A method for preparing a waterborne polyurethane / carbon nanotube composite adhesive for fiber bulletproof material

Abstract

The application discloses a preparation method of a water-based polyurethane / carbon nanotube composite adhesive for fiber bulletproof materials. The preparation method comprises the following steps: under the protection of a nitrogen atmosphere, a water-based polyurethane prepolymer is synthesized by taking a polyisocyanate and a polyol as polymerization monomers, taking dibutyltin dilaurate as a catalyst, and taking 2,2-bis(hydroxymethyl)propionic acid as a hydrophilic chain extender; a water-based polyurethane containing a maleimide group is synthesized by taking 4-maleimide phenol as a modified monomer; and the water-based polyurethane / carbon nanotube composite adhesive is prepared through a covalent chemical reaction. In the application, the preparation method is used for applying the water-based polyurethane / carbon nanotube composite adhesive on the surface of an ultrahigh molecular weight polyethylene fiber, so that the interface performance of the fiber composite material is improved, and problems, such as low friction coefficient and large back convexity, of the fiber composite material when used as a bulletproof material are effectively solved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of modified adhesives, and is suitable for fiber reinforced resin-based composite materials, and particularly relates to a preparation method of a water-based polyurethane / carbon nanotube composite adhesive for fiber bulletproof materials. TECHNICAL BACKGROUND

[0002] The statements herein are provided only to enhance understanding of the application and are not necessarily intended to constitute the prior art.

[0003] At present, the emergence of various advanced technologies leads to more severe challenges to personnel safety, and thus the performance and demand for bulletproof materials are increasing. At present, bulletproof materials mainly include metals, ceramics and high-performance fibers. Although the traditional metal bulletproof materials have the advantages of good protective performance and low price, they generally have the problems of heavy weight, inconvenience to wear and serious influence on the mobility of personnel and equipment. In recent years, high-performance fibers have made great progress in the comprehensive protective performance of bulletproof materials due to their high specific strength, high specific modulus and low density, and mainly include aramid fibers, ultra-high molecular weight polyethylene (UHMWPE) fibers, polyimide fibers and poly-p-phenylene benzobisoxazole fibers. Among them, UHMWPE fibers have been widely used in the protection field. However, UHMWPE fibers have low friction coefficient and are prone to large back convexity, and have strong surface chemical inertness.

[0004] The adhesives commonly used in the field of bulletproof materials mainly include water-based polyurethane and polyolefin resin. Water-based polyurethane has excellent bending, impact resistance and low temperature resistance, good designability, and is environmentally friendly. He Yemode et al. prepared a unidirectional orthogonal structure of ultra-high molecular weight polyethylene fiber / water-based polyurethane composite material by winding-composite-heat pressing process with water-based polyurethane as the adhesive, and the area seriously damaged by penetration was limited to a circle with a radius of 35 mm with the impact point as the center, showing excellent anti-multiple attack performance.

[0005] Carbon nanotubes have a large specific surface area, excellent mechanical, electrical, optical and thermal properties, and good compatibility with resins, and are widely used to improve the interfacial bonding performance of composite materials. Zamani et al. prepared a multi-walled carbon nanotube reinforced polypropylene nanocomposite material by melt compounding and injection molding process, and the prepared target material is light in quality and excellent in bulletproof performance. Therefore, introducing carbon nanotubes into the adhesive system is expected to improve some problems existing in fiber bulletproof materials. SUMMARY

[0006] In view of some problems existing in the current application of fiber bulletproof materials, the application provides a water-based polyurethane / carbon nanotube composite adhesive preparation method. The method introduces functionalized carbon nanotubes into water-based polyurethane containing maleimide groups through chemical structure design to prepare a water-based polyurethane / carbon nanotube composite adhesive. The adhesive is applied to the surface of fibers to improve the interface performance of fiber composites and effectively solve the problems of low friction coefficient and large back convexity of ultra-high molecular weight polyethylene fibers.

[0007] The technical scheme provided by the application is as follows:

[0008] In a first aspect, a water-based polyurethane / carbon nanotube composite adhesive preparation method for fiber bulletproof materials includes the following steps:

[0009] A water-based polyurethane prepolymer is synthesized under the protection of nitrogen atmosphere by taking isocyanate and polyol as polymerization monomers, taking dibutyltin dilaurate as a catalyst, and taking 2.2-bis(hydroxymethyl)propionic acid as a hydrophilic chain extender.

[0010] 4-Maleimide phenol is added as a modified monomer to the water-based polyurethane prepolymer to obtain water-based polyurethane containing maleimide groups through reaction.

[0011] Furan-functionalized carbon nanotubes are added to the water-based polyurethane containing maleimide groups, and the furan-functionalized carbon nanotubes are introduced in a covalent bond manner through Diels-Alder reaction and esterification reaction, then triethylamine is added for neutralization reaction, and finally deionized water is added for high-speed shearing emulsification to obtain the water-based polyurethane / carbon nanotube composite adhesive.

[0012] In some embodiments, the polyisocyanate in the polymerization monomer is selected from one or more of toluene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, and isophorone diisocyanate, and the polyol is selected from one or more of poly-1,4-butanediol adipate diol, polyethylene glycol adipate diol, polycaprolactone polyol, polyethylene glycol adipate diol, and polycarbonate polyol.

[0013] In some embodiments, the proportion of 4-maleimide phenol in the system is 0.1-20 wt%, preferably 5-10 wt%.

[0014] In some embodiments, the reaction temperature of the water-based polyurethane prepolymer reaction system containing maleimide groups is 40-90°C, and the reaction time is 0.5-2h.

[0015] In some embodiments, the addition amount of furan-functionalized carbon nanotubes in the water-based polyurethane / carbon nanotube composite adhesive system is 0.005-5%, preferably 0.01%-2%.

[0016] In some embodiments, the temperature of the Diels-Alder reaction and the esterification reaction is 50-90℃, and the reaction time is 0.5-2h.

[0017] In some embodiments, the mass ratio of the added amount of triethylamine to 2.2-bis(hydroxymethyl)propionic acid is 1:0.5, the temperature of the neutralization reaction is 30-60℃, and the reaction time is 0.5-1h.

[0018] In some embodiments, the mass ratio of ethylenediamine to deionized water is 1:10, the proportion of ethylenediamine / deionized water in the waterborne polyurethane / carbon nanotube composite adhesive system is 50%-80%, the speed of high-speed shearing emulsification is 500-5000rpm, and the treatment time is 0.5-3h.

[0019] In a second aspect, the present application provides a waterborne polyurethane / carbon nanotube composite adhesive for fiber bulletproof materials, which is prepared by the above preparation method.

[0020] The beneficial effects achieved by one or more embodiments of the present application are as follows:

[0021] (1) The present application introduces carbon nanotubes into the adhesive system by a chemical grafting method, effectively improving the interfacial properties of the fiber and the adhesive composite material.

[0022] (2) The excellent mechanical properties of carbon nanotubes effectively improve the problems of low friction coefficient and large back convexity of ultra-high molecular weight polyethylene fibers. DETAILED DESCRIPTION

[0023] It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used in the present application have the same meaning as generally understood by those skilled in the art to which the present application belongs.

[0024] The present application will be further described below in conjunction with examples.

[0025] Example 1

[0026] Step one: 6g of hexamethylene diisocyanate and 25g of polyhexanedioic acid diethylene glycol, 2µL of dibutyltin dilaurate, 2g of 2.2-bis(hydroxymethyl)propionic acid, were mechanically stirred at a reaction temperature of 105℃ under the protection of nitrogen atmosphere for 2h to obtain a waterborne polyurethane prepolymer;

[0027] Step two: 1.2g of 4-maleimide phenol was added to the waterborne polyurethane prepolymer, and the mixture was mechanically stirred at 90℃ for 1h to obtain a waterborne polyurethane prepolymer containing maleimide groups;

[0028] Step 3: Add 0.5g of furan-functionalized carbon nanotubes to the aqueous polyurethane prepolymer containing maleimide groups, and stir mechanically at 60℃ for 1h. Then add 1g of triethylamine for neutralization reaction, and finally add 80mL of ethylenediamine / deionized water for high-speed shear emulsification at a shear rate of 3000rpm to obtain the aqueous polyurethane / carbon nanotube composite adhesive.

[0029] Example 2

[0030] Step 1: Mix 6g of hexamethylene diisocyanate, 25g of poly(ethylene adipate diol), 2µL of dibutyltin dilaurate, and 2g of 2,2-bis(hydroxymethyl)propionic acid at 105℃ under a nitrogen atmosphere with mechanical stirring for 2 hours to obtain an aqueous polyurethane prepolymer.

[0031] Step 2: Add 0.6g of 4-maleimide-based phenol to the waterborne polyurethane prepolymer and react with mechanical stirring at 90℃ for 1h to obtain a waterborne polyurethane prepolymer containing maleimide groups.

[0032] Step 3: Add 0.1g of furan-functionalized carbon nanotubes to the aqueous polyurethane prepolymer containing maleimide groups, and react with mechanical stirring at 60℃ for 1h. Then add 1g of triethylamine for neutralization reaction, and finally add 80mL of ethylenediamine / deionized water for high-speed shear emulsification at a shear rate of 3000rpm to obtain the aqueous polyurethane / carbon nanotube composite adhesive.

[0033] Comparative Example 1

[0034] Step 1: Mix 6g of hexamethylene diisocyanate, 25g of poly(ethylene adipate diol), 2µL of dibutyltin dilaurate, and 2g of 2,2-bis(hydroxymethyl)propionic acid at 105℃ under a nitrogen atmosphere with mechanical stirring for 2 hours to obtain an aqueous polyurethane prepolymer.

[0035] Step 2: Add 1g of triethylamine for neutralization reaction, and finally add 60mL of ethylenediamine / deionized water for high-speed shear emulsification at a shear rate of 3000rpm to obtain waterborne polyurethane adhesive.

[0036] Comparative Example 2

[0037] Step 1: Mix 6g of hexamethylene diisocyanate, 25g of poly(ethylene adipate diol), 2µL of dibutyltin dilaurate, and 2g of 2,2-bis(hydroxymethyl)propionic acid at 105℃ under a nitrogen atmosphere with mechanical stirring for 2 hours to obtain an aqueous polyurethane prepolymer.

[0038] Step 2: Add 0.6g of 4-maleimide-based phenol to the waterborne polyurethane prepolymer and react with mechanical stirring at 90℃ for 1h to obtain a waterborne polyurethane prepolymer containing maleimide groups.

[0039] Step 3: Then add 1g of triethylamine for neutralization reaction, and finally add 60mL of ethylenediamine / deionized water for high-speed shear emulsification at a shear rate of 3000rpm to obtain waterborne polyurethane adhesive.

[0040] According to the JC / T 773-2010 standard, interlaminar shear test samples were prepared, and the interlaminar shear strength (ILSS) of the UHMWPE / adhesive composite material was determined using a universal tensile tester. Specific test results are shown in Table 1.

[0041] Fabrication of bulletproof chips for bulletproof testing:

[0042] (1) Preparation of UHMWPE nonwoven fabric:

[0043] The above adhesive is placed in a glue tank, and UHMWPE fibers are impregnated, spread, fixed and dried to obtain fiber cloth; then the two layers of fiber cloth are stacked at 0° / 90° and pressed to obtain UHMWPE non-woven fabric.

[0044] (2) The UHMWPE nonwoven fabric is pressed through a specific pressing process to obtain a fiber bulletproof layer;

[0045] (3) The bulletproof layer and the cushioning material are combined with a waterproof cloth and then sealed to obtain the bulletproof chip. The bulletproof chip is obtained by impregnating it with the adhesive prepared in Examples 1 and 2 and Comparative Examples 1 and 2.

[0046] The ballistic performance of the aforementioned bulletproof chip was tested using a target practice test conducted according to the U.S. Department of Justice NIJ0101.06 Class IIIA standard for body armor. This involved using a 15.6g .44 Magnum semi-jacketed hollow-point (SJHP) bullet with a velocity of (408±9.1) m / s. Specific test results are shown in Table 1.

[0047] Table 1. ILSS and ballistic protection performance of different embodiments and comparative examples

[0048]

[0049] The comparison of ILSS performance between the examples and comparative examples shows that the present invention introduces carbon nanotubes into the adhesive system through chemical grafting, achieving a uniform dispersion effect. Due to the mechanical entanglement and excellent mechanical properties of carbon nanotubes, the interfacial bonding performance of fiber composite materials is improved, while effectively addressing the problem of large back concavity in UHMWPE as a bulletproof material.

[0050] The above description is only the preferred embodiment of the present application, and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing a water-based polyurethane / carbon nanotube composite adhesive for fiber bulletproof materials, characterized in that, Includes the following steps: A waterborne polyurethane prepolymer was synthesized under a nitrogen atmosphere using polyisocyanate and polyol as monomers, dibutyltin dilaurate as catalyst, and 2,2-bis(hydroxymethyl)propionic acid as hydrophilic chain extender. 4-maleimide-phenol was added as a modifying monomer to the waterborne polyurethane prepolymer to obtain waterborne polyurethane containing maleimide groups. Furan-functionalized carbon nanotubes were added to waterborne polyurethane containing maleimide groups. They were introduced by covalent bonding through Diels-Alder reaction and esterification reaction. Then, triethylamine was added for neutralization reaction. Finally, ethylenediamine / deionized water was added for high-speed shear emulsification to obtain waterborne polyurethane / carbon nanotube composite adhesive. The ratio of isocyanate groups to hydroxyl groups in the polymer monomer is 2.0-3.

5.

2. The preparation method of the waterborne polyurethane / carbon nanotube composite adhesive for fiber bulletproof materials according to claim 1, characterized in that: The content of 2,2-bis(hydroxymethyl)propionic acid in the waterborne polyurethane prepolymer reaction system is 1%-12%.

3. The method for preparing the waterborne polyurethane / carbon nanotube composite adhesive for fiber bulletproof materials according to claim 2, characterized in that: The content of 2,2-bis(hydroxymethyl)propionic acid in the waterborne polyurethane prepolymer reaction system is 4%-8%.

4. The preparation method of the waterborne polyurethane / carbon nanotube composite adhesive for fiber bulletproof materials according to claim 1, characterized in that: The reaction temperature of the waterborne polyurethane prepolymer reaction system is 60-100℃, and the reaction time is 1-3h.

5. The method for preparing the waterborne polyurethane / carbon nanotube composite adhesive for fiber bulletproof materials according to claim 1, characterized in that: The content of 4-maleimide-based phenol in the aqueous polyurethane prepolymer reaction system containing maleimide groups is 1%-12%.

6. The method for preparing the waterborne polyurethane / carbon nanotube composite adhesive for fiber bulletproof materials according to claim 5, characterized in that: The content of 4-maleimide-based phenol in the aqueous polyurethane prepolymer reaction system containing maleimide groups is 3%-8%.

7. The method for preparing the waterborne polyurethane / carbon nanotube composite adhesive for fiber bulletproof materials according to claim 1, characterized in that: The reaction temperature of the aqueous polyurethane reaction system containing maleimide groups is 40-90℃, and the reaction time is 0.5-2h.

8. The method for preparing the waterborne polyurethane / carbon nanotube composite adhesive for fiber bulletproof materials according to claim 1, characterized in that: The amount of furan-functionalized carbon nanotubes added in the waterborne polyurethane / carbon nanotube composite adhesive system is 0.005-5%.

9. The method for preparing the waterborne polyurethane / carbon nanotube composite adhesive for fiber bulletproof materials according to claim 8, characterized in that: The amount of furan-functionalized carbon nanotubes added in the waterborne polyurethane / carbon nanotube composite adhesive system is 0.01%-2%.

10. The method for preparing the waterborne polyurethane / carbon nanotube composite adhesive for fiber bulletproof materials according to claim 1, characterized in that: The temperature for the Diels-Alder reaction and esterification reaction is 50-90℃.

11. The method for preparing the waterborne polyurethane / carbon nanotube composite adhesive for fiber bulletproof materials according to claim 1, characterized in that: The mass ratio of triethylamine to 2,2-bis(hydroxymethyl)propionic acid is 1:0.5, and the neutralization reaction temperature is 30-60℃.

12. The method for preparing the waterborne polyurethane / carbon nanotube composite adhesive for fiber bulletproof materials according to claim 1, characterized in that: The mass ratio of ethylenediamine to deionized water is 1:

10. The proportion of ethylenediamine / deionized water in the waterborne polyurethane / carbon nanotube composite adhesive system is 50%-80%, and the high-speed shear emulsification speed is 500-5000 rpm.

13. A water-based polyurethane / carbon nanotube composite adhesive for fiber bulletproof materials, characterized in that: Prepared by any of the preparation methods described in claims 1-12.

14. The application of the waterborne polyurethane / carbon nanotube composite adhesive of claim 13 in fiber bulletproof materials.

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