shows that by controlling the ratio of the two bio-based amines, castor oil polyamine and furanyl diamine, the glass transition temperature of the all-biobased flame retardant material can be regulated.

[0051] Test Example 3 Self-healing experiment

[0052] After scratching the all-biobased flame retardant materials prepared in Examples 1 to 5 with a blade (the scratch width was about 100 μm), a 500 g weight was placed on the surface and placed on a hot plate at 180°C. The scratches on the surface of the material were basically completely healed after 4 to 8 hours, indicating that the all-biobased flame retardant material provided by the present invention has self-healing properties.

[0053] Test Example 4 Reprocessing Experiment

[0054] The all-biobased flame retardant materials prepared in Examples 1 to 5 were cut into pieces, hot-pressed at 150°C and 20 MPa for 30 minutes, and then molded into complete samples again, indicating that the all-biobased flame retardant materials provided by the present invention have reprocessability.

[0055] Test Example 5 Acid degradation experiment

[0056] The all-biobased flame retardant materials prepared in Examples 1 to 5 were placed in a mixed solution of 1M HCl aqueous solution and THF (v:v=1:2). After stirring at room temperature for 8 hours, all the solids were dissolved in the solution, indicating that the all-biobased flame retardant materials provided by the present invention can be acid-degraded under mild conditions.

[0057] Test Example 6 Flame retardant performance test

[0058] (1) Thermal stability test: The bio-based flame retardant materials prepared in Examples 1 to 5 were tested using a STA449C thermogravimetric analyzer from Netzsch, Germany, with a heating rate of 20°C / min, a nitrogen atmosphere, and a temperature range of 35 to 800°C. The test results are shown in FIG4 , and the specific results are recorded in Table 3.

[0059] (2) Oxygen index test: The oxygen index test of the bio-based flame retardant materials prepared in Examples 1 to 5 was performed according to the method of GB / T2406-93. The test results are recorded in Table 3.

[0060] (3) Vertical combustion test: The bio-based flame retardant materials prepared in Examples 1 to 5 were subjected to a vertical combustion test according to the method of ASTM D3801. The test results are recorded in Table 3.

[0061] Table 3 Flame retardant performance test results of all-biobased flame retardant materials prepared in Examples 1 to 5

[0062] As can be seen from the results in Table 3, the residual carbon rate of the all-biobased flame retardant materials provided by the present invention exceeds 15%, and the vertical burning test shows that the flame retardancy level of all materials reaches the highest V-0 level. At the same time, the limiting oxygen index of the materials is greater than the oxygen content in the air, indicating that the all-biobased flame retardant materials prepared in Examples 1 to 5 have excellent flame retardant effects.

[0063] The phosphorus-containing free radicals generated by the phosphazene structure during the pyrolysis process can quench the combustion chain reaction. At the same time, NH3 is also produced during the pyrolysis process, which dilutes the combustible gas and oxygen, takes away heat, hinders the occurrence of the combustion process in the gas phase, interrupts the exothermic process and inhibits the combustion reaction. In the gel phase, the phosphorus-containing compound decomposes at high temperatures to release polyphosphoric acid and water. Water helps to reduce the temperature of the coating, and polyphosphoric acid further catalyzes the dehydration condensation of the organic substrate to form an insulating inorganic pyrophosphate polymer layer, which helps to hinder heat transfer and flammable volatiles and inhibit the combustion of the substrate. Therefore, the all-biobased flame retardant material provided by the present invention has excellent flame retardant effect, and the flame retardant effect can be regulated by the content of bio-based amine.

[0064] The above are only some embodiments of the present invention. For those skilled in the art, several modifications and improvements can be made without departing from the inventive concept of the present invention, which all fall within the scope of protection of the present invention.

Claims

1. All-biobased flame retardant material, characterized in that: The composition includes hexaaldehyde bio-based phosphazene monomer, castor oil polyamine and / or furanyl diamine; wherein, The molar ratio of the total amine groups in the castor oil polyamine and furanyl diamine to the aldehyde groups in the hexaaldehyde bio-based phosphazene monomer is 1:(0.8-1.2); The structural formula of the hexaaldehyde bio-based phosphazene monomer is shown in Formula I below, the structural formula of the castor oil polyamine is shown in Formula II below, and the structural formula of the furanyl diamine is shown in Formula III below:

2. The all-biobased flame retardant material according to claim 1, characterized in that: The molar ratio of the aldehyde group in the hexaaldehyde bio-based phosphazene monomer, the amine group in the castor oil polyamine, and the amine group in the furanyl diamine is 10:(0-10):(0-10).

3. The all-biobased flame retardant material according to claim 1, characterized in that: The method for preparing the hexaaldehyde bio-based phosphazene monomer comprises the following steps: Vanillin, hexachlorocyclotriphosphazene and an acid-binding agent are dissolved in an organic solvent to carry out an aromatic nucleophilic substitution reaction, and the reaction product is purified to obtain the product.

4. The all-biobased flame retardant material according to claim 3, characterized in that: The reaction temperature of the aromatic nucleophilic substitution reaction is 70-100° C., and the reaction time is 36-60 hours.

5. The all-biobased flame retardant material according to claim 1, characterized in that: The preparation method of the castor oil polyamine comprises the following steps: Dissolve castor oil, cysteamine hydrochloride and free radical photoinitiator in an organic solvent, react under ultraviolet light for 12 to 24 hours, and purify the reaction product to obtain the product.

6. The all-biobased flame retardant material according to claim 1, characterized in that: The preparation method of the furanyl diamine comprises the following steps: The furanylamine, acetone and concentrated hydrochloric acid are mixed to carry out condensation reaction, and the reaction product is purified to obtain the product.

7. The all-biobased flame retardant material according to claim 6, characterized in that: The reaction temperature of the condensation reaction is 35-45° C., and the reaction time is 3-6 hours.

8. The method for preparing a fully bio-based flame retardant material according to any one of claims 1 to 7, characterized in that: The steps include: The hexaaldehyde bio-based phosphazene monomer, castor oil polyamine, furanyl diamine and an organic solvent are mixed to obtain a mixed solution, and then the mixed solution is added into a mold, and the organic solvent is removed after the reaction to obtain the product.

9. The preparation method according to claim 8, characterized in that: The organic solvent is selected from at least one of dichloromethane, chloroform, dichloroethane, tetrahydrofuran, N,N-dimethylformamide and N,N-dimethylacetamide.

10. The preparation method according to claim 8 or 9, characterized in that: The reaction temperature is room temperature to 100° C., and the reaction time is 12 to 24 hours.

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