Preparation method of environment-friendly nano flame retardant BPU@PPA and epoxy resin nanocomposite

Abstract

The application discloses an environment-friendly nano flame retardant BPU@PPA and an epoxy resin nano composite material and a preparation method thereof, and the preparation method comprises the following steps: (1) preparing a BN@PEI nano hybrid material; (2) preparing a BN@PEI@UiO-66 nano hybrid material; (3) preparing the environment-friendly nano flame retardant BPU@PPA; and (4) preparing the epoxy resin nano composite material BPU@PPA / EP. In the preparation process, the designed environment-friendly nano flame retardant BPU@PPA is combined with the epoxy resin, and the prepared epoxy resin nano composite material BPU@PPA / EP overcomes the defects of strong flammability, poor flame retardancy and strong fire toxicity of the existing epoxy resin, the obtained epoxy resin nano composite material BPU@PPA / EP has the advantages of improved coke strength, enhanced flame retardancy, reduced smoke release and obviously reduced fire risk. The epoxy resin nano composite material has the advantages of simple and feasible preparation process, low production cost, environment-friendly product, suitability for industrialized production and great application value.

Description

Technical Field

[0001] This invention belongs to the field of flame retardants and preparation methods of epoxy nanocomposites, specifically relating to the preparation method and application of an environmentally friendly nanoflame retardant BPU@PPA and an epoxy resin nanocomposite BPU@PPA / EP. Background Technology

[0002] Epoxy resin (EP) is widely used in coatings, adhesives, electronics, and electrical appliances due to its excellent chemical resistance, physical properties, mechanical properties, adhesive properties, and application flexibility. However, the application of EP is limited by its inherent flammability, which leads to a high fire risk. For example, epoxy resin releases large amounts of smoke and toxic gases when burning, which are the main factors causing casualties and hindering rescue efforts in fires. Therefore, developing effective methods to improve the flame retardant properties of EP and reduce its fire toxicity is of great significance. Based on this, we have fully considered the synergistic effects of multi-component and multi-structure components and designed a novel environmentally friendly nano-flame retardant—BPU@PPA—to achieve high flame retardancy and low fire toxicity of EP, thereby promoting the further application of EP in specialized fields. Summary of the Invention

[0003] This invention addresses the inherent flammability and fire toxicity of epoxy resin by providing a method for preparing an environmentally friendly nano flame retardant, BPU@PPA, and expands the application of BPU@PPA flame retardant in the field of epoxy resin fire safety.

[0004] To achieve the above technical objectives, the present invention adopts the following technical solution:

[0005] A method for preparing an environmentally friendly nano-flame retardant BPU@PPA and epoxy resin nanocomposite material, characterized by the following steps:

[0006] S1: Preparation of BN@PEI nano-hybrid material: First, hexagonal boron nitride (BN) was added to 100 mL of deionized water and sonicated for 1 hour to obtain a uniform dispersion. Then, a certain amount of polyethyleneimine (PEI) was added to another 100 mL of water and dispersed. Then, it was added to the above dispersion and stirred for 6 hours. The resulting suspension was centrifuged and washed with deionized water. After drying, BN@PEI nano-hybrid material was obtained.

[0007] S2: Preparation of BN@PEI@UiO-66 nano-hybrid material: First, BN@PEI was added to 30 mL of N,N-dimethylformamide (DMF), sonicated for 30 minutes, and transferred to a 250 mL three-necked flask. Then, zirconium tetrachloride (ZrCl4) was dissolved in 10 mL of DMF and added to the three-necked flask. The mixture was stirred at room temperature for 1 hour. Then, the corresponding amounts of 2-aminoterephthalic acid and acetic acid (4 mL) were dissolved in 40 mL of DMF and added to the three-necked flask. The mixture was reacted at 120 °C for 24 hours. After cooling, the prepared composite was collected by centrifugation, washed several times with DMF, and dried to obtain BN@PEI@UiO-66 nano-hybrid material supported by zirconium-based metal-organic framework (UiO-66).

[0008] S3: Preparation of environmentally friendly nano flame retardant BPU@PPA: First, BN@PEI@UiO-66, 60mL of distilled water and aniline were added to a 250mL three-necked flask. Then, 40mL of aqueous solution containing ammonium persulfate ((NH4)2S2O8) was added dropwise to the three-necked flask in an ice bath. The pH was adjusted to 2.0 with phytic acid. The reaction was carried out at 0-5℃ for 8 hours to complete the oxidative polymerization process. Finally, the product was washed several times with ethanol and water and dried in a vacuum oven at 80℃ for 24 hours to obtain the environmentally friendly nano flame retardant BPU@PPA.

[0009] S4: Preparation of epoxy resin nanocomposite material BPU@PPA / EP: First, the flame retardant BPU@PPA and epoxy resin are dispersed in an acetone solution. Then, the mixture is placed in a vacuum oven at 80°C for 12 hours to remove the acetone. Subsequently, it is uniformly mixed with a certain amount of curing agent 4,4'-diaminodiphenylmethane (DDM). Finally, the mixture is cured at 100°C and 150°C for 2 hours respectively, and then naturally cooled to room temperature to obtain epoxy resin nanocomposite material BPU@PPA / EP.

[0010] Furthermore, in step S1, the mass ratio of BN to PEI is 1:5-10;

[0011] Furthermore, in step S2, the mass ratio of BN@PEI, ZrCl4, and 2-aminoterephthalic acid is 1.5-3:1.0-1.5:1;

[0012] Furthermore, in step S3, the mass ratio of BN@PEI@UiO-66, aniline, and (NH4)2S2O8 is 1:5-10:15-30;

[0013] Furthermore, in step S4, the mass ratio of 4,4'-diaminodiphenylmethane to epoxy resin is 1:3-6;

[0014] Furthermore, in step S4, the mass ratio of flame retardant BPU@PPA to epoxy resin is 0.01-0.1:1;

[0015] Beneficial effects:

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] This invention provides a method for preparing an environmentally friendly nano-flame retardant, BPU@PPA, and a method for preparing an epoxy resin nanocomposite material, BPU@PPA / EP. These methods overcome the dangerous defects of existing epoxy resins, such as high flammability, poor flame retardancy, and high fire toxicity. The resulting epoxy resin nanocomposite material, BPU@PPA / EP, exhibits improved char strength, enhanced flame retardancy, and reduced smoke emission, significantly reducing the fire risk. The preparation process of this epoxy resin nanocomposite material is simple and feasible, with low production costs and environmentally friendly products, making it suitable for industrial production. In this preparation process, the designed environmentally friendly nano-flame retardant BPU@PPA is combined with epoxy resin, resulting in a product with significantly enhanced flame retardant and smoke suppression properties, demonstrating significant application value. Attached Figure Description

[0018] Figure 1 X-ray diffraction patterns of BN, BN@PEI, UiO-66, BN@PEI@UiO-66, and BPU@PPA.

[0019] Figure 2 The images show transmission electron microscopy (TEM) and scanning electron microscopy (SEM) images of BN@PEI, BN@PEI@UiO-66, and BPU@PPA, where A is the SEM image of BN@PEI, B is the SEM image of BN@PEI@UiO-66, C is the SEM image of BPU@PPA, D is the TEM image of BN@PEI, E is the TEM image of BN@PEI@UiO-66, and F is the TEM image of BPU@PPA.

[0020] Figure 3 Scanning electron microscope (SEM) images of cross-sections of composite materials EP, UiO-66 / EP, BN / EP, BN@PEI / EP, BN@PEI@UiO-66 / EP, and BPU@PPA / EP, where A represents EP, B represents UiO-66 / EP, C represents BN / EP, D represents BN@PEI / EP, E represents BN@PEI@UiO-66 / EP, and F represents BPU@PPA / EP. Figure 4 The thermogravimetric analysis results are shown for the composite materials of EP, UiO-66 / EP, BN / EP, BN@PEI / EP, BN@PEI@UiO-66 / EP and BPU@PPA / EP. In A, the sample mass changes over time, and B is a magnified view of a local area.

[0021] Figure 5 The results are from a cone calorimeter test, where A is the average heat release rate (HRR), B is the average smoke release rate (SPR), C is the total heat release rate (THR), and D is the total smoke release rate (TSP).

[0022] Figure 6 The images show scanning electron microscope (SEM) images of residual carbon after cone calorimeter testing. In the images, A1 and A2 are EP, B1 and B2 are UiO-66 / EP, C1 and C2 are BN / EP, D1 and D2 are BN@PEI / EP, E1 and E2 are BN@PEI@UiO-66 / EP, and F1 and F2 are BPU@PPA / EP. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0024] Example:

[0025] A method for preparing an environmentally friendly nano-flame retardant BPU@PPA and epoxy resin nanocomposite material, specifically including the following steps:

[0026] S1: Preparation of BN@PEI nano-hybrid material: First, 0.4 g of hexagonal boron nitride (h-BN) was added to 100 mL of deionized water and sonicated for 1 hour to obtain a uniform dispersion. Then, polyethyleneimine (PEI mass fraction of 2% of the total mass) was added to another 100 mL of water and dispersed. Then, it was added to the above dispersion and stirred for 6 hours. The resulting suspension was centrifuged and washed with deionized water. After drying, BN@PEI nano-hybrid material was obtained.

[0027] S2: Preparation of BN@PEI@UiO-66 nano-hybrid material: First, 0.4 g of BN@PEI was added to 30 mL of N,N-dimethylformamide (DMF), sonicated for 30 minutes, and transferred to a 250 mL three-necked flask. Then, ZrCl4 (0.233 g) was dissolved in 10 mL of DMF and added to the three-necked flask. The mixture was stirred at room temperature for 1 hour. Then, 2-aminoterephthalic acid (0.181 g) and acetic acid (4 mL) were dissolved in 40 mL of DMF and added to the three-necked flask. The mixture was reacted at 120 °C for 24 hours. After cooling, the prepared composite was collected by centrifugation, washed several times with DMF, and dried to obtain BN@PEI@UiO-66 nano-hybrid material.

[0028] S3: Preparation of environmentally friendly nano flame retardant BPU@PPA: First, 0.25g BPM, 60mL distilled water and 1.86g aniline were added to a 250mL three-necked flask. Then, 40mL of aqueous solution containing 5.477g ammonium persulfate ((NH4)2S2O8) was added dropwise to the three-necked flask in an ice bath. The pH was adjusted to 2.0 with phytic acid. The reaction was carried out at 0-5℃ for 8 hours to complete the oxidative polymerization process. Finally, the product was washed several times with ethanol and water and dried in a vacuum oven at 80℃ for 24 hours to obtain the environmentally friendly nano flame retardant BPU@PPA.

[0029] S4: Preparation of epoxy resin nanocomposite material BPU@PPA / EP: First, 1.2g of flame retardant BPU@PPA and 60g of epoxy resin were dispersed in an acetone solution. Then, the mixture was placed in a vacuum oven at 80℃ for 12 hours to remove the acetone. Subsequently, it was uniformly mixed with 15g of curing agent 4,4'-diaminodiphenylmethane (DDM). Finally, the mixture was cured at 100℃ and 150℃ for 2 hours respectively, and then naturally cooled to room temperature to obtain epoxy resin nanocomposite material BPU@PPA / EP.

[0030] This embodiment demonstrates the experimental analysis results related to the preparation method of the environmentally friendly nano flame retardant BPU@PPA and epoxy resin nanocomposite materials proposed in this paper.

[0031] BN / EP, BN@PEI / EP, UiO-66 / EP, BN@PEI@UiO-66, and BPU@PPA were prepared using UiO-66, BN, BN@PEI, BN@PEI@UiO-66, and BPU@PPA, respectively, with a mass fraction of 2% epoxy resin. Pure epoxy resin (EP) was used as a control.

[0032] (1) The crystal structures of UiO-66, BN, BN@PEI, BN@PEI@UiO-66, and BPU@PPA were characterized by X-ray diffraction (XRD, X-ray perturbation, MPD, Cu Kα-ray diffraction, 5-80°). The results are shown in the appendix. Figure 1 .from Figure 1 As can be seen, after modification, the characteristic diffraction peaks of BN, UiO-66 and PANI (polyaniline) can be detected simultaneously in the XRD spectrum of the hybrid material BPU@PPA, indicating that UiO-66 and PANI were successfully grown on the BN surface.

[0033] (2) The morphology of BN@PEI, BN@PEI@UiO-66, and BPU@PPA hybrid materials was observed using a JEOL JEM-2100 high-resolution transmission electron microscope (HR-TEM) and a Thermo Scientific Apreo 2C scanning electron microscope (SEM). The results are shown in the appendix. Figure 2 .from Figure 2 A and Figure 2 As can be seen in D, after BN is coated with PEI, the surface of BN@PEI is rough, and an organic layer can be observed; after binding with UiO-66 ( Figure 2 B and Figure 2 E), it can be clearly observed that the UiO-66 octahedrons are uniformly loaded on the BN@PEI surface; after modification with phytic acid-doped dendritic polyaniline (PPA) ( Figure 2 C and Figure 2 F) The obvious dendritic structure observed on the surface of the hybrid material indicates that PPA was successfully coated on the material surface, indicating that the synthesis of the hybrid material was successful.

[0034] (3) The cross-sectional morphology of each coating was observed using a JSM-7500F scanning electron microscope. The results are shown in the appendix. Figure 3 .from Figure 3 As can be seen from A, the pure resin has a smooth fracture surface and exhibits brittle fracture characteristics. After adding filler, it exhibits ductile fracture characteristics. UiO-66 / EP ( Figure 3 B) The cross-section shows that UiO-66 is uniformly dispersed in the epoxy resin. BN / EP ( Figure 3 C) Nanomaterials with severe agglomeration on the cross-section, after PEI modification ( Figure 3 D), the material dispersion is improved. After loading UiO-66, BN@PEI@UiO-66 ( Figure 3 E) The cross-sectional material is more evenly dispersed. From Figure 3 As can be seen from F, after PPA modification, BPU@PPA is uniformly dispersed in the resin system.

[0035] (4) The thermal degradation behavior of different epoxy resin nanocomposites was tested using a thermal analyzer (TG, Mettler Toledo, Switzerland, DSC823 TGA / SDTA85 / e). The results are shown in the appendix. Figure 4 The thermal degradation curves showing the change in mass over time indicate that the addition of flame retardant BPU@PPA increased the residual coke content of epoxy resin by 36.2%, demonstrating that BPU@PPA can effectively improve the coke quality of epoxy resin.

[0036] (5) The combustion behavior of different epoxy resin nanocomposites was tested using a cone calorimeter (CCT, Kunshan Mortis Fire Protection Technology Co., Ltd.). The results are shown in the appendix. Figure 5 From the average heat release rate plot ( Figure 5 A) and the total heat release rate diagram ( Figure 5 C) shows that the addition of BPU@PPA reduced the peak average heat release rate and total heat release by 47.2% and 47.9%, respectively, indicating that BPU@PPA can effectively improve the flame retardant properties of epoxy resin; from the average smoke release graph ( Figure 5 B) and total smoke emission diagram ( Figure 5 D) It can be seen that the addition of BPU@PPA reduced the peak average smoke release rate and total smoke release by 46.0% and 52.7%, respectively, indicating that the flame retardant BPU@PPA has excellent smoke suppression performance.

[0037] (6) The structure of the coke after cone calorimeter testing was observed using a JSM-7500F scanning electron microscope. The results are shown in the appendix. Figure 6 .from Figure 6 It can be seen that the SEM image of pure EP ( Figure 6 A1 and Figure 6 A2) shows broken char, which is not conducive to heat and gaseous product barrier. After the addition of flame retardant, the residual char becomes more intact. BN / EP( Figure 6 C1 and Figure 6 C2) coke surface has large and wide cracks, BN@PEI / EP ( Figure 6 D1 and Figure 6 D2) coke cracks become narrower and fewer, UiO-66 / EP( Figure 6 B1 and Figure 6 B2), the carbon layer becomes more complete, but surface cracks still exist. BN@PEI@UiO-66 / EP( Figure 6 E1 and Figure 6 The surface cracks of the E2 coke disappeared, leaving only a few small pores. Adding BPU@PPA ( Figure 6 F1 and Figure 6 After F2), the coke becomes dense and intact, indicating that the coke strength increases and its barrier properties are enhanced.

[0038] This invention provides a method for preparing an environmentally friendly nano-flame retardant, BPU@PPA, and a method for preparing an epoxy resin nanocomposite material, BPU@PPA / EP. These methods overcome the dangerous defects of existing epoxy resins, such as high flammability, poor flame retardancy, and high fire toxicity. The resulting epoxy resin nanocomposite material, BPU@PPA / EP, exhibits improved char strength, enhanced flame retardancy, and reduced smoke emission, significantly reducing the fire risk. The preparation process of this epoxy resin nanocomposite material is simple and feasible, with low production costs and environmentally friendly products, making it suitable for industrial production. In this preparation process, the designed environmentally friendly nano-flame retardant BPU@PPA is combined with epoxy resin, resulting in a product with significantly enhanced flame retardant and smoke suppression properties, demonstrating significant application value.

[0039] The above description is not intended to limit the present invention in any way. Although the present invention has been disclosed through the above embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for preparing an environmentally friendly nano-flame retardant BPU@PPA and an epoxy resin nanocomposite material, characterized in that, Includes the following steps: S1: Preparation of BN@PEI nano-hybrid material: First, hexagonal boron nitride (BN) was added to 100 mL of deionized water and sonicated for 1 hour to obtain a uniform dispersion. Then, a certain amount of polyethyleneimine (PEI) was added to another 100 mL of water and dispersed. Then, it was added to the above dispersion and stirred for 6 hours. The resulting suspension was centrifuged and washed with deionized water. After drying, BN@PEI nano-hybrid material was obtained. S2: Preparation of BN@PEI@UiO-66 nano-hybrid material: First, BN@PEI was added to 30 mL of N,N-dimethylformamide (DMF), sonicated for 30 minutes, and transferred to a 250 mL three-necked flask. Then, zirconium tetrachloride (ZrCl4) was dissolved in 10 mL of DMF and added to the three-necked flask. The mixture was stirred at room temperature for 1 hour. Then, the corresponding amounts of 2-aminoterephthalic acid and acetic acid (4 mL) were dissolved in 40 mL of DMF and added to the three-necked flask. The mixture was reacted at 120 °C for 24 hours. After cooling, the prepared composite was collected by centrifugation, washed several times with DMF, and dried to obtain BN@PEI@UiO-66 nano-hybrid material supported by zirconium-based metal-organic framework (UiO-66). S3: Preparation of environmentally friendly nano flame retardant BPU@PPA: First, BN@PEI@UiO-66, 60mL of distilled water and aniline were added to a 250mL three-necked flask. Then, 40mL of aqueous solution containing ammonium persulfate ((NH4)2S2O8) was added dropwise to the three-necked flask in an ice bath. The pH was adjusted to 2.0 with phytic acid. The reaction was carried out at 0-5℃ for 8 hours to complete the oxidative polymerization process. Finally, the product was washed several times with ethanol and water and dried in a vacuum oven at 80℃ for 24 hours to obtain the environmentally friendly nano flame retardant BPU@PPA. S4: Preparation of epoxy resin nanocomposite material BPU@PPA / EP: First, the flame retardant BPU@PPA and epoxy resin are dispersed in an acetone solution. Then, the mixture is placed in a vacuum oven at 80°C for 12 hours to remove the acetone. Subsequently, it is uniformly mixed with a certain amount of curing agent 4,4'-diaminodiphenylmethane (DDM). Finally, the mixture is cured at 100°C and 150°C for 2 hours respectively, and then naturally cooled to room temperature to obtain epoxy resin nanocomposite material BPU@PPA / EP.

2. The preparation method of the environmentally friendly nano-flame retardant BPU@PPA and epoxy resin nanocomposite material as described in claim 1, characterized in that, In step S1, the mass ratio of BN to PEI is 1:5-10.

3. The preparation method of the environmentally friendly nano-flame retardant BPU@PPA and epoxy resin nanocomposite material as described in claim 1, characterized in that, In step S2, the mass ratio of BN@PEI, ZrCl4, and 2-aminoterephthalic acid is 1.5-3:1.0-1.5:

1.

4. The preparation method of the environmentally friendly nano-flame retardant BPU@PPA and epoxy resin nanocomposite material as described in claim 1, characterized in that, In step S3, the mass ratio of BN@PEI@UiO-66, aniline, and (NH4)2S2O8 is 1:5-10:15-30.

5. The preparation method of the environmentally friendly nano flame retardant BPU@PPA and epoxy resin nanocomposite material as described in claim 1, characterized in that, In step S4, the mass ratio of flame retardant BPU@PPA to epoxy resin is 0.01-0.1:1.

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