WO2015135196A1

WO2015135196A1 - Antistatic polyether sulfone composite material and preparation method therefor

Info

Publication number: WO2015135196A1
Application number: PCT/CN2014/073433
Authority: WO
Inventors: 曾学良; 汪学军
Original assignee: 绵阳鸿琪新材料科技有限公司
Priority date: 2014-03-14
Filing date: 2014-03-14
Publication date: 2015-09-17
Also published as: CN105283488B; CN105283488A

Abstract

The present invention relates to an antistatic polyether sulfone composite material and a preparation method therefor. The molecular structure of the composite material is represented by formula (I), where (a) is a carbon nanotube, and n is a polymerization degree ranging from 50 to 150. The composite material can be widely used in the fields of electronic and electrical appliances, mine mining and war industries, and different types of granular materials and various sections and workpieces can be provided according to market demands.

Description

Polyether sulfone antistatic composite material and preparation method thereof

TECHNICAL FIELD The present invention relates to a polyether sulfone antistatic composite material and a preparation method thereof, and belongs to the field of polymer materials. Technical Background Polyethersulfone Resin (PES) is a comprehensive thermoplastic polymer material developed by ICI in the United Kingdom in 1972. It is one of the few special engineering plastics to be applied. It has excellent heat resistance, physical and mechanical properties, flame retardant properties, etc. It has outstanding advantages such as continuous use at high temperatures and stable performance in environments with rapid temperature changes. It has been widely used in many fields. .

However, in the application process of polyethersulfone resin, due to its electrical insulating properties, the surface of the material is prone to generate static electricity, which is easy to damage various devices and electronic products in the application, especially in mine safety, so it is Antistatic treatment is necessary. At present, the most common method for preparing antistatic composite materials is to process composite conductive materials by subsequent processing, such as composite carbon nanotubes having excellent mechanical properties and electrical properties. However, the inorganic conductive nanomaterials including carbon nanotubes seriously affect the uniform dispersion of the carbon nanotubes due to their nanometer size, chemical inertness and surface sparsity, so that the excellent properties of the carbon nanotubes are not fully utilized. There are two core problems in the preparation of polymer/carbon nanotube composites: one is to improve the dispersion of carbon nanotubes in the polymer matrix; the other is to improve the interfacial adhesion between carbon nanotubes and polymers.

In order to solve these two core problems, the conventional method is to carry out surface modification of carbon nanotubes and then perform extrusion granulation with polyether sulfone resin. The disadvantage of this method is two points. First, since the carbon nanotubes are inorganic materials, the surface doubleness makes the coupling agent difficult to function, and it is difficult to improve the interfacial adhesion between the carbon nanotubes and the polymer. The carbon nanotubes have a large specific surface area and are easily agglomerated, resulting in poor dispersibility after blending and processing. SUMMARY OF THE INVENTION The present invention has been made in view of the above drawbacks, and provides a polyethersulfone antistatic composite material, which has excellent electrical properties and mechanical properties.

The first technical problem to be solved by the present invention provides a polyethersulfone antistatic composite material, the molecular structure of which is as follows:

Wherein ^ is a carbon nanotube, and n is a degree of polymerization, and its value ranges from 50 to 150.

The polyether sulfone antistatic composite material has a volume resistivity of 10 ^{7 to} 10 ^{1 ()} Ω · cm , a tensile strength of 100 to 130 MPa, and an elongation at break of 15 to 25%.

Further, the raw materials of the polyethersulfone antistatic composite material include: 4,4-dichlorodiphenyl sulfone, 4,4-dihydroxydiphenyl sulfone, solvent, acid chloride carbon nanotube, dehydrating agent, catalyst; The ratio is: 4,4-dichlorodiphenyl sulfone: 4,4-dihydroxydiphenyl sulfone: solvent: dehydrating agent: catalyst = 1: 1: 5~6: 1.3~1.5: 1, wherein, acyl chloride The amount of nanotubes used is 10 to 15% of the mass of 4,4-dichlorodiphenyl sulfone.

The solvent is sulfolane.

The dehydrating agent is toluene or benzene.

The catalyst is potassium hydroxide or sodium hydroxide.

The acid chloride carbon nanotubes are prepared by the following preparation steps: a. Preparation of carboxylated carbon nanotubes: The carbon nanotubes are acidified in a mixed acid composed of concentrated sulfuric acid and concentrated nitric acid, washed and dried. Drying to obtain surface carboxylated carbon nanotubes; b The carboxylated carbon nanotubes are reacted with thionyl chloride under the catalysis of dimethylformamide to obtain acid chlorided carbon nanotubes.

Further, the preparation steps of the acid chloride carbon nanotubes are as follows:

1) Acidification treatment of carbon nanotubes: carbon nanotubes containing 2 to 5% of the mixed acid mass are placed in a mixed acid for ultrasonic dispersion for 0.5-2 hours, reacted at 40-50 ° C for 20-30 hours, and then diluted with deionized water. After the suction filtration, the obtained precipitate is washed with deionized water to a pH of 4 to 6, and the product is dried to obtain a surface carboxylated carbon nanotube, wherein the mixed acid is a mixture of concentrated sulfuric acid and concentrated nitric acid, and the volume ratio of concentrated sulfuric acid to concentrated nitric acid. 3:1;

2) Adding the carboxylated carbon nanotubes to thionyl chloride, adding dimethylformamide as a catalyst, heating and refluxing at 60-80 ° C for 20-30 hours, and refluxing with toluene to remove chlorine after the reaction The sulfoxide is recovered, and the lower layer product is dried and sealed and stored to obtain an acid chlorided carbon nanotube; wherein the mass ratio of the carbon nanotube to the thionyl chloride is 1:1000, and the amount of the dimethylformamide is the chloride 1% of the mass of the sulfone.

The second technical problem to be solved by the present invention is to provide a preparation method of the above polyethersulfone antistatic composite material. Method: The carbon nanotubes are subjected to acid chloride treatment to obtain acid chloride carbon nanotubes, and the obtained acid chloride carbon nanotubes are further polymerized in situ with 4,4-dichlorodiphenyl sulfone and 4,4-dihydroxydiphenyl sulfone, and dried. The polyethersulfone antistatic composite material is obtained afterwards; the in situ polymerization reaction refers to: acid chlorided carbon nanotubes with 4,4-dichlorodiphenyl sulfone and 4,4-dihydroxydiphenyl sulfone in a catalyst, a solvent and The reaction is heated under reflux by a dehydrating agent, and the reaction product is cooled, pulverized, washed and centrifugally dehydrated, and dried to obtain a polyether sulfone antistatic composite material.

Further, in the preparation method of the polyethersulfone antistatic composite material, the molar ratio of each raw material is 4,4-dichlorodiphenyl sulfone: 4,4-dihydroxydiphenyl sulfone: solvent: dehydrating agent: catalyst=1 : 1: 5 to 6: 1.3 to 1.5: 1; The amount of the acid chloride carbon nanotubes is 10 to 15% by mass of the 4,4-dichlorodiphenyl sulfone.

Further, the preparation method of the polyethersulfone antistatic composite material comprises the following steps:

(1) Weigh the raw materials according to the molar ratio of the raw materials: 4,4-dichlorodiphenyl sulfone: 4,4-dihydroxydiphenyl sulfone: Solvent: Dehydrating agent: Catalyst = 1: 1: 5~6: 1.3- 1.5 : 1;

(2) Ultrasonic dispersion of the acid chloride carbon nanotubes in a solvent, and then 4,4-dichlorodiphenyl sulfone, 4,4-dihydroxydiphenyl sulfone, solvent, acid chloride carbon nanotubes, dehydrating agent, catalyst Heating the reflux reaction, wherein the amount of the acid chloride carbon nanotubes is 10 to 15% of the mass of the 4,4-dichlorodiphenyl sulfone;

(3) When the temperature of the material is 120-160 ° C, the temperature is reacted for 1-4 hours, and then the temperature is further increased to 170-210 ° C. The reaction is continued until no more water is formed. Then the dehydrating agent is completely distilled off and the temperature is raised to 255-265. The reaction was carried out for 2-4 hours at °C, and the obtained product was cooled, pulverized and washed. After the solvent and the catalyst were all removed, the mixture was centrifuged and dehydrated, and dried to obtain the polyethersulfone antistatic composite material of the present invention.

Preferably, in step 3 of the above method, when the temperature of the material is 120-160 ° C, the reaction is kept at a constant temperature for 2 hours, and then the temperature is further increased to 190 ° C to react to an anhydrous formation, and then the dehydrating agent is completely distilled off, and the temperature is further increased to The mixture is reacted at 255-265 °C for 2-4 hours, and the obtained product is cooled, pulverized and washed. After the solvent and the catalyst are completely removed, the mixture is centrifugally dehydrated, and dried to obtain the polyethersulfone antistatic composite material of the present invention.

Preferably, the reaction of step 2 in the process is carried out under nitrogen.

Advantageous Effects of the Invention: The main advantages of the method of the present invention are two points. One is to solve the problem of agglomeration of carbon nanotubes in the process of compounding with polyethersulfone, that is, the dispersion is uneven; The antistatic property of the polyethersulfone composite is superior to the polyethersulfone composite prepared by the prior art. The polyethersulfone antistatic composite material prepared by the invention not only has the excellent performance of special engineering plastics, but also has antistatic property, and can be widely used in the fields of electronic appliances, mine mining, military industry, etc., and materials can be provided according to market demand. Pellet and various profile parts. DRAWINGS

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a SEM photograph of a cross section of a polyethersulfone antistatic composite material in Example 1 of the present invention.

2 is a SEM photograph of a cross section of the polyethersulfone antistatic composite obtained in Example 2. detailed description

The first technical problem to be solved by the present invention provides a polyether sulfone antistatic composite material having a molecular structure such as

Where ' is carbon nanotubes, n is the degree of polymerization, and its value ranges from 50 to 150. n is greater than 50 in order to ensure that it reaches a high molecular weight, but it should not be too high to ensure that the polyethersulfone antistatic composite has good properties. Processing performance.

Further, the raw materials of the polyethersulfone antistatic composite material include: 4,4-dichlorodiphenyl sulfone, 4,4-dihydroxydiphenyl sulfone, a solvent, an acid chloride carbon nanotube, a dehydrating agent, a catalyst; The molar ratio is: 4,4-dichlorodiphenyl sulfone: 4,4-dihydroxydiphenyl sulfone: solvent: dehydrating agent: catalyst = 1: 1: 5~6: 1.3~1.5: 1, wherein acyl chloride The amount of carbon nanotubes used is 10 to 15% of the mass of 4,4-dichlorodiphenyl sulfone. In the present invention, the amount of the acid chloride carbon nanotubes is limited to 10 to 15% of the mass of the 4,4-dichlorodiphenyl sulfone, and the content of the acyl chloride carbon nanotubes should not be too high, otherwise the reaction will be affected, resulting in a low molecular weight of the polyethersulfone. Too low will result in poor antistatic properties of polyethersulfone.

1) Acidification treatment of carbon nanotubes: The carbon nanotubes having a mixed acid content of 2 to 5% are ultrasonically dispersed in a mixed acid for 0.5 to 2 hours (preferably 1 hour at 40-50 ° CC, preferably 60 ° C) Reaction 20-30 hours (; preferably 24 hours) After dilution with deionized water, the resulting precipitate is washed with deionized water to a pH of 4-6 (preferably 5), and the product is dried (preferably dried in a vacuum oven) to obtain surface carboxylated carbon nanotubes. Wherein, the mixed acid is a mixture of concentrated sulfuric acid and concentrated nitric acid having a volume ratio of 3:1; 2) adding the carboxylated carbon nanotubes to thionyl chloride, and then adding dimethylformamide as a catalyst, at 60 -80 ° C (preferably 70 ° C) is heated to reflux for 20-30 hours (preferably 24 hours). After the reaction is completed, the thionyl chloride is refluxed with toluene, and the lower layer product is recovered for drying (drying in a vacuum oven). After the seal is preserved, the acid chlorided carbon nanotubes are obtained; the reaction process equation is as shown in the following figure:

The second technical problem to be solved by the present invention is to provide a method for preparing the above polyethersulfone antistatic composite material: the carbon nanotube is subjected to acid chloride treatment to obtain an acid chloride carbon nanotube, and the obtained acid chloride carbon nanotube is further combined with 4,4- Dichlorodiphenyl sulfone and 4,4-dihydroxydiphenyl sulfone are subjected to in-situ polymerization to obtain a polyether sulfone antistatic composite material after drying; the in-situ polymerization reaction refers to: acid chlorided carbon nanotubes and 4, 4-Dichlorodiphenyl sulfone and 4,4-dihydroxydiphenyl sulfone are heated under reflux by a catalyst, a solvent and a dehydrating agent, and the reaction product is cooled, pulverized, washed and filtered.

Further, in the preparation method of the polyethersulfone antistatic composite material, the molar ratio of each raw material is 4,4-dichlorodiphenyl sulfone: 4,4-dihydroxydiphenyl sulfone: catalyst: solvent: dehydrating agent=1 : 1: 1: 5 to 6: 1.3 to 1.5; The amount of the acid chloride carbon nanotubes is 10 to 15% of the mass of the 4,4-dichlorodiphenyl sulfone.

(1) Weigh the raw materials according to the molar ratio of the raw materials: 4,4-dichlorodiphenyl sulfone: 4,4-dihydroxydiphenyl sulfone: potassium hydroxide: sulfolane: toluene = 1: 1 : 1 : 5 to 6: 1.3—1.5;

Preferably, in step 3 of the above method, when the temperature of the material is 120-160 ° C, the reaction is kept at a constant temperature for 2 hours, and then the temperature is further increased to 190 ° C to react to an anhydrous formation, and then the dehydrating agent is completely distilled off, and the temperature is further increased to 255-265 °C anti It should be discharged for 2-4 hours (the polymerization time is generally 2-4 hours, mainly to ensure its molecular weight is within a reasonable range). The obtained product is cooled, pulverized and washed. After the solvent and catalyst are completely removed, it is centrifugally dehydrated and dried. The polyethersulfone antistatic composite of the present invention. The synthesis reaction of the polyethersulfone in the step 3 of the present invention is divided into three stages. First, the reaction forms an oligomer. During this period, water is formed, and it needs to be taken out by a dehydrating agent. Second, all the dehydrating agent needs to be distilled out. The solvent is well-solved to ensure the normal reaction, and the third is to polymerize at a high temperature to form a high molecular weight polymer.

The surface of the antistatic agent carbon nanotube of the invention is subjected to acid chloride treatment, and the carbon nanotubes after acid chloride chlorination are directly dissolved in the solvent to participate in the polymerization of the polyethersulfone resin, thereby realizing the in-situ polymerization of the polyethersulfone/carbon nanotube.

The invention abandons the traditional method for surface modification of carbon nanotubes, and directly participates in the polymerization reaction of the polyethersulfone resin by dissolving the carbon nanotubes in the solvent by molecular structure design, thereby realizing polyethersulfone/ The in-situ polymerization of carbon nanotubes completely solved the problem of dispersion and interface of carbon nanotubes.

The present invention is specifically described by the following examples, and it is to be understood that the embodiments are only used to further illustrate the invention, and are not to be construed as limiting the scope of the invention. Improvements and adjustments.

Example 1 Surface Treatment of Carbon Nanotubes by Acid Chloride Treatment

The first step is to acidify the carbon nanotubes: 0.5g of carbon nanotubes are placed in 500ml of mixed acid (concentrated sulfuric acid: concentrated nitric acid in a volume ratio of 3:1) for ultrasonic dispersion for 1 hour, and reacted at 60 ° C for 24 hours. The precipitate obtained by dilution with deionized water and suction filtration was washed with deionized water to a pH of about 5, and the product was dried in a vacuum oven to obtain surface-carboxylated carbon nanotubes (MWNT-COOH). In the second step, 0.2 g of the carboxylated carbon nanotubes was added to 200 ml of thionyl chloride, and 2 ml of DMF was added as a catalyst, and the mixture was heated and refluxed at 70 ° C for 24 hours. After the reaction, refluxing with toluene was carried out to remove the thionyl chloride. The lower layer product was recovered in a vacuum oven and then sealed and stored to obtain an acid chlorided carbon nanotube (MWNT-COCl). The SEM photograph of the carbon nanotubes after acid chloride chlorination is shown in Fig. 1. It can be seen from Fig. 1 that there is a large amount of organic coating on the surface of the carbon nanotubes, indicating that the treatment by the acid chloride method achieves an ideal effect.

Example 2 Preparation of Polyethersulfone Antistatic Composite Material

First, according to the following molar ratio: 4,4-dichlorodiphenyl sulfone: 4,4-dihydroxydiphenyl sulfone: sulfolane: Toluene: potassium hydroxide = 1: 1: 5: 1.3: 1 Weigh the raw materials, then weigh The acid chloride carbon nanotube obtained in Example 1 which is 10% by mass of 4,4-dichlorodiphenyl sulfone is put into a solvent sulfolane for ultrasonic dispersion treatment for 10 minutes, and then 4,4-dichlorodiphenyl sulfone, 4, 4 - Dihydroxydiphenyl sulfone, sulfolane, acid chloride carbon nanotubes, toluene, and potassium hydroxide were placed together in a reaction vessel equipped with a reflux apparatus, and stirred under a nitrogen atmosphere to be heated. When the temperature of the material is 155 °C, the reaction is kept at constant temperature for 2 hours. The temperature was further increased to 190 ° C until the reaction was completed, and then the toluene was completely distilled off, and the temperature was further raised to 255 Torr. The reaction was diluted for 2.5 hours and then diluted. The material was placed in cold water to be cooled, taken out, crushed and centrifuged, and the solid was washed five times in boiling water for four times, filtered, and then dried at 150 ° C for 8 hours to obtain a 200-500 mesh polyethersulfone/carbon nanotube antistatic composite material. The electrical properties of the composite (test temperature 25 °C, humidity 70%) and mechanical properties are shown in Table 1. Fig. 2 is a SEM photograph of a cross section of the obtained composite material, and the photograph shows that the carbon nanotubes are uniformly dispersed in the polyethersulfone resin matrix, and the compatibility is good.

In the examples of the present invention, the volume resistivity is tested in accordance with GB/T 15662-1995; the glass transition temperature is tested by a DSC instrument of TA Company of the United States; tensile strength and elongation at break are tested in accordance with GB/T 1040.2.

Table 1 Electrical and mechanical properties of polyethersulfone antistatic composite prepared in Example 2

Example 3 Preparation of Polyethersulfone Antistatic Composite Material

First, weigh the raw materials according to the following molar ratio: 4 4-dichlorodiphenyl sulfone: 4 4-dihydroxydiphenyl sulfone: sulfolane: Toluene: potassium hydroxide = 1: 1: 5: 1.3: 1, 4 4-dichlorodiphenyl sulfone mass 15% acid chloride carbon nanotubes were put into the solvent sulfolane for ultrasonic dispersion treatment for 10 minutes, then 4 4 -dichlorodiphenyl sulfone, 4 4 -dihydroxydiphenyl sulfone, sulfolane, The carbon nanotubes, toluene, and potassium hydroxide were put together in a reaction vessel equipped with a reflux apparatus, and stirred under a nitrogen atmosphere to be heated. When the temperature of the material was 155 ° C, the reaction was carried out at a constant temperature for 2 hours, and the temperature was further increased to 190 ° C until the reaction became anhydrous. Then, the toluene was completely distilled off, and the temperature was further raised to 260 ° C for 2.5 hours to dilute the discharge. The material was placed in cold water to be cooled, taken out, crushed and centrifuged, and the solid was washed five times in boiling water for four times, filtered, and then dried at 150 ° C for 8 hours to obtain a 200-500 mesh polyethersulfone/carbon nanotube antistatic composite material. The electrical properties of the composite (test temperature 25 °C, humidity 70%) and mechanical properties are shown in Table 2: Table 2 Electrical and mechanical properties of the polyethersulfone antistatic composite prepared in Example 3

Comparative example 1

The raw material ratio and process were the same as in Example 2 except that the carbon nanotubes in Comparative Example 1 were not subjected to acid chloride treatment, and the electrical properties and mechanical properties of the obtained composite materials are shown in Table 3.

Table 3 Comparative Example 1 Electrical properties and mechanical properties of polyethersulfone antistatic composites prepared

It can be seen from Table 3 that the antistatic property of the composite material obtained by the same process without the acid chloride treatment of the carbon nanotubes is decreased, and the mechanical properties are degraded.

Claims

claims

1,

Where ^ is the carbon nanotube, _n is the degree of polymerization, and its value range is 50~15(

2. The polyethersulfone antistatic composite material according to claim 1, characterized in that: the volume resistivity of the polyethersulfone antistatic composite material is 10 ⁷ ~ 10 ^{1 ()} Ω . cm, and the tensile strength is 100~130MPa, elongation at break 15~25%.

3. The polyethersulfone antistatic composite material according to claim 1 or 2, characterized in that: the raw materials of the polyethersulfone antistatic composite material include: 4,4-dichlorodiphenylsulfone, 4,4- Dihydroxydiphenylsulfone, solvent, acyl chloride carbon nanotubes, dehydrating agent, catalyst; the molar ratio of raw materials is: 4,4-dichlorodiphenylsulfone: 4,4-dihydroxydiphenylsulfone: solvent: dehydrating agent: Catalyst = 1: 1: 5~6: 1.3~1.5: 1, wherein the amount of acyl chloride carbon nanotubes is 10~15% of the mass of 4,4-dichlorodiphenylsulfone.

4. The polyethersulfone antistatic composite material according to claim 3, characterized in that: the solvent is sulfolane.

5. The polyethersulfone antistatic composite material according to claim 3, characterized in that: the dehydrating agent is toluene or benzene.

6. The polyethersulfone antistatic composite material according to claim 3, characterized in that: the catalyst is potassium hydroxide or sodium hydroxide.

7. The polyethersulfone antistatic composite material according to claim 3, characterized in that: the acid chloride carbon nanotubes are prepared by the following preparation steps: a. Preparation of carboxylated carbon nanotubes: The carbon nanotubes are acidified in a mixed acid composed of concentrated sulfuric acid and concentrated nitric acid, washed and dried to obtain surface carboxylated carbon nanotubes; b. The carboxylated carbon nanotubes are reacted with the catalytic action of dimethylformamide The sulfoxide chloride reacts to obtain acid chloride carbon nanotubes.

8. The preparation method of polyethersulfone antistatic composite material according to claims 1 to 7, characterized in that: carbon nanotubes are first subjected to acyl chlorination treatment to obtain acyl chloride carbon nanotubes, and the obtained acyl chloride carbon nanotubes are then mixed with 4 ,4-Dichlorobiphenyl Sulfone and 4,4-dihydroxydiphenylsulfone undergo in-situ polymerization, and after drying, a polyethersulfone antistatic composite material is obtained; the in-situ polymerization refers to: acid chloride carbon nanotubes and 4,4-dichloro Diphenyl sulfone and 4,4-dihydroxydiphenyl sulfone are heated and refluxed under the action of catalyst, solvent and dehydrating agent. After cooling, the reaction product is crushed, washed, centrifuged and dehydrated, and dried to obtain polyethersulfone antistatic composite material.

9. The method for preparing polyethersulfone antistatic composite materials according to claim 8, characterized in that: first, the acyl chloride carbon nanotubes are evenly dispersed in the solvent by ultrasonic, and then mixed with 4,4-dichlorodiphenylsulfone, 4,4-Dihydroxydiphenylsulfone undergoes in-situ polymerization.

10. The preparation method of polyethersulfone antistatic composite material according to claim 8 or 9, characterized in that: the heating reflux reaction is: when the reaction temperature is 120-160°C, constant temperature reaction for 1-4 hours, and then Continue to raise the temperature to 170-210°C to react until no water is produced, then evaporate all the dehydrating agent, and continue to raise the temperature to 255-265°C to react for 2-4 hours.

11. The method for preparing polyethersulfone antistatic composite material according to claim 8 or 9, characterized in that: the in-situ polymerization reaction is carried out under nitrogen protection.