CN113717511B - Mxene-based flame-retardant unsaturated resin material and preparation method thereof - Google Patents

Abstract

The invention discloses an MXene-based flame-retardant unsaturated resin material, which belongs to the technical field of flame-retardant materials. The MXene-based flame-retardant unsaturated resin material includes the following components in parts by mass: 75.2 to 94 parts of unsaturated polyester resin, 0 to 20 parts of ammonium polyphosphate, and 0 to 0.4 parts of MXene material, wherein the MXene material can be Modification with 1-butyl-3-methylimidazolium hexafluorophosphate and silane coupling agent. The MXene-based flame-retardant unsaturated resin material provided by the present invention further reacts with curing agent and accelerator for crosslinking and curing to generate an MXene-based flame-retardant unsaturated resin molding material, and the generated MXene-based flame-retardant unsaturated resin molding material has good flame retardancy performance.

Description

A kind of Mxene-based flame-retardant unsaturated resin material and preparation method thereof

technical field

The invention belongs to the technical field of flame retardant materials, and in particular relates to a Mxene-based flame retardant unsaturated resin material and a preparation method thereof.

Background technique

Unsaturated polyester resin is formed by polycondensation of dihydric alcohol and saturated dibasic acid at high temperature, and its main chain contains polymerizable double bonds, which are copolymerized with various vinyl monomers under the action of an initiator to obtain thermal Solid plastic. Unsaturated polyester resin has excellent technological properties such as high strength, light weight, radiation resistance, shock resistance, heat insulation, electrical insulation and microwave transmission, and can be molded under normal temperature and pressure, so it is widely used as paint, putty, adhesive Agents, artificial marble, buttons, corrugated boards, building materials and car casings, etc. However, unsaturated polyester resin is flammable, and the place where the material is used is prone to fire, causing immeasurable losses to life and property. Therefore, it is particularly urgent to optimize the flame retardancy of unsaturated resin materials.

In actual production, the method of adding flame retardants is often used to improve the flame retardancy of unsaturated polyester resins. Most of the added flame retardants are phosphorus, boron, aluminum, nitrogen flame retardants and halogen-containing flame retardants. When phosphorus, boron, aluminum, and nitrogen flame retardants are used, the flame retardant effect can only be achieved when the amount is relatively large. Due to the large amount of flame retardants, the mechanical properties of the polymer are seriously affected; while the halogen-containing flame retardant Although the amount of flame retardant is small, it has little effect on the physical and mechanical properties of polymers, but halogen-containing flame retardants will produce a lot of smoke at high temperatures, and even produce toxic smoke. There are great limitations. Therefore, it is of great significance to develop an unsaturated polyester resin material with less amount of flame retardant, good flame retardant effect and less smoke generation.

Contents of the invention

In order to solve the above problems, the object of the present invention is to provide an unsaturated resin material with less amount of flame retardant, good flame retardant effect and less smoke generation.

To achieve the above object, the present invention provides the following technical solutions:

One of the technical solutions of the present invention is an MXene-based flame-retardant unsaturated resin material, which comprises the following components in parts by mass: 75.2-94 parts of unsaturated polyester resin, 0-20 parts of ammonium polyphosphate, MXene material 0 to 0.4 parts, of which ammonium polyphosphate is not 0, and MXene material is not 0.

Further, the following components are included in parts by mass: 77-78 parts of unsaturated polyester resin, 17 parts of ammonium polyphosphate, and 0.4 parts of MXene material.

Further, the following components are included in parts by mass: 77.644 parts of unsaturated polyester resin, 17 parts of ammonium polyphosphate, and 0.4 parts of MXene material.

Further, the MXene material is a transition metal carbide (nitride), which is a graphene-like material containing a transition metal, and the molecular formula is Ti ₃ C ₂ X _n (X=OH; n=1,2,3) .

Further, the preparation method of the etching solution is: dissolving 0.5-2g LiF in 20-50mL of 5-10M HCl solution, and mixing to obtain the etching solution; the Ti ₃ A1C ₂ and the etching solution The solid-to-liquid ratio is 0.5-2g:20-50mL, and the reaction temperature is 35-55°C.

Further, the MXene material is modified. The modification method is: disperse the MXene material in absolute ethanol, then add 1-butyl-3-methylimidazolium hexafluorophosphate and water, and then drop in silane Coupling agent, reaction, filtration, washing, drying, and grinding to obtain modified MXene materials.

Further, the solid-to-liquid ratio of the MXene material and absolute ethanol is 1g:250ml, the solid-to-liquid ratio of the MXene material and 1-butyl-3-methylimidazolium hexafluorophosphate is 1g:5ml, and the MXene material and water The solid-to-liquid ratio of the MXene material and the silane coupling agent is 1g: 0.5ml.

The second technical solution of the present invention is an MXene-based flame-retardant unsaturated resin molding material, which is prepared by reacting the above-mentioned MXene-based flame-retardant unsaturated resin material with a curing agent and an accelerator.

Further, the mass ratio of the MXene-based flame retardant unsaturated resin material, curing agent, and accelerator is 94:3:3.

Compared with the prior art, the present invention has the following beneficial effects:

(1) The present invention mixes high-efficiency wood flame retardant ammonium polyphosphate, MXene material and unsaturated polyester resin, has made the MXene-based flame-retardant unsaturated resin material with good flame-retardant properties, and the MXene-based flame-retardant unsaturated resin material The high-efficiency wood flame retardant ammonium polyphosphate and a small amount of MXene materials added in the fire can promote a series of reactions such as material decomposition and dehydration, and form a continuous compact non-porous carbon layer on the surface of the unsaturated resin material, which can Effectively block oxygen and heat exchange, thereby preventing the internal matrix from continuing to burn. Ammonium polyphosphate can solidify the carbon layer, and MXene material can improve the toughness and continuity of the carbon layer on the surface of the material. The combined use of the two effectively reduces the total amount of heat release, mass change rate, heat release rate, and CO of unsaturated polyester resin. ₂ The amount of release and the risk of fire have improved the flame retardancy of unsaturated polyester resin materials.

(2) The transition metal carbide (nitride) compound (MXene) prepared by the present invention is a new type of two-dimensional nanomaterial, its structure is a graphene-like material containing a transition metal, and it has "barrier effect" and "catalytic effect" in theory. ", which has a good flame retardant effect on polymers. At the same time, compared with other two-dimensional nanomaterials, Mxene also has the advantages of large specific surface area, mild preparation conditions, and easy-to-control surface. However, the "catalytic effect" of titanium in transition metal carbide (nitride) (MXene) is weak, and it is difficult to meet the flame retardant requirements when used alone, and as a nanomaterial, it has a clustering effect between particles and is not easy to disperse uniformly. The functional modified substances used to solve the problem of easy agglomeration and poor dispersion in their applications are limited to surfactants or cation exchange resins, which have obvious limitations in compatibilization of organic molecules and the introduction of flammable groups. In view of this, in the present invention, a strong catalytic carbon-forming group is used to functionalize MXene, and by increasing the stereoprotective effect and "catalytic effect" of MXene, its dispersibility and flame retardancy are improved, and the flame retardancy and smoke suppression of MXene materials are improved. Performance, the MXene material processed by the modification method of the present invention can be better and more evenly dispersed in the MXene-based flame-retardant unsaturated resin material system, and the MXene-based flame-retardant unsaturated resin material prepared by it has more excellent Flame retardant properties.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings required in the embodiments. Obviously, the accompanying drawings in the following description are only some of the present invention. Embodiments, for those of ordinary skill in the art, other drawings can also be obtained based on these drawings without any creative effort.

Fig. 1 is the thermogravimetric curve diagram of UPR0, UPR1, UPR2, UPR3 sample;

Fig. 2 is the heat release rate curve diagram of UPR0, UPR1, UPR2, UPR3 sample;

Fig. 3 is the smoke release rate curve of UPR0, UPR1, UPR2, UPR3 samples;

Fig. 4 is the photograph of the carbon residue after UPR0, UPR1, UPR2, UPR3 sample is tested by cone calorimeter, wherein (a) and (b) are UPR0, (c) and (d) are UPR1, (e) and (f) is UPR2, (g) and (h) are UPR3.

Detailed ways

Various exemplary embodiments of the present invention will now be described in detail. The detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features and embodiments of the present invention.

It should be understood that the terminology described in the present invention is only used to describe specific embodiments, and is not used to limit the present invention. In addition, regarding the numerical ranges in the present invention, it should be understood that each intermediate value between the upper limit and the lower limit of the range is also specifically disclosed. Each smaller range between any stated value or intervening value in a stated range and any other stated value or intervening value in a stated range is encompassed within the invention. The upper and lower limits of these smaller ranges may independently be included or excluded from the range.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although only the preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and/or materials in connection with which the documents are described. In case of conflict with any incorporated document, the contents of this specification control.

It will be apparent to those skilled in the art that various modifications and changes can be made in the specific embodiments of the present invention described herein without departing from the scope or spirit of the present invention. Other embodiments will be apparent to the skilled person from the description of the present invention. The description and examples of the invention are illustrative only.

As used herein, "comprising", "comprising", "having", "comprising" and so on are all open terms, meaning including but not limited to.

Example 1

1. Preparation of MXene (Ti ₃ C ₂ X _n ) material

Dissolving 1g of LiF in 30mL of 6M HCl solution to prepare an etching solution, and then slowly adding 1g of Ti ₃ A1C ₂ into the above etching solution at 45° C. under magnetic stirring for 7 hours to react. After the reaction is completed, wash with deionized water and centrifuge, and repeat the washing several times until a dark green supernatant with pH>6 is obtained. Then, the obtained precipitate was sonicated in absolute ethanol for 1 h in an ice bath, centrifuged, and then 40 mL of deionized water was added to the precipitate, sonicated for 20 min, and after centrifugation, the supernatant was freeze-dried for 24 hours to obtain the MXene material.

2. Preparation of MXene-based flame-retardant unsaturated resin materials and MXene-based flame-retardant unsaturated resin molding materials

(1) Selection of the amount of ammonium polyphosphate (APP)

The total mass of the MXene-based flame-retardant unsaturated resin material is set to 94 parts, the content of the MXene material is first set to 0 parts, and the content of APP is 0 parts, 8 parts, 10 parts, 13 parts, 15 parts, 17 parts, 19 parts and 20 parts, and the balance is unsaturated polyester resin (UPR). Weigh the raw materials, first add MXene to the unsaturated polyester resin, ultrasonically mix for 0.5h, and then add APP with a particle size of 200 mesh , stirred for 10min, prepared into 8 groups of different MXene-based flame-retardant unsaturated resin materials, and then respectively adding curing agent and accelerator (by mass ratio, MXene-based Flame retardant unsaturated resin material: curing agent: accelerator=94:3:3, that is (UPR+APP): curing agent: accelerator=94:3:3) to carry out cross-linking curing reaction, the condition of cross-linking curing reaction It is as follows: first keep warm at 60°C for 4 hours, and then keep warm at 80°C for 8 hours to obtain 8 groups of MXene-based flame-retardant unsaturated resin molding material samples, and perform oxygen index analysis on each group of MXene-based flame-retardant unsaturated resin molding material sample strips. Determination, the oxygen index is measured with an oxygen index tester. Under the condition of an adjustable oxygen and nitrogen mixed gas, it is strictly implemented according to the standard of GB-T2406-1993. According to the tested oxygen index, the MXene-based flame retardancy is judged The flame retardant effect of unsaturated resin molding materials is good or bad. The composition of each group of MXene-based flame-retardant unsaturated resin materials and the oxygen index of the MXene-based flame-retardant unsaturated resin molding material sample (the total mass of the molding material sample is 100g) obtained by crosslinking and curing are shown in Table 1.

Table 1

It can be seen from Table 1 that the flame retardant effect of the MXene-based flame-retardant unsaturated resin molding material obtained when the amount of APP is 17 parts is better, and the flame-retardant effect of further increasing the amount of APP on the basis of 17 parts is very limited. Improve the flame retardant performance of the material while ensuring the effective use of raw materials without causing unnecessary waste of resources. The amount of APP is fixed at 17 parts. On this basis, the amount of MXene material is further selected.

(2) Selection of MXene material dosage

Set the total mass of MXene-based flame retardant unsaturated resin material to 94 parts, and the content of APP to 17 parts, respectively according to the content of MXene material is 0.5 parts, 1 part, 1.5 parts, 2 parts, and the balance is UPR Weigh the raw materials, first add MXene to the unsaturated polyester resin, mix evenly by ultrasonication for 0.5h, then add APP with a particle size of 200 mesh, stir for 10min, and prepare 4 different MXene-based flame-retardant unsaturated resin materials, and then In each group of MXene-based flame-retardant unsaturated resin materials obtained, add respectively curing agent and accelerator (by mass ratio, UPR: curing agent: accelerator=94:3:3, that is (UPR+APP+MXene material ): Curing agent: Accelerator = 94:3:3) for cross-linking curing reaction, the conditions of cross-linking curing reaction are: first heat preservation at 60°C for 4h, and then heat preservation at 80°C for 8h, to obtain 4 groups of MXene-based flame retardant Saturated resin molding material sample strips, the oxygen index of each group of MXene-based flame-retardant unsaturated resin molding material samples obtained was measured, the composition of each group of MXene-based flame-retardant unsaturated resin materials and the MXene-based flame-retardant unsaturated resin materials obtained by cross-linking and curing The oxygen index of the unsaturated resin molding material sample (the total mass of the molding material sample is 100g) is shown in Table 2.

Table 2

It can be seen from Table 2 that to a certain extent, the combination of MXene material and APP can improve the flame retardant effect of UPR, but with the further increase of the concentration ratio of MXene material, the limiting oxygen index of the system is decreasing, which shows that adding too much The MXene material will not enhance the flame retardant effect of the MXene-based flame retardant unsaturated resin molding material, but interferes with the APP flame retardant to promote the dehydration of the material into carbon. Excessive MXene material will cause the formed carbon layer to have no continuity and integrity. property, which in turn reduces the flame retardant performance of MXene-based flame retardant unsaturated resin molding materials, and it can be concluded that when the content of MXene material is 0.5 parts, it has a better flame retardant effect.

In order to obtain a more excellent flame retardant effect, and to explore whether the equivalent or even better flame retardant effect can be obtained while reducing the amount of MXene material, the amount of MXene material is 0.1 phr, 0.2 phr. , 0.3 and 0.4 parts of the test, the composition of the MXene-based flame-retardant unsaturated resin material of each group and the oxygen index of the MXene-based flame-retardant unsaturated resin molding material sample obtained by cross-linking and curing are shown in Table 3.

table 3

It can be seen from Table 3 that the flame retardant effect of the MXene-based flame-retardant unsaturated resin molding material obtained when the amount of APP is 17 parts and the amount of MXene material is 0.4 parts is the best.

Example 2

1. Modification of MXene (Ti ₃ C ₂ X _n )

(1) Weigh 0.2g of the MXene material prepared in Example 1 and disperse it in 50mL of absolute ethanol, seal it with a plastic wrap and ultrasonically disperse it for 30min to obtain a uniform dispersion of the MXene material;

(2) After adding 1mL 1-butyl-3-methylimidazolium hexafluorophosphate (IL) and 20mL deionized water, magnetically stir, and add 0.1mL (2 drops) of silane coupling agent KH550 (3 -aminopropyltriethylsilane), stirred and reacted for 1 hour;

(3) Suction filtration and washing with absolute ethanol for 3 times, drying and grinding to obtain the modified MXene material.

2. Preparation of MXene-based flame-retardant unsaturated resin materials and MXene-based flame-retardant unsaturated resin molding materials

The total mass of the MXene-based flame-retardant unsaturated resin material is set to 94 parts, the content of APP is set to 17 parts, and the content of the modified MXene material is set to 0.4 parts. Each raw material is weighed according to the number of parts by mass. MXene was added to the unsaturated polyester resin, ultrasonically mixed for 0.5h, then APP with a particle size of 200 mesh was added, stirred for 10min, and mixed to prepare an MXene-based flame-retardant unsaturated resin material, and then the prepared MXene-based flame-retardant Add curing agent and accelerator in saturated resin material (in terms of mass ratio, MXene base flame retardant unsaturated resin material: curing agent: accelerator=94:3:3, namely (UPR+APP+ modified MXene material): curing agent : Accelerator=94:3:3) to carry out cross-linking and curing reaction, the conditions of cross-linking and curing reaction are: first heat preservation at 60°C for 4h, and then heat preservation at 80°C for 8h, to obtain MXene-based flame-retardant unsaturated resin molding material spline , the obtained MXene-based flame-retardant unsaturated resin molding material sample was measured for oxygen index, the composition of the MXene-based flame-retardant unsaturated resin material and the obtained MXene-based flame-retardant unsaturated resin molding material sample (molding The oxygen index of the material sample with a total mass of 100 g) is shown in Table 4.

Table 4

Comparing the oxygen index data in Table 4 with the oxygen index data when 0.4 parts of unmodified MXene material is used in the MXene-based flame retardant unsaturated resin material in Table 3, it can be found that when the modified MXene material is used, the obtained MXene-based flame-retardant unsaturated resin molding materials have better flame-retardant performance, that is, the modified MXene material and APP have a better flame-retardant effect on UPR when used in conjunction with APP.

Effect verification

The MXene-based flame-retardant unsaturated resin material was prepared according to the APP content of 0 parts and the MXene material content of 0 parts, and a curing agent and an accelerator were added in proportion to form a MXene-based flame-retardant unsaturated resin molding material sample as a blank control group. The serial number is UPR0; the MXene-based flame-retardant unsaturated resin material is prepared according to the APP content of 17 parts and the MXene material content of 0 parts, and the curing agent and accelerator are added in proportion to form a MXene-based flame-retardant unsaturated resin molding material sample as Experimental group 1, numbered UPR1; MXene-based flame-retardant unsaturated resin material was prepared according to APP content of 17 parts and MXene material content of 0.4 parts, and curing agent and accelerator were added in proportion to form MXene-based flame-retardant unsaturated resin molding The material sample was taken as the experimental group 2, numbered UPR2; MXene-based flame-retardant unsaturated resin materials were prepared according to the APP content of 17 parts and the modified MXene material content of 0.4 parts, and curing agents and accelerators were added in proportion to form MXene-based The flame-retardant unsaturated resin molding material sample is taken as the experimental group 3, and the code is UPR3. The composition of each group of MXene-based flame-retardant unsaturated resin materials and the oxygen index of the MXene-based flame-retardant unsaturated resin molding material sample (the total mass of the molding material sample is 100g) obtained by crosslinking and curing are shown in Table 5.

table 5

The sample labels UPR0, UPR1, UPR2, and UPR3 in Table 5 represent pure unsaturated polyester resins UPR, APP/UPR, APP/UPR/MXene, APP/UPR/modified MXene, respectively. It can be seen from Table 5 that the oxygen index of pure UPR0 Only 20.9, which is a flammable material and does not have flame retardant properties. This is because the charcoal layer formed after combustion is relatively loose, and oxygen will continue to enter the interior of the material and continue to burn; the oxygen index of the UPR1 sample material after adding 17 parts of APP It has been raised to 25.9, but it is still a flammable material. At this time, this material has a certain flame retardancy, because APP can promote the material to produce a charcoal layer, but when the temperature is too high, it will also cause the charcoal layer to burst, which in turn will make the material Combustion; the oxygen index of the UPR2 sample material after adding 17 parts of APP and 0.4 parts of MXene material increased to 28.0, which belongs to flame retardant material and has good flame retardancy; after adding 17 parts of APP and 0.4 part of modified MXene material The oxygen index of the UPR3 sample material reached 29.0, which is a flame retardant material, and its flame retardant performance is more prominent. This is because the addition of MXene material and modified MXene material can make the carbon layer denser, isolate the entry of oxygen, and achieve flame retardant In particular, the modified MXene material can be more uniformly dispersed, making the effect more obvious. It can be seen that the compounding of APP and MXene material will have a better synergistic flame retardant effect, which can effectively improve the flame retardant performance of UPR , the MXene-based flame-retardant unsaturated resin material prepared by mixing UPR, APP, and MXene materials has good flame-retardant properties.

1. Horizontal and vertical combustion analysis

The above-mentioned control group and experimental group samples were taken for horizontal and vertical combustion analysis. The test method was implemented according to the GB 2408-80 standard, and the flame retardant standard grades of the samples in each group were obtained, as shown in Table 6.

Table 6

It can be seen from Table 6 that the combustion level of UPR0 is V ₂ , the level of UPR1 after adding 17 parts of APP is raised to V ₁ , and the level of the sample material is raised to V ₀ after adding MXene material, which is consistent with the oxygen index result, so it can be concluded that The compounding of APP and MXene materials can improve the flame retardant performance of UPR, and the MXene-based flame retardant unsaturated resin material prepared by mixing UPR, APP and MXene materials has good flame retardant performance.

2. Thermogravimetric analysis

The above-mentioned control group and experimental group samples were taken for thermogravimetric analysis. The thermogravimetric curves are shown in Figure 1. It can be seen from Figure 1 that the thermogravimetric curves of the four samples are very straight before 100 ° C, and almost no weight loss occurs. The thermogravimetric curves of the four samples all decreased smoothly between 300°C, and the UPR of the pure sample dropped the fastest, and decomposed at about 300°C, while the decomposition temperatures of UPR1, UPR2, and UPR3 samples were all around 350°C, at 350～ The thermogravimetric curves of UPR1, UPR2 and UPR3 in the range of 400 °C are on the right side of UPR0, and the final weight loss UPR0>UPR1>UPR2>UPR3 shows that the thermal stability of the material added with APP and MXene is improved, because APP can make the material form a carbon layer In order to protect the matrix structure, delay and prevent the internal combustion, achieve the flame retardant effect, and the flame retardant effect of APP and modified MXene materials is the best.

3. Analysis of carbon residue rate

The carbon residue rate refers to the percentage of the original mass of the remaining mass after the substance is burned under a certain temperature and external conditions. Weigh the weight of each group of splines before thermogravimetric analysis and the weight after thermogravimetric analysis at a certain temperature for a certain period of time, and calculate the carbon residue rate of each group. The carbon residue rate analysis was carried out on the samples of the above control group and the experimental group. The carbon residue rate of pure UPR, APP/UPR, APP/UPR/MXene, APP/UPR/modified MXene was calculated to be 7.78%, 16.68% at 700°C %, 23.82%, and 27.56%. The calculated carbon residue rates show that the carbon residue rates of UPR1, UPR2, and UPR3 sample materials are greatly improved compared with pure UPR, which also shows that APP and MXene materials And modified MXene materials have obvious effects on the flame retardant modification of materials from the perspective of the mechanism of charcoal flame retardant. Under the same circumstances, the carbon residue rate of UPR3 material is slightly better than that of UPR1 and UPR2 materials, indicating that APP/UPR/modified MXene has the strongest char formation effect after the material is ignited. The MXene group endows the MXene material with a stronger ability to catalyze carbon formation, thereby effectively blocking the transfer and diffusion of oxygen and heat, protecting the internal substrate from damage, and has good flame retardancy. It is made of UPR, APP, and MXene materials. MXene-based flame-retardant unsaturated resin materials have the best flame-retardant properties.

4. Cone calorimetry analysis

The samples of the control group and the experimental group were taken according to ISO5660 and tested under the experimental conditions of the heat radiation amount of 50kW/m ² .

(1) Heat release rate

Heat Release Rate (HRR) is one of the very important parameters to measure fire spread and fire development, it provides us with a measure of fire size, called fire intensity. The larger the HRR, the more energy transferred to the surface of the material per unit time, the faster the thermal degradation rate of the material, and the more easily volatile combustibles generated, thus accelerating the spread of the flame. So the greater the HRR, the more dangerous the material is in a fire. The HRR curves of UPR0, UPR1, UPR2, and UPR3 sample materials are shown in Figure 2. It can be seen from Figure 2 that the PHRR value of pure UPR has reached more than 650kW/ ^m2 . After adding 17 parts of APP, the UPR1 spline The PHRR value dropped to 500kW/m ² . Compounding 0.4 parts of MXene material with APP, the PHRR value of the MXene-based flame-retardant unsaturated resin molding material UPR2 prepared together with UPR did not change much, but compared with pure UPR, it decreased by 23%. Compounding 0.4 parts of modified MXene material with APP, the PHRR value of the MXene-based flame-retardant unsaturated resin molding material UPR3 produced together with UPR has changed greatly, and the PHRR value has dropped from 500kW/ ^m2 of pure UPR. To 350kW/m ² , a reduction of 30%. At the same time, the shape of the HRR curve of pure UPR is quite different from that of APP/UPR/modified MXene. The HRR curve of pure UPR has one and only one heat release rate peak, while APP/UPR/modified MXene has two peaks. The reason for the first peak of the APP/UPR/modified MXene system may be the thermal decomposition of UPR Combustion of flammable gases releases heat peaks. The phosphorus source flame retardant is decomposed by heat, and through a series of reactions, the polymer material is accelerated to decompose and dehydrate and carbonize on the surface of the material to form a continuous, compact, and void-free carbon layer. The carbon layer can isolate oxygen and heat exchange to achieve the purpose of preventing further combustion of the material, thereby slowing down the thermal degradation rate, and the amount of flammable gas generated is reduced, so the heat generated by combustion is also reduced, and the HRR is reduced, so that on the curve There are peaks and valleys. The appearance of the second peak of APP/UPR/modified MXene is due to the further oxidation of the formed char layer, although the heat release rate at the peak valley is the lowest, but the THR will still continue to increase, when reaching a certain temperature, The further oxidation and combustion of the carbon layer will generate a new carbon layer with the inside of the matrix, which leads to the appearance of the second peak. The pure UPR decomposes to produce flammable gas when it burns, but there is no compact carbon layer formed, which has no protective effect on the inner matrix of the polymer, so the degradation rate of the material matrix is very fast, the rate of flammable gas generation is very large, and the burning release The heat is also very large, and the flame will not go out until the UPR can no longer provide the fuel required for combustion, so it exists in the form of a single peak on the HRR curve. For APP/UPR/modified MXene materials, the HRR curve has a similar trend to that of unsaturated resins, but the maximum heat release rate is the smallest, which indicates that MXene and APP can promote the formation of high-quality carbon layers. It can effectively prevent the heat exchange between the inner matrix and the outside and effectively isolate oxygen so as to achieve flame retardancy. It can also be seen from the HRR curve that the TTI (ignition time) of APP/UPR/modified MXene is the longest, indicating that the material is the most difficult to ignite and has the best flame retardancy.

(2) Analysis of smoke release rate

The smoke release rate curves of UPR0, UPR1, UPR2, and UPR3 sample materials are shown in Figure 3. It can be seen from Figure 3 that the peak value of the smoke release rate of UPR1 with only APP added is higher than that of pure UPR. After further adding MXene, the peak value of the smoke release rate of UPR2 decreased, because the barrier effect of MXene as a nanosheet inhibited the smoke release, and the lowest smoke release rate was UPR3 with the addition of APP and modified MXene, because after adding the modified MXene , its dispersibility is improved, the barrier effect is increased, and it shows obvious smoke suppression effect.

5. Direct observation of carbon residue

Photos of carbon residue after cone calorimeter test of pure UPR, APP/UPR, APP/UPR/MXene, APP/UPR/modified MXene sample materials are shown in Figure 4, where (a) and (b) are UPR0, (c) and (d) are UPR1, (e) and (f) are UPR2, (g) and (h) are UPR3. (a), (c), (e), and (g) are top views, from which it can be directly observed that UPR0(a) burns very fully and only fine flocculent substances are left; UPR1(c) has a lumpy carbon layer formed, but the carbon layer has been broken; UPR2(e) has a larger carbon layer but is still broken; while UPR3(g) has a relatively complete and compact carbon layer; (b), (d), ( f), (h) are side views. It can be seen from the side view that the carbon layers of UPR1(d) and UPR2(f) have been completely broken, while UPR3(h) is complete, indicating that the flame retardancy of UPR1 and UPR2 is not as good as that of UPR3 The flame retardant performance of the modified MXene is good, which further shows that the use of modified MXene and APP can promote the formation of a higher strength carbon layer and improve the flame retardant performance of UPR. Saturated resin materials have the best flame retardant properties.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention within.

Claims (7)

1. An MXene-based flame-retardant unsaturated resin material, characterized in that, in parts by mass, it comprises the following components: 77 to 78 parts of unsaturated polyester resin, 17 parts of ammonium polyphosphate, and 0.4 part of MXene material; The MXene material is modified, and the modification method is: disperse the MXene material in absolute ethanol, then add 1-butyl-3-methylimidazolium hexafluorophosphate and water, and then drop into the silane coupling agent , react, filter, wash, dry, and grind to obtain the modified MXene material. 2. The MXene-based flame-retardant unsaturated resin material according to claim 1, wherein the MXene material is Ti ₃ C ₂ X _n , where X=OH, n=1, 2 or 3. 3. MXene-based flame-retardant unsaturated resin material according to claim 2, is characterized in that, the preparation method of described Ti ₃ C ₂ X _n is: Ti ₃ A1C ₂ is added to react in etching solution, centrifugal, washing , adding the washed precipitate into absolute ethanol for ultrasonic treatment for 0.5-1 h, centrifuging, then adding deionized water for ultrasonic treatment for 10-30 min, after centrifuging, taking the supernatant and freeze-drying to obtain Ti ₃ C ₂ X _n . 4. The MXene-based flame-retardant unsaturated resin material according to claim 3, characterized in that, the preparation method of the etching solution is: dissolving 0.5-2g LiF in 20-50mL of 5-10M HCl solution, Mix to obtain an etching solution; the solid-to-liquid ratio of the Ti ₃ A1C ₂ to the etching solution is 0.5-2g:20-50mL, and the reaction temperature is 35-55°C. 5. MXene-based flame-retardant unsaturated resin material according to claim 1, is characterized in that, the solid-to-liquid ratio of described MXene material and dehydrated alcohol is 1g:250ml, and MXene material and 1-butyl-3-methanol The solid-to-liquid ratio of imidazole hexafluorophosphate is 1g:5ml, the solid-to-liquid ratio of MXene material to water is 1g:100ml, and the solid-to-liquid ratio of MXene material to silane coupling agent is 1g:0.5ml. 6. A MXene-based flame-retardant unsaturated resin molding material, characterized in that it is prepared by reacting the MXene-based flame-retardant unsaturated resin material described in any one of claims 1-5 with a curing agent and an accelerator. 7. MXene base flame retardant unsaturated resin molding material according to claim 6, is characterized in that, the mass ratio of described MXene base flame retardant unsaturated resin material, curing agent, accelerator is 94:3:3.

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