CN107286310B

CN107286310B - Reactive antistatic polyurethane elastomer containing epoxy nano fluid and preparation method thereof

Info

Publication number: CN107286310B
Application number: CN201710315451.8A
Authority: CN
Inventors: 邱志明; 何厚刚; 严玉蓉
Original assignee: South China University of Technology SCUT
Current assignee: South China University of Technology SCUT
Priority date: 2017-05-08
Filing date: 2017-05-08
Publication date: 2020-07-28
Anticipated expiration: 2037-05-08
Also published as: CN107286310A

Abstract

The invention relates to a reactive antistatic polyurethane elastomer containing epoxy nano fluid and a preparation method thereof. Then weighing 8-10g of oligomer polyol and 4-5g of isocyanate, reacting for a certain time at a specific temperature and a specific stirring rate to obtain a polyurethane prepolymer, then adding an epoxy nano fluid serving as a reaction cross-linking agent in an amount of 2-8 wt.% into the prepolymer for a cross-linking reaction, finally coating the reacted viscous liquid on a glass plate mold, and drying and curing in vacuum to obtain the final reaction type antistatic polyurethane elastomer.

Description

Reactive antistatic polyurethane elastomer containing epoxy nano fluid and preparation method thereof

Technical Field

The invention belongs to the field of preparation of high polymer materials, and particularly relates to a reactive antistatic polyurethane elastomer containing epoxy nano fluid and a preparation method thereof.

Background

Polyurethane has been developed for 70 years so far, and is a high polymer material with wide application and superior comprehensive performance. According to different proportions of the prepolymer polyether and the isocyanate, polyurethane with wide hardness range and high elasticity can be synthesized. Meanwhile, polyurethane has high strength, high wear resistance, oil resistance and radiation capability, so that the polyurethane can be used in the aspects of automobiles, buildings, paving materials, mines, mining, electronics, aerospace and the like. The polyurethane elastomer belongs to a large class of polyurethane materials, has a wide performance range, is a high polymer material between rubber and plastic, and can be applied to solid tires, adhesive tapes, rubber roll linings, oil seals, sealing rings, die pads, electrical component encapsulation, adhesives, coatings and the like.

However, the volume resistivity of polyurethanes is generally between 10 ¹³-10¹⁵Omega, is a dielectric insulating material. Insulator materials tend to accumulate static electricity, thereby causing associated equipment malfunctions, such as degradation or damage to the precision of precision instruments, interference with electronic device usage, and the like. Polyurethane antistatic materials are used in various fields such as aerospace fuel storage tanks, electronic or household electrical products and chemical engineering due to their superior electrical conductivity and ability to discharge static electricity. The polyurethane antistatic materials can be classified into two types according to the use of the antistatic agent, and one type is to perform surface treatment such as impregnation, coating or grafting of a suitable functional group to the polyurethane material that is molded. The other is an internal additive antistatic material comprising a composite additive type and a reactive type. The composite additive antistatic agent comprises graphite, carbon black, metal oxide, metal powder or functional polymer, etc. The reactive antistatic material is a permanent antistatic material prepared by adding an antistatic agent which has both antistatic groups and active groups such as hydroxyl, amino or isocyanate groups and the like, and can be chemically crosslinked with a polyurethane prepolymer. However, the surface-treated polyurethane has a short duration of antistatic properties, and the antistatic coating is easily washed off, and is only a temporary antistatic agent. The composite antistatic polyurethane has good electrostatic property and low cost, but the addition amount of the antistatic agent is large, but the addition amount is large, so that the mechanical property of the material is greatly influenced. The reactive antistatic material has obvious advantages, and has permanent antistatic performance and no sensitivity to humidity because the antistatic agent is chemically crosslinked with a polymer matrix. However, there are few reports on such antistatic agents, so the development of such antistatic agents is urgently needed, and the development of such antistatic agents will also be a future hot spot.

The nano-type fluid can be used in various fields, such as antistatic agents, lubricants, electrolytes, etc., because of its room temperature fluidity, zero vapor pressure, high thermal stability, and electrical conductivity.

Disclosure of Invention

In order to solve the defects and shortcomings of the prior art, the invention mainly aims to provide a preparation method (NSiF-Hs for short) of a reactive antistatic polyurethane elastomer containing epoxy nano fluid;

The second purpose of the invention is to provide a reactive antistatic polyurethane elastomer containing epoxy nano-class fluid, and the method can effectively improve the comprehensive mechanical property and antistatic property of the polyurethane elastomer.

The purpose of the invention is realized by the following technical scheme:

A preparation method of a reactive antistatic polyurethane elastomer containing epoxy nano fluid comprises the following preparation steps:

Firstly, silane coupling agent gamma-glycidol ether oxygen propyl trimethoxy silicane is used for modifying nano particles, the nano particles are activated, then the activated nano particles are ammonium salted to obtain products with abundant hydroxyl side chains, and the products are continuously subjected to ion exchange with organic salt to obtain the epoxy nano fluid. Then weighing 8-10g of oligomer polyol and 4-5g of isocyanate, and reacting for a certain time at a specific temperature and a specific stirring rate to obtain the polyurethane prepolymer. Then, the epoxy nanometer fluid is used as a reaction cross-linking agent according to 2-8 wt.%, and the chain extender is added into the prepolymer for cross-linking reaction. And finally, coating the reacted viscous liquid on a glass plate mold, and drying and curing in vacuum to obtain the final reactive antistatic polyurethane elastomer.

The method comprises the following specific steps:

Step one preparation of hydroxyl-containing epoxy nano fluid

Firstly, ultrasonically dispersing a nanoparticle aqueous solution, and then modifying the nanoparticles by using a gamma-glycidyl ether oxypropyl trimethoxy silane coupling agent to activate the nanoparticles according to the molar ratio of 1:1, wherein the activation condition is that the nanoparticles react in an ethanol aqueous solution at 70 ℃ for 24 hours;

Firstly, hydrolyzing a silane coupling agent to obtain active hydroxyl, and then further dehydrating and condensing with the hydroxyl of the nano particles;

Secondly, reacting the activated nano particles with tri-n-butylamine and concentrated hydrochloric acid in a molar ratio of 1:1:1, and further performing ammonium salinization to obtain an organic chain with rich active hydroxyl groups;

Finally, carrying out ion exchange reaction on the ammonium salinization product and organic salt poly (ethylene glycol) 4-nonylphenyl-3-thiopropyl ether potassium salt to obtain epoxy nano fluid, after the reaction is finished, carrying out rotary evaporation to remove the solvent, adding tetrahydrofuran into the obtained viscous liquid, removing potassium chloride precipitate insoluble in tetrahydrofuran, and finally permeating the obtained product for 7d in a 3A molecular sieve to fully remove small molecular impurities to finally obtain a pure product;

Preparation of step two reaction type polyurethane elastomer prepolymer

weighing 8-10g of oligomer polyol and 4-5g of isocyanate, adding the oligomer polyol and 4-5g of isocyanate into an 80-100ml N, N-dimethylformamide 250m L three-neck flask, mechanically stirring at a specific speed under the protection of nitrogen at a specific temperature, reacting for a specific time under condensation reflux, and naturally cooling to room temperature after the reaction is finished;

Step three preparation of reaction type polyurethane elastomer

Weighing 0.4-0.6g of chain extender and 0.32-1.36g of hydroxyl-containing epoxy nano fluid prepared in the first step, dissolving the chain extender and the hydroxyl-containing epoxy nano fluid by using 20ml of N, N-dimethylformamide, adding the dissolved chain extender into the cooled prepolymer in the second step, continuously stirring the mixture at a low speed for 3 hours, finally coating the obtained viscous liquid on a glass plate mold, reacting the viscous liquid for 12 hours at the temperature of 60 ℃ in a vacuum drying oven, and continuously curing the viscous liquid for 12 hours at the temperature of 80 ℃ in vacuum to finally obtain a transparent polyurethane elastomer film, wherein the mass contents of the epoxy nano fluid in the film are respectively 2 wt%, 4 wt%, 6 wt% and 8 wt%.

Preferably, the nanoparticles in step yi 'zho' g are inorganic core structures of nano-class fluid, the mass ratio is generally selected to be between 5 and 20 percent, and the nanoparticles comprise SiO ₂、TiO₂、ZnO、Fe₃O₄More than one of graphene, carbon nano tube and quantum dot.

Preferably, the organic salt in the first step includes an organic sulfate or sulfonate.

Preferably, the oligomer polyol comprises polyester polyol, polyether polyol and poly-caprolactone polyol, wherein the polyester polyol is specifically one or more of polyethylene glycol adipate glycol, polyethylene glycol adipate glycol propylene glycol, polyethylene glycol adipate glycol and polyethylene castor oil adipate glycol, and the polyether polyol comprises one or more combinations of polypropylene oxide glycol, polypropylene oxide triol, polypropylene oxide tetraol, polypropylene oxide pentaol and polytetrahydrofuran glycol.

Preferably, the isocyanate includes more than one combination of diphenylmethane diisocyanate, toluene diisocyanate, hexamethylene diisocyanate and 1, 5-naphthalene diisocyanate.

Preferably, the chain extender comprises one or more of glycols, diamines, ethanolamines, such as ethylene glycol, propylene glycol, butylene glycol, 3, 3' -dichloro-4, 4-diphenylmethanediamine and allyl ethers.

Preferably, said specific temperature is 70-95 ℃.

Preferably, the specific time is 2 to 3.5 hours.

Preferably, the stirring rate is 200-300 rpm.

preferably, the glass plate mold is a square plate of 10cm × 10cm × 0.3 cm.

The reactive antistatic polyurethane elastomer containing the epoxy nano fluid is prepared by the method, and has the molecular formula:

The obtained epoxy nano fluid has a nano structure of an inorganic core and an organic shell, has rich active hydroxyl, belongs to third-generation ionic liquid, and has room-temperature fluidity. Room temperature ionic conductance up to 10 ^-5S/cm, as shown in FIG. 1, the tensile strength of the polyurethane antistatic material obtained is up to 30.1MPa (16.7 MPa for pure PU without nano-fluid), the hardness is maintained at 80 Shore A, as shown in FIG. 2, the surface resistivity is up to 7.35 × 10 ⁷Omega/sp, antistatic, efficient and durable.

The preparation method and the obtained product have the following advantages and beneficial effects:

(1) The whole process of synthesizing the epoxy nano fluid uses a mixed solvent of ethanol and water, is green and pollution-free, simultaneously three reaction steps are continuous and integrated, almost no raw material is wasted, and the synthesis process is simple and pollution-free;

(2) According to the invention, gamma-glycidoxypropyltrimethoxysilane is selected as a coupling agent, and then the coupling agent is subjected to quaternization reaction with tri-n-butylamine and hydrochloric acid to successfully prepare the nano fluid containing rich hydroxyl groups, and then the nano fluid is used as a polyurethane antistatic agent, so that not only are members of the nano fluid newly added, but also a way for functionalized nano fluid is developed, and the practical application of the nano fluid is widened;

(3) The preparation method of the invention has simple process and no pollution, and simultaneously, the prepared antistatic polyurethane elastomer has higher tensile strength than that of the same system, and the surface electrical impedance is inferior to that of the same system.

Drawings

FIG. 1 is a graph of ionic conductivity of epoxy nano-based fluids at different temperatures;

FIG. 2 is a graph of the mechanical properties of reactive antistatic polyurethane with different epoxy nano-fluid contents.

Detailed Description

The present invention will be described in further detail with reference to examples and drawings, but the present invention is not limited thereto.

Example 1

(1) the preparation of the prepolymer of the reactive polyurethane elastomer comprises the steps of strictly controlling the moisture content in the polyurethane reaction, drying N, N-dimethylformamide used in the reaction by using a molecular sieve for one week before the reaction, treating the molecular sieve at 400 ℃ in advance in a high-temperature furnace for 4 hours, drying the solvent at 120 ℃ for 2 hours before the reaction in order to remove the moisture of synthetic monomer ethers of the polyurethane, weighing 10.0g of PTMEG and 5.0g of diphenylmethane diisocyanate (MDI), adding the PTMEG and the MDI into a 100ml of N, N-dimethylformamide 250m L three-neck flask, mechanically stirring at the speed of 300rpm under the protection of nitrogen at 90 ℃, condensing and refluxing for reaction for 3 hours, and naturally cooling to room temperature after the reaction is finished.

(2) The preparation method of the reactive polyurethane elastomer comprises the following steps: 0.56g of ethylene glycol based on (1) was weighed out, dissolved in 20ml of N, N-dimethylformamide, added to the cooled prepolymer and stirring was continued at 150rpm for 3 h. The viscous liquid obtained finally was applied to a glass plate, reacted at 60 ℃ for 12h and cured further at 80 ℃ for 12 h. Finally, a transparent film was obtained

(3) mechanical properties were measured on a UT-208 universal material tester from U-CAN, Inc. at a tensile rate of 30mm/min, 10cm × 1cm sample strips were cut out in advance, three samples were measured for each percentage, and the surface resistivity of the polyurethane elastomer was measured with an AC L-800 surface resistance meter.

the polyurethane elastomer film prepared in this example was a pure film containing 0 wt.% of epoxy nanofluid, and had a tensile strength of 16.3MPa, an elongation at break of 525%, a shore hardness of 78.8, as shown in fig. 1, and a surface resistivity of 2.25 × 10 ¹³Omega/sq, as shown in Table 1. The molecular formula is as follows:

Wherein PEG-SO ₃ ^-Is poly (ethylene glycol) 4-nonylphenyl-3-thiopropyl ether anion.

Example 2

A preparation method of a reactive antistatic polyurethane elastomer containing epoxy nano fluid comprises the following steps:

(1) Preparation of epoxy nano-fluid: first, 2.000g of an aqueous silica solution was weighed, and 40ml of pure water was added thereto to ultrasonically disperse the solution for 30 minutes. Then, the mass of the silane modifier is calculated according to the mass ratio of the silicon dioxide to the organic chain of 0.15:0.85, 0.794g of gamma-glycidyl ether oxypropyl trimethoxy silane modifier is weighed, dissolved by 50ml of ethanol and added into the silicon dioxide aqueous solution dispersed by ultrasound, and the mixture reacts for 24 hours under the protection of nitrogen at 70 ℃. Then, according to the molar ratio of the silane modifier to the tri-n-butylamine and the concentrated hydrochloric acid of 1: 1: 0.190g of tri-n-butylamine and 0.370g of concentrated hydrochloric acid were weighed out and added to the solvent after the reaction, and the reaction was continued at 70 ℃ for 24 hours. The obtained organic chain has abundant active hydroxyl groups. Finally 4.233g of poly (ethylene glycol) 4-nonylphenyl-3-thiopropyl ether potassium salt are weighed out and added The reaction mixture was added to the above solution and the reaction was continued for 24 hours at a temperature of 70 ℃. After the reaction, the solvent was evaporated by rotation, and the resulting viscous liquid was added to 70ml of tetrahydrofuran, stirred for one hour, and then the potassium chloride precipitate was filtered off. Finally, the obtained product is infiltrated for 7 days in a 3A molecular sieve to fully remove small molecular impurities, and finally the pure epoxy nano fluid is obtained. The nanometer fluid belongs to ionic liquid, the ionic conductivity of the nanometer fluid changes with the temperature as shown in figure 1, and the room temperature reaches 10 ^-5S/cm, its own ionic conductivity and abundance of hydrophilic hydroxyl groups contribute to a reduction in the surface resistivity of the polyurethane.

(2) Preparing a reaction type polyurethane elastomer prepolymer: the same as in example 1 (1).

(3) Preparation of reactive polyurethane elastomer containing 2 wt.% epoxy nanofluid: 0.56g of ethylene glycol and 0.32g (2 wt.%) of the epoxy nanofluid obtained in (1) were weighed out on the basis of example 2(2), dissolved in 20ml of N, N-dimethylformamide, and added to the cooled prepolymer.

(4) The same as in example 1 (3).

the polyurethane elastomer film prepared in this example was a pure film containing 2 wt.% of epoxy nanofluid, and had a tensile strength of 27.0MPa, an elongation at break of 644%, a shore hardness of 79.6, as shown in fig. 1, and a surface resistivity of 2.46 × 10 ¹²Omega/sq, as shown in Table 1, the surface resistance is reduced by one order of magnitude compared to example 1.

Example 3

(1) The same as in (1) in example 2.

(2) The same as in (2) in example 2.

(3) The same as (3) in example 2, except that 0.66g (4 wt.%) of the epoxy nano-based fluid was added, dissolved in 20ml of N, N-dimethylformamide, and added to the cooled prepolymer.

(4) The same as in (3) in example 1.

The polyurethane elastomer film produced in this example was a pure film containing 4 wt.% epoxy nanofluid the tensile strength reaches 30.7MPa and reaches the maximum value, and the performance is better than that of other similar systems, the elongation at break is 625%, the Shore hardness is 79.1, as shown in figure 1, the surface resistivity is 4.34 × 10 ¹¹Omega/sq, as shown in Table 1, the surface resistance is reduced by one order of magnitude compared to example 2.

Example 4

(1) The same as in (1) in example 2.

(2) The same as in (2) in example 2.

(3) The same as (3) in example 2, except that 1.00g (6 wt.%) of the epoxy nano-based fluid was added, dissolved in 20ml of N, N-dimethylformamide, and added to the cooled prepolymer.

(4) The same as in (3) in example 1.

the polyurethane elastomer film prepared in this example was a pure film containing 6 wt.% epoxy nanofluid, with a tensile strength of 15.3MPa, an elongation at break of 606%, a shore hardness of 80.4, as shown in fig. 1, a surface resistivity of 1.59 × 10 ⁹Omega/sq, as shown in Table 1, the surface resistance is reduced by two orders of magnitude compared to example 2.

Example 5

(1) The same as in example 2 (1).

(2) The same as in example 2 (2).

(3) The same as in example 2(3), except that 1.36g (8 wt.%) of the epoxy nano-based fluid was added, dissolved in 20ml of N, N-dimethylformamide, and added to the cooled prepolymer.

(4) The same as in example 1 (3).

the polyurethane elastomer film prepared in this example was a pure film containing 8 wt.% of epoxy nanofluid, and had a tensile strength of 11.9MPa, an elongation at break of 508%, a shore hardness of 74.3, as shown in fig. 1, and a surface resistivity of 7.35 × 10 ⁷Omega/sq, as shown in Table 1, relative to the implementation Example 2, the surface resistance was reduced by four orders of magnitude.

TABLE 1 surface resistivity of reactive antistatic polyurethanes of different epoxy nanofluid content

Sample name	Surface resistivity/(Ω/sq)
		PU/0wt％	2.25×10¹³
PU/2wt％NSiF-Hs	2.46×10¹²
		PU/4wt％NSiF-Hs	4.34×10¹¹
PU/6wt％NSiF-Hs	1.59×10⁹
		PU/8wt％NSiF-Hs	7.35×10⁷

The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, combinations, and simplifications are intended to be included in the scope of the present invention.

Claims

1. A preparation method of a reactive antistatic polyurethane elastomer containing epoxy nano fluid comprises the following preparation steps:

Step one preparation of hydroxyl-containing epoxy nano fluid

Firstly, ultrasonically dispersing a nanoparticle aqueous solution, and modifying the nanoparticles by using a gamma-glycidoxypropyltrimethoxysilane coupling agent according to a molar ratio of 1:1 to activate the nanoparticles, wherein the activation condition is that the nanoparticles react for 24 hours in an ethanol aqueous solution at 70 ℃;

Secondly, reacting the activated nano particles with tri-n-butylamine and concentrated hydrochloric acid in a molar ratio of 1:1:1 to obtain an organic chain with rich active hydroxyl groups;

Finally, the epoxy nanometer fluid is obtained by ion exchange reaction with poly (ethylene glycol) 4-nonyl phenyl-3-thiopropyl ether sylvite;

Preparation of step two reaction type polyurethane elastomer prepolymer

weighing 8-10g of PTMEG and 4-5g of diphenylmethane diisocyanate, adding the PTMEG and 4-5g of diphenylmethane diisocyanate into an 80-100ml N, N-dimethylformamide 250m L three-neck flask, mechanically stirring at the speed of 200-300rpm under the protection of nitrogen at the temperature of 70-90 ℃, reacting for 2-3.5h under condensation reflux, and naturally cooling to room temperature after the reaction is finished;

Step three preparation of reaction type polyurethane elastomer

Weighing 0.4-0.6g of chain extender and 0.32-1.36g of hydroxyl-containing epoxy nano-class fluid prepared in the first step, dissolving the chain extender and the hydroxyl-containing epoxy nano-class fluid by using 20ml of N, N-dimethylformamide, adding the dissolved chain extender into the cooled prepolymer in the second step, continuously stirring the mixture for 3 hours, finally coating the obtained viscous liquid on a glass plate mold, reacting the viscous liquid for 12 hours at the temperature of 60 ℃ in a vacuum drying oven, and continuously curing the viscous liquid for 12 hours at the temperature of 80 ℃ in vacuum to finally obtain a transparent polyurethane elastomer film.

2. The method for preparing the reactive antistatic polyurethane elastomer containing the epoxy nano-class fluid according to the claim 1 is characterized in that: the nano particles in the step one are inorganic core structures of nano fluid, the mass percentage is selected to be between 5 and 20 percent, and the nano particles comprise SiO ₂、TiO₂、ZnO、Fe₃O₄More than one of graphene, carbon nano tube and quantum dot.

3. The method of claim 1, wherein: in the third step, the chain extender comprises glycols, diamines and ethanolamine.

4. The method of claim 1, wherein: the stirring speed in the third step is 200-300 rpm;

the glass plate mold is a square plate with the thickness of 10cm multiplied by 0.3 cm.

5. A reactive antistatic polyurethane elastomer containing epoxy nano fluid is characterized in that: prepared by the process of any one of claims 1 to 4, of the formula:

6. the reactive antistatic polyurethane elastomer of claim 5, wherein the polyurethane antistatic material has a tensile strength of up to 30.1MPa, a hardness of 80 Shore A, and a surface resistivity of up to 7.35 × 10 ⁷Ω/sp。