CN116199941A - Ammonium phytate silicon dioxide flame retardant, and preparation method and application thereof - Google Patents

Abstract

The invention belongs to the technical field of flame retardant materials, and particularly relates to an ammonium phytate silica flame retardant, a preparation method and application thereof. The ammonium phytate silicon dioxide flame retardant provided by the invention comprises silicon dioxide and ammonium phytate chemically combined with the silicon dioxide, has good compatibility with PBAT, and can not only remarkably improve the flame retardance, but also has the functions of reinforcing and toughening after being compounded with PBAT.

Description

Ammonium phytate silicon dioxide flame retardant, and preparation method and application thereof

Technical Field

The invention belongs to the technical field of flame retardant materials, and particularly relates to an ammonium phytate silica flame retardant, a preparation method and application thereof.

Background

Poly (butylene adipate/terephthalate) (PBAT) has been attracting attention as a biodegradable and environmentally friendly polymer material, and has become a research hotspot in the field of materials in recent years. The PBAT has good processability and mechanical properties, also has good heat resistance and biocompatibility, and is widely applied to the fields of agricultural films, cutlery boxes, express packages, heat insulation materials and the like. However, the defects of easy combustion, poor flame retardant property, small strength, low modulus and the like become main limiting factors for the comprehensive popularization and application of the flame retardant.

The phosphorus-nitrogen synergistic flame retardant system is still the best system suitable for PBAT flame retardant according to the literature report. The phytic acid is taken as an organic phosphorus compound extracted from plant seeds, and has great potential to flame-retardant modification of PBAT by preparing a nitrogen-phosphorus flame retardant through molecular design or modification based on the advantages of biological sources and rich phosphorus elements in molecules.

Currently, flame retardants applied to PBAT-based flame-retardant composite materials mainly comprise traditional flame retardants such as ammonium phosphate, phosphate and the like, or inorganic particles containing flame-retardant elements such as Carbon Nanotubes (CNT), montmorillonite (OMMT), silicon dioxide and the like. However, when the flame retardant is applied to the PBAT composite material, the compatibility of the flame retardant and the PBAT is poor, and the flame retardance of the PBAT-based flame retardant composite material is improved to a certain extent, but the toughness, the strength or the rigidity of the PBAT-based flame retardant composite material is damaged, and the strength or the rigidity of the PBAT-based flame retardant composite material is obviously reduced.

Disclosure of Invention

The invention aims to provide an ammonium phytate silicon dioxide flame retardant, a preparation method and application thereof.

In order to achieve the above object, the present invention provides the following technical solutions:

the invention provides an ammonium phytate silica flame retardant, which comprises silica and ammonium phytate chemically combined with the silica.

Preferably, the mass ratio of the ammonium phytate to the silicon dioxide is 1-2:1.

The invention also provides a preparation method of the phytic acid ammonium silicon dioxide flame retardant, which comprises the following steps:

mixing an ammonium phytate solution and a silicon dioxide aqueous dispersion, and performing substitution reaction to obtain the ammonium phytate silicon dioxide flame retardant; the pH value of the silicon dioxide aqueous dispersion is 2-4.

Preferably, the ammonium phytate solution comprises ammonium phytate, ethanol and water.

Preferably, the concentration of the ammonium phytate in the ammonium phytate solution is 3-20wt%; the volume ratio of ethanol to water in the ammonium phytate solution is 0.5:1 to 3:1.

preferably, the temperature of the substitution reaction is 40-60 ℃ and the time is 3-6 h.

The invention also provides application of the phytic acid ammonification silicon dioxide flame retardant or the phytic acid ammonification silicon dioxide flame retardant prepared by the preparation method in flame retardant materials.

The invention also provides a PBAT-based flame-retardant composite material, which comprises the following preparation raw materials in parts by mass:

80-95 parts of PBAT;

5-20 parts of phytic acid ammonification silicon dioxide flame retardant;

the phytic acid ammonium silicon dioxide flame retardant is the phytic acid ammonium silicon dioxide flame retardant.

The invention also provides a preparation method of the composite material, which comprises the following steps:

and mixing the PBAT and the phytic acid ammonium silicon dioxide flame retardant, and sequentially carrying out melt blending and extrusion molding to obtain the PBAT-based flame retardant composite material.

Preferably, the temperature of the melt blending is 150 to 200 ℃.

The invention provides an ammonium phytate silica flame retardant, which comprises silica and ammonium phytate chemically combined with the silica. The flame retardant provided by the invention is based on the existence of functional groups such as biomass phytic acid, amino and the like, so that the flame retardant can easily generate surface effect with a PBAT matrix, and the biocompatibility is improved. In addition, the flame retardant is rich in flame retardant elements such as phosphorus, nitrogen, silicon and the like, and can play a remarkable role in improving the flame retardant property of the resin by being introduced into a matrix. Therefore, the phytic acid ammonium silicon dioxide flame retardant provided by the invention has good compatibility with PBAT, and after being compounded with PBAT, the flame retardance can be obviously improved, and the flame retardant has the functions of strengthening and toughening.

The data of the examples show that the flame retardant performance of the composite material compounded by the flame retardant and the PBAT can reach the V-1 grade of UL-94, the elongation at break of the composite material is improved by 13.0% compared with that of pure PBAT, and the tensile strength and the bending strength can be respectively improved by 31.4% and 44.4%.

The invention also provides a preparation method of the phytic acid ammonium silicon dioxide flame retardant, which comprises the following steps: mixing an ammonium phytate solution and a silicon dioxide aqueous dispersion, and performing substitution reaction to obtain the ammonium phytate silicon dioxide flame retardant; the pH value of the silicon dioxide aqueous dispersion is 2-4. The preparation method is simple, easy to control and convenient for industrial production.

Drawings

FIG. 1 is a Mapping spectrum of the ammonium phytate silica flame retardant of example 1;

FIG. 2 is a Mapping spectrum of the ammonium phytate silica flame retardant of example 2;

FIG. 3 is a Mapping spectrum of silica particles.

Detailed Description

The invention provides an ammonium phytate silica flame retardant, which comprises silica and ammonium phytate chemically combined with the silica.

In the present invention, the mass of the ammonium phytate and the silica is preferably 1 to 2:1, more preferably 1.5 to 2:1.

The invention also provides a preparation method of the phytic acid ammonium silicon dioxide flame retardant, which comprises the following steps:

mixing an ammonium phytate solution and a silicon dioxide aqueous dispersion, and performing substitution reaction to obtain the ammonium phytate silicon dioxide flame retardant; the pH value of the silicon dioxide aqueous dispersion is 2-4.

In the present invention, the ammonium phytate solution preferably includes ammonium phytate, ethanol and water. In the present invention, the mass concentration of the ammonium phytate in the ammonium phytate solution is preferably 3 to 20wt%, more preferably 10wt%. In the invention, the mass ratio of ethanol to water in the ammonium phytate solution is preferably 0.5:1 to 3:1, more preferably 1:1. In the present invention, the ammonium phytate solution is preferably prepared by dispersing ammonium phytate in a mixed solvent of ethanol and water.

In the present invention, the ammonium phytate is preferably self-made.

In the present invention, the preparation method of ammonium phytate preferably comprises the following steps:

and mixing an amine compound aqueous solution and a phytic acid aqueous solution, and carrying out amidation reaction to obtain ammonium phytate.

In the present invention, the amine compound in the aqueous amine compound solution preferably includes diamine and/or polyamine. In the present invention, the diamine preferably includes one or more of adipoyl diamine, polyoxyethylene diamine, dicyano diamine, and p-phenylenediamine and m-phenylenediamine, more preferably dicyano diamine, and the diamine preferably includes one or more of diethylenetriamine, tris (4-aminophenyl) amine, and tris (2-cyanoethyl) amine, more preferably tris (4-aminophenyl) amine. In the present invention, the concentration of the amine compound in the aqueous amine compound solution is preferably 0.1 to 1mol/L, more preferably 0.4 to 0.6mol/L.

In the present invention, the preparation of the aqueous solution of the amine compound is preferably obtained by dispersing the amine compound in deionized water. In the present invention, the dispersing means is preferably magnetic stirring, and the temperature of the magnetic stirring is preferably 80 to 100 ℃, more preferably 90 ℃, and the time is preferably 1 to 2 hours, more preferably 1.5 hours.

In the present invention, the concentration of phytic acid in the phytic acid aqueous solution is preferably 25 to 35wt%, more preferably 30wt%. In the present invention, the molar ratio of the amine compound in the aqueous amine compound solution to the phytic acid of the aqueous phytic acid solution is preferably 2:1 to 10:1, more preferably 6:1.

in the present invention, the aqueous amine compound solution and the aqueous phytic acid solution are preferably mixed by dropping the aqueous phytic acid solution into the aqueous amine compound solution. In the present invention, the dropping speed is preferably 10 to 120 drops/min, more preferably 30 drops/min. In the present invention, the dropping is preferably dropping through a constant pressure dropping funnel.

In the present invention, the temperature of the amidation reaction is preferably 80 to 100 ℃, more preferably 85 to 95 ℃, and the holding time is preferably 2 to 5 hours, more preferably 3 to 4 hours.

In the present invention, after the amidation reaction, it is preferable that the system obtained by the amidation reaction is further subjected to standing precipitation, suction filtration, washing and drying in this order. In the present invention, the time for the standing precipitation is preferably 0.5 to 1 hour, more preferably 0.6 to 0.7 hour. The suction filtration is not particularly limited in the present invention, and may be performed by operations well known to those skilled in the art. In the present invention, the washing is preferably deionized water washing, and the number of times of the washing is preferably not less than 3, more preferably 3 to 5. The present invention is not particularly limited to drying, and the washed doped water may be removed by an operation well known in the art.

In the present invention, the preparation of the aqueous silica dispersion preferably comprises: the silica was dispersed in deionized water and pH adjusted.

In the present invention, the mass concentration of silica in the aqueous silica dispersion is preferably 5 to 20%, more preferably 10%. The dispersion is preferably carried out under magnetic stirring. In the present invention, the pH adjusting agent is preferably hydrochloric acid, and the mass concentration of the hydrochloric acid is preferably 37%. In the present invention, the pH of the aqueous silica dispersion is preferably 2 to 4, more preferably 3.

In the present invention, the mass ratio of the ammonium phytate in the ammonium phytate solution to the silica in the aqueous silica dispersion is preferably 1 to 2:1, more preferably 1.2 to 1.5:1.

In the present invention, the mixing is preferably by dropping an ammonium phytate solution into an aqueous silica dispersion.

In the present invention, the temperature of the substitution reaction is preferably 40 to 60 ℃, more preferably 50 ℃, and the time is preferably 3 to 6 hours, more preferably 4 to 5 hours. In the present invention, the substitution reaction is preferably carried out under magnetic stirring. In the present invention, the substitution reaction is NH in the ammonium phytate structure ₄ ⁺ And SiO ₂ The silicon hydroxyl groups on the surface react.

In the present invention, after the substitution reaction, it is preferable to further include sequentially subjecting the suspension obtained by the substitution reaction to standing precipitation, suction filtration, washing and drying. In the present invention, the time for the standing precipitation is preferably 0.5 to 1 hour, more preferably 0.6 to 0.7 hour. The suction filtration is not particularly limited in the present invention, and may be performed by operations well known to those skilled in the art. In the present invention, the washing is preferably deionized water washing, and the number of times of the washing is preferably not less than 3, more preferably 3 to 5. In the present invention, the drying temperature is preferably 70 to 90 ℃, more preferably 80 ℃, and the time is preferably 12 to 24 hours, more preferably 15 to 20 hours.

The invention also provides application of the flame retardant in flame retardant materials.

The invention also provides a PBAT-based flame-retardant composite material, which comprises the following preparation raw materials in parts by mass:

80-95 parts of PBAT;

5-20 parts of phytic acid ammonification silicon dioxide flame retardant;

the phytic acid ammonium silicon dioxide flame retardant is the phytic acid ammonium silicon dioxide flame retardant.

In the invention, the preparation raw materials of the PBAT-based flame-retardant composite material preferably comprise 80-95 parts by mass of PBAT, more preferably 85-90 parts by mass. In the present invention, the melt index of the PBAT is preferably 5 to 7g/10min. In the present invention, the PBAT is preferably one or more of TH801T PBAT, jin Huizhao T PBAT, 1908PBAT, and Ecoflex PBAT, more preferably 1908PBAT, which are provided by the company BASF, germany, jin Huizhao T, high technologies, and the company BASF, more preferably Jin Huizhao T.

In the invention, the preparation raw materials of the PBAT-based flame-retardant composite material preferably comprise 5-20 parts by mass of the phytic acid ammonification silica flame retardant, and more preferably 10-15 parts by mass.

The invention also provides a preparation method of the PBAT-based flame-retardant composite material, which comprises the following steps:

and mixing the PBAT matrix resin and the phytic acid ammonium silicon dioxide flame retardant, and sequentially carrying out melt blending and extrusion molding to obtain the PBAT-based flame retardant composite material.

In the present invention, the mixing preferably further comprises separately drying the PBAT and the phytic acid aminated silica flame retardant. In the present invention, the temperature of the drying is independently preferably 60 to 100 ℃, more preferably 70 to 90 ℃, and the time of the drying is independently preferably 6 to 10 hours, more preferably 8 to 9 hours.

In the present invention, the PBAT and the phytic acid aminated silica flame retardant are preferably mixed by stirring at a rotation speed of preferably 500 to 2000rpm, more preferably 1000rpm. In the present invention, the temperature of the melt blending is preferably 150 to 200 ℃, more preferably 170 to 180 ℃. In the present invention, the extrusion molding is preferably performed in a twin screw extruder, and the extrusion conditions of the extrusion molding preferably include: the rotation speed of the screw is preferably 80 to 200rpm, more preferably 150rpm, and the feeding rate is 10 to 15rpm. In the present invention, the injection temperature of the extrusion molding is particularly preferably: the first zone temperature is preferably 145.+ -. 10 ℃, the second zone temperature is preferably 160.+ -. 10 ℃, the third zone temperature is preferably 175.+ -. 10 ℃, the fourth zone temperature is preferably 190.+ -. 10 ℃, and the fifth zone temperature is preferably 205.+ -. 10 ℃.

The following describes the invention in detail with reference to examples for further illustration of the invention, but they should not be construed as limiting the scope of the invention.

Example 1

(1) Dispersing 0.1moL of tris (4-aminophenyl) amine in 1L of deionized water, and magnetically stirring for 2 hours at 100 ℃ to obtain a stably dispersed 0.1moL/L tris (4-aminophenyl) amine aqueous solution;

(2) slowly dripping 12mL of a water solution of phytic acid with the mass fraction of 30 percent into 100mL of an aqueous solution of (4-aminophenyl) amine through a constant pressure dropping funnel (the dropping speed is 30 drops/min), magnetically stirring and uniformly mixing, carrying out amidation reaction for 3 hours at the temperature of 100 ℃, sequentially standing and precipitating the product obtained by the amidation reaction for 1 hour, carrying out vacuum suction filtration, washing with deionized water for 3 times, and drying to obtain ammonium phytate;

(3) 10g of dried silica was dispersed in deionized water under magnetic stirring and pH was adjusted to 2-3 with 37wt% hydrochloric acid to give a 10wt% aqueous silica dispersion.

(4) Dispersing 5g of ammonium phytate in 50mL of a mixed solvent of ethanol and water in a mass ratio of 1:1, and magnetically stirring for 1h at room temperature to obtain an ammonium phytate solution;

(5) slowly dripping ammonium phytate solution (the dripping speed is 50 drops/min) into the silicon dioxide aqueous dispersion, heating to 50 ℃ and magnetically stirring for 5 hours, standing the obtained suspension for 1 hour, vacuum filtering, washing with deionized water for 5 times, and drying at80 ℃ for 24 hours to obtain the ammonium phytate silicon dioxide flame retardant.

Example 2

The only difference from example 1 is that: the mass of the ammonium phytate in the step (4) is 10g.

Application example 1

The PBAT and the phytic acid aminated silica flame retardant prepared in example 1 were dried in a vacuum oven at80 deg.c for 6 hours.

Weighing 95 parts of PBAT and 5 parts of phytic acid ammonified silica flame retardant in parts by weight, mixing for 15min in a high-speed mixer at the rotating speed of 1000rpm, and performing melt blending and extrusion molding on the obtained mixture at 180 ℃ to obtain the PBAT-based flame retardant composite material. The temperature of the heating zone for extrusion molding was set to 145℃in the first zone, 160℃in the second zone, 175℃in the third zone, 190℃in the fourth zone, and 205℃in the fifth zone in this order. The host screw speed was 150rpm and the feed rate was 15rpm.

Application example 2

The only difference from application example 1 is that: 90 parts of PBAT and 10 parts of phytic acid ammonium silicon dioxide flame retardant.

Application example 3

The only difference from application example 1 is that: 85 parts of PBAT and 15 parts of phytic acid ammonium silicon dioxide flame retardant.

Application example 4

The only difference from application example 1 is that: 80 parts of PBAT and 20 parts of phytic acid ammonium silicon dioxide flame retardant.

Application example 5

The only difference from application example 1 is that: the ammonium phytate silica flame retardant prepared in example 1 was replaced with the ammonium phytate silica flame retardant prepared in example 2.

Application example 6

The only difference from application example 2 is that: the ammonium phytate silica flame retardant prepared in example 1 was replaced with the ammonium phytate silica flame retardant prepared in example 2.

Application example 7

The only difference from application example 3 is that: the ammonium phytate silica flame retardant prepared in example 1 was replaced with the ammonium phytate silica flame retardant prepared in example 2.

Application example 8

The only difference from application example 4 is that: the ammonium phytate silica flame retardant prepared in example 1 was replaced with the ammonium phytate silica flame retardant prepared in example 2.

Comparative application example 1

The only difference from application example 1 is that: the comparative application examples do not contain an ammonium phytate silica flame retardant.

Comparative application example 2

The only difference from application example 2 is that: the ammonium phytate silica flame retardant prepared in example 1 was replaced with silica particles.

Comparative application example 3

The only difference from application example 2 is that: the ammonium phytate silica flame retardant prepared in example 1 was replaced with ammonium phytate.

Comparative application example 4

The only difference from application example 2 is that: the ammonium phytate silica flame retardant prepared in example 1 was replaced with a commercially available ammonium polyphosphate intumescent flame retardant.

Comparative application example 5

The only difference from comparative application example 2 is that: PBAT was 85 parts and silica particles were 15 parts.

Comparative application example 6

The only difference from comparative application example 3 is that: PBAT is 85 parts and ammonium phytate is 15 parts.

Comparative application example 7

The only difference from comparative application example 4 is that: 85 parts of PBAT and 15 parts of ammonium polyphosphate flame retardant.

Test case

The products prepared in application examples 1 to 8 and comparative application examples 1 to 7 were prepared into flame retardant property and mechanical property test bars, wherein the flame retardant property test bars were long by width by thickness=130 mm by 10mm by 3.2mm, and the mechanical property standard test bars were 150mm by 20mm by 4mm dumbbell-shaped plastic tensile property bars and 80mm by 10mm by 4mm plastic bending property test bars. The testing method comprises the following steps: vertical burning (UL-94) test was performed according to GB/T24082008 standard, and mechanical properties were tested according to GB/T10402006 standard. The flame retardancy test data and the mechanical property test results are shown in tables 1 and 2, respectively.

Table 1 flame retardancy test data for application examples 1 to 8 and comparative application examples 1 to 7

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In Table 1, t ₁ ^a (s) is the average time of the first combustion, t ₁ ^b (s) is the average time of the second combustion, NR ^c Indicating that the flame retardant rating is not reached, the LOI value is the limiting oxygen index value.

As can be seen from table 1, the material prepared from pure PBAT resin (comparative application example 1) was easy to burn, was severely dropped, had no flame retardant rating, and had an LOI value of 20.1%; the materials with the silica particles (comparative application example 2 and comparative application example 5) alone still tend to burn and fail to reach the flame retardant rating; the dripping phenomenon of the materials (comparative application example 3 and comparative application example 6) is improved to a certain extent after the ammonium phytate flame retardant is singly added, the comparative application example 3 and the comparative application example 6 achieve the V-2 flame retardant grade of UL94, and the LOI is slightly increased; after the commercial ammonium polyphosphate flame retardant is singly added (comparative application example 4 and comparative application example 7), the flame retardant performance of the material is improved, wherein the comparative application example 7 can reach V-1 flame retardant grade of UL94, and the LOI value reaches 23.5%.

The phytic acid ammonium silicon dioxide flame retardant (the mass ratio of silicon dioxide to phytic acid ammonium is 2:1) (application examples 1-4) is added, the material can obviously inhibit melt dripping, the LOI value is improved along with the increase of the hybridized flame retardant, the application examples 3 and 4 can reach V-1 flame retardant grade, and the LOI value is 23.6%; and the mass ratio of the added silicon dioxide to the ammonium phytate is 1: in the flame retardant prepared by the method 1, the flame retardant effect of the composite material (application examples 5-8) is better and more remarkable, and the flame retardant grade is gradually improved along with the increase of the content of the hybrid flame retardant. Wherein, all application examples 6-8 reach V-1 flame retardant grade, the effect of inhibiting dripping is obvious, and the LOI value of application example 8 is improved to 25.1%. Comparing two mass ratios of ammonium phytate coated silica hybrid flame-retardant systems, wherein the mass ratio of the added silica to the ammonium phytate is 1: the anti-dripping performance, flame burning time inhibition and LOI value improvement of the flame-retardant PBAT composite material of the hybrid flame retardant prepared by the method 1 are superior to those of silicon dioxide and ammonium phytate in mass ratio of 2:1, and a hybrid particle flame retardant system prepared by the method.

As can be seen from Table 1, under the same addition amount, the anti-dripping capability, the flame retardant grade, the LOI value and the like of the composite material prepared by adding the phytic acid ammonium silicon dioxide flame retardant are obviously superior to those of a flame retardant system which is independently added with silicon dioxide, phytic acid ammonium and commercial ammonium polyphosphate.

TABLE 2 mechanical test data for application examples 1 to 8 and comparative application examples 1 to 7

As can be seen from table 2, the pure PBAT resin (comparative application example 1) has a higher elongation at break, shows excellent ductility, but has lower strength and modulus; the silicon dioxide particles (comparative application example 2 and comparative application example 5) are singly introduced, so that the strength and the modulus of the material are improved, and the elongation at break is slightly reduced; and the performance of the material is not obviously improved after the ammonium phytate or ammonium polyphosphate flame retardant is singly added.

The tensile strength, the elastic modulus and the bending strength of the composite material are obviously improved compared with those of comparative application examples 1 to 7 by adding the phytic acid ammonium silicon dioxide flame retardant (application examples 1 to 8). Wherein, when the addition amount of the phytic acid ammonification silicon dioxide flame retardant is 15 parts (application example 3 and application example 7), the tensile strength and the bending strength of the material reach the maximum value, and the application example 3 is respectively improved by 31.4 percent and 44.4 percent compared with the comparative application example 1. The elongation at break of the composite material shows a trend of rising and then reducing along with the increase of the content of the hybrid flame retardant, when the adding amount of the hybrid flame retardant is 10 parts, the elongation at break of the material can reach an optimal value, and the application example 2 is improved by 13.0 percent compared with the comparative application example 1.

By combining the test results in tables 1 and 2, the phytic acid ammonified silica flame retardant modified and reinforced PBAT flame retardant composite material can obviously improve the flame retardant grade and the anti-dripping capability of matrix resin and has obvious flame retardant effect; the strength and the modulus of the material can be improved, and meanwhile, the excellent elongation at break and toughness are maintained, so that the material has good compatibility with PBAT resin. Wherein, when the mass ratio of silicon dioxide to ammonium phytate is 1: when the hybrid flame retardant prepared by the method 1 is used for modifying PBAT, the flame retardant effect of the composite material is more remarkable. Therefore, the ammonium phytate coated silica modified reinforced PBAT flame-retardant composite material provided by the invention can obviously improve the defects of low PBAT strength and insufficient rigidity, can improve the comprehensive mechanical property of the system, and simultaneously endows the composite system with excellent flame-retardant property.

The invention also carries out characteristic spectrum analysis (Mapping spectrum) on the phytic acid ammonium silicon dioxide flame retardant and the silicon dioxide particles prepared in the embodiment 1 and the embodiment 2, and the test results are respectively shown in figures 1 to 3. Fig. 1 (a) is an SEM topography of example 1, fig. 1 (b) is a Mapping nitrogen element distribution diagram of example 1, fig. 1 (c) is a Mapping phosphorus element distribution diagram of example 1, and fig. 1 (d) is an element distribution spectrum overview of example 1. Fig. 2 (a) is an SEM topography of example 2, fig. 2 (b) is a map of the nitrogen element distribution of Mapping of example 2, fig. 2 (c) is a map of the phosphorus element distribution of Mapping of example 2, and fig. 2 (d) is a total elemental distribution spectrum of example 2. Fig. 3 (a) is a SEM morphology diagram of silica particles, fig. 3 (b) is a map of oxygen element distribution of Mapping of silica particles, fig. 3 (c) is a map of silicon element distribution of Mapping of silica particles, and fig. 3 (d) is a total elemental distribution spectrum diagram of silica particles.

As can be seen from fig. 1 to 3, the pure silica particles have smooth surfaces and are composed of Si and O elements; after the silicon dioxide particles are coated and modified by the ammonium phytate, the surfaces of the hybrid particles are covered and coated by organic matters, and particularly, the mass ratio of the silicon dioxide to the ammonium phytate is 1: the surface organic covering of the hybrid flame retardant prepared in the step 1 is compact and complete, uniformly wraps the particle surface, and the surface organic matter component is mainly P, N, C element and is the main component of the ammonium phytate organic matter through element analysis test. The test result shows that the ammonium phytate can be uniformly and completely coated on the surface of the silicon dioxide.

Although the foregoing embodiments have been described in some, but not all embodiments of the invention, other embodiments may be obtained according to the present embodiments without departing from the scope of the invention.

Claims (10)

1. An ammonified silica flame retardant comprising silica and ammonium phytate chemically bonded to the silica.

2. The ammonium phytate silica flame retardant according to claim 1, characterized in that the mass ratio of the ammonium phytate to the silica is 1-2:1.

3. The method for preparing the phytic acid ammonium silicon dioxide flame retardant according to claim 1 or 2, which is characterized by comprising the following steps:

mixing an ammonium phytate solution and a silicon dioxide aqueous dispersion, and performing substitution reaction to obtain the ammonium phytate silicon dioxide flame retardant; the pH value of the silicon dioxide aqueous dispersion is 2-4.

4. The method of claim 3, wherein the ammonium phytate solution comprises ammonium phytate, ethanol and water.

5. The method according to claim 3 or 4, wherein the concentration of ammonium phytate in the ammonium phytate solution is 3 to 20wt%; the volume ratio of ethanol to water in the ammonium phytate solution is 0.5:1 to 3:1.

6. the method according to claim 3, wherein the temperature of the substitution reaction is 40 to 60℃and the time is 3 to 6 hours.

7. The use of the phytic acid ammonified silica flame retardant according to claim 1 or 2 or the phytic acid ammonified silica flame retardant prepared by the preparation method according to any one of claims 3 to 6 in flame retardant materials.

8. The PBAT-based flame-retardant composite material is characterized by comprising the following preparation raw materials in parts by weight:

80-95 parts of PBAT;

5-20 parts of phytic acid ammonification silicon dioxide flame retardant;

the phytic acid ammonium silicon dioxide flame retardant is the phytic acid ammonium silicon dioxide flame retardant of claim 1.

9. The method for preparing the PBAT-based flame retardant composite material of claim 8, comprising the steps of:

and mixing the PBAT and the phytic acid ammonium silicon dioxide flame retardant, and sequentially carrying out melt blending and extrusion molding to obtain the PBAT-based flame retardant composite material.

10. The method of claim 9, wherein the melt blending is performed at a temperature of 150 to 200 ℃.

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