阅读说明：本技术 一种协同阻燃聚丙烯复合材料及其制备方法 (Synergistic flame-retardant polypropylene composite material and preparation method thereof ) 是由 严小飞 赵志奎 祝成炎 戚栋明 于 2021-08-26 设计创作，主要内容包括：本发明公开了一种协同阻燃聚丙烯复合材料及其制备方法,涉及改性聚丙烯材料技术领域,解决现有聚丙烯复合材料阻燃性较差、力学性能不佳以及制备成本较高技术问题,包含以下重量百分比的成分：热塑性聚丙烯树脂90％、磷腈阻燃剂0％～10％、协同阻燃剂0％～10％；本发明将热塑性聚丙烯树脂、磷腈阻燃剂、协同阻燃剂以不同的质量比混合均匀,通过熔融共混、挤出、造粒、烘干即得到磷腈阻燃剂与协同阻燃的热塑性复合材料；其氧指数可达到33.6％,阻燃等级达到UL-94的V-0等级,拉伸强度为31.8MPa；其中二维的MXene能够很好的协助磷腈阻燃剂,形成物理隔热碳层,阻止了树脂基的进一步氧化；由于二维的MXene材料具有优异的力学性能,还有助于提高复合材料的力学性能。(The invention discloses a synergistic flame-retardant polypropylene composite material and a preparation method thereof, relates to the technical field of modified polypropylene materials, solves the technical problems of poor flame retardance, poor mechanical property and high preparation cost of the existing polypropylene composite material, and comprises the following components in percentage by weight: 90% of thermoplastic polypropylene resin, 0% -10% of phosphazene flame retardant and 0% -10% of synergistic flame retardant; uniformly mixing thermoplastic polypropylene resin, a phosphazene flame retardant and a synergistic flame retardant in different mass ratios, and carrying out melt blending, extrusion, granulation and drying to obtain a phosphazene flame retardant and synergistic flame retardant thermoplastic composite material; the oxygen index can reach 33.6 percent, the flame retardant grade reaches the V-0 grade of UL-94, and the tensile strength is 31.8 MPa; the two-dimensional MXene can well assist the phosphazene flame retardant to form a physical heat insulation carbon layer, so that the resin base is prevented from being further oxidized; the two-dimensional MXene material has excellent mechanical property, and is favorable for improving the mechanical property of the composite material.)

1. The synergistic flame-retardant polypropylene composite material is characterized by being prepared from the following components in percentage by weight: 0 to 10 percent of phosphorus flame retardant, 0 to 10 percent of synergistic flame retardant and the balance of thermoplastic polypropylene resin.

2. The synergistic flame-retardant polypropylene composite material as claimed in claim 1, wherein the synergistic flame-retardant polypropylene composite material is prepared from the following components in percentage by weight: 2 to 8 percent of phosphorus flame retardant, 2 to 8 percent of synergistic flame retardant and the balance of thermoplastic polypropylene resin.

3. The synergistic flame-retardant polypropylene composite material as claimed in claim 1, wherein the synergistic flame-retardant polypropylene composite material is prepared from the following components in percentage by weight: 4% of phosphorus nitrile flame retardant, 6% of synergistic flame retardant and the balance of thermoplastic polypropylene resin.

4. The synergistic flame-retardant polypropylene composite material as claimed in claim 1, wherein the synergistic flame-retardant polypropylene composite material is prepared from the following components in percentage by weight: 6 percent of phosphorus nitrile flame retardant, 4 percent of synergistic flame retardant and the balance of thermoplastic polypropylene resin.

5. The synergistic flame retardant polypropylene composite according to claim 1, wherein the phosphazene flame retardant is hexa- (4-allyl ether phenoxy) cyclotriphosphazene flame retardant PACP.

6. The synergistic flame retardant polypropylene composite according to claim 5, wherein the synthesis of the hexa- (4-allyl ether phenoxy) cyclotriphosphazene flame retardant PACP comprises the following steps:

dissolving p-hydroxyphenyl ether in tetrahydrofuran, adding sodium hydroxide, dropwise adding a cyclotriphosphazene/tetrahydrofuran solution by using a constant-pressure dropping funnel after the p-hydroxyphenyl ether is dissolved, heating to 70-80 ℃ after the dropwise adding is finished, reacting for 20-30 hours, and obtaining a first product after the reaction is finished by suction filtration, rotary evaporation, washing and drying; wherein, the mass volume ratio of the p-hydroxyanisole, the tetrahydrofuran, the sodium hydroxide and the cyclotriphosphazene/tetrahydrofuran solution is 2 g-3 g: 15 mL-25 mL: 0.9 g-1.0 g: 1g/(4 mL-5 mL);

dissolving the first product prepared in the step (1) in dichloromethane, dropwise adding boron tribromide/dichloromethane solution by using a constant-pressure dropping funnel after complete dissolution, reacting at normal temperature for 48-56 hours after dropwise adding, and performing rotary evaporation, washing and drying after reaction to obtain a second product; wherein the mass volume ratio of the first product to the dichloromethane to the boron tribromide/dichloromethane solution is 1 g: 10 mL-20 mL:

(0.7mL～0.9mL)/(10mL～20mL)；

step (3), dissolving the second product prepared in the step (2) in an allyl bromide/acetone solution, reacting for 16-24 hours at normal temperature, and performing rotary evaporation and drying on the obtained reaction liquid to obtain the hexa- (4-allyl ether phenoxy) cyclotriphosphazene flame retardant PACP; wherein, the mass volume ratio of the second product to the allyl bromide/acetone solution is 1 g: (0.9-1.0 mL)/(30-50 mL).

7. The synergistic flame retardant polypropylene composite according to claim 1, wherein the synergistic flame retardant is MXene.

8. The synergistic flame retardant polypropylene composite material as claimed in claim 7, wherein the synthesis of MXene as the synergistic flame retardant comprises the following steps:

step one, mixing and stirring LiF and HCl solution with the concentration of 10-15 mol/L for 10-20 min at room temperature, wherein the stirring speed is 10-30 r/min, and then adding Ti₃AlC₂Heating to 40-50 ℃, and stirring for 12-24 hours to obtain multilayer MXene; wherein, LiF, HCl and Ti₃AlC₂The mass-volume ratio of the three is 1 g: 10 mL-20 mL: 1g of a compound;

and secondly, oscillating the multilayer MXene obtained in the first step for 20-40 min under ultrasonic wave in an ice-water bath, wherein the ultrasonic frequency is 40-50 KHz, and thus obtaining the monolayer MXene.

9. The preparation method of the synergistic flame retardant polypropylene composite material as claimed in any one of the claims 1 to 8, comprising the following steps: firstly, respectively weighing the thermoplastic polypropylene resin, the phosphorus-nitrile flame retardant and the synergistic flame retardant according to the weight percentage, respectively drying for 6 hours in a vacuum oven at the temperature of 50-80 ℃, then mixing the phosphorus-nitrile flame retardant, the synergistic flame retardant and the thermoplastic polypropylene resin in a high-speed mixer for 30min, finally putting the mixture into a double-screw extruder for melt mixing, extruding, granulating, drying and tabletting to obtain the synergistic flame-retardant polypropylene composite material, wherein the mixing temperature of the double-screw extruder is 150-220 ℃, and the screw rotating speed is 80-100 r/min.

Technical Field

The invention relates to the technical field of modified polypropylene materials, in particular to a synergistic flame-retardant polypropylene composite material and a preparation method thereof.

Background

The polypropylene has good mechanical property, high heat resistance, good chemical property, good electrical insulation property, almost no water absorption and good molding and processing properties, and is widely applied to the fields of automobiles, building materials, household appliances and the like, but the polypropylene is flammable and greatly limits the application of the polypropylene, so the polypropylene has more application values through flame retardant modification.

At present, for the flame-retardant polypropylene composite material, suitable flame retardants include magnesium hydroxide, aluminum hydroxide, phosphoric acid triester, ammonium polyphosphate, octabromoether, triphenyl phosphate, hexabromocyclododecane, nitrogen-phosphorus flame retardants, zinc borate, decabromodiphenylethane, coated red phosphorus, triisocyanurate and the like; although the currently commonly used halogen flame retardant has excellent flame retardant performance, toxic gas is generated in the processing and combustion processes of the halogen flame retardant, and the halogen flame retardant is harmful to human health, so that more halogen-free flame retardants are researched by people; on the contrary, phosphazene flame retardants are widely studied because of their natural flame retardant effect and no harmful gas is generated during combustion; as for the PACP flame retardant, although the PACP flame retardant has a good flame retardant effect, the influence of the addition amount of the PACP flame retardant on the mechanical property of the material is large; therefore, by adding other flame-retardant systems, the synergistic flame retardance is realized, and the use ratio of the PACP in the flame-retardant composite material is reduced.

MXene materials, a new two-dimensional material, are generally used to enhance the flame retardancy and mechanical properties of polymeric materials due to their high aspect ratio, excellent mechanical strength and stiffness; meanwhile, MXene also has good conductivity, stability and abundant surface functional groups, and polar functional groups such as hydroxyl and the like on the surface of MXene can obviously enhance a high polymer material; the MXene two-dimensional planar structure is beneficial to enhancing the mechanical property of the material; on the other hand, the carbon coating is beneficial to isolating gas, so that the formed carbon layer is thicker and denser.

Therefore, the PACP and the MXene are mixed according to a certain mass ratio and added into the polypropylene material together, and the consumption of the PACP is reduced on the premise of improving the flame retardant property of the polypropylene material through mutual synergistic flame retardance; in addition, MXene can be used for improving the mechanical property of the composite material.

Disclosure of Invention

The invention aims to: in order to solve the problems of poor flame retardance, poor mechanical property and high preparation cost of the conventional polypropylene composite material, the invention provides a synergistic flame-retardant polypropylene composite material and a preparation method thereof.

The invention specifically adopts the following technical scheme for realizing the purpose:

the synergistic flame-retardant polypropylene composite material is prepared from the following components in percentage by weight: 0 to 10 percent of phosphorus flame retardant, 0 to 10 percent of synergistic flame retardant and the balance of thermoplastic polypropylene resin.

Further, the synergistic flame-retardant polypropylene composite material is prepared from the following components in percentage by weight: 2 to 8 percent of phosphorus flame retardant, 2 to 8 percent of synergistic flame retardant and the balance of thermoplastic polypropylene resin.

Further, the synergistic flame-retardant polypropylene composite material is prepared from the following components in percentage by weight: 4% of phosphorus nitrile flame retardant, 6% of synergistic flame retardant and the balance of thermoplastic polypropylene resin.

Further, the synergistic flame-retardant polypropylene composite material is prepared from the following components in percentage by weight: 6 percent of phosphorus nitrile flame retardant, 4 percent of synergistic flame retardant and the balance of thermoplastic polypropylene resin.

Further, the phosphazene flame retardant is a hexa- (4-allyl ether phenoxy) cyclotriphosphazene flame retardant PACP.

Further, the synthesis steps of the hexa- (4-allyl ether phenoxy) cyclotriphosphazene flame retardant PACP are as follows:

dissolving p-hydroxyphenyl ether in tetrahydrofuran, adding sodium hydroxide, dropwise adding a cyclotriphosphazene/tetrahydrofuran solution by using a constant-pressure dropping funnel after the p-hydroxyphenyl ether is dissolved, heating to 70-80 ℃ after the dropwise adding is finished, reacting for 20-30 hours, and obtaining a first product after the reaction is finished by suction filtration, rotary evaporation, washing and drying; wherein, the mass volume ratio of the p-hydroxyanisole, the tetrahydrofuran, the sodium hydroxide and the cyclotriphosphazene/tetrahydrofuran solution is 2 g-3 g: 15 mL-25 mL: 0.9 g-1.0 g: 1g/(4 mL-5 mL);

dissolving the first product prepared in the step (1) in dichloromethane, dropwise adding boron tribromide/dichloromethane solution by using a constant-pressure dropping funnel after complete dissolution, reacting at normal temperature for 48-56 hours after dropwise adding, and performing rotary evaporation, washing and drying after reaction to obtain a second product; wherein the mass volume ratio of the first product to the dichloromethane to the boron tribromide/dichloromethane solution is 1 g: 10 mL-20 mL:

(0.7mL～0.9mL)/(10mL～20mL)；

step (3), dissolving the second product prepared in the step (2) in an allyl bromide/acetone solution, reacting for 16-24 hours at normal temperature, and performing rotary evaporation and drying on the obtained reaction liquid to obtain the hexa- (4-allyl ether phenoxy) cyclotriphosphazene flame retardant PACP; wherein, the mass volume ratio of the second product to the allyl bromide/acetone solution is 1 g: (0.9-1.0 mL)/(30-50 mL).

Further, the synergistic flame retardant is MXene.

Further, the synthesis step of MXene as the synergistic flame retardant comprises the following steps:

step one, mixing and stirring LiF and HCl solution with the concentration of 10-15 mol/L for 10-20 min at room temperature, wherein the stirring speed is 10-30 r/min, and then adding Ti₃AlC₂Heating to 40-50 ℃, and stirring for 12-24 hours to obtain multilayer MXene; wherein, LiF, HCl and Ti₃AlC₂The mass-volume ratio of the three is 1 g: 10 mL-20 mL: 1g of a compound;

and secondly, oscillating the multilayer MXene obtained in the first step for 20-40 min under ultrasonic wave in an ice-water bath, wherein the ultrasonic frequency is 40-50 KHz, and thus obtaining the monolayer MXene.

The invention also aims to provide a preparation method of the synergistic flame-retardant polypropylene composite material, which comprises the following steps: firstly, respectively weighing the thermoplastic polypropylene resin, the phosphorus-nitrile flame retardant and the synergistic flame retardant according to the weight percentage, respectively drying for 6 hours in a vacuum oven at the temperature of 50-80 ℃, then mixing the phosphorus-nitrile flame retardant, the synergistic flame retardant and the thermoplastic polypropylene resin in a high-speed mixer for 30min, finally putting the mixture into a double-screw extruder for melt mixing, extruding, granulating, drying and tabletting to obtain the synergistic flame-retardant polypropylene composite material, wherein the mixing temperature of the double-screw extruder is 150-220 ℃, and the screw rotating speed is 80-100 r/min.

The invention has the following beneficial effects:

according to the PACP and MXene synergistic flame-retardant polypropylene composite material prepared by the invention, on one hand, the flame retardant property of the composite material is improved by MXene on the premise of reducing the use amount of PACP, and on the other hand, the mechanical property of the composite material is improved by virtue of the mechanical property of the MXene;

the oxygen index of the synergistic flame-retardant polypropylene composite material prepared by the invention can reach 33.6%, the flame-retardant grade reaches V-0 grade of UL-94, the tensile strength is 31.8MPa, and the synergistic flame-retardant polypropylene composite material can be widely applied to the fields of automobiles, building materials, household appliances and the like.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are a part of the embodiments of the present invention, but not all of the embodiments.

All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

The synergistic flame-retardant polypropylene composite material provided in the embodiment 1 and the preparation method thereof are as follows: weighing 90g of thermoplastic polypropylene resin, 90g of PACP0g and 10g of MXene, placing the thermoplastic polypropylene resin in a vacuum oven at the temperature of 50 ℃ for drying for 6h, then mixing the phosphorus nitrile flame retardant, the synergistic flame retardant and the thermoplastic polypropylene resin in a high-speed mixer for 30min, placing the mixture in a double-screw extruder for melt mixing, extrusion, granulation, drying and tabletting, controlling the mixing temperature of the double-screw extruder to be 150 ℃ and the screw rotation speed to be 80r/min, and thus obtaining the synergistic flame-retardant polypropylene composite material.

Wherein the phosphazene flame retardant is a hexa- (4-allyl ether phenoxy) cyclotriphosphazene flame retardant PACP; the synthesis steps of the hexa- (4-allyl ether phenoxy) cyclotriphosphazene flame retardant PACP are as follows:

dissolving p-hydroxyphenyl ether in tetrahydrofuran, adding sodium hydroxide, dropwise adding a cyclotriphosphazene/tetrahydrofuran solution by using a constant-pressure dropping funnel after the p-hydroxyphenyl ether is dissolved, heating to 70 ℃ after the dropwise adding is finished, reacting for 20 hours, and obtaining a first product after the reaction is finished by suction filtration, rotary evaporation, washing and drying; wherein, the mass volume ratio of p-hydroxyanisole, tetrahydrofuran, sodium hydroxide and cyclotriphosphazene/tetrahydrofuran solution is 2 g: 15mL of: 0.9 g: (1g/4 mL);

dissolving the first product prepared in the step (1) in dichloromethane, dropwise adding boron tribromide/dichloromethane solution by using a constant-pressure dropping funnel after complete dissolution, reacting at normal temperature for 48 hours after dropwise adding, and performing rotary evaporation, washing and drying after the reaction is finished to obtain a second product; wherein the mass volume ratio of the first product to the dichloromethane to the boron tribromide/dichloromethane solution is 1 g: 10mL of: (0.7mL/10 mL);

step (3), dissolving the second product prepared in the step (2) in an allyl bromide/acetone solution to react for 16 hours at normal temperature, and performing rotary evaporation and drying on the obtained reaction liquid to obtain the hexa- (4-allyl ether phenoxy) cyclotriphosphazene flame retardant PACP; wherein, the mass volume ratio of the second product to the allyl bromide/acetone solution is 1 g: (0.9mL/50 mL).

Wherein the synergistic flame retardant is MXene; the synthesis of MXene as synergistic flame retardant comprises the following steps:

step one, mixing and stirring LiF and HCl solution with the concentration of 10mol/L for 10min at room temperature, wherein the stirring speed is10r/min, then adding Ti₃AlC₂Heating to 40 ℃, and stirring for 12 hours to obtain multilayer MXene; wherein, LiF, HCl and Ti₃AlC₂The mass-volume ratio of the three is 1 g: 10mL of: 1g of a compound;

and secondly, oscillating the multilayer MXene obtained in the step one for 20min under ultrasonic wave in an ice-water bath, wherein the ultrasonic frequency is 40KHz, and thus obtaining the monolayer MXene.

The standard sample strips of the synergistic flame-retardant polypropylene composite material obtained in the example 1 were subjected to a limiting oxygen index test, a UL-94 vertical burning test and a tensile strength test, and the results are shown in table 1.

Example 2

The synergistic flame-retardant polypropylene composite material provided in the embodiment 2 and the preparation method thereof are as follows: weighing 90g of thermoplastic polypropylene resin, 90g of PACP2g and 8 MXene8g, placing the thermoplastic polypropylene resin in a vacuum oven at the temperature of 80 ℃ for drying for 6h, then mixing the phosphorus nitrile flame retardant, the synergistic flame retardant and the thermoplastic polypropylene resin in a high-speed mixer for 30min, placing the mixture in a double-screw extruder for melt mixing, extrusion, granulation, drying and tabletting, controlling the mixing temperature of the double-screw extruder to be 220 ℃ and the rotating speed of a screw to be 100r/min, and thus obtaining the synergistic flame-retardant polypropylene composite material.

Wherein the phosphazene flame retardant is a hexa- (4-allyl ether phenoxy) cyclotriphosphazene flame retardant PACP; the synthesis steps of the hexa- (4-allyl ether phenoxy) cyclotriphosphazene flame retardant PACP are as follows:

dissolving p-hydroxyphenyl ether in tetrahydrofuran, adding sodium hydroxide, dropwise adding a cyclotriphosphazene/tetrahydrofuran solution by using a constant-pressure dropping funnel after the p-hydroxyphenyl ether is dissolved, heating to 80 ℃ after the dropwise adding is finished, reacting for 30 hours, and obtaining a first product after the reaction is finished by suction filtration, rotary evaporation, washing and drying; wherein, the mass volume ratio of p-hydroxyanisole, tetrahydrofuran, sodium hydroxide and cyclotriphosphazene/tetrahydrofuran solution is 3 g: 25mL of: 1.0 g: (1g/5 mL);

dissolving the first product prepared in the step (1) in dichloromethane, dropwise adding boron tribromide/dichloromethane solution by using a constant-pressure dropping funnel after complete dissolution, reacting at normal temperature for 48-56 hours after dropwise adding, and performing rotary evaporation, washing and drying after reaction to obtain a second product; wherein the mass volume ratio of the first product to the dichloromethane to the boron tribromide/dichloromethane solution is 1 g: 20mL of:

(0.9mL/20mL)；

step (3), dissolving the second product prepared in the step (2) in an allyl bromide/acetone solution to react for 24 hours at normal temperature, and performing rotary evaporation and drying on the obtained reaction liquid to obtain the hexa- (4-allyl ether phenoxy) cyclotriphosphazene flame retardant PACP; wherein, the mass volume ratio of the second product to the allyl bromide/acetone solution is 1 g: (1.0mL/50 mL).

Wherein the synergistic flame retardant is MXene; the synthesis of MXene as synergistic flame retardant comprises the following steps:

step one, mixing and stirring LiF and HCl solution with the concentration of 15mol/L for 20min at room temperature, wherein the stirring speed is 30r/min, and then adding Ti₃AlC₂Heating to 50 ℃, and stirring for 24 hours to obtain a multilayer MXene; wherein, LiF, HCl and Ti₃AlC₂The mass-volume ratio of the three is 1 g: 20mL of: 1g of a compound;

and secondly, oscillating the multilayer MXene obtained in the first step for 40min under ultrasonic wave in an ice-water bath, wherein the ultrasonic frequency is 50KHz, and thus obtaining the monolayer MXene.

The standard sample strips of the synergistic flame-retardant polypropylene composite material obtained in the example 2 were subjected to a limiting oxygen index test, a UL-94 vertical burning test and a tensile strength test, and the results are shown in table 1.

Example 3

The synergistic flame-retardant thermoplastic polypropylene composite material provided in the embodiment 3 and the preparation method thereof are as follows: weighing 90g of thermoplastic polypropylene resin, 90g of PACP4g and MXene6g, placing the thermoplastic polypropylene resin in a vacuum oven at the temperature of 60 ℃ for drying for 6h, then mixing the phosphorus nitrile flame retardant, the synergistic flame retardant and the thermoplastic polypropylene resin in a high-speed mixer for 30min, placing the mixture in a double-screw extruder for melt mixing, extrusion, granulation, drying and tabletting, controlling the mixing temperature of the double-screw extruder to be 180 ℃ and the screw rotation speed to be 85r/min, and thus obtaining the synergistic flame-retardant polypropylene composite material.

Wherein the phosphazene flame retardant is a hexa- (4-allyl ether phenoxy) cyclotriphosphazene flame retardant PACP; the synthesis steps of the hexa- (4-allyl ether phenoxy) cyclotriphosphazene flame retardant PACP are as follows:

dissolving p-hydroxyphenyl ether in tetrahydrofuran, adding sodium hydroxide, dropwise adding a cyclotriphosphazene/tetrahydrofuran solution by using a constant-pressure dropping funnel after the p-hydroxyphenyl ether is dissolved, heating to 78 ℃ after the dropwise adding is finished, reacting for 24 hours, and performing suction filtration, rotary evaporation, washing and drying after the reaction is finished to obtain a first product; wherein, the mass volume ratio of p-hydroxyanisole, tetrahydrofuran, sodium hydroxide and cyclotriphosphazene/tetrahydrofuran solution is 2.5 g: 20mL of: 0.95 g: (1g/4.5 mL);

dissolving the first product prepared in the step (1) in dichloromethane, dropwise adding boron tribromide/dichloromethane solution by using a constant-pressure dropping funnel after complete dissolution, reacting at normal temperature for 48 hours after dropwise adding, and performing rotary evaporation, washing and drying after the reaction is finished to obtain a second product; wherein the mass volume ratio of the first product to the dichloromethane to the boron tribromide/dichloromethane solution is 1 g: 15mL of: (0.8mL/15 mL);

step (3), dissolving the second product prepared in the step (2) in an allyl bromide/acetone solution to react for 20 hours at normal temperature, and performing rotary evaporation and drying on the obtained reaction liquid to obtain the hexa- (4-allyl ether phenoxy) cyclotriphosphazene flame retardant PACP; wherein, the mass volume ratio of the second product to the allyl bromide/acetone solution is 1 g: (0.95mL/40 mL).

Wherein the synergistic flame retardant is MXene; the synthesis of MXene as synergistic flame retardant comprises the following steps:

step one, mixing and stirring LiF and HCl solution with the concentration of 12mol/L for 15min at room temperature, wherein the stirring speed is 20r/min, and then adding Ti₃AlC₂Heating to 45 ℃, and stirring for 18 hours to obtain a multilayer MXene; wherein, LiF, HCl and Ti₃AlC₂The mass-volume ratio of the three is 1 g: 15mL of: 1g of a compound;

and secondly, oscillating the multilayer MXene obtained in the step one for 30min under ultrasonic wave in an ice water bath, wherein the ultrasonic frequency is 45KHz, and thus obtaining the monolayer MXene.

The standard sample strips of the synergistic flame-retardant polypropylene composite material obtained in the embodiment 3 are subjected to a limited oxygen index test, a UL-94 vertical burning test and a tensile strength test, and the results are shown in Table 1.

Example 4

The synergistic flame-retardant thermoplastic polypropylene composite material provided in this embodiment 4 and the preparation method thereof are as follows: weighing 90g of thermoplastic polypropylene resin, 90g of PACP6g and MXene4g, placing the thermoplastic polypropylene resin in a vacuum oven at the temperature of 70 ℃ for drying for 6h, then mixing the phosphorus nitrile flame retardant, the synergistic flame retardant and the thermoplastic polypropylene resin in a high-speed mixer for 30min, placing the mixture in a double-screw extruder for melt mixing, extruding, granulating, drying and tabletting, controlling the mixing temperature of the double-screw extruder to be 200 ℃ and the screw rotation speed to be 90r/min, and thus obtaining the synergistic flame-retardant polypropylene composite material.

Wherein the phosphazene flame retardant is a hexa- (4-allyl ether phenoxy) cyclotriphosphazene flame retardant PACP; the synthesis steps of the hexa- (4-allyl ether phenoxy) cyclotriphosphazene flame retardant PACP are as follows:

dissolving p-hydroxyphenyl ether in tetrahydrofuran, adding sodium hydroxide, dropwise adding a cyclotriphosphazene/tetrahydrofuran solution by using a constant-pressure dropping funnel after the p-hydroxyphenyl ether is dissolved, heating to 70 ℃ after the dropwise adding is finished, reacting for 20 hours, and obtaining a first product after the reaction is finished by suction filtration, rotary evaporation, washing and drying; wherein, the mass volume ratio of p-hydroxyanisole, tetrahydrofuran, sodium hydroxide and cyclotriphosphazene/tetrahydrofuran solution is 2 g: 15mL of: 0.9 g: (1g/4 mL);

dissolving the first product prepared in the step (1) in dichloromethane, dropwise adding boron tribromide/dichloromethane solution by using a constant-pressure dropping funnel after complete dissolution, reacting at normal temperature for 48 hours after dropwise adding, and performing rotary evaporation, washing and drying after the reaction is finished to obtain a second product; wherein the mass volume ratio of the first product to the dichloromethane to the boron tribromide/dichloromethane solution is 1 g: 10mL of: (0.7mL/10 mL);

step (3), dissolving the second product prepared in the step (2) in an allyl bromide/acetone solution to react for 16 hours at normal temperature, and performing rotary evaporation and drying on the obtained reaction liquid to obtain the hexa- (4-allyl ether phenoxy) cyclotriphosphazene flame retardant PACP; wherein, the mass volume ratio of the second product to the allyl bromide/acetone solution is 1 g: (0.9mL/50 mL).

Wherein the synergistic flame retardant is MXene; the synthesis of MXene as synergistic flame retardant comprises the following steps:

step one, mixing and stirring LiF and HCl solution with the concentration of 10mol/L for 10min at room temperature, wherein the stirring speed is 10r/min, and then adding Ti₃AlC₂Heating to 40 ℃, and stirring for 12 hours to obtain multilayer MXene; wherein, LiF, HCl and Ti₃AlC₂The mass-volume ratio of the three is 1 g: 10mL of: 1g of a compound;

and secondly, oscillating the multilayer MXene obtained in the step one for 20min under ultrasonic wave in an ice-water bath, wherein the ultrasonic frequency is 40KHz, and thus obtaining the monolayer MXene.

The standard sample strips of the synergistic flame-retardant polypropylene composite material obtained in the embodiment 4 were subjected to a limiting oxygen index test, a UL-94 vertical burning test and a tensile strength test, and the results are shown in table 1.

Example 5

The synergistic flame-retardant thermoplastic polypropylene composite material provided in this embodiment 5 and the preparation method thereof are as follows: weighing 90g of thermoplastic polypropylene resin, 90g of PACP8g and MXene2g, placing the thermoplastic polypropylene resin in a vacuum oven at the temperature of 65 ℃ for drying for 6h, then mixing the phosphorus nitrile flame retardant, the synergistic flame retardant and the thermoplastic polypropylene resin in a high-speed mixer for 30min, placing the mixture in a double-screw extruder for melt mixing, extruding, granulating, drying and tabletting, controlling the mixing temperature of the double-screw extruder to be 190 ℃ and the rotating speed of a screw to be 90r/min, and thus obtaining the synergistic flame-retardant polypropylene composite material.

Wherein the phosphazene flame retardant is a hexa- (4-allyl ether phenoxy) cyclotriphosphazene flame retardant PACP; the synthesis steps of the hexa- (4-allyl ether phenoxy) cyclotriphosphazene flame retardant PACP are as follows:

dissolving p-hydroxyphenyl ether in tetrahydrofuran, adding sodium hydroxide, dropwise adding a cyclotriphosphazene/tetrahydrofuran solution by using a constant-pressure dropping funnel after the p-hydroxyphenyl ether is dissolved, heating to 80 ℃ after the dropwise adding is finished, reacting for 30 hours, and obtaining a first product after the reaction is finished by suction filtration, rotary evaporation, washing and drying; wherein, the mass volume ratio of p-hydroxyanisole, tetrahydrofuran, sodium hydroxide and cyclotriphosphazene/tetrahydrofuran solution is 3 g: 25mL of: 1.0 g: (1g/5 mL);

dissolving the first product prepared in the step (1) in dichloromethane, dropwise adding boron tribromide/dichloromethane solution by using a constant-pressure dropping funnel after complete dissolution, reacting at normal temperature for 48-56 hours after dropwise adding, and performing rotary evaporation, washing and drying after reaction to obtain a second product; wherein the mass volume ratio of the first product to the dichloromethane to the boron tribromide/dichloromethane solution is 1 g: 20mL of:

(0.9mL/20mL)；

step (3), dissolving the second product prepared in the step (2) in an allyl bromide/acetone solution to react for 24 hours at normal temperature, and performing rotary evaporation and drying on the obtained reaction liquid to obtain the hexa- (4-allyl ether phenoxy) cyclotriphosphazene flame retardant PACP; wherein, the mass volume ratio of the second product to the allyl bromide/acetone solution is 1 g: (1.0mL/50 mL).

Wherein the synergistic flame retardant is MXene; the synthesis of MXene as synergistic flame retardant comprises the following steps:

step one, mixing and stirring LiF and HCl solution with the concentration of 15mol/L for 20min at room temperature, wherein the stirring speed is 30r/min, and then adding Ti₃AlC₂Heating to 50 ℃, and stirring for 24 hours to obtain a multilayer MXene; wherein, LiF, HCl and Ti₃AlC₂The mass-volume ratio of the three is 1 g: 20mL of: 1g of a compound;

and secondly, oscillating the multilayer MXene obtained in the first step for 40min under ultrasonic wave in an ice-water bath, wherein the ultrasonic frequency is 50KHz, and thus obtaining the monolayer MXene.

The standard sample strips of the synergistic flame-retardant polypropylene composite material obtained in the example 5 were subjected to a limiting oxygen index test, a UL-94 vertical burning test and a tensile strength test, and the results are shown in Table 1.

Example 6

The synergistic flame-retardant thermoplastic polypropylene composite material provided in this embodiment 6 and the preparation method thereof are as follows: weighing 90g of thermoplastic polypropylene resin, 90g of PACP10g and 0g of MXene, placing the thermoplastic polypropylene resin in a vacuum oven at the temperature of 65 ℃ for drying for 6h, then mixing the phosphorus nitrile flame retardant, the synergistic flame retardant and the thermoplastic polypropylene resin in a high-speed mixer for 30min, placing the mixture in a double-screw extruder for melt mixing, extrusion, granulation, drying and tabletting, controlling the mixing temperature of the double-screw extruder to be 190 ℃ and the screw rotation speed to be 90r/min, and thus obtaining the synergistic flame-retardant polypropylene composite material.

Wherein the phosphazene flame retardant is a hexa- (4-allyl ether phenoxy) cyclotriphosphazene flame retardant PACP; the synthesis steps of the hexa- (4-allyl ether phenoxy) cyclotriphosphazene flame retardant PACP are as follows:

dissolving p-hydroxyphenyl ether in tetrahydrofuran, adding sodium hydroxide, dropwise adding a cyclotriphosphazene/tetrahydrofuran solution by using a constant-pressure dropping funnel after the p-hydroxyphenyl ether is dissolved, heating to 78 ℃ after the dropwise adding is finished, reacting for 24 hours, and performing suction filtration, rotary evaporation, washing and drying after the reaction is finished to obtain a first product; wherein, the mass volume ratio of p-hydroxyanisole, tetrahydrofuran, sodium hydroxide and cyclotriphosphazene/tetrahydrofuran solution is 2.5 g: 20mL of: 0.95 g: (1g/4.5 mL);

dissolving the first product prepared in the step (1) in dichloromethane, dropwise adding boron tribromide/dichloromethane solution by using a constant-pressure dropping funnel after complete dissolution, reacting at normal temperature for 48 hours after dropwise adding, and performing rotary evaporation, washing and drying after the reaction is finished to obtain a second product; wherein the mass volume ratio of the first product to the dichloromethane to the boron tribromide/dichloromethane solution is 1 g: 15mL of: (0.8mL/15 mL);

step (3), dissolving the second product prepared in the step (2) in an allyl bromide/acetone solution to react for 20 hours at normal temperature, and performing rotary evaporation and drying on the obtained reaction liquid to obtain the hexa- (4-allyl ether phenoxy) cyclotriphosphazene flame retardant PACP; wherein, the mass volume ratio of the second product to the allyl bromide/acetone solution is 1 g: (0.95mL/40 mL).

Wherein the synergistic flame retardant is MXene; the synthesis of MXene as synergistic flame retardant comprises the following steps:

step one, mixing and stirring LiF and HCl solution with the concentration of 12mol/L for 15min at room temperature, wherein the stirring speed is 20r/min, and then adding Ti₃AlC₂Heating to 45 ℃, and stirring for 18 hours to obtain a multilayer MXene; wherein, LiF, HCl and Ti₃AlC₂The mass-volume ratio of the three is 1 g: 15mL of: 1g of a compound;

and secondly, oscillating the multilayer MXene obtained in the step one for 30min under ultrasonic wave in an ice water bath, wherein the ultrasonic frequency is 45KHz, and thus obtaining the monolayer MXene.

The standard sample strips of the synergistic flame-retardant polypropylene composite material obtained in the example 6 were subjected to a limiting oxygen index test, a UL-94 vertical burning test and a tensile strength test, and the results are shown in Table 1.

Comparative example

The synergistic flame-retardant thermoplastic polypropylene composite material provided by the comparative example and the preparation method thereof are as follows: weighing 90g of thermoplastic polypropylene resin, 90g of PACP0g and 0g of MXene, placing the thermoplastic polypropylene resin in a vacuum oven at the temperature of 65 ℃ for drying for 6h, then mixing the phosphorus nitrile flame retardant, the synergistic flame retardant and the thermoplastic polypropylene resin in a high-speed mixer for 30min, placing the mixture in a double-screw extruder for melt mixing, extrusion, granulation, drying and tabletting, controlling the mixing temperature of the double-screw extruder to be 190 ℃ and the rotating speed of a screw to be 90r/min, and thus obtaining the polypropylene composite material.

Wherein the phosphazene flame retardant is a hexa- (4-allyl ether phenoxy) cyclotriphosphazene flame retardant PACP; the synthesis steps of the hexa- (4-allyl ether phenoxy) cyclotriphosphazene flame retardant PACP are as follows:

dissolving p-hydroxyphenyl ether in tetrahydrofuran, adding sodium hydroxide, dropwise adding a cyclotriphosphazene/tetrahydrofuran solution by using a constant-pressure dropping funnel after the p-hydroxyphenyl ether is dissolved, heating to 78 ℃ after the dropwise adding is finished, reacting for 24 hours, and performing suction filtration, rotary evaporation, washing and drying after the reaction is finished to obtain a first product; wherein, the mass volume ratio of p-hydroxyanisole, tetrahydrofuran, sodium hydroxide and cyclotriphosphazene/tetrahydrofuran solution is 2.5 g: 20mL of: 0.95 g: (1g/4.5 mL);

dissolving the first product prepared in the step (1) in dichloromethane, dropwise adding boron tribromide/dichloromethane solution by using a constant-pressure dropping funnel after complete dissolution, reacting at normal temperature for 48 hours after dropwise adding, and performing rotary evaporation, washing and drying after the reaction is finished to obtain a second product; wherein the mass volume ratio of the first product to the dichloromethane to the boron tribromide/dichloromethane solution is 1 g: 15mL of: (0.8mL/15 mL);

step (3), dissolving the second product prepared in the step (2) in an allyl bromide/acetone solution to react for 20 hours at normal temperature, and performing rotary evaporation and drying on the obtained reaction liquid to obtain the hexa- (4-allyl ether phenoxy) cyclotriphosphazene flame retardant PACP; wherein, the mass volume ratio of the second product to the allyl bromide/acetone solution is 1 g: (0.95mL/40 mL).

Wherein the synergistic flame retardant is MXene; the synthesis of MXene as synergistic flame retardant comprises the following steps:

step one, mixing and stirring LiF and HCl solution with the concentration of 12mol/L for 15min at room temperature, wherein the stirring speed is 20r/min, and then adding Ti₃AlC₂Heating to 45 ℃, and stirring for 18 hours to obtain a multilayer MXene; wherein, LiF, HCl and Ti₃AlC₂The mass-volume ratio of the three is 1 g: 15mL of: 1g of a compound;

and secondly, oscillating the multilayer MXene obtained in the step one for 30min under ultrasonic wave in an ice water bath, wherein the ultrasonic frequency is 45KHz, and thus obtaining the monolayer MXene.

The standard sample strips of the synergistic flame-retardant polypropylene composite material obtained in the comparative example are subjected to a limited oxygen index test, a UL-94 vertical burning test and a tensile strength test, and the results are shown in Table 1.

In summary, the results of the limited oxygen index test, the UL-94 vertical burning test and the tensile strength test performed on the standard sample bars of the synergetic flame retardant polypropylene composite prepared in the above examples 1 to 6 and comparative examples are shown in table 1:

table 1: combustion test results of the flame-retardant thermoplastic polypropylene composite materials prepared in the above examples 1-6 and comparative examples of the present invention

As can be seen from Table 1, the composite formula of PACP and MXene and the comparative example in the embodiments 1-6 of the invention can obviously show that although PACP has good flame retardant property, the PACP has great influence on the mechanical property of the composite material; by adding the synergistic flame retardant MXene, the improvement of flame retardant performance is facilitated, and the influence of PACP on the material performance is compensated, so that the synergistic flame retardant propylene composite material with flame retardant and mechanical properties is realized.

According to the PACP and MXene synergistic flame-retardant thermoplastic polypropylene composite material provided by the invention, MXene can enhance the flame retardant property of the composite material and improve the mechanical property of the composite material; the flame retardant additive does not contain halogen, is environment-friendly, can be recycled, and can be widely applied to the fields of automobiles, building materials, household appliances and the like.

The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited by the above description, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be regarded as equivalent replacements within the protection scope of the present invention.