Si-P-N-C quaternary hybrid flame-retardant system composition and preparation method thereof

Abstract

The invention discloses a Si-P-N-C quaternary hybrid flame-retardant system composition and a preparation method thereof.The method comprises the steps that a nitrogen-phosphorus flame retardant, thermoplastic resin and a silane coupling agent are added into a graphene oxide suspension, and a graphene oxide grafted nitrogen-phosphorus flame retardant and graphene oxide grafted thermoplastic resin are obtained through a functionalization reaction; and mixing the graphene oxide grafted nitrogen-phosphorus flame retardant, the graphene oxide grafted thermoplastic resin, the modified wollastonite and a silane coupling agent to obtain the Si-P-N-C quaternary hybrid flame-retardant system composition. On the basis of the modified wollastonite, the nitrogen-phosphorus flame retardant, the thermoplastic resin and the graphene oxide are introduced, so that the system composition has good compatibility with a high polymer matrix so as to have better mechanical properties and processability, and Si, P, N and C have synergistic flame retardance so as to show excellent flame retardance.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer materials, and particularly relates to a Si-PNC quaternary hybrid flame retardant system composition and a preparation method thereof. Background Art

[0002] Wollastonite is a unique needle-like fiber with good insulation, wear resistance and high refractive index. It is a good filling material for plastic and rubber products. Adding wollastonite powder to rubber and plastic products can not only improve the impact strength and fluidity of rubber and plastic products, but also improve its tensile strength, impact strength, linear stretching and mold shrinkage. However, as an inorganic filler, if wollastonite is directly filled in a polymer, due to the difference in interface properties, the two have poor compatibility and uneven dispersion, which leads to a decrease in the mechanical properties of the matrix material. Studies have shown that the mixed use of two or more flame retardants can achieve a synergistic flame retardant effect. For example, the mixed use of phosphorus flame retardants and nitrogen flame retardants has a synergistic flame retardant effect, which can greatly improve the flame retardancy of the material; however, due to the poor compatibility between the materials, the mechanical strength of the material is affected. Therefore, it is urgent to study a system composition that can reuse multiple flame retardants and achieve a synergistic flame retardant effect without affecting the mechanical strength of the material. Summary of the invention

[0003] The object of the present invention is to provide a Si-PNC quaternary hybrid flame retardant system composition and a preparation method thereof, which can take into account both the synergistic flame retardant effect and the mechanical strength of the material, in view of the above-mentioned problems existing in the prior art.

[0004] To achieve the above objectives, the technical solution of the present invention is as follows:

[0005] In a first aspect, the present invention provides a method for preparing a Si-PNC quaternary hybrid flame retardant system composition, the preparation method comprising:

[0006] S1, adding a nitrogen-phosphorus flame retardant, a thermoplastic resin, and a silane coupling agent to a graphene oxide suspension, and obtaining a graphene oxide-grafted nitrogen-phosphorus flame retardant and a graphene oxide-grafted thermoplastic resin through a functionalization reaction;

[0007] S2. Mixing the graphene oxide grafted nitrogen-phosphorus flame retardant, the graphene oxide grafted thermoplastic resin, the modified wollastonite and the silane coupling agent to obtain the Si-PNC quaternary hybrid flame retardant system composition.

[0008] The nitrogen-phosphorus flame retardant is any one of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, melamine polyphosphate, and piperazine pyrophosphate.

[0009] The thermoplastic resin is any one of polyetheretherketone and MQ resin.

[0010] The silane coupling agent is any one of KH-550, KH-560, KH-570 and KH-590.

[0011] The preparation method of the modified wollastonite is as follows: wollastonite fiber and a silane coupling agent are placed in a high-speed stirrer, and the modified wollastonite is obtained after high-speed stirring.

[0012] The mass ratio of the nitrogen-phosphorus flame retardant, the thermoplastic resin, and the silane coupling agent in S1 is 5-8:2-4:1-1.2; the mass ratio of the graphene oxide grafted nitrogen-phosphorus flame retardant, the graphene oxide grafted thermoplastic resin, the modified wollastonite, and the silane coupling agent in S2 is 5-8:88-95:1-1.2.

[0013] The addition ratio of the nitrogen-phosphorus flame retardant to the graphene oxide suspension is 5-8g:0.5L; the concentration of the graphene oxide suspension is 5-8g / L.

[0014] The reaction conditions of the functionalization reaction are: heating to 73-80° C. and reflux under nitrogen for 10-12 h.

[0015] In S1, the reaction product obtained by the functionalization reaction is dried under vacuum at 105-110° C. to obtain a graphene oxide grafted nitrogen-phosphorus flame retardant and a graphene oxide grafted thermoplastic resin.

[0016] In a second aspect, the present invention provides a Si-PNC quaternary hybrid flame retardant system composition, wherein the Si-PNC quaternary hybrid flame retardant system composition is prepared by the aforementioned preparation method.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The preparation method of the Si-PNC quaternary hybrid flame retardant system composition of the present invention comprises the following steps: firstly grafting graphene oxide onto a nitrogen-phosphorus flame retardant and a thermoplastic resin, and then mixing and modifying the grafted nitrogen-phosphorus flame retardant, the thermoplastic resin and the improved wollastonite to obtain the Si-PNC quaternary hybrid flame retardant system composition; based on the modified wollastonite, the present design introduces the nitrogen-phosphorus flame retardant, the thermoplastic resin and graphene oxide by using a silane coupling agent; on the one hand, since the silane coupling agent has multiple active functional groups such as amino, epoxy and vinyl groups, the obtained system composition has good compatibility with the polymer matrix, thereby having better mechanical properties and processing properties; on the other hand, Si, P, N and C are synergistically flame retardant, showing excellent flame retardant properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1This is a schematic diagram of the structure of the nitrogen-phosphorus flame retardant grafted with graphene oxide according to the present invention.

[0020] Figure 2 It is a schematic diagram of the structure of the thermoplastic resin grafted with graphene oxide according to the present invention.

[0021] Figure 3 It is a schematic structural diagram of the Si-PNC quaternary hybrid flame retardant system composition of the present invention. DETAILED DESCRIPTION

[0022] The present invention is further described in detail below in conjunction with specific implementations and drawings.

[0023] See also Figure 1 , a method for preparing a Si-PNC quaternary hybrid flame retardant system composition, the preparation method comprising:

[0024] S1, adding a nitrogen-phosphorus flame retardant, a thermoplastic resin, and a silane coupling agent to a graphene oxide suspension, and obtaining a graphene oxide-grafted nitrogen-phosphorus flame retardant and a graphene oxide-grafted thermoplastic resin through a functionalization reaction;

[0025] S2. Mixing the graphene oxide grafted nitrogen-phosphorus flame retardant, the graphene oxide grafted thermoplastic resin, the modified wollastonite and the silane coupling agent to obtain the Si-PNC quaternary hybrid flame retardant system composition.

[0026] The nitrogen-phosphorus flame retardant is any one of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, melamine polyphosphate, and piperazine pyrophosphate.

[0027] The thermoplastic resin is any one of polyetheretherketone and MQ resin.

[0028] The silane coupling agent is any one of KH-550, KH-560, KH-570 and KH-590.

[0029] The preparation method of the modified wollastonite is as follows: wollastonite fiber and a silane coupling agent are placed in a high-speed stirrer, and the modified wollastonite is obtained after high-speed stirring.

[0030] The mass ratio of the nitrogen-phosphorus flame retardant, the thermoplastic resin, and the silane coupling agent in S1 is 5-8:2-4:1-1.2; the mass ratio of the graphene oxide grafted nitrogen-phosphorus flame retardant, the graphene oxide grafted thermoplastic resin, the modified wollastonite, and the silane coupling agent in S2 is 5-8:88-95:1-1.2.

[0031] The addition ratio of the nitrogen-phosphorus flame retardant to the graphene oxide suspension is 5-8g:0.5L; the concentration of the graphene oxide suspension is 5-8g / L.

[0032] The reaction conditions of the functionalization reaction are: heating to 73-80° C. and reflux under nitrogen for 10-12 h.

[0033] In S1, the reaction product obtained by the functionalization reaction is dried under vacuum at 105-110° C. to obtain a graphene oxide grafted nitrogen-phosphorus flame retardant and a graphene oxide grafted thermoplastic resin.

[0034] A Si-PNC quaternary hybrid flame retardant system composition is prepared by the above-mentioned preparation method.

[0035] Embodiment 1:

[0036] A method for preparing a Si-PNC quaternary hybrid flame retardant system composition is carried out in the following steps:

[0037] S1. Suspending 2.5 g of graphene oxide in 500 mL of tetrahydrofuran solvent, and treating in an ultrasonic bath for 30 min to obtain a graphene oxide suspension; adding 50 g of nitrogen-phosphorus flame retardant, 30 g of thermoplastic resin, and 10 g of silane coupling agent to the obtained graphene oxide suspension while stirring, heating to 75° C. and refluxing under nitrogen for 12 h to perform a functionalization reaction to obtain a reaction product, and drying the reaction product under vacuum at 80° C. overnight to remove the solvent to obtain a structure as shown in Figure 1 The graphene oxide grafted nitrogen-phosphorus flame retardant shown in FIG. Figure 2 The graphene oxide grafted thermoplastic resin shown; wherein the nitrogen-phosphorus flame retardant is 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO); the thermoplastic resin is polyetheretherketone; the silane coupling agent is KH-550;

[0038] S2, placing 1000g of wollastonite fiber and 10g of silane coupling agent in a high-speed mixer, and stirring at high speed to obtain modified wollastonite; mixing 5g of graphene oxide grafted nitrogen-phosphorus flame retardant, 3g of graphene oxide grafted thermoplastic resin and 90g of modified wollastonite, and adding 1g of silane coupling agent dropwise thereto to obtain a structure as shown in Figure 3 The Si-PNC quaternary hybrid flame retardant system composition shown.

[0039] Embodiment 2:

[0040] A method for preparing a Si-PNC quaternary hybrid flame retardant system composition is carried out in the following steps:

[0041] S1. 3 g of graphene oxide is suspended in 500 mL of tetrahydrofuran solvent and treated in an ultrasonic bath for 30 min to obtain a graphene oxide suspension; 80 g of a nitrogen-phosphorus flame retardant, 40 g of a thermoplastic resin and 1.2 g of a silane coupling agent are added to the graphene oxide suspension while stirring, and the mixture is heated to 75° C. and refluxed under nitrogen for 12 h to perform a functionalization reaction to obtain a reaction product, and the reaction product is dried overnight at 80° C. in a vacuum to remove the solvent, to obtain a graphene oxide-grafted nitrogen-phosphorus flame retardant and a graphene oxide-grafted thermoplastic resin; wherein the nitrogen-phosphorus flame retardant is piperazine pyrophosphate; the thermoplastic resin is MQ resin; and the silane coupling agent is KH-560;

[0042] S2. Place 1000 g of wollastonite fiber and 10 g of silane coupling agent in a high-speed mixer, and obtain modified wollastonite after high-speed stirring; mix 6.5 g of graphene oxide grafted nitrogen-phosphorus flame retardant, 4 g of graphene oxide grafted thermoplastic resin and 95 g of modified wollastonite, and then drop 1.2 g of silane coupling agent thereto to obtain the Si-PNC quaternary hybrid flame retardant system composition.

[0043] Embodiment 3:

[0044] A method for preparing a Si-PNC quaternary hybrid flame retardant system composition is carried out in the following steps:

[0045] S1. Suspending 4 g of graphene oxide in 500 mL of tetrahydrofuran solvent, treating in an ultrasonic bath for 30 min to obtain a graphene oxide suspension; adding 6 g of nitrogen-phosphorus flame retardant, 2 g of thermoplastic resin, and 1.1 g of silane coupling agent to the graphene oxide suspension while stirring, heating to 75° C. and refluxing under nitrogen for 12 h, performing a functionalization reaction to obtain a reaction product, and drying the reaction product under vacuum at 80° C. overnight to remove the solvent, to obtain a graphene oxide-grafted nitrogen-phosphorus flame retardant and a graphene oxide-grafted thermoplastic resin; wherein the nitrogen-phosphorus flame retardant is melamine polyphosphate; the thermoplastic resin is MQ resin; and the silane coupling agent is KH-570;

[0046] S2. Place 1000 g of wollastonite fiber and 10 g of silane coupling agent in a high-speed mixer, and obtain modified wollastonite after high-speed stirring; mix 8 g of graphene oxide grafted nitrogen-phosphorus flame retardant, 5 g of graphene oxide grafted thermoplastic resin and 88 g of modified wollastonite, and then drop 1.1 g of silane coupling agent thereto to obtain the Si-PNC quaternary hybrid flame retardant system composition.

[0047] Embodiment 4:

[0048] A method for preparing a Si-PNC quaternary hybrid flame retardant system composition is carried out in the following steps:

[0049] S1. Suspending 2.5 g of graphene oxide in 500 mL of tetrahydrofuran solvent, treating in an ultrasonic bath for 30 min to obtain a graphene oxide suspension; adding 6 g of nitrogen-phosphorus flame retardant, 4 g of thermoplastic resin, and 1 g of silane coupling agent to the graphene oxide suspension while stirring, heating to 75° C. and refluxing under nitrogen for 12 h, performing a functionalization reaction to obtain a reaction product, and drying the reaction product under vacuum at 80° C. overnight to remove the solvent, to obtain a graphene oxide-grafted nitrogen-phosphorus flame retardant and a graphene oxide-grafted thermoplastic resin; wherein the nitrogen-phosphorus flame retardant is melamine polyphosphate; the thermoplastic resin is MQ resin; and the silane coupling agent is KH-590;

[0050] S2. Place 1000 g of wollastonite fiber and 10 g of silane coupling agent in a high-speed mixer, and obtain modified wollastonite after high-speed stirring; mix 7 g of graphene oxide grafted nitrogen-phosphorus flame retardant, 5 g of graphene oxide grafted thermoplastic resin and 90 g of modified wollastonite, and then drop 1 g of silane coupling agent thereto to obtain the Si-PNC quaternary hybrid flame retardant system composition.

[0051] Comparative Example 1:

[0052] 90 g of modified wollastonite, 5 g of DOPO, 3 g of polyetheretherketone, and 0.5 g of graphene oxide were added into a high-speed mixer at room temperature, and 1 g of silane coupling agent KH550 was added dropwise, and a Si-PNC quaternary mixture was obtained after high-speed stirring.

[0053] Comparative Example 2:

[0054] 1000 g of wollastonite fiber and 10 g of silane coupling agent were placed in a high-speed mixer and stirred at high speed to obtain modified wollastonite.

[0055] Performance Verification:

[0056] In order to verify that the system composition of the present invention has better mechanical properties and excellent flame retardant properties, 100 parts by mass of polypropylene (2.16 kg load and melt flow rate at 230°C measured according to JIS K7210 = 8 g / 10 min), 0.1 parts by mass of calcium stearate (organic crystal nucleating agent), 0.1 parts by mass of tetrakis [3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate methyl] methane (phenolic antioxidant), 0.1 parts by mass of tris (2,4-di-tert-butylphenyl) phosphite (phosphorus antioxidant), and 0.3 parts by mass of glycerol monostearate (lubricant) were added to the polypropylene resin composition obtained, respectively, to obtain a flame retardant synthetic resin composition. In the obtained flame retardant synthetic resin composition, the mass proportion of the product of Example 1-4 and the product of Comparative Example 1-2 is 35%. The flame retardant synthetic resin composition was pressed for 15 min under the conditions of 220° C. and 5-15 MPa to obtain a test piece, which was then subjected to surface inspection, flame retardancy test and oxygen index test.

[0057] Surface testing: The compatibility of nitrogen-phosphorus flame retardant, modified wollastonite, graphene oxide and polypropylene resin matrix is ​​judged based on whether the surface of the test piece is smooth and whether there are white spots.

[0058] Flame retardancy test: The test piece is made into a strip with a length of 127mm, a width of 12.7mm, and a thickness of 1.6mm. The strip is placed vertically and in contact with the flame of the lower end burner for 10 seconds. The flame is removed and the time for the fire on the strip to go out is measured. Then, after the first fire is extinguished, the second flame contact is carried out for 10 seconds, and the time for the fire on the strip to go out is measured; in addition, whether the cotton under the strip is ignited by the falling fire is evaluated. The combustion level is determined according to the UL-94V standard based on the first and second burning times, whether the cotton is ignited, etc. For the combustion level, V-0 is the highest, and the flame retardancy decreases in the order of V-1 and V-2.

[0059] Oxygen index test: Make the test piece into a strip with a length of 150mm, a width of 10mm and a thickness of 4mm. Draw a line at 50mm on one end and insert the other end into the combustion tube sample clamp. Adjust the concentrations of nitrogen and oxygen, and then ignite the top of the sample with an igniter for no longer than 30s. Remove the igniter and start the timer immediately. The minimum oxygen concentration required for the sample to naturally extinguish after burning for just 3min or 50mm is the oxygen index.

[0060] The test results are shown in Table 1:

[0061] Table 1 Test results of surface testing, flame retardancy test and oxygen index test

[0062]

[0063]

[0064] From Table 1, the Si-PNC quaternary hybrid flame retardant system composition prepared in Example 1-4 was used as a flame retardant, and was added to the polypropylene resin composition in an amount of 35 parts by mass. The test pieces obtained all passed the UL-94 flame retardant test, and the oxygen index was greater than 34, and the surface of the test piece was smooth without white spots, which showed that it had good flame retardant properties and processing properties. However, the test piece obtained by adding 35 parts by mass of the flame retardant to the polypropylene resin composition as a flame retardant in Comparative Example 1-2 failed to pass the UL-94 flame retardant test, and the oxygen index was only 27 and 28, and the surface of the test piece was relatively rough with white spots, indicating that its flame retardant properties and processing properties were worse than those of Example 1-4. The above results show that the Si-PNC quaternary hybrid flame retardant system composition prepared by the present invention has better flame retardant properties, and has better mechanical properties and processing properties.

[0065] The above is a detailed description of the embodiments of the present invention, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in the relevant technical field without departing from the purpose of the present invention. In addition, the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

Claims

1. A method for preparing a Si-PNC quaternary hybrid flame retardant system composition, characterized in that: The preparation method comprises: S1, adding a nitrogen-phosphorus flame retardant, a thermoplastic resin, and a silane coupling agent to a graphene oxide suspension, and obtaining a graphene oxide-grafted nitrogen-phosphorus flame retardant and a graphene oxide-grafted thermoplastic resin through a functionalization reaction; S2. Mixing the graphene oxide grafted nitrogen-phosphorus flame retardant, the graphene oxide grafted thermoplastic resin, the modified wollastonite and the silane coupling agent to obtain the Si-PNC quaternary hybrid flame retardant system composition.

2. The method for preparing a Si-PNC quaternary hybrid flame retardant system composition according to claim 1, characterized in that: The nitrogen-phosphorus flame retardant is any one of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, melamine polyphosphate, and piperazine pyrophosphate.

3. The method for preparing a Si-PNC quaternary hybrid flame retardant system composition according to claim 1 or 2, characterized in that: The thermoplastic resin is any one of polyetheretherketone and MQ resin.

4. The method for preparing a Si-PNC quaternary hybrid flame retardant system composition according to claim 1 or 2, characterized in that: The silane coupling agent is any one of KH-550, KH-560, KH-570 and KH-590.

5. The method for preparing a Si-PNC quaternary hybrid flame retardant system composition according to claim 1 or 2, characterized in that: The preparation method of the modified wollastonite is as follows: wollastonite fiber and a silane coupling agent are placed in a high-speed stirrer, and the modified wollastonite is obtained after high-speed stirring.

6. The method for preparing a Si-PNC quaternary hybrid flame retardant system composition according to claim 1 or 2, characterized in that: The mass ratio of the nitrogen-phosphorus flame retardant, the thermoplastic resin, and the silane coupling agent in S1 is 5-8:2-4:1-1.2; the mass ratio of the graphene oxide grafted nitrogen-phosphorus flame retardant, the graphene oxide grafted thermoplastic resin, the modified wollastonite, and the silane coupling agent in S2 is 5-8:3-5:88-95:1-1.

2.

7. The method for preparing a Si-PNC quaternary hybrid flame retardant system composition according to claim 6, characterized in that: The addition ratio of the nitrogen-phosphorus flame retardant to the graphene oxide suspension is 5-8g:0.5L; the concentration of the graphene oxide suspension is 5-8g / L.

8. The method for preparing a Si-PNC quaternary hybrid flame retardant system composition according to claim 1 or 2, characterized in that: The reaction conditions of the functionalization reaction are: heating to 73-80° C. and reflux under nitrogen for 10-12 h.

9. The method for preparing a Si-PNC quaternary hybrid flame retardant system composition according to claim 1 or 2, characterized in that: In S1, the reaction product obtained by the functionalization reaction is dried under vacuum at 105-110° C. to obtain a graphene oxide grafted nitrogen-phosphorus flame retardant and a graphene oxide grafted thermoplastic resin.

10. A Si-PNC quaternary hybrid flame retardant system composition, characterized in that: The Si-PNC quaternary hybrid flame retardant system composition is prepared by the preparation method described in any one of claims 1 to 9.

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