阅读说明：本技术 一种用于改性聚硫密封剂的多硫寡聚物修饰氧化石墨烯及其改性方法 (Polysulfide oligomer modified graphene oxide for modified polysulfide sealant and modification method thereof ) 是由 陈鹏鹏 章谏正 李喜莲 毛昌杰 全燕南 吴松华 吴明元 于 2020-04-30 设计创作，主要内容包括：本发明公开了一种用于改性聚硫密封剂的多硫寡聚物修饰氧化石墨烯及其改性方法,该多硫寡聚物修饰氧化石墨烯是通过多硫寡聚物对氧化石墨烯表面进行修饰,使多硫寡聚物上的巯基与氧化石墨烯上的含氧官能团反应,从而获得。将本发明的多硫寡聚物修饰氧化石墨烯作为填料,加入到聚硫密封剂的原料体系中,对其中的聚硫橡胶改性,可以提高聚硫密封剂的力学性能。(The invention discloses a polysulfide oligomer modified graphene oxide for a modified polysulfide sealant and a modification method thereof. The polysulfide oligomer modified graphene oxide is used as a filler, added into a raw material system of a polysulfide sealant, and used for modifying polysulfide rubber in the polysulfide sealant, so that the mechanical property of the polysulfide sealant can be improved.)

1. A polysulfide oligomer modified graphene oxide for a modified polysulfide sealant is characterized in that: the polysulfide oligomer modified graphene oxide is obtained by modifying the surface of graphene oxide through polysulfide oligomer, and reacting sulfydryl on the polysulfide oligomer with an oxygen-containing functional group on the graphene oxide.

2. A method for preparing the polysulfide oligomer-modified graphene oxide of claim 1, wherein the method comprises the following steps: dispersing polysulfide oligomer and lamellar graphene oxide in an N, N-dimethylformamide solvent, adding 2,4, 6-tris (dimethylaminomethyl) phenol as a catalyst, carrying out condensation reflux reaction for 24 hours in a three-neck flask at the temperature of 30-50 ℃, and mechanically stirring at the rotating speed of 300-400rpm in the reaction process; and after the reaction is finished, centrifuging the obtained product, washing the product for multiple times by using N, N-dimethylformamide, and freeze-drying the product to obtain the polysulfide oligomer modified graphene oxide.

3. The method of preparing a polysulfide oligomer-modified graphene oxide of claim 2, wherein the method comprises: the mass ratio of the polysulfide oligomer to the graphene oxide sheet is 0.1-1.5:1, and the mass of the catalyst accounts for 1-10% of that of the graphene oxide sheet.

4. The method of preparing a polysulfide oligomer-modified graphene oxide of claim 2, wherein the method comprises: the lamellar graphene oxide is prepared by an improved Hummer method.

5. A method of modifying a polysulfide sealant using the polysulfide oligomer-modified graphene oxide of claim 1, wherein the method comprises: and adding the polysulfide oligomer modified graphene oxide serving as a filler into a raw material system of the polysulfide sealant to modify polysulfide rubber in the polysulfide sealant, so that the mechanical property of the polysulfide sealant is improved.

6. The method of claim 5, wherein: the addition amount of the polysulfide oligomer modified graphene oxide accounts for 0.1-2.0% of the mass of the polysulfide rubber in a polysulfide sealant raw material system.

Technical Field

The invention belongs to the field of functional polymer materials, and particularly relates to polysulfide oligomer modified graphene oxide for a modified polysulfide sealant and a modification method thereof.

Background

Polysulfide sealant is a sealant prepared by using liquid polysulfide rubber as a main material and compounding with auxiliary agents such as a vulcanizing agent, a reinforcing agent, a tackifier, an accelerator and the like, and is an elastic sealant with a long history. The polysulfide sealant has the characteristics of uniform curing, good chemical resistance, good weather resistance and the like, and is widely applied to the fields of buildings, traffic, manufacture and the like. However, in some environments with harsh external conditions, the sealing performance of the sealant is still significantly reduced. To prepare high performance polysulfide sealants, improving filler dispersion and filler-rubber interaction are recognized as key factors.

The graphene oxide is taken as a filler and introduced into the polysulfide rubber, so that the composite material is expected to have excellent physical and chemical properties such as force, heat, electricity, magnetism and the like, but the reaction inertia and the characteristics of easy agglomeration and difficult dispersion of the graphene oxide limit the application of the graphene oxide in the polysulfide sealant. The Chinese patent CN106520058A is to add graphene oxide into rubber to obtain the graphene-nickel composite conductive anti-corrosion polysulfide sealant. The invention patent CN106479185A of China uses silane coupling agent to modify graphene oxide, and obtains a graphene-containing heavy-duty anticorrosion sealant which can be used for anti-corrosion parts such as integral fuel tanks, cabins, air-tight cabins, body structure lap joint interface gaps and covers of airplanes. According to the method, the untreated graphene oxide or the graphene oxide treated by the silane coupling agent is used as the filler, so that the problems of poor compatibility between the graphene and the polysulfide rubber and poor crosslinking between the graphene and the polysulfide rubber still exist, and the mechanical property of the obtained polysulfide sealant cannot meet the requirement.

Disclosure of Invention

In order to avoid the defects of the prior art, the invention discloses polysulfide oligomer modified graphene oxide for a modified polysulfide sealant and a modification method thereof, and aims to solve the technical problems that: by carrying out surface treatment on the lamellar graphene oxide through the polysulfide oligomer, the compatibility problem of the graphene oxide and polysulfide rubber is solved, and the crosslinking effect between the graphene oxide and the polysulfide rubber is enhanced, so that the mechanical property of the polysulfide sealant is improved.

In order to realize the purpose of the invention, the following technical scheme is adopted:

the invention firstly discloses a polysulfide oligomer modified graphene oxide for a modified polysulfide sealant, which is characterized in that: the polysulfide oligomer modified graphene oxide is obtained by modifying the surface of graphene oxide through polysulfide oligomer, and reacting sulfydryl on the polysulfide oligomer with an oxygen-containing functional group on the graphene oxide.

The preparation method of the polysulfide oligomer modified graphene oxide comprises the following steps: dispersing polysulfide oligomer and lamellar graphene oxide in an N, N-dimethylformamide solvent, adding 2,4, 6-tris (dimethylaminomethyl) phenol as a catalyst, carrying out condensation reflux reaction for 24 hours in a three-neck flask at the temperature of 30-50 ℃, and mechanically stirring at the rotating speed of 300-400rpm in the reaction process; and after the reaction is finished, centrifuging the obtained product, washing the product for multiple times by using N, N-dimethylformamide, and freeze-drying the product to obtain the polysulfide oligomer modified graphene oxide.

Preferably, the mass ratio of the polysulfide oligomer to the graphene oxide sheet is 0.1-1.5:1, and the mass of the catalyst accounts for 1-10% of the mass of the graphene oxide sheet. Most preferably, the mass ratio of the polysulfide oligomer to the graphene oxide sheet is 1:1, and the mass of the catalyst accounts for 5% of the mass of the graphene oxide sheet.

Preferably, the lamellar graphene oxide is prepared by a modified Hummer method.

Most preferably, the reaction temperature is 30 ℃.

The invention further discloses a method for modifying a polysulfide sealant by using the polysulfide oligomer modified graphene oxide, which is characterized by comprising the following steps: and adding the polysulfide oligomer modified graphene oxide serving as a filler into a raw material system of the polysulfide sealant to modify polysulfide rubber in the polysulfide sealant, so that the mechanical property of the polysulfide sealant is improved. Compared with graphene oxide as a filler, the polysulfide oligomer modified graphene oxide as the filler can improve the dispersibility of the filler and enhance the crosslinking of the graphene oxide and polysulfide rubber, so that the mechanical property of the polysulfide sealant is remarkably improved.

Preferably, the addition amount of the polysulfide oligomer modified graphene oxide accounts for 0.1-2.0% of the mass of the polysulfide rubber in a raw material system of the polysulfide sealant.

The polysulfide oligomer modified graphene oxide is suitable for modifying polysulfide sealants of various types and formula systems in the market. Specifically, a typical formulation system for polysulfide sealants is composed of a base paste and a curing paste. The base paste consists of a reinforcing agent (one or a mixture of more of heavy calcium carbonate, light calcium carbonate, fumed silica, precipitated silica, titanium dioxide, talcum powder and kaolin), a plasticizer (one or a mixture of more of phthalic acid substances, chlorinated paraffin and tributyl phosphate), a silane coupling agent and liquid polysulfide rubber, and the vulcanizing paste consists of active manganese dioxide, dibutyl phthalate and an accelerator (one or a mixture of more of diphenyl guanidine, tetramethyl thiuram dithionate and di-n-butyl dithiocarbamate). When the polysulfide oligomer modified graphene oxide is modified, the polysulfide oligomer modified graphene oxide is added into a base paste, and then the polysulfide sealant is prepared according to the existing method.

The invention has the beneficial effects that:

1. according to the invention, the surface of graphene oxide is modified by polysulfide oligomer, so that the dispersibility and stability of graphene oxide in liquid polysulfide rubber are increased, and the crosslinking density of graphene oxide and polysulfide rubber is increased, thereby obviously improving the mechanical property of the polysulfide sealant.

2. According to the preparation method, the lamellar graphene oxide is prepared by an improved Hummers method, the damage degree of the traditional graphene oxide preparation method to a graphite structure is large, the oxidation degree is low, a high-temperature oxidation stage at 95 ℃ is omitted, and the reaction time of a medium-temperature reaction stage at 35 ℃ is increased, so that the oxidation of graphite is more sufficient, the oxidation degree of the graphene oxide is higher, and the structural damage degree of the graphene oxide is smaller.

Drawings

FIG. 1 is an X-ray photoelectron spectroscopy (XPS) analysis of a graphene oxide sheet (GO) prepared according to the present invention and a polysulfide oligomer-modified graphene oxide (L PO-GO) obtained under different reaction conditions;

FIG. 2 is a Fourier transform infrared (FT-IR) spectrum of graphene oxide platelet (GO) and oligomer polysulfide modified graphene oxide (L PO-GO) prepared according to the present invention;

FIG. 3 is a Transmission Electron Microscope (TEM) image of lamellar Graphene Oxide (GO) and polysulfide oligomer-modified graphene oxide (L PO-GO) prepared according to the present invention;

FIG. 4 is an X-ray diffraction spectrum (XRD) of Graphene Oxide (GO) sheets and oligomer polysulfide modified graphene oxide (L PO-GO) prepared by the present invention;

FIG. 5 is a thermogravimetric analysis (TGA) of the lamellar Graphene Oxide (GO) and the polysulfide oligomer-modified graphene oxide (L PO-GO) prepared according to the present invention;

FIG. 6 is a dynamic thermo-mechanical analysis chart (DMTA) of a polysulfide oligomer-modified graphene oxide-modified polysulfide rubber composite material (L PO-GO/PS) prepared by the present invention;

FIG. 7 is a graph showing the tensile properties of a polysulfide oligomer-modified graphene oxide-modified polysulfide rubber composite material (L PO-GO/PS) prepared according to the present invention;

FIG. 8 is a graph of elongation at break performance of the polysulfide oligomer-modified graphene oxide-modified polysulfide rubber composite material (L PO-GO/PS) prepared by the present invention.

Detailed Description

The following examples are given to illustrate the present invention, and the following examples are carried out on the premise of the technical solution of the present invention, and give detailed embodiments and specific procedures, but the scope of the present invention is not limited to the following examples.

The preparation method of the graphene sheet oxide used in the following examples is as follows: 2g of graphite powder and 1g of NaNO₃The powder was charged into a three-necked flask, and then concentrated H (50 m L mass% 98%) was added₂SO₄Magnetic stirring in ice-water bath, adding 6g KMnO₄Adding solid particles into a three-neck flask in batches at 5 ℃, heating to 35 ℃ after the addition, stirring and reacting for 24 hours, adding 100m L deionized water into reaction liquid after the reaction is finished, stirring and mixing uniformly, then adding 250m L deionized water, then dropwise adding 15m L30 wt% of hydrogen peroxide into the reaction liquid, adding 200m L1 mol/L HCl solution, stirring and mixing uniformly, then centrifuging at the rotating speed of 4500r/min, removing supernatant, washing with water, centrifuging precipitate until the pH is close to neutral, transferring the centrifuged precipitate into a 500m L large beaker, adding 300m L deionized water, performing ultrasonic treatment for more than 2 hours, then centrifuging the solution at the rotating speed of 4500r/min for 20 minutes, collecting liquid on the upper part of a centrifuge tube, namely brown graphene oxide solution, dialyzing for one week by using a dialysis bag with the molecular weight cutoff of 14000 for 14000, and then freeze-drying for 24 hours at-50 ℃ to obtain the lamellar graphene oxide.