Preparation method of pinecone-shaped cobalt-manganese-phosphorus nano-cluster / graphene oxide flame-retardant polyurethane

Abstract

The invention belongs to the field of nano flame-retardant materials, and particularly discloses a preparation method of pinecone-shaped cobalt-manganese-phosphorus nano-cluster / graphene oxide flame-retardant polyurethane, which comprises the following steps: weighing four reagents, namely ammonium fluoride, cobalt nitrate hexahydrate, manganese sulfate monohydrate and urea, adding into deionized water, uniformly stirring, adding graphene oxide, fully stirring, and uniformly stirring to obtain the pinecone-shaped cobalt-manganese-phosphorus nano-cluster / graphene oxide flame-retardant polyurethane. Pouring the mixed solution into a reaction kettle for hydrothermal reaction, taking out the solution after the hydrothermal reaction is finished, washing the solution with ethanol and deionized water, and drying to obtain a precursor; and phosphating the precursor and sodium hypophosphite to obtain the pinecone-shaped cobalt-manganese-phosphorus nano-cluster flame retardant growing on the graphene oxide, namely the pinecone-shaped cobalt-manganese-phosphorus nano-cluster / graphene oxide flame retardant. Compounding the pinecone-shaped cobalt-manganese-phosphorus nano-cluster / graphene oxide flame retardant with oligomeric phosphate, ammonium polyphosphate and melamine, adding the mixture into thermoplastic polyurethane, extruding, and performing hot pressing to obtain the pinecone-shaped cobalt-manganese-phosphorus nano-cluster / graphene oxide flame-retardant polyurethane material.

Description

Technical Field

[0001] The invention belongs to the field of nano flame retardant materials, and in particular relates to a method for preparing pine cone-shaped cobalt manganese phosphorus nano clusters / graphene oxide flame retardant polyurethane. Background Art

[0002] Thermoplastic polyurethane (TPU) has good mechanical strength, excellent processing performance and biocompatibility, and is widely used in electronics, automobiles, medicine and other fields. However, it is very flammable, and combustion is accompanied by severe dripping, which brings secondary disasters and poses a serious threat to human life and property safety. Improving the flame retardant properties of TPU can not only prevent problems before they occur, but also further expand the application scenarios of TPU.

[0003] For flame retardant modification of TPU, commonly used flame retardants can be divided into phosphorus-containing flame retardants, nitrogen-containing flame retardants, silicon-containing flame retardants, inorganic nano flame retardants and intumescent flame retardants. With the development of nanotechnology, the research on nanomaterials and nanotechnology in TPU flame retardant materials has become more and more in-depth. Inorganic nanoparticles (nanoclay, nano Al2O3, carbon nanotubes, nano ZnO, nano Fe2O3) have the advantages of wide source of raw materials, high thermal stability, long-lasting flame retardancy, and good smoke suppression performance. However, the amount of addition required for single use is high, which seriously deteriorates the mechanical properties and processing properties of the matrix.

[0004] Therefore, it is very necessary to develop a new method for preparing flame retardant polyurethane. Summary of the invention

[0005] The purpose of the present invention is to overcome the defects of the prior art and provide a method for preparing a pine cone-shaped cobalt manganese phosphorus nanocluster / graphene oxide flame retardant polyurethane. The pine cone-shaped cobalt manganese phosphorus nanocluster / graphene oxide flame retardant is compounded with other phosphorus-containing flame retardants and added to thermoplastic polyurethane to give the thermoplastic polyurethane good flame retardant properties and significantly increase its residual carbon content.

[0006] In order to achieve the above objectives, one of the technical solutions of the present invention is: a method for preparing pine cone-shaped cobalt manganese phosphorus nanocluster / graphene oxide flame retardant polyurethane, which specifically comprises the following steps:

[0007] (1) Preparing a precursor: Weighing ammonium fluoride, cobalt nitrate hexahydrate, manganese sulfate monohydrate, and urea, adding them to deionized water, stirring evenly, adding graphene oxide, stirring sufficiently to obtain a mixed solution, pouring the mixed solution into a reactor for hydrothermal reaction, taking out the solution after the hydrothermal reaction is completed, washing it with ethanol and deionized water, and drying it to obtain a precursor;

[0008] (2) preparing a pine cone-shaped cobalt manganese phosphorus nanocluster / graphene oxide flame retardant: phosphating the precursor prepared in step (1) and sodium hypophosphite to obtain a pine cone-shaped cobalt manganese phosphorus nanocluster flame retardant grown on graphene oxide, i.e., a pine cone-shaped cobalt manganese phosphorus nanocluster / graphene oxide flame retardant;

[0009] (3) Preparation of pine cone-shaped cobalt manganese phosphorus nanocluster / graphene oxide flame retardant polyurethane: Compound the pine cone-shaped cobalt manganese phosphorus nanocluster / graphene oxide flame retardant prepared in step (2) with oligophosphate, ammonium polyphosphate and melamine, add them to thermoplastic polyurethane (TPU), extrude and hot press to obtain pine cone-shaped cobalt manganese phosphorus nanocluster / graphene oxide flame retardant polyurethane material.

[0010] In a preferred embodiment of the present invention, the mixed solution in step (1) contains 14-22 mM ammonium fluoride, 1.5-3 mM cobalt nitrate hexahydrate, 1-2 mM manganese sulfate monohydrate, 25-35 mM urea, and 0.01-0.02 g / ml graphene oxide.

[0011] In a preferred embodiment of the present invention, the reaction temperature of the hydrothermal reaction in step (2) is 110-130° C., and the reaction time is 4-8 h.

[0012] In a preferred embodiment of the present invention, the volume ratio of deionized water to ethanol for rinsing in step (1) is 1:1.

[0013] In a preferred embodiment of the present invention, the drying temperature in step (1) is 60-80° C. and the drying time is 6-10 h.

[0014] In a preferred embodiment of the present invention, the molar ratio of sodium hypophosphite to precursor in step (2) is 2-3:1.

[0015] In a preferred embodiment of the present invention, the heating rate of the phosphating in step (2) is 3-6°C / min, the temperature is raised to 300-400°C, kept at this temperature for 2-4 hours, and then naturally cooled to room temperature and taken out.

[0016] In a preferred embodiment of the present invention, the protective gas used during the phosphating in step (2) is argon.

[0017] In a preferred embodiment of the present invention, in step (3), the mass ratio of pine cone-shaped cobalt manganese phosphorus nanoclusters / graphene oxide flame retardant, oligomeric phosphate, ammonium polyphosphate, and melamine is 0.5-3:3-6:8-1:2-5.

[0018] In a preferred embodiment of the present invention, the three temperatures during extrusion in step (3) are 150-165°C, 160-175°C, and 170-185°C.

[0019] In a preferred embodiment of the present invention, the temperature of the upper and lower plates during hot pressing in step (3) is 175-200°C.

[0020] In order to achieve the above purpose, the second technical solution of the present invention is: a pine cone-shaped cobalt manganese phosphorus nanocluster / graphene oxide flame retardant polyurethane prepared by a preparation method of pine cone-shaped cobalt manganese phosphorus nanocluster / graphene oxide flame retardant polyurethane.

[0021] Compared with the prior art, the present invention has the following beneficial effects: the pine cone-shaped cobalt manganese phosphorus nanocluster / graphene oxide flame retardant polyurethane prepared by the preparation method of the present invention is compounded with an organic phosphorus-containing flame retardant, and the pine cone-shaped cobalt manganese phosphorus nanocluster / graphene oxide flame retardant is used as a carbon source, ammonium polyphosphate is used as an acid source, and melamine is used as a gas source, so as to form an intumescent flame retardant integrating a carbon source, an acid source, and a gas source, which is used to perform flame retardant modification on TPU, can give TPU good flame retardant efficiency, and significantly improve its residual carbon content. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a scanning electron microscope image of the pine cone-shaped cobalt manganese phosphorus nanocluster / graphene oxide flame retardant polyurethane prepared in Example 1 of the present invention;

[0023] Figure 2 This is a UL-94 vertical combustion test diagram of the pine cone-shaped cobalt manganese phosphorus nanocluster / graphene oxide flame retardant polyurethane prepared in Example 1 of the present invention, a: pure TPU, b: flame retardant TPU prepared by the preparation method of the present invention. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is described in more detail below with reference to the accompanying drawings and specific embodiments, but the protection scope of the present invention is not limited to these embodiments.

[0025] A method for preparing pine cone-shaped cobalt manganese phosphorus nanocluster / graphene oxide flame retardant polyurethane, specifically comprising the following steps:

[0026] (1) Preparing a precursor: Weighing ammonium fluoride, cobalt nitrate hexahydrate, manganese sulfate monohydrate, and urea, adding them to deionized water, stirring evenly, adding graphene oxide, stirring sufficiently to obtain a mixed solution, pouring the mixed solution into a reactor for hydrothermal reaction, taking out the solution after the hydrothermal reaction is completed, washing it with ethanol and deionized water, and drying it to obtain a precursor;

[0027] (2) preparing a pine cone-shaped cobalt manganese phosphorus nanocluster / graphene oxide flame retardant: phosphating the precursor prepared in step (1) and sodium hypophosphite to obtain a pine cone-shaped cobalt manganese phosphorus nanocluster flame retardant grown on graphene oxide, i.e., a pine cone-shaped cobalt manganese phosphorus nanocluster / graphene oxide flame retardant;

[0028] (3) Preparation of pine cone-shaped cobalt manganese phosphorus nanocluster / graphene oxide flame retardant polyurethane: Compound the pine cone-shaped cobalt manganese phosphorus nanocluster / graphene oxide flame retardant prepared in step (2) with oligophosphate, ammonium polyphosphate and melamine, add them to thermoplastic polyurethane (TPU), extrude and hot press to obtain pine cone-shaped cobalt manganese phosphorus nanocluster / graphene oxide flame retardant polyurethane material.

[0029] The mixed solution in step (1) contains 14-22 mM ammonium fluoride, 1.5-3 mM cobalt nitrate hexahydrate, 1-2 mM manganese sulfate monohydrate, 25-35 mM urea, and 0.01-0.02 g / ml graphene oxide.

[0030] The reaction temperature of the hydrothermal reaction in step (2) is 110-130° C., and the reaction time is 4-8 hours.

[0031] In the step (1), the volume ratio of deionized water to ethanol for rinsing is 1:1.

[0032] In the step (1), the drying temperature is 60-80° C. and the drying time is 6-10 h.

[0033] In the step (2), the molar ratio of sodium hypophosphite to precursor is 2-3:1.

[0034] The heating rate of the phosphating in step (2) is 3-6°C / min, the temperature is raised to 300-400°C, kept at this temperature for 2-4 hours, and then naturally cooled to room temperature and taken out.

[0035] The protective gas during the phosphating in step (2) is argon.

[0036] In the step (3), the mass ratio of pine cone-shaped cobalt manganese phosphorus nanoclusters / graphene oxide flame retardant, oligomeric phosphate, ammonium polyphosphate and melamine is 0.5-3:3-6:8-1:2-5.

[0037] During extrusion in step (3), the three temperature stages are 150-165°C, 160-175°C, and 170-185°C.

[0038] During the hot pressing in step (3), the temperature of the upper and lower plates is 175-200°C.

[0039] A method for preparing pine cone-shaped cobalt manganese phosphorus nanocluster / graphene oxide flame retardant polyurethane is disclosed to obtain pine cone-shaped cobalt manganese phosphorus nanocluster / graphene oxide flame retardant polyurethane.

[0040] Example 1

[0041] A pine cone-shaped cobalt manganese phosphorus nanocluster / graphene oxide flame retardant polyurethane is prepared by the following method:

[0042] (1) Weigh 18 mmol of ammonium fluoride, 6 mmol of cobalt nitrate hexahydrate, 1.5 mmol of manganese sulfate monohydrate, and 30 mmol of urea, add them to 1000 mL of deionized water, stir for 20 min, then add 1.5 g of graphene oxide, stir for 30 min to obtain a mixed solution, pour the mixed solution into a reactor, place the reactor in a 120° C. atmosphere furnace for hydrothermal reaction for 6 h, after the hydrothermal reaction is completed and cooled naturally, take out the solution and rinse it with 1 L of ethanol and deionized water (volume ratio 1:1), and place the solid in a 60° C. forced air drying oven for 6 h to obtain a precursor.

[0043] (2) 0.6 g of the precursor and 0.6 g of sodium hypophosphite were placed in a tubular furnace for phosphating, and argon gas was introduced as a protective gas. The phosphating program was set to heat up to 300 ° C at a rate of 5 ° C / min. After keeping warm for 3 hours, it was naturally cooled to room temperature and taken out to obtain a pine cone-shaped cobalt manganese phosphorus nanocluster flame retardant grown on graphene oxide, that is, a pine cone-shaped cobalt manganese phosphorus nanocluster / graphene oxide flame retardant.

[0044] (3) 1 part of pine cone-shaped cobalt manganese phosphorus nanoclusters / graphene oxide flame retardant, 5 parts of oligomeric phosphate, 10 parts of ammonium polyphosphate, and 4 parts of melamine were compounded and added into thermoplastic polyurethane (TPU) according to their mass proportions, mixed evenly, extruded at three extrusion stages with temperatures of 160°C, 170°C, and 180°C, and then hot pressed at 190°C into pine cone-shaped cobalt manganese phosphorus nanoclusters / graphene oxide flame retardant polyurethane samples of various sizes.

[0045] The surface morphology of the prepared pine cone-shaped cobalt manganese phosphorus nanocluster / graphene oxide flame retardant polyurethane sample was observed by scanning electron microscopy. Figure 1 shown.

[0046] Example 2

[0047] A pine cone-shaped cobalt manganese phosphorus nanocluster / graphene oxide flame retardant polyurethane is prepared by the following method:

[0048] (1) Weigh 18 mM ammonium fluoride, 6 mM cobalt nitrate hexahydrate, 1.5 mM manganese sulfate monohydrate, and 30 mM urea, add them to 1000 mL of deionized water, stir for 20 min, add 1.5 g of graphene oxide, and stir for 30 min to obtain a mixed solution, pour the mixed solution into a reactor, place the reactor in a 120°C atmosphere furnace for hydrothermal reaction for 6 h, and after the hydrothermal reaction is completed and cooled naturally, take out the solution and rinse it with 1 L of ethanol and deionized water (volume ratio 1:1), and place the solid in a 60°C forced air drying oven for drying for 6 h to obtain a precursor.

[0049] (2) 0.6 g of the precursor and 0.6 g of sodium hypophosphite were placed in a tubular furnace for phosphating, and argon gas was introduced as a protective gas. The phosphating program was set to heat up to 300 ° C at a rate of 5 ° C / min. After keeping warm for 3 hours, it was naturally cooled to room temperature and taken out to obtain a pine cone-shaped cobalt manganese phosphorus nanocluster flame retardant grown on graphene oxide, that is, a pine cone-shaped cobalt manganese phosphorus nanocluster / graphene oxide flame retardant.

[0050] (3) Add 2 parts of pine cone-shaped cobalt manganese phosphorus nanoclusters / graphene oxide flame retardant, 5 parts of oligomeric phosphate, 10 parts of ammonium polyphosphate, and 3 parts of melamine into thermoplastic polyurethane (TPU) according to their mass proportions, mix well, extrude at three extrusion stages with temperatures of 160°C, 170°C, and 180°C, and then hot press at 190°C to form pine cone-shaped cobalt manganese phosphorus nanoclusters / graphene oxide flame retardant polyurethane samples of various sizes.

[0051] Example 3

[0052] A pine cone-shaped cobalt manganese phosphorus nanocluster / graphene oxide flame retardant polyurethane is prepared by the following method:

[0053] (1) Weigh 18 mM ammonium fluoride, 6 mM cobalt nitrate hexahydrate, 1.5 mM manganese sulfate monohydrate, and 30 mM urea, add them to 100 mL of deionized water, stir for 20 min, add 1.5 g of graphene oxide, and stir for 30 min to obtain a mixed solution, pour the mixed solution into a reactor, place the reactor in a 120°C atmosphere furnace for hydrothermal reaction for 6 h, and after the hydrothermal reaction is completed and cooled naturally, take out the solution and rinse it with 1 L of ethanol and deionized water (volume ratio 1:1), and place the solid in a 60°C forced air drying oven for drying for 6 h to obtain a precursor.

[0054] (2) 0.6 g of the precursor and 0.6 g of sodium hypophosphite were placed in a tubular furnace for phosphating, and protective gas argon was introduced. The phosphating program was set to increase the temperature to 350° C. at 5° C. / min. After keeping the temperature for 3 hours, the mixture was naturally cooled to room temperature and taken out to obtain a pine cone-shaped cobalt manganese phosphorus nanocluster flame retardant grown on graphene oxide, namely, a pine cone-shaped cobalt manganese phosphorus nanocluster / graphene oxide flame retardant.

[0055] (3) Add 3 parts of pine cone-shaped cobalt manganese phosphorus nanoclusters / graphene oxide flame retardant, 5 parts of oligomeric phosphate, 10 parts of ammonium polyphosphate, and 2 parts of melamine into thermoplastic polyurethane (TPU) according to their mass proportions, mix well, extrude at three extrusion stages with temperatures of 160°C, 170°C, and 180°C, and then hot press at 190°C to form pine cone-shaped cobalt manganese phosphorus nanoclusters / graphene oxide flame retardant polyurethane samples of various sizes.

[0056] The pine cone-shaped cobalt manganese phosphorus nanocluster / graphene oxide flame retardant polyurethane samples prepared in Examples 1-3 were subjected to UL-94 vertical combustion test, and the residual carbon content was tested by TGA thermogravimeter in a nitrogen environment at 10°C / min and heated to 800°C. The specific test results are shown in the following table:

[0057] Table 1 Test results of pine cone-shaped cobalt manganese phosphorus nanocluster / graphene oxide flame retardant polyurethane samples prepared in Examples 1-3

[0058]

[0059] From the above test results, it can be seen that the residual carbon value of thermoplastic polyurethane (pure TPU) without adding flame retardant is 5.9% at 800℃. Figure 2 It can be seen that the combustion experiment is accompanied by serious dripping, and the dripping will ignite cotton and cause secondary damage. The flame spread rate of thermoplastic polyurethane with flame retardant is reduced, and a complete carbon layer is formed after combustion. The residual carbon value is greater than 20% at 800°C, which is more than 4 times that of pure thermoplastic polyurethane. The pine cone-shaped cobalt manganese phosphorus nanocluster / graphene oxide flame retardant expands when heated to cover the surface of the substrate to form an insulating carbon layer. Other phosphorus-containing flame retardants promote the thermal decomposition of the substrate and form phosphorus-enriched products that melt at high temperature, further improving the strength and density of the carbon layer on the surface of the substrate, so that the thermoplastic polyurethane with compound flame retardant can reach V-0 UL-94 rating. It gives thermoplastic polyurethane excellent flame retardant properties.

[0060] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some or all of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing pine cone-shaped cobalt manganese phosphorus nanocluster / graphene oxide flame retardant polyurethane, characterized in that: The steps include: (1) Preparing a precursor: Weighing ammonium fluoride, cobalt nitrate hexahydrate, manganese sulfate monohydrate, and urea, adding them to deionized water, stirring evenly, adding graphene oxide, stirring sufficiently to obtain a mixed solution, pouring the mixed solution into a reactor for hydrothermal reaction, taking out the solution after the hydrothermal reaction is completed, washing it with ethanol and deionized water, and drying it to obtain a precursor; (2) preparing a pine cone-shaped cobalt manganese phosphorus nanocluster / graphene oxide flame retardant: phosphating the precursor prepared in step (1) and sodium hypophosphite to obtain a pine cone-shaped cobalt manganese phosphorus nanocluster flame retardant grown on graphene oxide, i.e., a pine cone-shaped cobalt manganese phosphorus nanocluster / graphene oxide flame retardant; (3) Preparation of pine cone-shaped cobalt manganese phosphorus nanocluster / graphene oxide flame retardant polyurethane: compound the pine cone-shaped cobalt manganese phosphorus nanocluster / graphene oxide flame retardant prepared in step (2) with oligophosphate, ammonium polyphosphate and melamine, add them to thermoplastic polyurethane, extrude and hot press to obtain pine cone-shaped cobalt manganese phosphorus nanocluster / graphene oxide flame retardant polyurethane material.

2. The method for preparing the pine cone-shaped cobalt manganese phosphorus nanocluster / graphene oxide flame retardant polyurethane according to claim 1, characterized in that: The mixed solution in step (1) contains 14-22 mM ammonium fluoride, 1.5-3 mM cobalt nitrate hexahydrate, 1-2 mM manganese sulfate monohydrate, 25-35 mM urea, and 0.01-0.02 g / ml graphene oxide.

3. The method for preparing the pine cone-shaped cobalt manganese phosphorus nanocluster / graphene oxide flame retardant polyurethane according to claim 1, characterized in that: The reaction temperature of the hydrothermal reaction in step (1) is 110-130° C., and the reaction time is 4-8 hours.

4. The method for preparing the pine cone-shaped cobalt manganese phosphorus nanocluster / graphene oxide flame retardant polyurethane according to claim 1, characterized in that: In the step (1), the volume ratio of deionized water to ethanol for rinsing is 1:

1.

5. The method for preparing the pine cone-shaped cobalt manganese phosphorus nanocluster / graphene oxide flame retardant polyurethane according to claim 1, characterized in that: In the step (1), the drying temperature is 60-80° C. and the drying time is 6-10 h.

6. The method for preparing the pine cone-shaped cobalt manganese phosphorus nanocluster / graphene oxide flame retardant polyurethane according to claim 1, characterized in that: In the step (2), the molar ratio of sodium hypophosphite to precursor is 2-3:

1.

7. The method for preparing the pine cone-shaped cobalt manganese phosphorus nanocluster / graphene oxide flame retardant polyurethane according to claim 1, characterized in that: The protective gas during phosphating in step (2) is argon, the heating rate is 3-6°C / min, the temperature is raised to 300-400°C, and after keeping the temperature for 2-4 hours, it is naturally cooled to room temperature and taken out.

8. The method for preparing the pine cone-shaped cobalt manganese phosphorus nanocluster / graphene oxide flame retardant polyurethane according to claim 1, characterized in that: In the step (3), the mass ratio of pine cone-shaped cobalt manganese phosphorus nanoclusters / graphene oxide flame retardant, oligomeric phosphate, ammonium polyphosphate, and melamine is 0.5-3:3-6:8-1:2-5.

9. The method for preparing the pine cone-shaped cobalt manganese phosphorus nanocluster / graphene oxide flame retardant polyurethane according to claim 1, characterized in that: In the step (3), the three temperature sections during extrusion are 150-165°C, 160-175°C, and 170-185°C, and the temperature of the upper and lower plates during hot pressing is 175-200°C.

10. A pine cone-shaped cobalt manganese phosphorus nanocluster / graphene oxide flame retardant polyurethane prepared by the method for preparing pine cone-shaped cobalt manganese phosphorus nanocluster / graphene oxide flame retardant polyurethane according to any one of claims 1 to 9.

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