CN111875764A - Novel nanometer hybrid flame-retardant polyurethane elastomer and preparation method thereof - Google Patents

Abstract

The invention discloses a novel nanometer hybrid flame-retardant polyurethane elastomer, which mainly comprises the following components: 42.3-45g of polyester polyol, 7-8.7g of TDI, 4-5g of MOCA and 0.5-1.5g of novel nano hybrid flame retardant; wherein, the sodiumThe rice hybrid flame retardant is CuMoO₄@ h-BN. The invention also discloses a preparation method of the novel nanometer hybrid flame-retardant polyurethane elastomer. The novel nano hybrid flame-retardant polyurethane elastomer prepared by the invention solves the problem of poor dispersibility of a nano material (h-BN) in the processing process of a polymer, so that the h-BN is uniformly dispersed in a polymer matrix; realizes the synergistic effect of various elements and more effectively improves the flame retardant property and the smoke suppression property of the polymer.

Description

Novel nanometer hybrid flame-retardant polyurethane elastomer and preparation method thereof

Technical Field

The invention belongs to the field of high polymer materials, and particularly relates to a novel nano hybrid flame-retardant polyurethane elastomer and a preparation method thereof.

Background

Polyurethane elastomers (PUE) are polymeric materials formed by reacting together diisocyanate-based molecules such as diphenylmethane diisocyanate (MDI) or Toluene Diisocyanate (TDI) with macromolecular polyols and low-molecular polyols (chain extenders). The PUE has excellent abrasion resistance, oil resistance and elasticity, and is widely used in various fields such as sporting goods, toys, decorative materials and the like. However, PUEs are capable of burning rapidly and producing large quantities of noxious substances and smoke under continuous heating, which is often the first in a fire and is the most hazardous factor for human life safety. Therefore, it is very important that the flame retardant not only improves the flame retardancy of the material, but also suppresses smoke and reduces toxicity.

There is an increasing demand for clean type flame retardant polymers. Generally, the addition of inorganic flame retardants to polymers generally reduces their fire hazard, reduces the toxic materials produced during the combustion of the materials, and does not create a hazard during use. However, a single inorganic flame retardant generally needs to be added in a high amount to achieve high flame retardant efficiency, and at the same time, has a certain influence on other properties of the substrate. Therefore, a novel synergistic flame-retardant system is formed by two or more components, and the aims of low addition amount of the inorganic flame retardant and high flame-retardant smoke suppression efficiency are fulfilled.

Hexagonal boron nitride (h-BN) has a layered structure similar to graphite. It is composed of B and N atoms, each bonded by weak van der waals forces. The boron nitride material has a plurality of excellent physical and chemical properties, and is widely applied to high-tech fields such as machinery, metallurgy, electronics, aerospace and the like. BN also shows a very important role in improving the flame retardant properties of polymers due to its unique lamellar structure. BN can improve the flame retardant property of the polymer mainly by virtue of the sheet layer barrier effect and good thermal stability of the polymer. However, h-BN is chemically stable, has few active groups on the surface, and has weak interaction with most organic molecules and polymer molecular chains, so that the dispersibility of the h-BN in a polymer matrix is poor, and the improvement effect of the h-BN on the performance of the polymer material is greatly limited. Therefore, it is necessary to perform a clustering treatment on the h-BN surface.

Disclosure of Invention

The invention provides a novel flame-retardant smoke suppressant with high efficiency. On one hand, the superiority of the chemical property of boron nitride is fully exerted; on the other hand, the surface hydroxylation treatment of boron nitride effectively improves the loading capacity of copper molybdate; in addition, the introduction of copper molybdate realizes the synergistic effect of various elements, and more effectively overcomes the defects that the polymer matrix is rapidly combusted under the condition of continuous heating and generates a large amount of harmful substances and smoke. At present, in the field of flame retardance, similar research on surface modification of hydroxylated boron nitride by copper molybdate has not been carried out.

A novel nanometer hybrid flame-retardant polyurethane elastomer mainly comprises the following components: 42.3-45g of polyester polyol, 7-8.7g of TDI, 4-5g of MOCA and 0.5-1.5g of novel nano hybrid flame retardant;

wherein the nano hybrid flame retardant is CuMoO4@ h-BN.

Preferably, it comprises essentially the following components: 44.4g of polyester polyol, 7.83g of TDI, 4.6g of MOCA and 1g of novel nano hybrid flame retardant.

Preferably, the preparation method of the novel nano hybrid flame retardant comprises the following steps:

(1) mixing concentrated sulfuric acid and a concentrated nitric acid solution according to a volume ratio of 1:3 to obtain a concentrated acid solution, placing hexagonal boron nitride powder in the concentrated acid solution, and performing ultrasonic treatment for 6 hours to obtain a light yellow viscous liquid;

(2) refluxing the light yellow viscous liquid obtained in the step (1) in an oil bath, washing, centrifuging, and freeze-drying to obtain surface functionalized h-BN;

(3) placing the h-BN with the functionalized surface obtained in the step (2) in deionized water, and ultrasonically stirring to obtain h-BN suspension;

(4) 0.85g of CuCl₂Putting the mixture into deionized water, stirring the mixture until the mixture is completely dissolved, dropwise adding the h-BN suspension obtained in the step (3), ultrasonically stirring the mixture for 0.5 to 1 hour, and then reacting the mixture for 10 to 24 hours under the condition of oil bath at the temperature of between 55 and 65 ℃ to obtain a mixed solution;

(5) adding 0.06mol/L of Na₂MoO₄Dropwise adding the aqueous solution into the mixed solution obtained in the step (3), stirring for 1-3h, cooling and standing, removing supernatant, washing with deionized water, centrifuging, and freeze-drying to obtain CuMoO₄@h-BN。

Preferably, the temperature of the oil bath reflux in the step (2) is 60-80 ℃, and the time is 60-84 h.

Preferably, the time of ultrasonic stirring in the step (3) is 15-60 min.

A preparation method of a novel nanometer hybrid flame-retardant polyurethane elastomer comprises the following steps:

(1) placing polyester polyol in a reaction kettle, dehydrating at the temperature of 105-110 ℃ for 1.5-2h, cooling to 65-70 ℃, adding TDI, heating to 70-75 ℃, stirring for 2-2.5h, and dehydrating in vacuum at the temperature of 75-85 ℃ for 30-45min to obtain a prepolymer;

(2) mixing the nano hybrid CuMoO₄Uniformly dispersing the @ h-BN in a proper amount of acetone solution under the ultrasonic condition, pouring the acetone solution into the prepolymer, and stirring for 5min under the ultrasonic condition of 70-75 ℃ to form a uniform mixture;

(3) adding MOCA into the mixture, stirring vigorously, pouring into a mold, heating at 75-85 deg.C for 5-7h, and heating at 110-130 deg.C for 2-3h to obtain CuMoO₄@h-BN/PUE。

THE ADVANTAGES OF THE PRESENT INVENTION

CuMoO₄Flame retardant and smoke suppression performance of @ h-BN/PUE: on one hand, the h-BN nano-sheet layer and the carbon layer formed in the combustion process have physical barrier effect and inhibit the polymer from decomposingThe combustible gas generated in the process volatilizes, oxygen is isolated, the radiation effect of heat on the material is reduced, and on the other hand, CuMoO₄Can be decomposed to generate Cu during heating₂O and MoO₃，Cu₂O and MoO₃The catalyst has the function of catalyzing and forming a compact carbon layer, and the compact carbon layer can further prevent the combustion of the following materials and reduce the release of smoke; meanwhile, the invention solves the problem of poor dispersibility of the nano material (h-BN) in the processing process of the polymer, so that the h-BN is uniformly dispersed in the polymer matrix; realizes the synergistic effect of various elements and more effectively improves the flame retardant property and the smoke suppression property of the polymer.

Drawings

FIG. 1 is CuMoO₄@ h-BN and CuMoO₄Schematic of the preparation of @ h-BN/PUE.

FIG. 2 shows h-BN, CuMoO₄Transmission electron microscope images of @ h-BN.

FIG. 3 is CuMoO₄Energy spectrum analysis chart of @ h-BN.

FIG. 4 is CuMoO₄Scanning electron microscope images of the dispersion of @ h-BN in the PUE.

Detailed Description

The present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein, and equivalents and modifications thereof available to those skilled in the art are intended to be within the scope of the present invention. The protection scope of the invention is subject to the claims.

Example 1

Preparation of the nano hybrid flame retardant:

(1) mixing concentrated sulfuric acid and a concentrated nitric acid solution according to a volume ratio of 1:3 to obtain a concentrated acid solution, placing hexagonal boron nitride powder in the concentrated acid solution, and performing ultrasonic treatment for 6 hours to obtain a light yellow viscous liquid;

(2) refluxing the light yellow viscous liquid obtained in the step (1) in an oil bath pot for 72h at the temperature of 80 ℃, washing, centrifuging, and freeze-drying to obtain h-BN with functionalized surface;

(3) placing the h-BN with the functionalized surface obtained in the step (2) in deionized water, and carrying out ultrasonic stirring treatment for 30min to obtain h-BN suspension;

(4) 0.85g of CuCl₂Putting the mixture into deionized water, stirring the mixture until the mixture is completely dissolved, dropwise adding the mixture into the suspension obtained in the step (3) to obtain h-BN suspension, ultrasonically stirring the suspension for 1h, and then reacting the suspension for 12h under the condition of oil bath at the temperature of 60 ℃ to obtain a mixed solution;

(5) adding 0.06mol/L of Na₂MoO₄Dropwise adding the aqueous solution into the mixed solution obtained in the step (4), stirring for 2 hours, cooling and standing, removing supernatant, washing with deionized water, centrifuging, and freeze-drying to obtain CuMoO₄@ h-BN, namely the nano hybrid flame retardant.

Example 2

44.4g of polyester polyol, 7.83g of TDI, 4.6g of MOCA and 1g of novel nano hybrid flame retardant prepared in example 1, the novel nano hybrid flame retardant polyurethane elastomer is prepared by the following method, and the specific preparation steps are as follows:

(1) placing polyester polyol in a reaction kettle, dehydrating for 2h at 110 ℃, then cooling to 70 ℃, adding TDI, heating to 75 ℃, stirring for 2h, and dehydrating for 30min in vacuum at 80 ℃ to obtain a prepolymer;

(2) mixing the nano hybrid CuMoO₄Uniformly dispersing the @ h-BN in a proper amount of acetone solution under the ultrasonic condition, pouring the acetone solution into the prepolymer, and stirring the acetone solution for 5min under the ultrasonic condition of 75 ℃ to form a uniform mixture;

(3) adding MOCA into the mixture, stirring vigorously, pouring into a mold, heating at 80 deg.C for 6 hr, and heating at 120 deg.C for 2 hr to obtain CuMoO₄And @ h-BN/PUE, namely the novel nano hybrid flame-retardant polyurethane elastomer.

Example 3

45g of polyester polyol, 7.9g of TDI, 4.7g of MOCA and 0.5g of novel nano hybrid flame retardant prepared in example 1, and the novel nano hybrid flame retardant polyurethane elastomer is prepared by the following method, and the specific preparation steps are as follows:

(1) placing polyester polyol in a reaction kettle, dehydrating at 105 ℃ for 1.7 h, cooling to 67 ℃, adding TDI, heating to 72 ℃, stirring for 2.3h, and dehydrating at 75 ℃ for 45min in vacuum to obtain a prepolymer;

(2) mixing the nano hybrid CuMoO₄Uniformly dispersing the @ h-BN in a proper amount of acetone solution under the ultrasonic condition, pouring the acetone solution into the prepolymer, and stirring the acetone solution for 5min under the ultrasonic condition of 70 ℃ to form a uniform mixture;

(3) adding MOCA into the mixture, stirring vigorously, pouring into a mold, heating at 75 deg.C for 7 hr, and heating at 130 deg.C for 2.5 hr to obtain CuMoO₄And @ h-BN/PUE, namely the novel nano hybrid flame-retardant polyurethane elastomer.

Example 4

43.9g of polyester polyol, 7.7g of TDI, 4.5g of MOCA and 1.5g of novel nano hybrid flame retardant prepared in example 1, and the novel nano hybrid flame retardant polyurethane elastomer is prepared by the following method, and the specific preparation steps are as follows:

(1) placing polyester polyol in a reaction kettle, dehydrating at 103 ℃ for 1.5 h, cooling to 65 ℃, adding TDI, heating to 70 ℃, stirring for 2.5h, and dehydrating at 85 ℃ for 38 min in vacuum to obtain a prepolymer;

(2) mixing the nano hybrid CuMoO₄Uniformly dispersing the @ h-BN in a proper amount of acetone solution under the ultrasonic condition, pouring the acetone solution into the prepolymer, and stirring the acetone solution for 5min under the ultrasonic condition of 73 ℃ to form a uniform mixture;

(3) adding MOCA into the mixture, stirring vigorously, pouring into a mold, heating at 85 deg.C for 5 hr, and heating at 110 deg.C for 3 hr to obtain CuMoO₄And @ h-BN/PUE, namely the novel nano hybrid flame-retardant polyurethane elastomer.

From the transmission electron microscope image of h-BN in fig. 2, it can be clearly seen that h-BN is in the shape of a circle or an oblate circle, stacked on each other and has a uniform size of about 100 nm; in FIG. 2, b is CuMoO₄The transmission electron microscope image of @ h-BN clearly shows that a great deal of CuMoO appears on the h-BN surface₄A lamella of (b), indicating CuMoO₄Successfully loaded on the surface of h-BN; from FIG. 3, CuMoO can be known₄The element composition of @ h-BN, B and N belong to h-BN, Cu, Mo and O all belong to CuMoO₄Further proves that CuMoO₄@ h-BN was successfully prepared. FIG. 4 is CuMoO₄@ h-BN dispersed in PUEThe scanning electron microscope image of (2) shows that CuMoO₄@ h-BN did not agglomerate significantly in the PUE.

Comparative example 1

Preparation of the PUE composite:

(1) placing 45.3g of polyester polyol into a reaction kettle, dehydrating for 2h at 110 ℃, then cooling to 70 ℃, adding 7.97g of TDI, heating to 75 ℃, stirring for 2h, and dehydrating for 30min in vacuum at 80 ℃ to obtain a prepolymer;

(2) adding 4.7g of MOCA into the prepolymer, stirring vigorously, pouring into a mold, heating at 80 ℃ for 6h, and heating at 120 ℃ for 2h to obtain PUE, namely the polyurethane elastomer.

Comparative example 2

Preparation of h-BN/PUE composite material:

(1) placing 44.4g of polyester polyol into a reaction kettle, dehydrating for 2h at 110 ℃, then cooling to 70 ℃, adding 7.83g of TDI, heating to 75 ℃, stirring for 2h, and dehydrating for 30min in vacuum at 80 ℃ to obtain a prepolymer;

(2) uniformly dispersing 1g h-BN in an appropriate amount of acetone solution under the ultrasonic condition, mixing with the prepolymer obtained in the step (1), and stirring under the ultrasonic condition of 75 ℃ to form a uniform mixture;

(3) adding 4.6g of MOCA into the uniform mixture obtained in the step (2), stirring vigorously, pouring into a mold, heating for 6h at 80 ℃ and heating for 2h at 120 ℃ to obtain the h-BN/PUE composite material.

Comparative example 3

h-BN /CuMoO₄Preparation of the/PUE composite:

(1) placing 44.4g of polyester polyol into a reaction kettle, dehydrating for 2h at 110 ℃, then cooling to 70 ℃, adding 7.83g of TDI, heating to 75 ℃, stirring for 2h, and dehydrating for 30min in vacuum at 80 ℃ to obtain a prepolymer;

(2) 0.5g h-BN and 0.5g CuMoO₄Uniformly dispersing the mixture into a proper amount of acetone solution under the ultrasonic condition, mixing the mixture with the prepolymer obtained in the step (1), and stirring the mixture under the ultrasonic condition of 75 ℃ to form a uniform mixture;

(3) adding 4.6g M to the homogeneous mixture of step (2)OCA, stirring vigorously, pouring into a mold, heating at 80 deg.C for 6 hr, heating at 120 deg.C for 2 hr to obtain h-BN/CuMoO₄A/PUE composite material.

The thermal performance measurements are shown in table 1 below:

。

table 1 shows the thermogravimetric analysis detection data of PUE and its composite material under air condition, wherein T is_10%(initial thermal decomposition temperature) is the temperature at which the material loses 10wt%, T_max(maximum decomposition temperature) is the temperature at which the pyrolysis rate of the material reaches a maximum. As can be seen from Table 1, CuMoO is a pure sample ratio to PUE₄Addition of @ h-BN makes T of PUE composite material_10%A slight decrease occurs because of the CuMoO₄The metal oxides formed on decomposition catalyze the degradation of the PUE. CuMoO₄Addition of @ h-BN T of PUE composite_maxA slight increase occurred due to the physical barrier effect of h-BN. In addition, at 700 ℃, the carbon residue rate of pure PUE is less than 0.1 percent, and the composite materials are h-BN/PUE, h-BN/CuMoO₄(PUE) and CuMoO₄The char yields of @ h-BN/PUE are improved to various degrees. Notably, the h-BN, h-BN/CuMoO comparisons₄And CuMoO₄Sample with the same amount of @ h-BN added, CuMoO₄The char yield of @ h-BN is improved most remarkably, indicating that CuMoO₄The synergistic effect of @ h-BN in the thermal decomposition of polymers is optimal. This aspect is due to the better dispersion properties of h-BN acting as a better sheet barrier, hindering thermal degradation of the matrix; CuMoO on the other hand₄The metal oxide generated by decomposition of @ h-BN has catalytic char formation effect, and the thicker char layer can effectively slow down the further degradation of the matrix.

The results of the flame retardant property, smoke suppressing property and mechanical property measurements are shown in Table 2

。

Table 2 shows PUE andflame retardant property, smoke suppression property and mechanical property data of the composite material. As can be seen from Table 2, the samples were comparable to PUE as CuMoO₄The increase of the added parts of @ h-BN, the peak value of the heat release rate, the total heat release amount and the smoke density value of the sample are all reduced to different degrees, which shows that CuMoO₄The addition of @ h-BN can ensure that the PUE composite material has good flame retardant property and smoke suppression property. Comparison of h-BN, h-BN/CuMoO₄And CuMoO₄Sample with the same amount of @ h-BN added, CuMoO₄The peak value of the heat release rate, the total heat release amount and the smoke density value of @ h-BN/PUE are reduced most obviously, which indicates that the hybrid CuMoO₄The @ h-BN can show better synergistic effect and has better flame retardant and smoke suppression effects. Furthermore, as can be seen from Table 2, with CuMoO₄The elongation at break of the PUE composite material gradually decreases with the increase of the addition amount of @ h-BN. In general, 1g of CuMoO was added₄The @ h-BN can ensure that the PUE composite material has good flame retardant property and smoke suppression property, and does not have great influence on the mechanical property of a matrix.

The determination conditions of the thermogravimetric analysis (TGA) of the flame retardant composite in each of the above examples were: the temperature rise rate is 20 ℃/min under the air atmosphere; the measurement method of the cone calorimeter is ISO5660-1:2002 standard, and the size of a test sample is 100 multiplied by 3mm³Thermal radiation of 50 kW.m^-2(ii) a The smoke density measuring method comprises the following steps: ISO5659-2 standard, sample size 75X 2.5mm³Thermal radiation of 50 kW.m^-2。

Claims (6)

1. A novel nanometer hybrid flame-retardant polyurethane elastomer is characterized by mainly comprising the following components: 43.9-45g of polyester polyol, 7.7-7.9g of TDI, 4.5-4.7g of MOCA and 0.5-1.5g of novel nano hybrid flame retardant;

wherein the nano hybrid flame retardant is CuMoO₄@h-BN。

2. The novel nano hybrid flame retardant polyurethane elastomer according to claim 1, which is characterized by mainly comprising the following components: 44.4g of polyester polyol, 7.83g of TDI, 4.6g of MOCA and 1g of novel nano hybrid flame retardant.

3. The novel nano-hybrid flame retardant polyurethane elastomer according to claim 1 or 2, wherein the preparation method of the novel nano-hybrid flame retardant comprises the following steps:

(1) mixing concentrated sulfuric acid and a concentrated nitric acid solution according to a volume ratio of 1:3 to obtain a concentrated acid solution, placing hexagonal boron nitride powder in the concentrated acid solution, and performing ultrasonic treatment for 6 hours to obtain a light yellow viscous liquid;

(2) refluxing the light yellow viscous liquid obtained in the step (1) in an oil bath, washing, centrifuging, and freeze-drying to obtain surface functionalized h-BN;

(3) placing the h-BN with the functionalized surface obtained in the step (2) in deionized water, and ultrasonically stirring to obtain h-BN suspension;

(4) 0.85g of CuCl₂Putting into deionized water, stirring until the suspension is completely dissolved, dropwise adding the h-BN suspension obtained in the step (3), ultrasonically stirring for 0.5-1h, and then reacting for 10-24h under the condition of oil bath at the temperature of 55-65 ℃ to obtain the modified liquid;

(5) adding 0.06mol/L of Na₂MoO₄Dropwise adding the aqueous solution into the mixed solution obtained in the step (3), stirring for 1-3h, cooling and standing, removing supernatant, washing with deionized water, centrifuging, and freeze-drying to obtain CuMoO₄@h-BN。

4. The novel nano hybrid flame retardant polyurethane elastomer as claimed in claim 3, wherein the oil bath reflux temperature in step (2) is 60-80 ℃ and the time is 60-84 h.

5. The novel nano hybrid flame retardant polyurethane elastomer as claimed in claim 3, wherein the time of the ultrasonic agitation in the step (3) is 15-60 min.

6. The preparation method of the novel nano-hybrid flame retardant polyurethane elastomer according to claim 3, wherein the preparation method comprises the following steps:

(1) placing polyester polyol in a reaction kettle, dehydrating at the temperature of 105-110 ℃ for 1.5-2h, cooling to 65-70 ℃, adding TDI, heating to 70-75 ℃, stirring for 2-2.5h, and dehydrating in vacuum at the temperature of 75-85 ℃ for 30-45min to obtain a prepolymer;

(2) mixing the nano hybrid CuMoO₄Uniformly dispersing the @ h-BN in a proper amount of acetone solution under the ultrasonic condition, pouring the acetone solution into the prepolymer, and stirring for 5min under the ultrasonic condition of 70-75 ℃ to form a uniform mixture;

(3) adding MOCA into the mixture, stirring vigorously, pouring into a mold, heating at 75-85 deg.C for 5-7h, and heating at 110-130 deg.C for 2-3h to obtain CuMoO₄@h-BN/PUE。

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