CN104592430A - Ultrahigh molecular weight polyethylene catalyst carrier material and preparation method thereof - Google Patents

Abstract

The invention provides an ultra-high molecular weight polyethylene catalyst carrier material and a preparation method thereof. The preparation method comprises: mixing the graphene oxide aqueous solution with the silica sol to obtain a mixed dispersion; spraying the mixed dispersion into liquid nitrogen, solidifying instantly after atomization, volatilizing to remove the liquid nitrogen, and vacuum drying to remove moisture to obtain a sample; The sample is heated and activated to obtain a graphene oxide/silicon dioxide spherical catalyst support material; in a tetrahydrofuran solution, the graphene oxide/silicon dioxide spherical catalyst support is mixed with butylmagnesium chloride, stirred and reacted to obtain a reaction product; the reaction The product is cleaned, and then heated at a high temperature of 600° C. for 2 hours to obtain an ultra-high molecular weight polyethylene catalyst carrier material. The catalyst carrier of the invention can effectively reduce polymer molecular chain entanglement, and prepare graphene/ultra-high molecular weight polyethylene composite material.

Description

A kind of ultrahigh molecular weight polyethylene catalyst carrier material and preparation method thereof

technical field

The invention relates to an ultra-high molecular weight polyethylene catalyst carrier material and a preparation method thereof, belonging to the technical field of catalysts.

Background technique

Ultra-high molecular weight polyethylene (English name ultra-high molecular weight polyethylene, referred to as UHMWPE), is polyethylene with a molecular weight of more than 1.5 million. Compared with ordinary engineering plastics, UHMWPE has advantages that general materials do not have due to its ultra-high molecular weight (Kwideok Park, Gladius Lewis, JoonB.Park, et al.UHMWPE[J].Encyclopedia of Biomaterials and Biomedical Engineering. 2012(4): 2925-2934). However, the mechanical properties of polymers are strongly dependent on their molecular characteristics, and while increasing the molecular weight of a polymer, its processability is also adversely affected, mainly due to the reduction in the number of chain terminations that each chain has with its neighbors. The number of entanglements between chains increases (Lippits, D.R. Controlling themelting kinetics of polymers; a route to a new melt state. PhD. Thesis, Eindhoven University of Technology, 2007.). Therefore, how to find the balance of chain growth and chain entanglement in the polymerization process is an important factor to solve its processing performance (Yohan Champouret, Sanjay Rastogi, eterogeneity in the Distribution of Entanglement Density during Polymerization in Disentangled Ultrahigh Molecular Weight Polyethylene.Macromolecules 2011,44 , 4952–4960). At present, the research on molecular weight regulation in industry mainly focuses on the adjustment of polymerization process and "hydrogen adjustment". The effect is not good and the repeatability is poor.

At present, in the domestic industrial market, UHMWPE catalysts are mainly metallocene catalysts and Zieger-Natta catalysts, and the Zieger-Natta catalytic system occupies the main domestic market due to its stable polymerization activity and low cost. In the high-efficiency Zieg-Natta catalytic system polymerization with heterogeneous supports, there is a certain relationship between the catalyst morphology and the polymer morphology and particles prepared by polymerization. But only under suitable catalyst preparation conditions and specific polymerization conditions, can the catalyst and polymer particle state reappear results be obtained. Because of the appropriate molecular weight and its distribution, well-formed polymer particles are of great significance for the processing and wide application of ultra-high molecular weight polyethylene. In view of this, how to better combine the structure and steric effect of the catalyst support with the performance of the catalyst active center, so that it can control the structure and morphology of the polymer during the catalytic process has always been an urgent problem to be solved.

Graphene is a new material with a single-layer sheet structure composed of carbon atoms. It is a planar film composed of carbon atoms in a hexagonal honeycomb lattice with sp2 hybrid orbitals. It is only one carbon atom thick. 2D materials. Not only is graphene the thinnest known material, it is also very strong and strong; as a single substance, it can transfer electrons faster than known conductors at room temperature, and graphene is chemically very similar to carbon nanotubes , and similar to layered clay in structure, this structural feature makes it have great potential in improving the properties of polymers, not only improving mechanical properties, but also changing functional properties such as electrical and thermal properties of polymers.

At present, there are four main methods for the preparation of graphene/polymer composites: melt blending, solution mixing, emulsion mixing, and in-situ polymerization. The in-situ polymerization method is to mix graphene with monomers, add an initiator to initiate the reaction, and finally obtain a polymer composite material. Compared with the other three methods, the in-situ polymerization method has two important advantages. One is that the catalyst and polymer particle state can be obtained by loading active centers; the other is that graphene can be evenly dispersed in the polymer matrix. In this process, the properties of the composite material are more stable, the components are uniform, and the characteristics are consistent. These two points are particularly important in the preparation of special materials. However, the disadvantage of the currently used in-situ polymerization method to prepare graphene/polymer composites is that the viscosity of the polymer added with graphene (or graphene oxide) increases, which makes the polymerization reaction complicated.

Due to the stable surface properties of graphene, it is difficult to load active centers by chemical methods. Compared with graphene, the surface of graphene oxide sheet has abundant oxygen-containing functional groups. These functional groups make graphene and other substances composite very well. easy. Moreover, since graphene is a planar film composed of carbon atoms in a hexagonal honeycomb lattice with sp2 hybrid orbitals, and a two-dimensional material with a thickness of only one carbon atom, it has a super large theoretical specific surface area of 2630m ² /g (Novoselov KS, Geim AK, Morozov SV, Jiang D, Zhang Y, Dubonos SV, et al.Electric Field Effect in Atomically Thin Carbon Films.Science.2004; 306(5696):666-669.), and the distribution of functional groups is relatively neat, However, due to the close proximity of abundant oxygen-containing functional groups on the surface of graphene oxide sheets, it is easy to cause molecular chain entanglement during the initial growth process of polymerization.

The literatures that have been reported so far all use graphene sheets without specific morphology and active centers for loading, and then prepare graphene/polyolefin composite materials through polymerization. Although such materials can improve the performance of polyolefin materials, but due to the graphene The distribution between sheets is relatively random, which is easy to cause agglomeration, and the polymer chains grown between different sheets during polymerization cannot prevent a large number of molecular chains from entanglement due to their different growth directions.

In addition, due to the low bulk density of graphene materials and the insufficient strength of spherical particles after being made into catalyst supports, the spheres are easily broken during the loading reaction process. Ultrasonic self-assembly of oxygen-containing functional groups on the surface of graphene oxide and nano-silica particles , Higher strength graphene/silica composite materials can be obtained, and the excellent improvement effect of graphene on polymers will not be changed, and the cost can be greatly reduced, the catalyst bulk density can be increased, and the carrier strength can be improved.

Contents of the invention

In view of the defects in the above-mentioned prior art, the purpose of the present invention is to propose a UHMWPE catalyst carrier material and a preparation method thereof. The material contains spherical graphene groups. Entanglement occurs, and a graphene/UHMWPE composite carrier material with good dispersion and uniform mixing is prepared.

The purpose of the present invention is achieved through the following technical solutions:

A preparation method for ultra-high molecular weight polyethylene catalyst carrier material, comprising the steps of:

Mix the graphene oxide aqueous solution with the silica sol, stir, and ultrasonically disperse evenly to obtain a mixed dispersion;

Spray the mixed dispersion into liquid nitrogen, solidify instantly after atomization, volatilize to remove liquid nitrogen, put the cured product into a vacuum chamber, vacuum dry to remove moisture, and obtain a sample;

The sample is heated and reacted to obtain a graphene oxide/silicon dioxide spherical catalyst support material;

In the tetrahydrofuran solution, the graphene oxide/silicon dioxide spherical catalyst support material is mixed with the butylmagnesium chloride solution, and the reaction is continuously stirred at 50-80° C. for 12-48 hours to obtain a reaction product;

The reaction product is cleaned to remove excess butylmagnesium chloride, and then heated at a high temperature of 400-800°C for 30-120 minutes under an argon atmosphere to obtain an ultra-high molecular weight polyethylene catalyst carrier material.

According to specific embodiments, the preparation method of above-mentioned ultra-high molecular weight polyethylene catalyst carrier material, comprises the steps:

Mixing the graphene oxide aqueous solution with the silica sol, stirring for 30 minutes, and ultrasonically dispersing for 1 hour to obtain a mixed dispersion;

Adjust the air intake of the spray gun to 30mL/s, spray the mixed dispersion into liquid nitrogen, solidify instantly after atomization, remove the liquid nitrogen by volatilization, and put the cured product into a vacuum chamber (use a molecular pump to vacuum to 10 ^-6 MPa , continuous pumping for 8 hours), vacuum drying to remove moisture, and obtain a sample with good fluidity and uniform particle size;

Put the sample in an oven at a certain temperature, heat it for a period of time, and carry out a heating reaction. On the one hand, excess oxygen-containing functional groups are removed, on the other hand, trace moisture in the sample is removed, and at the same time, it has a certain curing and strengthening effect on the sample, and graphite oxide is obtained. Alkene/Silica Spherical Catalyst Support Material.

In a tetrahydrofuran solution, the graphene oxide/silicon dioxide spherical catalyst support material is mixed with butylmagnesium chloride, and the reaction is continuously stirred at 80° C. for 48 hours to obtain a reaction product;

The reaction product was washed three times with tetrahydrofuran and n-hexane to remove excess butylmagnesium chloride, and then heated at 600° C. for 2 hours under an argon atmosphere to obtain an ultra-high molecular weight polyethylene catalyst support material.

In the above preparation method, the sample is heated and reacted, that is, the graphene oxide is subjected to preliminary heat treatment, which can effectively control the oxygen-containing functional groups on the surface of the sample, so that the remaining functional groups can reduce the excess of adjacent functional groups while not affecting the active center of the loaded catalyst. Therefore, there is a large distance between the oxygen-containing functional groups after loading butylmagnesium chloride, so that there is a significant distance between the active center and the active center of the load, so as to effectively avoid chain growth during the growth of the polymer chain. With the occurrence of chain entanglement, this feature is very beneficial to improve and enhance the processing performance of ultra-high molecular weight polyethylene (UHMWPE). Moreover, the prepared composite carrier material undergoes heat treatment at a higher temperature during the processing of the polymer material, so that it can be further naturally reduced to graphene, thus showing the excellent comprehensive properties of graphene in the composite material.

In the above-mentioned preparation method, (in liquid nitrogen) spray freezing (under vacuum environment) drying method fixes graphene sheet morphology, prepares the graphene spherical particle of uniform size, particle size controllable, in polymerization process In the middle, the growth of the polymer chain is centered on the spherical carrier material, and the divergent growth is very effective in reducing the phenomenon of entanglement and agglomeration of a large number of molecular chains, and solving the bottleneck problem of large-scale production of ultra-high molecular weight polyethylene.

In the above preparation method, silica sol is used. As a traditional catalyst carrier material, silica has the advantages of low cost and high strength. In the preparation method, the sample is heated and reacted to form a composite of nano-silica and graphene, which not only does not affect The specific surface area of the composite support material will not change the excellent modification effect of graphene on the polymer, and will greatly reduce the cost, increase the bulk density of the catalyst, and improve the strength of the support material.

In the above preparation method, preferably, based on the mass of solid matter, graphene oxide aqueous solution: silica sol = 1:10-1:5; more preferably, graphene oxide aqueous solution: silica sol = 1:10.

In the above preparation method, preferably, the concentration of the graphene oxide aqueous solution is 0.05-0.5 g graphene oxide/50-500 mL deionized water.

In the above preparation method, preferably, the vacuum degree of vacuum drying is 10 ^-5 to 10 ^-7 MPa, and the drying time is 6 to 10 hours; more preferably, the vacuum degree of vacuum drying is 10 ^-6 MPa, and the drying time is 8 hours.

In the above preparation method, preferably, the temperature of the heating reaction is 30-60° C., and the time is 6-12 hours.

In the above-mentioned preparation method, preferably, the mass volume ratio of the graphene oxide/silicon dioxide spherical catalyst support material and the butylmagnesium chloride solution is 0.5～1g: 30～50mL, wherein, the concentration of the butylmagnesium chloride solution is 0.01～0.1mol/mL.

In the above-mentioned preparation method, preferably, the preparation method also includes the step of preparing graphene oxide:

Adding a solid mixture of graphite powder and sodium nitrate to concentrated sulfuric acid with a concentration of 98 wt%, and then adding potassium permanganate, stirring and reacting at a temperature of 5-20°C for 1-2 hours to obtain a first mixed solution;

Raise the temperature of the first mixed solution to 30-40°C, continue to stir and react for 20-40 minutes to obtain the second mixed solution;

Add deionized water to the second mixed solution, continue stirring at 95-100° C. for 20-40 minutes, and then add H ₂ O ₂ with a concentration of 30 wt % to obtain a suspension;

The suspension is filtered, the filtrate is washed until no sulfate is detected, dried, and pulverized into powder to obtain graphene oxide;

Among them, the dosage ratio of concentrated sulfuric acid, graphite powder, sodium nitrate, potassium permanganate, deionized water, and H ₂ O ₂ is 20~30mL: 0.5~2g: 0.5~1g: 3~5g: 40~60mL: 3~ 5mL.

According to specific embodiment, the preparation of graphene oxide comprises:

Adding a solid mixture of graphite powder and sodium nitrate to 98% concentrated sulfuric acid, then adding potassium permanganate, stirring and reacting for 2 hours at a temperature not exceeding 20°C, to obtain the first mixed solution;

The temperature of the first mixed solution was raised to 35°C, and the stirring reaction was continued for 30 minutes to obtain the second mixed solution;

Add deionized water to the second mixed solution, continue stirring at 100°C for 20 minutes, and then add H ₂ O ₂ with a concentration of 30 wt% to obtain a suspension;

Filter the suspension, wash the filtrate until no sulfate is detected, dry, pulverize, and sieve to obtain graphene oxide;

Wherein, the consumption of concentrated sulfuric acid: the consumption of graphite powder: the consumption of sodium nitrate: the consumption of potassium permanganate: the consumption of deionized water: the consumption of _{H 2} O ₂ consumption=23mL: 1g: 0.5g: 3g: 46mL: 3mL.

In the above preparation method, the graphene oxide solution is prepared in the following way: take 0.05-0.5 g of graphene oxide powder, add it to 50-500 mL of deionized water, stir evenly, and ultrasonicate for 0.5-2 hours to obtain a graphene oxide solution .

According to specific embodiments, the preparation of above-mentioned graphene oxide adopts traditional Hummers method, comprises:

Add 23mL of concentrated sulfuric acid to a dry beaker, cool in an ice bath to about 0°C, add a solid mixture of 1g of graphite powder and 0.5g of sodium nitrate, stir, slowly add 3g of potassium permanganate, at a temperature not exceeding 20°C Stirring and reacting for 2 hours, the first mixed solution was obtained, and the solution was viscous and dark green;

Raise the temperature of the first mixed solution to about 35°C, and continue to stir and react for 30 minutes to obtain the second mixed solution, which turns from dark green to brown;

Continuously and slowly add 46 mL of deionized water dropwise to the second mixed solution, control the temperature at about 100 ° C, continue stirring for 20 minutes, stop stirring, and then add 3 mL of 30% H ₂ O ₂ to reduce the residual oxidant to obtain a suspension. The solution turned bright yellow;

The suspension was filtered while it was hot, and the filtrate was washed with 5% HCl solution until no sulfate group was detected in the filtrate, and then placed in a drying oven at 60°C to fully dry, the color changed from golden yellow to black, and then Pulverize and sieve with a pulverizer to obtain graphene oxide. The graphene oxide is ultrasonically dispersed in deionized water to obtain a graphene oxide aqueous solution.

In the above preparation method, preferably, the preparation method also includes the step of preparing silica sol: stirring ethanol, ammonia water, and deionized water at 30-50°C for 5-10 minutes, then adding ethyl orthosilicate, and continuing to stir the reaction After 8-12 hours, the silica sol is obtained; wherein, the ratio of ethanol, ammonia water, deionized water, and ethyl orthosilicate is 80-100mL: 3-5mL: 3-6mL: 1-3mL.

According to a specific embodiment, the above-mentioned silica sol is prepared by stober method, including:

In 90mL of ethanol, add 3.8mL of ammonia water and 4.6mL of deionized water, put it in a constant temperature tank at 50°C and stir. After 5 minutes, add 2mL of ethyl orthosilicate, and react for 12 hours to form a silica sol. According to the temperature of the constant temperature reaction, the particle size of the silica sol can be adjusted. For example, react at 50°C to obtain a silica sol with a particle diameter of 30nm, and react at 60°C to obtain a silica sol with a particle diameter of 60nm.

In the above-mentioned preparation method, preferably, the preparation method also includes the step of preparing butylmagnesium chloride: mixing the mixed solution of n-chlorobutane and tetrahydrofuran with a volume ratio of 1:1 to 1:5 at a rate of 0.5 to 1 mL/min Use a constant pressure funnel to drip into the reaction vessel containing magnesium powder, dehydrated tetrahydrofuran and iodine, and continuously stir and react at 50-80°C for 2-4 hours to obtain a butylmagnesium chloride solution; The dosage ratio of the mixed solution, magnesium powder, dehydrated tetrahydrofuran and iodine is 20-28mL: 1-1.5g: 15-20mL: 0.05-0.1g. More preferably, the preparation of butylmagnesium chloride includes: first adding 1-1.5g of magnesium powder, 15-20mL of tetrahydrofuran after dehydration, and 0.05-0.1g of iodine particles into a flask. Then add 5-8mL of chlorobutane and 15-20mL of tetrahydrofuran into the beaker, mix well and transfer to the constant pressure dropping funnel. Finally, the re-concentrated solution was slowly dropped into a flask containing magnesium powder, and after about 5-8 mL was dropped, the temperature was raised to 50-80° C. and stirred continuously for 2-4 hours, and the residual solid was filtered to obtain a butylmagnesium chloride solution. Store the solution tightly sealed.

According to the specific embodiment, the preparation method also includes the step of preparing butylmagnesium chloride: first, add 1.2g of magnesium powder, 15mL of tetrahydrofuran after water removal, and 0.08g of iodine particles into the flask. Then add 5mL chlorobutane and 15mL tetrahydrofuran solution into the beaker, mix evenly and transfer to the constant pressure dropping funnel, slowly drop this solution into the flask with magnesium powder at a speed of 0.8mL/min, drop into After about 5 mL, start to stir at 80° C. for 4 hours, filter off the residual solid to obtain a butylmagnesium chloride solution, and store the solution sealed.

The present invention also provides the ultra-high molecular weight polyethylene catalyst carrier material obtained by the above preparation method. The carrier material is a spherical composite carrier material of graphene/silicon dioxide/butylmagnesium chloride with a molecular weight of 2 to 4 million.

The invention synthesizes a high-efficiency ultra-high molecular weight polyethylene catalyst through catalyst composition and structure design, and synthesizes an ultra-high molecular weight polyethylene catalyst with controllable molecular weight and molecular weight distribution and good polymer morphology and processability through compounding of catalyst components and optimization of polymerization process. High molecular weight polyethylene; can reduce the viscosity of the polymer after adding graphene in the in-situ polymerization method, reduce the complexity of the polymerization reaction, can expand the interval between the oxygen-containing functional groups on the surface of the graphene oxide sheet, and fix the graphene The lamella morphology avoids chain-to-chain entanglement during the growth of polymer chains, and prevents the phenomenon of entanglement and agglomeration of a large number of molecular chains. In addition, it can also improve the particle strength of the catalyst support material.

The outstanding effects of the present invention are:

1) The preparation method of the present invention can obtain a carrier material in which polymer particles "reproduce" the morphology of catalyst particles. After the porous spherical carrier is prepared, the active centers can be dispersed on the pore walls or holes on the surface of the spherical carrier compared to the direct use of graphene sheets.

Compared with traditional ultra-high molecular weight polyethylene catalysts, traditional catalysts such as silica, alumina, magnesium chloride, etc., only improve the catalytic activity, but cannot improve the molecular weight, molecular weight distribution and other important properties of ultra-high molecular weight polyethylene polymers. Improvement, so that the traditional polymerization needs to improve the entanglement phenomenon in the polymerization by controlling the polymerization rate and the crystallization rate. The catalyst of the present invention can solve the problem of adjacent functional groups between the remaining functional groups by effectively controlling the oxygen-containing functional groups on the surface of the support material. The problem of being too close makes there is a large gap between the loaded butylmagnesium chloride through the oxygen-containing functional group, so that there is a clear gap between the active center and the active center, which greatly reduces the entanglement of the molecular chains in the early stage of polymerization, which is very effective. Helps increase the crystallization rate.

2) The morphology of the graphene sheet is fixed by spray freeze-drying method, and the polymer chain grows centered on the spherical carrier material during the polymerization process, and the divergent growth can effectively reduce the phenomenon of entanglement and agglomeration of a large number of molecular chains , to solve the bottleneck problem of large-scale production of ultra-high molecular weight polyethylene.

3) Micron spherical graphene particles with a three-dimensional spherical structure are prepared, and relying on the regular network structure of graphene, the active centers can be evenly distributed and the entanglement of molecular chains can be effectively reduced.

4) The catalyst support material of the present invention can not only synthesize ultra-high molecular weight polyethylene with controllable molecular weight and molecular weight distribution and good polymer morphology and processability through the compounding of catalyst components and optimization of the polymerization process, but also because of the graphene Existence, in-situ polymerization can be used to uniformly and effectively compound graphene and ultra-high molecular weight polyethylene, and a graphene/ultra-high molecular weight polyethylene high-performance composite material can be prepared.

Description of drawings

Fig. 1 a is the TEM figure of the graphene oxide of embodiment 1;

Fig. 1b is the XRD figure of the graphene oxide of embodiment 1;

Fig. 1c is the TEM figure of the silica sol of embodiment 2;

Fig. 1 d is the TEM figure of the graphene oxide of embodiment 3 and silica sol composite solution;

Fig. 2 a is the graphene oxide/silicon dioxide spherical catalyst support material (SGO-SiO ₂ ) SEM figure of embodiment 3;

Fig. 2 b is the SEM figure under high magnification of the graphene oxide/silicon dioxide spherical catalyst support material of embodiment 3;

Fig. 2c is the SEM figure of the spherical composite carrier material of the graphene/silicon dioxide/butylmagnesium chloride of embodiment 3;

Fig. 2 d is the spherical catalyst EDX element characterization figure of the graphene/silicon dioxide/butylmagnesium chloride/titanium tetrachloride of embodiment 4;

2e is an SEM image of the spherical catalyst of graphene/silicon dioxide/butylmagnesium chloride/titanium tetrachloride in Example 4.

Detailed ways

The method of the present invention will be described below through specific examples to make the technical solution of the present invention easier to understand and grasp, but the present invention is not limited thereto. The experimental methods described in the following examples, unless otherwise specified, are conventional methods; the reagents and materials, unless otherwise specified, can be obtained from commercial sources.

Example 1

This embodiment provides a kind of graphene oxide used for ultra-high molecular weight polyethylene catalyst support material, and this graphene oxide is prepared by the following method:

Add 23mL of concentrated sulfuric acid with a concentration of 98wt% into a dry beaker, cool it to about 0°C in an ice bath, add a solid mixture of 1g graphite powder and 0.5g sodium nitrate, stir, and slowly add 3g potassium permanganate. Stirring and reacting at a temperature of 20°C for 2 hours, the first mixed solution was obtained, and the solution was viscous and dark green;

Raise the temperature of the first mixed solution to about 35°C, and continue to stir and react for 30 minutes to obtain the second mixed solution, which turns from dark green to brown;

Continuously and slowly add 46 mL of deionized water dropwise to the second mixed solution, control the temperature at about 100° C., continue stirring for 20 minutes, stop stirring, and then add 3 mL of H ₂ O ₂ with a concentration of 30 wt % to reduce the residual oxidant to obtain a mixed solution. suspension, the solution turned bright yellow;

The suspension was filtered while it was hot, and the filtrate was washed with a 5wt% HCl solution until no sulfate was detected in the filtrate, and then placed in a drying oven at 60°C to fully dry, its color changed from golden yellow to Black, and then crushed and sieved with a pulverizer to obtain graphene oxide (as shown in Figure 1a, 1b). The sheet size of the obtained graphene oxide is 5-50 μm.

Example 2

This embodiment provides a kind of silica sol used for ultra-high molecular weight polyethylene catalyst support material, and this silica sol is prepared by the following method:

In 90mL of ethanol, add 3.8mL of ammonia water and 4.6mL of deionized water, put it in a constant temperature tank at 50°C and stir, add 2mL of tetraethyl orthosilicate after 5 minutes, and form a silica sol (30nm particle size) after 12 hours of reaction. As shown in Figure 1c.

Example 3

The present embodiment provides a kind of ultra-high molecular weight polyethylene catalyst support material, and this support material is the spherical composite support material of graphene/silicon dioxide/butylmagnesium chloride, and this support material is prepared by the following method:

The graphene oxide obtained in Example 1 was ultrasonically prepared in deionized water for 30 minutes to form a uniform graphene oxide aqueous solution with a concentration of 10 mg/mL, and the graphene oxide aqueous solution and the silica sol obtained in Example 2 were mixed at a solid content of 1:7.5. The mass ratio is mixed, stirred for 30 minutes, and ultrasonically dispersed for 1 hour to obtain a mixed dispersion (as shown in Figure 1d);

Adjust the air intake of the spray gun, spray the mixed dispersion liquid into the liquid nitrogen, make the solution atomize first and then solidify instantly, volatilize to remove the liquid nitrogen, wait until the liquid nitrogen is completely volatilized, put the solidified product into the vacuum cavity, and pump it with a molecular pump To 10 ^-6 MPa, continue pumping for 8 hours to remove water and obtain a sample with good fluidity and uniform particle size;

Put the sample in an oven at 200°C, heat it for 2 hours, and carry out the heating reaction. On the one hand, excess oxygen-containing functional groups are removed, on the other hand, trace moisture in the sample is removed, and at the same time, it has a certain curing and strengthening effect on the sample to obtain graphene oxide. /Silicon dioxide spherical catalyst support material (as shown in Figure 2a and Figure 2b ), passed the BET test, with a specific surface area of 459.28m ² /g.

In tetrahydrofuran solution, mix 0.8g of graphene oxide/silicon dioxide spherical catalyst support material with 50mL of butylmagnesium chloride with a concentration of 0.02mol/mL, and continue to stir uniformly at 60°C for 24 hours to obtain a reaction product;

The reaction product was washed 3 times with tetrahydrofuran and n-hexane respectively, and excess butylmagnesium chloride was removed. Under an argon atmosphere, 600° C. of high temperature heating was carried out for 2 hours to obtain a spherical composite carrier material of graphene/silicon dioxide/butylmagnesium chloride ( as shown in Figure 2c).

Example 4

In this example, the composite carrier material in Example 3 was used as a catalyst carrier for preparing UHMWPE, and the catalytic activity was evaluated.

The main catalyst of the present embodiment is titanium tetrachloride, the internal electron donor is diisobutyl phthalate, and the composite support material supports the catalyst, wherein the Ti content is 9%, and the UHMWPE catalyst (graphene/silicon dioxide/ Spherical catalysts of butylmagnesium chloride/titanium tetrachloride, as shown in Figure 2d, 2e).

The UHMWPE catalyst is used for UHMWPE polymerization. According to the conventional method, the pressure in the kettle is controlled to 0.8 MPa, the temperature is adjusted to 70° C., and the reaction is performed for 2 hours to obtain UHMWPE.

The catalytic results were evaluated, and the test results were: catalytic activity 2.45×10 ⁴ g/(mmolTi h), relatively stable polymerization kinetics, Young’s modulus of 826±34MPa, tensile strength of 87±9MPa, tested by conventional viscosity method The molecular weight of the obtained polymer was measured to be 2.3×10 ⁶ g/mol, and the electrical conductivity was measured to be 0.2 S/m by a conventional four-probe method.

It can be seen from the above that a graphene/silica spherical catalyst support material with a large specific surface area was prepared by ultrasonic self-assembly of graphene oxide and silica and spray freeze-drying, and a uniformly mixed catalyst was prepared by loading the catalyst on the carrier. graphene/UHMWPE composites.

Claims (10)

1. a preparation method for extra high-molecular polythene catalyst solid support material, comprises the steps:

Graphene oxide water solution mixed with silicon sol, stir, ultrasonic disperse is even, obtains mixed dispersion liquid;

Mixed dispersion liquid be sprayed in liquid nitrogen, instantaneous solidification after atomization, liquid nitrogen is removed in volatilization, and cured product is inserted vacuum cavity, and moisture is removed in vacuum-drying, obtains sample;

Sample is carried out reacting by heating, obtains the spherical catalyst support material of graphene oxide/silicon-dioxide;

In tetrahydrofuran solution, mixed by spherical for graphene oxide/silicon-dioxide catalyst support material with butyl magnesium chloride solution, at 50 ~ 80 DEG C, Keep agitation reaction 12 ~ 48 hours, obtains reaction product;

Reaction product carried out cleaning the excessive butylmagnesium chloride of removing, then under ar gas environment, 400 ~ 800 DEG C of heat 30 ~ 120 minutes, obtain extra high-molecular polythene catalyst solid support material.

2. preparation method according to claim 1, is characterized in that: in the quality of solid matter, graphene oxide water solution: silicon sol=1: 10 ~ 1:5.

3. preparation method according to claim 2, is characterized in that: the concentration of described graphene oxide water solution is 0.05 ~ 0.5g graphene oxide/50 ~ 500mL deionized water.

4. preparation method according to claim 1, is characterized in that: vacuum drying vacuum tightness is 10 ^-5~ 10 ^-7mPa, time of drying is 6 ~ 10 hours.

5. preparation method according to claim 1, is characterized in that: the temperature of reacting by heating is 30 ~ 60 DEG C, and the time is 6 ~ 12 hours.

6. preparation method according to claim 1, it is characterized in that: the ratio of the spherical catalyst support material of graphene oxide/silicon-dioxide and butyl magnesium chloride solution is 0.5 ~ 1g: 30 ~ 50mL, wherein, the concentration of described butyl magnesium chloride solution is 0.01 ~ 0.1mol/mL.

7. preparation method according to claim 1, is characterized in that: this preparation method also comprises the step preparing graphene oxide:

Be the solid mixture adding Graphite Powder 99 and SODIUMNITRATE in the vitriol oil of 98wt% to concentration, then add potassium permanganate, at the temperature of 5 ~ 20 DEG C, stirring reaction 1 ~ 2 hour, obtains the first mixed solution;

First mixed solution is warming up to 30 ~ 40 DEG C, continues stirring reaction 20 ~ 40min, obtain the second mixed solution;

In the second mixed solution, add deionized water, after continuing stirring 20 ~ 40min at 95 ~ 100 DEG C, add the H that concentration is 30wt% ₂o ₂, obtain suspension;

Filtered by suspension, much filtrate washing, to sulfate radical-free is detected, dry, pulverize and powderedly namely obtains graphene oxide;

Wherein, the vitriol oil, Graphite Powder 99, SODIUMNITRATE, potassium permanganate, deionized water, H ₂o ₂amount ratio be 20 ~ 30mL:0.5 ~ 2g:0.5 ~ 1g:3 ~ 5g:40 ~ 60mL:3 ~ 5mL.

8. preparation method according to claim 1, is characterized in that: this preparation method also comprises the step preparing silicon sol:

By ethanol, ammoniacal liquor, deionized water 30 ~ 50 DEG C of mix and blends 5 ~ 10 minutes, then add tetraethoxy, continue stirring reaction 8 ~ 12 hours, namely obtain silicon sol;

Wherein, the amount ratio of ethanol, ammoniacal liquor, deionized water, tetraethoxy is 80 ~ 100mL:3 ~ 5mL:3 ~ 6mL:1 ~ 3mL.

9. preparation method according to claim 1, is characterized in that: this preparation method also comprises the step of preparation butylmagnesium chloride:

Be that the n-propylcarbinyl chloride of 1:1 ~ 1:5 and the mixing solutions of tetrahydrofuran (THF) instill with the speed of 0.5 ~ 1ml/min and magnesium powder is housed, dewaters in the reaction vessel of tetrahydrofuran (THF) and iodine by volume ratio, 50 ~ 80 DEG C of continuously stirring reactions 2 ~ 4 hours, obtain butyl magnesium chloride solution;

Wherein, the amount ratio of the mixing solutions of n-propylcarbinyl chloride and tetrahydrofuran (THF), magnesium powder, the tetrahydrofuran (THF) that dewaters, iodine is 20 ~ 28mL:1 ~ 1.5g:15 ~ 20mL:0.05 ~ 0.1g.

10. the extra high-molecular polythene catalyst solid support material of the molecular weight that the preparation method described in any one of claim 1 ~ 9 obtains, is characterized in that: this solid support material is the spherical complex carrier material of the graphene/silicon dioxide/butylmagnesium chloride of molecular weight 200 ~ 4,000,000.