阅读说明：本技术 一种用于太空气球的氧化石墨烯和/或层状硅酸盐天然橡胶复合材料及其制备方法 (Graphene oxide and/or layered silicate natural rubber composite material for space balloon and preparation method thereof ) 是由 吴晓辉 尹田雨 李鹏举 张立群 肖迪娥 谌志鹏 于 2019-02-27 设计创作，主要内容包括：本发明公开了一种用于太空气球的氧化石墨烯和/或层状硅酸盐天然橡胶复合材料及其制备方法。所述复合材料包括天然橡胶100份、氧化石墨烯和/或层状硅酸盐0.1～10份以及稳定剂0.1～6份；其中,氧化石墨烯和层状硅酸盐经过界面剂的预改性。本发明通过界面剂对氧化石墨烯和/或层状硅酸盐进行预处理,降低其极性,实现和天然胶乳的良好相容,实现强界面结合。通过天然胶乳与氧化石墨烯、层状硅酸盐的纳米复合,大幅改善其机械性能、抗辐射老化性能以及气密性,可作为一种改进太空气球球膜的先进技术。(The invention discloses a graphene oxide and/or layered silicate natural rubber composite material for a space balloon and a preparation method thereof. The composite material comprises 100 parts of natural rubber, 0.1-10 parts of graphene oxide and/or layered silicate and 0.1-6 parts of a stabilizer; wherein, the graphene oxide and the layered silicate are pre-modified by the interface agent. According to the invention, the graphene oxide and/or the layered silicate are pretreated by the interfacial agent, so that the polarity of the graphene oxide and/or the layered silicate is reduced, good compatibility with natural latex is realized, and strong interface combination is realized. The mechanical property, the radiation aging resistance and the air tightness of the composite material are greatly improved by nano-compounding the natural latex, the graphene oxide and the layered silicate, and the composite material can be used as an advanced technology for improving a space balloon membrane.)

1. The graphene oxide and/or layered silicate natural rubber composite material for the space balloon is characterized by being prepared from the following raw materials in parts by weight:

100 parts of natural rubber;

0.1-10 parts of graphene oxide and/or layered silicate;

0.1-6 parts of a stabilizer;

wherein, the graphene oxide and the layered silicate are pre-modified by the interface agent.

2. The natural rubber composite according to claim 1, characterized in that the composite is prepared from raw materials comprising, in parts by weight:

100 parts of natural rubber;

3-9 parts of graphene oxide and/or layered silicate;

3-5 parts of a stabilizer.

3. The natural rubber composite of claim 1, wherein:

the solid content of the natural rubber is 20-70%, and preferably 40-60%.

4. The natural rubber composite of claim 1, wherein:

the number of graphene oxide layers is 1-10, the thickness of each layer is 0.3-3 nm, and the transverse size is 1-4 microns.

5. The natural rubber composite of claim 1, wherein:

the phyllosilicate is at least one of montmorillonite, clay, rectorite, mica, talc and kaolin.

6. The natural rubber composite of claim 1, wherein:

the stabilizer is at least one selected from ammonia water, potassium hydroxide, hexadecyl benzene sulfonic acid sodium salt and lauryl sodium sulfate.

7. The natural rubber composite of claim 1, wherein:

the dosage of the interface agent A of the graphene oxide is 1-100% of that of the graphene oxide, and the interface agent A is selected from a silane coupling agent, a quaternary ammonium salt or epoxy natural rubber latex;

the dosage of the interface agent B of the layered silicate is 10-100% of the dosage of the layered silicate, and the interface agent B is selected from substances capable of performing ion exchange with the layered silicate, and quaternary ammonium salt or pyridine is preferred.

8. The natural rubber composite according to any one of claims 1 to 7, characterized in that the composite comprises at least one of the following components in parts by weight:

0.5-1 part of an anti-aging agent;

2-4 parts of a vulcanization accelerator;

1-3 parts of a vulcanizing agent.

9. A method for preparing a natural rubber composite material according to any one of claims 1 to 8, characterized by comprising the steps of:

(1) pre-modifying graphene oxide and/or layered silicate:

preparing graphite oxide slurry with the concentration of 1-10 per mill, adjusting the pH value to 6.8-8.1, ultrasonically preparing a graphene oxide dispersion liquid, adding an interfacial agent at the temperature of 60-80 ℃, stirring the mixed liquid of the graphene oxide dispersion liquid and the interfacial agent at the stirring speed of 80-120 r/min for 5-10 h, filtering, removing residues, and collecting the obtained modified graphene oxide dispersion liquid;

and/or preparing the phyllosilicate into water slurry with the concentration of 1-5%, adding an interfacial agent, and stirring for 40-60 min under the stirring action of the rotating speed of 50-120 r/min to form the phyllosilicate sheet layer nano water dispersion;

(2) preparing a natural rubber composite material:

adding a stabilizer into natural rubber, and stirring at room temperature for 10 min-2 h; adding the modified graphene oxide dispersion liquid and/or the layered silicate sheet nano water dispersion liquid obtained in the step (1), and continuously stirring for 10-40 min; and (3) adding other components after uniformly mixing, and continuously stirring for 1-2 h to obtain the composite material.

10. The method for producing a natural rubber composite according to claim 9, characterized in that:

in the step (1), the ultrasonic power for dispersing the graphene oxide is 750-1000W, the working interval is 1.5-2 s, and the total ultrasonic time is 60-80 min.

In the step (2), the stirring speed of adding the stabilizer is 50-120 r/min.

Technical Field

The invention relates to the field of composite material preparation, in particular to a graphene oxide and/or layered silicate natural rubber composite material for optimizing the air tightness, tensile strength and tensile strength of the existing space balloon membrane and a preparation method thereof.

Background

The near space is broadly defined as a region between 20 and 100 km. The air in the near space airspace is very thin, most fixed wing aircrafts cannot fly in the space, and the satellite is too large under the action of gravity to maintain the flying orbit. But the air flow in the area is stable, the air flow is relatively small, and the high-altitude hovering balloon or airship is an ideal airspace for deploying. The high-altitude scientific balloon is an important vehicle for high-altitude and aerial reading scientific research. The balloon is of zero pressure type and has a volume of 10⁴～10⁶m³The effective load is hundreds of kilograms to tons, the lift-off height reaches 30 to 50 kilometers, and the device has practical significance for national defense and scientific research.

The fact proves that scientific detection and tasks can be excellently completed by using the high-altitude balloon, and the high-altitude balloon can be well complemented with satellites and manned spacecrafts. The high-altitude balloon is low in cost, short in preparation period and easy to flexibly implement. The space inflatable structure product is light in material weight, foldable, adaptable to space complex environment and good in rigidity after being inflated, so that the development on inflatable structures and materials is fast abroad in nearly 10 years. However, the wind speed of the near space is increased with the increase of the altitude, and the wind speed of the near space is also changed with the difference of the latitude, and the wind speed is generally larger at the higher latitude. Atmospheric pressure is also an important factor in the near space environment. When the atmospheric pressure is reduced by 50%, the volume of the balloon is increased by about 1 time, and the balloon has higher requirements on the tensile strength, tear resistance, toughness and the like of the material. Meanwhile, the working altitude of the high-altitude balloon is generally 30-40 kilometers (stratosphere), when the balloon is lifted to the working altitude, the working altitude passes through a troposphere (the top altitude of the stratosphere is 15 kilometers), the top temperature is-75 ℃, in addition, the wind speed gradient of high-altitude wind exerts shearing force on the balloon, the balloon membrane material is required to have excellent low-temperature performance, the test of low-temperature embrittlement can be carried out, the low-temperature elongation is as large as possible, the head of the balloon and local stress can be concentrated by the balloon in the lifting and flying processes, the stress is isotropic, and the longitudinal and transverse strength of the sphere membrane is required to be basically consistent and the thickness uniformity of the membrane is. Meanwhile, the near-space ozone and ultraviolet rays have the effects of corroding and aging the surface material of the near-space platform, so that the ozone and ultraviolet rays are also factors to be considered in the design process. (Dynasty, Jiangruhua, Xuanbaiyu. improvement of balloon membrane performance of high-altitude balloon [ C ]// seventh academic conference of space exploration professional committee of Chinese space science institute, 1994.)

The main material of the latex balloon is rubber latex. The kind of latex has great influence on the technological performance of the balloon, the physical and mechanical performance of the adhesive film, the ageing resistance and the lift-off performance. The latex varieties widely applied in the research and production of foreign rubber balloons: one is centrifugal concentrated latex of natural rubber; the other is synthetic neoprene latex, the former mainly has excellent film forming performance, manufacturability and cold resistance but poor weather resistance and air tightness, and the latter has excellent weather resistance and air tightness but poor cold resistance. The raw material latex adopted in the production of the current domestic sounding balloon is mainly natural rubber centrifugal concentrated latex. (WangleMing, Liuyongyi.950 g, 750 g natural latex sounding balloon development [ J ] Special rubber products, 1984(6):27-34.)

The layered silicate and the graphene which are used as lamellar materials have high specific surface area and large length-diameter ratio, and can obviously improve the air tightness of the composite material. Graphene Oxide (GO) is an important derivative of Graphene, also known as functionalized Graphene. Compared with graphene, the graphene has the advantages of losing certain electrothermal property, still having the characteristics of high specific surface area, high modulus, large aspect ratio, gas impermeability and the like, and having the structure which is basically the same as that of graphene, and only connecting functional groups, mainly oxygen-containing functional groups, such as hydroxyl, carboxyl, epoxy groups and the like, on two-dimensional surfaces, wherein the hydroxyl and epoxy functional groups are mainly positioned on the basal planes of graphite sheets, and the hydroxyl and partial carboxyl are positioned at the edges, so that some polar organic molecules and polymers can be easily compounded with graphene oxide, thereby preparing the nanocomposite. (Yangyangrou, Chengdongkuang, Wenyoufang, etc.. graphene oxide and its composite with polymer [ J ] novel carbon material, 2008,23(3):193-

Layered silicates such as montmorillonite (MMT), hectorite, sepiolite, etc., have a crystal lattice of a layered structure formed by one aluminum oxy (magnesium oxy) octahedron sandwiched between two silicon oxy tetrahedrons by sharing oxygen atoms, vary in length and width from 30nm to several micrometers, and are bonded by van der waals force between layers and form van der waals furrows (also called layer gaps). Since the aluminum 3-valent in the aluminooctahedron in the 2/1-type layered silicate partial unit cell is isomorphously replaced by magnesium 2-valent, the wafer is charged with electronegativity, and therefore cations are adsorbed on the surface of the sheet to compensate for the excess negative charge to maintain electroneutrality. The layered silicate/rubber nano composite material has excellent comprehensive physical property, gas barrier property, fatigue resistance and some functional properties.

However, how to introduce graphene oxide and phyllosilicate into a natural rubber matrix and realize uniform dispersion so as to obtain a composite material with strong interface bonding is a technical problem which needs to be solved. Meanwhile, natural rubber is used as nonpolar rubber and has poor compatibility with graphene oxide and phyllosilicate, so that the graphene oxide and the phyllosilicate are difficult to uniformly disperse among rubber molecular chains in a rubber matrix, a large amount of agglomeration of the graphene oxide and the phyllosilicate is caused, and the perfect mechanical property of the application is lost.

Disclosure of Invention

In order to solve the problems in the prior art, the invention aims to prepare a natural rubber composite material which can be applied to a space hot-air balloon membrane, and graphene oxide and/or layered silicate are introduced into a rubber matrix. In order to realize the uniform dispersion of the graphene oxide and the layered silicate in the rubber matrix, strong interface combination is formed. The method pretreats the graphene oxide and the layered silicate, aims to enhance the compatibility of the graphene oxide, the layered silicate and a rubber matrix, and enables the graphene oxide to react with an interfacial agent by virtue of a large amount of oxygen-containing functional groups on the surface of the graphene oxide, such as hydroxyl, epoxy, carboxyl and the like, so that the polarity of the graphene oxide is improved, and the compatibility with natural latex is enhanced; after the phyllosilicate is pretreated by the interfacial agent, the surface of the lamella is modified, the distance between crystal layers is increased, the affinity of the clay and macromolecules is increased, and the intercalation of polymer macromolecules into the lamella is facilitated.

One of the purposes of the invention is to provide a graphene oxide and/or phyllosilicate natural rubber composite material for a space balloon, which is prepared from the following raw materials in parts by weight:

100 parts of natural rubber;

0.1-10 parts of graphene oxide and/or layered silicate; preferably 3-9 parts;

0.1-6 parts of a stabilizer; preferably 3 to 5 parts.

Wherein, the graphene oxide and the layered silicate are pre-modified by the interface agent.

The solid content of the natural rubber is preferably 20-70%, and more preferably 40-60%.

Preferably, the number of the graphene oxide layers is 1-10, the thickness of each layer is 0.3-3 nm, and the transverse dimension is 1-4 microns.

Preferably, the phyllosilicate is selected from at least one of montmorillonite, clay, rectorite, mica, talc and kaolin.

Preferably, the stabilizer is selected from at least one of ammonia water, potassium hydroxide, hexadecyl benzene sulfonic acid, sodium hexadecyl benzene sulfonate and sodium dodecyl sulfate.

Preferably, the amount of the graphene oxide interface agent A is 1-100%, more preferably 3-15% of the amount of the graphene oxide, and the interface agent A is selected from a silane coupling agent, a quaternary ammonium salt, or an epoxidized natural rubber latex, more preferably an aminopropyltriethoxysilane coupling agent (KH550), a gamma- (methacryloyloxy) propyltrimethoxysilane coupling agent (KH570), an epoxidized natural rubber latex having an epoxy degree of 10-80%, and the like.

Preferably, the amount of the interface agent B of the layered silicate is 10-100%, more preferably 10-20% of the amount of the layered silicate, and the interface agent B is selected from substances capable of performing ion exchange with the layered silicate, more preferably quaternary ammonium salt or pyridine.

The composite material also comprises at least one of the following components in parts by weight based on 100 parts by weight of natural rubber:

0.5-1 part of an anti-aging agent;

2-4 parts of a vulcanization accelerator;

1-3 parts of a vulcanizing agent.

The anti-aging agent is selected from anti-aging agents commonly used in the field, and preferably at least one of anti-aging agent D, anti-aging agent RD, anti-aging agent 124 and anti-aging agent 4010 NA.

The vulcanization accelerator is selected from the vulcanization accelerators commonly used in the field, and is preferably N-cyclohexyl-2-benzothiazole sulfonamide (accelerator CZ), accelerator DPG, accelerator D and the like.

The vulcanizing agent is selected from vulcanizing agents commonly used in the field, and is preferably sulfur.

The invention also aims to provide a preparation method of the natural rubber composite material, which comprises the following steps:

(1) pre-modifying graphene oxide and/or layered silicate:

preparing graphite oxide slurry with the concentration of 1-10 per mill, adjusting the pH value to 6.8-8.1, ultrasonically preparing a graphene oxide dispersion liquid, adding an interfacial agent at the temperature of 60-80 ℃, stirring the mixed liquid of the graphene oxide dispersion liquid and the interfacial agent at the stirring speed of 80-120 r/min for 5-10 h, filtering, removing residues, and collecting the obtained modified graphene oxide dispersion liquid;

and/or preparing the phyllosilicate into water slurry with the concentration of 1-5%, adding an interfacial agent, and stirring for 40-60 min under the stirring action of the rotating speed of 50-120 r/min to form the phyllosilicate sheet layer nano water dispersion;

(2) preparing a natural rubber composite material:

adding a stabilizer into natural rubber, and stirring at room temperature for 10 min-2 h; adding the modified graphene oxide dispersion liquid and/or the layered silicate sheet nano water dispersion liquid obtained in the step (1), and continuously stirring for 10-40 min; and (3) adding other components after uniformly mixing, and continuously stirring for 1-2 h to obtain the composite material.

Preferably, in the step (1), the ultrasonic power for dispersing the graphene oxide is 750-1000W, more preferably 750-850W, the working interval is 1.5-2 s, and the total ultrasonic time is 60-80 min, more preferably 60-75 min.

Preferably, in the step (2), the stirring speed of adding the stabilizer is 50-120 r/min.

Specifically, the preparation method may include the steps of:

(1) preparing and pretreating graphene oxide:

adding deionized water into graphite oxide slurry with the concentration of 1-8% for dilution, wherein the diluted concentration is 1-10 per mill, and adjusting the pH to 6.8-8.1 for later use. Preparing graphene oxide dispersion liquid by ultrasonic waves in a cell crushing instrument according to the following conditions: the ultrasonic power for dispersing the graphene oxide is 750-1000W, the working interval is 1.5-2 s, the total ultrasonic time is 60-80 min, the preferred power is 750-850W, and the ultrasonic time is 60-75 min; the number of the prepared graphene oxide layers is preferably 1-10, the thickness of each layer is 0.3-3 nm, and the transverse dimension is preferably 1-4 mu m. Adding an interfacial agent at the temperature of 60-80 ℃, stirring at a low speed of 80-120 r/min by adopting traditional mechanical stirring, and pretreating the mixed solution of the graphene oxide dispersion liquid and the interfacial agent for 5-10 h. And filtering the mixed solution after stirring, removing residues remained in the solution, and collecting the obtained modified graphene oxide dispersion liquid.

And/or pretreatment of the layered silicate: the method comprises the steps of modifying a phyllosilicate mineral by using quaternary ammonium salt at the concentration of 1-5%, stirring for 40-60 min under the stirring action of 50-120 r/min by utilizing the strong hydration action of interlayer cations (such as sodium ions and calcium ions), so that the mineral self-existing lamellar structure is dissociated and dispersed in water in a nano level manner to form the phyllosilicate lamellar nano water dispersion.

(2) Taking natural latex with the solid content of 20-70 percent, wherein the content of other components such as protein and the like is not more than 5 percent, adding a proper amount of stabilizer, and stirring for 10-2 hours at the room temperature of 20-25 ℃ at the conventional stirring speed of 50-120 r/min; subsequently, the modified graphene oxide dispersion liquid and/or the modified phyllosilicate sheet nano-water dispersion liquid prepared in the step (1) are added into natural latex, and the stirring is continuously carried out

10min to 40 min; and (3) after uniformly mixing, sequentially adding an anti-aging agent, a vulcanization accelerator and a vulcanizing agent, and continuously stirring for 1-2 hours to obtain the composite material.

And then, dipping the space balloon mold in the prepared composite material, and then demolding, washing the balloon, inflating and shaping → vulcanizing → obtaining the space balloon.

The invention mainly provides a technology of improved natural latex for preparing a space balloon membrane. The graphene oxide and/or the layered silicate are pretreated by the interfacial agent, so that the polarity of the graphene oxide and/or the layered silicate is reduced, good compatibility with natural latex is realized, and strong interface combination is realized. The mechanical property, the radiation aging resistance and the air tightness of the composite material are greatly improved by nano-compounding the natural latex and the graphene oxide and/or the layered silicate, and the composite material can be used as an advanced technology for improving a space balloon membrane.

The invention aims to prepare a graphene oxide and/or layered silicate natural latex composite material and apply the graphene oxide and/or layered silicate natural latex composite material to a space hot air balloon. The method utilizes the excellent mechanical properties of graphene oxide and phyllosilicate: the tensile property, the tear resistance, the air tightness and the ageing resistance of the composite material improve the mechanical property of the composite material. Because the graphene oxide and the phyllosilicate are both lamellar materials and have high specific surface area and large length-diameter ratio, the air tightness of the composite material can be obviously improved; and the free radicals generated by radiation are captured and quenched by the large specific surface area, the strong electron transfer capacity and the surface addition reaction of GO, so that the occurrence of radiation aging degradation and crosslinking reaction is weakened, the performance of the NR/GO composite material is not greatly reduced, the high mechanical property and the high thermal stability are still maintained, and the radiation resistance of the material is improved. Finally, the coating is applied to a spherical film of the space hot air balloon, so that the service life of the space hot air balloon is greatly prolonged, the cost is reduced, and the development of the space hot air balloon industry in China is accelerated.

Drawings

FIG. 1 is a schematic diagram of a process for making a space balloon.

Wherein, 1-graphite oxide or layered silicate water slurry; 2-graphene oxide or layered silicate water dispersion; 3-modified graphene oxide or layered silicate water dispersion; 4-graphene oxide and/or layered silicate natural rubber composite; 5-graphite oxide or layered silicate; 6-graphene oxide or layered silicate with single or few layers; 7-an interfacial agent; 8-natural rubber.

Firstly, water slurry (1) of graphite oxide or layered silicate (5) is subjected to ultrasonic treatment or stirring treatment to obtain graphene oxide or layered silicate (6) water dispersion (2) existing in a single-sheet layer or a few-sheet layer, and then an interfacial agent (7) is adopted to pre-modify the graphene oxide or layered silicate water dispersion, so that the polarity of the graphene oxide or layered silicate water dispersion is reduced to a great extent, and the compatibility with a natural latex matrix is improved; and then mechanically stirring and mixing the mixture with natural rubber (8) emulsion, adding an anti-aging agent, an accelerator, a vulcanizing agent and the like to prepare a composite material which can be applied to a space fire balloon membrane, and finally obtaining a balloon finished product through processing technologies such as ball mould gum dipping, demoulding and ball washing, inflation and shaping, vulcanization treatment and the like.

Detailed Description

For a better understanding of the present invention, the present invention is further illustrated below with reference to specific examples in which an aqueous slurry of graphite oxide is purchased from Hexith elements of Heizhou, having a 60% solids natural rubber latex, manufactured by Hainan Natural rubber, Inc., and all other raw materials are commercially available.