CN108624059A - A method of improving methyl vinyl silicone rubber thermal stability - Google Patents

Abstract

The present invention provides a kind of methods improving methyl vinyl silicone rubber thermal stability, the methyl vinyl silicone rubber of 100 mass parts are added in ethyl acetate first, heating water bath simultaneously continues stirring to obtain raw rubber solution；Then the silicon-carbon composite nano tube for weighing 4~6 mass parts is placed in ethyl acetate solution, obtains uniform dispersion liquid；Then mixed liquor is added in raw rubber solution, stirred evenly and be evaporated while stirring, SNTs@CNTs/ raw-silastic continuouslies are obtained after vacuum drying；Then by 100 mass parts raw rubbers in the double roller of 45~50 DEG C of temperature, mixing makes its uniform roll banding；Then 2,5 dimethyl, 2,5 di-t-butyl hexane peroxide of 0.6~1 mass parts is added, continues 10~12min of mixing, is kneaded and uniformly obtains rubber compound；Finally rubber compound is fitted into mold, hot pressing 11~12min sulfidization moldings.The mechanical property after the thermo-oxidative ageing of silicon rubber and the incipient degradation temperature under air is greatly improved in silicon-carbon composite nano tube of the present invention, improves the thermo-oxidative stability of silicon rubber.

Description

A method of improving methyl vinyl silicone rubber thermal stability

Technical field

The invention belongs to field of rubber materials, more particularly, are related to a kind of raising methyl vinyl silicone rubber heat The method of stability.

Background technology

Silicon rubber (SR) raw rubber, i.e. linear polysiloxane are with Si-O alternately for main chain, and side group is the line style of organic group Half inorganic polymer can become rubber-like elastic body by crosslinking.SR has many excellent performances, and such as heat resistance resists cold Property, weatherability etc., are widely used in the national economy such as aerospace, defence and military, electric field.As China's aviation is navigated The continuous development of it and national defense and military, the requirement for material is higher and higher, is applied to extreme condition especially for some The demand of the high performance material with certain function is growing under (such as high and low temperature, strong irradiation etc.).In order to make silicon rubber It remains to use for a long time under the high temperature conditions, and keeps good mechanical property, improve silicon rubber thermal stability (such as thermo-oxidative ageing Front and back mechanical property) research carry out extensively.Currently, the approach for improving silicon rubber thermal stability, which mainly has, changes main chain and side group Structure, eliminate the influence of silicone hydroxyl in terminal hydroxy group and filler and heat-resisting additive be added etc..Wherein, heat-resisting additive is added Mode effectively, it is easy, obtained wider application.

With the fast development of nanosecond science and technology, silicon rubber is modified using nano material, has made the multinomial property of silicon rubber Breakthrough can be obtained.Carbon nanotube (Carbon nanotubes, CNTs) has big draw ratio, unique quantum ruler Very little effect, small-size effect, skin effect, macroscopical tunnel-effect and excellent heat conductivility and thermal stability.With carbon nanometer Pipe, which is heat-resisting additive, improves silicon rubber heat-resisting, has certain feasibility.In recent years, in relation to CNTs and silicon rubber composite wood In terms of the research of material is concentrated mainly on mechanics, photoelectricity and heat conduction, and it is more rare for the research of thermal stability.

Invention content

The technical purpose of the present invention is to overcome the deficiencies of the prior art and provide a kind of raising methyl vinyl silicone rubber heat The method of stability.Thermal stability before and after thermo-oxidative ageing in order to improve SR, the present invention is first by nano-tube (silica Nanotubes, abbreviation SNTs) surfaces CNTs are coated to, it is then that it is compound with SR progress, improve heat before and after the thermo-oxidative ageing of SR Stability.

The technical purpose of the present invention is achieved by following technical proposals：

A method of methyl vinyl silicone rubber thermal stability being improved, steps are as follows：

Step 1, the raw-silastic continuously of 100 mass parts is added in ethyl acetate, 65~70 DEG C of heating water baths simultaneously continue Stirring to obtain raw rubber solution；

Step 2, the silicon-carbon composite nano tube (SNTs@CNTs) for weighing 4~6 mass parts is placed in ethyl acetate solution, is surpassed Sonication obtains uniform dispersion liquid；Then mixed liquor is added in raw rubber solution made from step 1, is stirred evenly and 93 It is evaporated while stirring at~96 DEG C, SNTs CNTs/ raw-silastic continuouslies is obtained after being then dried in vacuo；

Step 3, by raw rubber made from 100 mass parts steps 3 in the double roller of 45~50 DEG C of temperature, it is kneaded 2~5min, is made Its uniform roll banding；Then 2,5- dimethyl -2,5- di-t-butyl hexane peroxides of 0.6~1 mass parts are added, continue mixing 10 ~12min is kneaded and uniformly obtains rubber compound；

Step 4, rubber compound prepared by step 3 is fitted into mold, temperature is 180 ± 1 DEG C, the condition of 9~12MPa of pressure Lower hot pressing 11~12min sulfidization moldings obtain sulfide film after cooling；

Silica is arranged on the outer wall of carbon nanotube using carbon nanotube as inner tube in the silicon-carbon composite nano tube Layer, to form Silica Nanotube on the outside of carbon nanotube；In the structure of silicon-carbon composite nano tube, carbon nanotube and dioxy SiClx nanotube forms coaxial sleeve structure, and inner tube is carbon nanotube, and outer tube is Silica Nanotube；

The preparation method of the silicon-carbon composite nano tube is, simultaneously by the evenly dispersed formation suspension of carboxylic carbon nano-tube It is alkalinity to adjust pH value, then ethyl orthosilicate is added in the suspension of carboxylic carbon nano-tube, be sufficiently mixed and is uniformly divided It dissipates；Solid matter is detached, 550~650 DEG C is heated to from room temperature in an inert atmosphere and is heat-treated, then cooled to room temperature .

In the step 1, the raw-silastic continuously is methyl vinyl silicone rubber.

In the step 2, carboxylic carbon nano-tube is dispersed in absolute ethyl alcohol and forms suspension, uses ammonium hydroxide It is 8~10 to adjust pH value, specifically, weighs carboxylic carbon nano-tube (CNTs-COOH) and is put into beaker, anhydrous second is added Alcohol, stirring keep CNTs dispersions abundant.Dispersion liquid is put into ultrasonic cell disrupte machine, ice-bath ultrasonic process 1h, power 500W, work It is 3s, intermittent time 2s to make the time, weighs ammonium hydroxide, is added rapidly to adjust pH value in suspension obtained above to be alkalinity 8 ~10, strong stirring 0.5h obtain the suspension of carboxylic carbon nano-tube.

In the step 2, ethyl orthosilicate (TEOS) is dispersed in absolute ethyl alcohol, is forming stable homogeneous just Ethyl silicate solution, then teos solution is added in the suspension of carboxylic carbon nano-tube, specifically, weigh just Silester (TEOS), is put into the absolute ethyl alcohol of 300ml, and stirring fully obtains the solution of stable homogeneous.Solution is quickly added Enter in suspension, strong stirring 2h obtains mixed liquor, this mixed liquor is put into ultrasonic cell disrupte machine again, ice-bath ultrasonic process 30min (power 500W, working time 3s, intermittent time 2s) takes out after the completion of processing, and sealing and standing is for 24 hours.

In the step 2, inert atmosphere is nitrogen, helium or argon gas；From 20~25 DEG C of room temperature with 5~10 DEG C/min Speed is warming up to 550~650 DEG C and is heat-treated at least 2 hours, and preferably 600~650 DEG C are heat-treated 2~5 hours, specific next It says, is filtered after standing, filter product and be placed in vacuum drying oven, dried at 60~80 DEG C, after dry, with mortar by solid Sample grinds to obtain powder, and powder is placed in Muffle furnace and is heat-treated.

It is as shown in Fig. 1, bonded using carboxyl and the ethyl orthosilicate realization of carbon nano tube surface in the step 2, It heats up and is heat-treated again, so that ethyl orthosilicate is in carbon nano tube surface in-situ preparation silica.Pass through carbon nanotube table The carboxyl-content in face, the dosage of ethyl orthosilicate adjust the appearance structure of silicon-carbon composite nano tube, i.e., to silicone tube thickness, silicone tube Continuity degree etc. is regulated and controled；If carboxylic carbon nano-tube usage amount is 1 parts by weight (i.e. each parts by weight are 1g), positive silicic acid second Ester usage amount is respectively 2.5 parts by weight, 5 parts by weight and 7.5 parts by weight, and silicone tube thickness is 5~15nm；And in carbon nanotube outer wall Form the preferable silicone tube of continuity degree (sectional silicone tube, the content because of carbon nano tube surface carboxyl and distribution).

In the step 3, vacuum drying condition is that 48~49h is dried in vacuo at 61~62 DEG C.

In the step 3,0.7~0.9 parts by weight 2,5- dimethyl -2,5- di-t-butyl hexane peroxides are preferably taken.

In the step 4, die size is 140 × 140 × 2mm³, preferably in 180 ± 1 DEG C of temperature, pressure 10MPa Under the conditions of hot pressing 11min sulfidization moldings.

Beneficial effects of the present invention：

Thermo-oxidative ageing post-tensioning intensity is carried out using nano-tube enveloped carbon nanometer tube modified silicon rubber prepared by the present invention Thermogravimetic analysis (TGA) under test and air.The mechanical property of blank sample can not test after thermo-oxidative ageing, and CNTs-COOH/SR Composite material keeps certain tensile strength, and two kinds of SNTs@CNTs/SR composite material aging post-tensioning intensity still keep good It is good, it is above CNTs-COOH/SR composite materials.In addition, compared to blank sample, CNTs-COOH/SR composite materials initially drop It solves temperature and promotes 25 DEG C, and to be above CNTs-COOH/SR compound for the incipient degradation temperature of two kinds of SNTs@CNTs/SR composite materials Material.Therefore, the mechanical property after the thermo-oxidative ageing of silicon rubber and the initial drop under air is greatly improved in SNTs@CNTs Temperature is solved, the thermo-oxidative stability of silicon rubber is improved.

Description of the drawings

Fig. 1 is the structure of silicon-carbon composite nano tube of the present invention and prepares schematic diagram.

Fig. 2 is infrared spectrum (FTIR spectrums) figure of several substances in the present invention, wherein (a) is CNTs, CNTs-COOH；(b) For CNTs, SNTs and SNTs@CNTs.

Fig. 3 is X-ray diffraction spectrum (XRD) figure of several substances in the present invention, wherein (a) is CNTs, it is (b) SNTs, (c) For SNTs-1@CNTs, it is (d) SNTs-2@CNTs, is (e) SNTs-3@CNTs.

Fig. 4 is transmission electron microscope (TEM) figure (1) of silicon-carbon composite nano tube of the present invention.

Fig. 5 is the TEM figures (2) of silicon-carbon composite nano tube of the present invention, wherein (a) is CNTs, it is (b) SNTs-1@CNTs, (c) it is SNTs-2@CNTs, is (d) SNTs-3@CNTs.

Fig. 6 is the EDS energy spectrum analysis figures of SNTs@CNTs in the present invention, wherein (a) is SNTs-1@CNTs, it is (b) SNTs- 2@CNTs (c) are SNTs-3@CNTs.

Fig. 7 is the transmission electron microscope photo of SNTs in the present invention, wherein (a) is SNTs-1, is (b) SNTs-2, is (c) SNTs-3。

Fig. 8 is the thermogravimetric curve of several substances in the present invention, and (a) is that thermal weight loss is bent under CNTs, CNTs-COOH argon gas Line (b) is thermogravimetric curve under CNTs, SNTs and SNTs@CNTs air.

Fig. 9 is the Fracture scan figure of the composite material of several substances and silicon rubber in the present invention, wherein (a) is CNTs/SR, (b) it is SNTs-1@CNTs/SR, is (c) SNTs-2@CNTs/SR, be (d) SNTs-3@CNTs/SR, is (e) SNTs/SR.

Figure 10 is the thermogravimetric curve of silicon rubber composite material under air.

Specific implementation mode

The present invention is further detailed with reference to embodiment and attached drawing.

The material essential information used is as shown in the table：

Key instrument and equipment are as shown in the table：

Title	Model	Manufacturer
			Electronic balance	AL104	Plum Teller-support benefit Instrument Ltd.
Ultrasonic cell disruptor	JY92-IIN	Xin Zhi bio tech ltd, Ningbo
			Multiplex vavuum pump of circulating water type	SHB-III	Zhengzhou Greatwall Scientific Industrial ＆ Trading Co., Ltd.
Electric vacunm drying case	DZG-401B	Tianjin sky laboratory apparatus Co., Ltd
			Electric drying oven with forced convection	DGG-101-0B	Tianjin sky laboratory apparatus Co., Ltd
Double roll mill	SR-160B	Zhanjiang machinery plant
			High temperature hydraulic forming machine	YJ450	Yuyao Hua Cheng hydraulic pressure electromechanics Co., Ltd
Punching testing machine	CP-25	Shanghai rubber machinery plant
			Fourier Transform Infrared Spectrometer	NICOLET 560	NICOLET companies of the U.S.
Thermogravimetric analyzer	STA449F3	Netzsch
			Universal tensile testing machine	M350-20KN	Testometric

By the way of collosol and gel, make nano-tube (SNTs) with the CNTs (CNTs-COOH) after acidification for mould Plate grows up on its surface.

First, acidification is carried out to original CNTs.2.0g graphitized carbon nano pipes are weighed to be placed in there-necked flask.It weighs The 180ml concentrated sulfuric acids and 60ml concentrated nitric acids are placed in graduated cylinder, and the concentrated sulfuric acid is added in there-necked flask first, are opened and are stirred, heating water bath, Heating temperature is set as 60 DEG C.After to be heated to 60 DEG C, concentrated nitric acid is added in there-necked flask, makes system in sealed condensating reflux condition 4h is reacted under part.After reaction, all drugs in there-necked flask are poured into the large beaker for having filled appropriate distilled water, it is heavy to stand Drop.It waits for that upper layer spent acid is poured out recycling after particle precipitation, then the carbon after appropriate distilled water washing acidification is added into beaker Nanotube continues standing sedimentation, then so cycle is filtered, is first washed with distilled water up to the close neutrality of supernatant liquor, It is washed with ethanol in proper amount when pH is close to 7.Filtered product is placed in baking oven and is dried for 24 hours.Product after drying is placed in It grinds in mortar, until being in powdered, product is preserved mounted in labeling in sample sack.

Then, SNTs is coated to by the surfaces CNTs by sol-gal process.Specifically, first, weigh CNTs-COOH powder End, ultrasonic disperse obtain the uniform suspension of CNTs-COOH in ethanol solution；Second, ammonium hydroxide is weighed, is added rapidly to above-mentioned In suspension obtained, strong stirring 0.5h, it is 10 to obtain the mixed liquor of stable homogeneous and adjust pH；Third weighs 2.5 respectively Again, the TEOS of 5 times, 7.5 times CNTs-COOH mass is put into ethanol solution and is uniformly mixed；4th, third is walked into acquired solution It is added in mixing suspension obtained by second step, strong stirring 2h obtains the evenly dispersed suspension of SNTs claddings CNTs；5th, it will SNTs@CNTs suspensions settle 2 days at room temperature, filter, ultrasonic disperse；6th, repeat filter and ultrasound 3-4 times, will most Gained suspension filters eventually, and is dried at 60 DEG C；7th, the product after drying is heat-treated under 600 DEG C of nitrogen atmosphere 5h obtains three kinds of SNTs@CNTs powder.Three kinds of SNTs@CNTs powder of gained are respectively designated as the dosage of TEOS from less to more SNTs-1@CNTs, SNTs-2@CNTs and SNTs-3@CNTs.

Simultaneously by SNTs-1@CNTs, SNTs-2@CNTs and SNTs-3@CNTs powder in air atmosphere at 600 DEG C at heat Corresponding SNTs powder is made in reason 5h.

As shown in Fig. 2, (a) is the FTIR spectrograms of CNTs and CNTs-COOH.Hydroxyl, carboxyl and carbon nanotube absorb Water O-H keys stretching vibration characteristic peak, correspond in CNTs and CNTs-COOH infrared lines, in 3407cm^-1With 1643cm^-1Locate the larger absorption peak of intensity；1565cm^-1The absorption peak at place belongs to the vibration peak of the C=C keys of carbon material, and This peak is considered as the property and concentration for being strongly depend on oxide on surface.It can be seen that original carbon pipe is in 1565cm^-1Place Peak is not occurred, and there is apparent new peak in the position in the carbon pipe after being acidified.In addition, acidification carbon pipe is in 1713cm^-1Wavelength Place shows that a weaker absorption peak, this peak correspond to the C=O vibration peaks of carboxyl functional group, and intensity is by the surfaces CNTs The carboxyl functional group concentration connect influences very big.It is acidified carbon pipe C=C stretching vibration peaks (1565cm^-1) and C=O stretching vibration peaks (1713cm^-1) enhancing, this can be attributed to the effect of oxygen-containing group (- COOH ,-OH etc.).This result confirms that acidification carbon is received The surface of mitron produces oxygen-containing functional group, this is conducive to generations of the subsequent SNTs on the surfaces CNTs.(b) it is CNTs, SNTs With the infrared spectrogram of SNTs@CNTs.In SNTs spectrograms, 1109cm^-1, 798cm^-1And 476cm^-1The absorption peak at place is SNTs Upper Si-O-Si keys stretching vibration peak；1627cm^-1, 957cm^-1And 3460cm^-1Nearby width absorption peak represents silicone hydroxyl and silicon is received The stretching vibration characteristic peak of the O-H keys for the water that mitron absorbs.On the infrared spectrum of SNTs@CNTs, it not only observed and come from The distinctive absorption peaks of SNTs, also in 1380-1410cm^-1Occurs a new characteristic peak in range, this peak is in original CNTs With do not occur on SNTs, it is considered to be covalently bound on CNTs and be formed by as SNTs -- caused by Si-O-C- key chatterings. In addition, the absorption peak and-OH structures of SNTs-1@CNTs, SNTs-2@CNTs and SNTs-3@CNTs at-Si-O-Si- structures Stretching vibration peak intensity is incremented by successively.This may be due in SNTs-1@CNTs, SNTs-2@CNTs and SNTs-3@CNTs SNTs contents gradually increase.According to infrared spectrum comparative analysis, it can further assert that SNTs is successfully coated to CNTs tables Face, and the covering amount different from of three kinds of SNTs@CNTs.

Such as the XRD spectra that attached drawing 3 is CNTs, SNTs and SNTs@CNTs.In CNTs spectrograms, two characteristic peaks go out respectively At present 2 θ=26 ° and 43 °, it is belonging respectively to the diffraction maximum of carbon nanotube (002) and (100) face.Amorphous state is presented in SNTs, In SNTs spectrograms, there is no apparent characteristic crystalline peaks to occur, and only shows as occurring one in 15 ° to 30 ° diffraction angular regions A wide and weak amorphous peak, the diffraction maximum of SNTs is consistent with document description in figure.And the XRD spectra of SNTs@CNTs, it is in simultaneously Show and has come from CNTs and SNTs characteristic peaks.It is worth noting that, the wide and weak amorphous diffraction maximum of SNTs is brilliant with CNTs (002) The diffraction overlap of peaks in face, and the peak blurring on each crystal faces of CNTs, become wide and weak.By taking SNTs-2@CNTs as an example, spectral line On show at 2 θ=43 ° diffraction maximum broaden and die down.In one wide and strong diffraction maximum of appearance of 15-30 ° of range, wherein Nearby there are one the diffraction maximums of the crystal face of CNTs outstanding (100) for 2 θ=26 °, and this diffraction maximum does not have compared to original CNTs It is so clear.In addition, the intensity of amorphous diffraction maximum is gradual in SNTs-1@CNTs, SNTs-2@CNTs and SNTs-3@CNTs Enhancing, each crystallographic plane diffraction peaks of CNTs gradually weaken.This may be due to SNTs-1@CNTs, SNTs-2@CNTs and SNTs-3@ SNTs contents in CNTs gradually increase.

TEM figures as shown in drawings, the surfaces CNTs being not decorated are smooth；And the surfaces SNTs@CNTs after coating become Coarse and particle diameter becomes larger.Energy spectrum analysis has been carried out to SNTs@CNTs series particles.It can be found that three's by EDS pictures Common feature is that observed C, O, Si and Cu element.Wherein Cu elements are interference elements caused by back end copper mesh, and are received Rice corpuscles itself is unrelated.As it can be seen that SNTs has been coated on CNTs really.The different characteristic of three is tri- kinds of elements of C, O, Si Different degrees of variation has occurred in peak intensity.In SNTs-1@CNTs, SNTs-2@CNTs and SNTs-3@tri- kinds of particles of CNTs, Si, O elements are gradually increased relative to the intensity at C element peak, show that SNTs covering amounts are continuously increased.In order to further analyze SNTs packets SNTs-1@CNTs, SNTs-2@CNTs and SNTs-3@CNTs are carried out heat under air atmosphere by the specific pattern of coating respectively in experiment Processing obtains the TEM image of corresponding SNTs particles, as shown in figure 5, SNTs-1@CNTs, SNTs-2@CNTs and SNTs-3@CNTs The pipe thickness of the SNTs clads of particle is continuously increased, respectively 4~5nm, 8~10nm and 13~15nm.

Thermogravimetric curve figure as shown in drawings, (a) are thermal weight loss of the front and back CNTs particles of acidification under ar gas environment Curve.100 DEG C to 500 DEG C of CNTs particle thermal weight losses are typically that the thermal decomposition of the oxygen-containing functional groups such as carbon pipe surface carboxyl causes 's.In other words, particle directly reflects CNTs acidification success or not and its surface carboxyl groups in 100 DEG C to 500 DEG C of thermal weight loss How much is content.Fig. 8 (a) curves show that minimum quality thermal degradation only has occurred in original CNTs, and residual qualities are up to 97.8%, And CNTs thermal degradations quality greatly improves after acidification, residual qualities drop to 91.9%.As it can be seen that CNTs is successfully acidified, And the oxygen-containing functional groups such as surface carboxyl groups content 5.9%.Fig. 8 (b) is thermal weight loss under CNTs, SNTs and three kinds of SNTs@CNTs air Curve.As seen from the figure, SNTs does not have that weightlessness, CNTs, SNTs-1@CNTs, SNTs-2@CNTs, SNTs-3@occurs substantially Different degrees of thermal weight loss has occurred in CNTs successives, and CNTs there is no residual qualities (mf), almost all degradation.It is based on In thermal weight loss test temperature section, nano-tube quality keeps stablizing, and carbon nanotube is almost thoroughly weightless, therefore, we Think in thermal weight loss is tested, the difference of the residual qualities between SNTs CNTs and CNTs is the quality hundred of coated nano-tube Divide ratio.

Significant data in air atmosphere on CNTs, SNTs and SNTs@CNTs thermogravimetric curves

Upper table is the significant data on CNTs, SNTs and SNTs@CNTs thermogravimetric curves in air atmosphere.In TG curves In, incipient degradation temperature (Ti indicates thermal degradation temperature corresponding when particle thermal weight loss mass fraction is 5%) is to weigh material One important indicator of thermal stability.By table as it can be seen that the cladding of nano-tube particle, is greatly improved the heat of carbon nanotube Oxidative stability energy, and be continuously improved with the increase Ti of nano-tube covering amount, SNTs-2 is increased to by SNTs-1 in covering amount When, Ti increases by 33.71 DEG C, and increasing degree is maximum.By mf it can be calculated that being coated in carbon nanotube in SNTs@CNTs Nano-tube content be respectively：42.47wt% (SNTs-1@CNTs), 53.11wt% (SNTs-2@CNTs) and 69.74wt% (SNTs-3@CNTs)。

Fig. 9 is Fracture scan (SEM) photo of silicon rubber composite material, and (a) is the SEM photograph of CNTs/SR composite materials, There is agglomeration in fracture surface；(b-d) it is respectively SNTs-1@CNTs/SR, SNTs-2@CNTs/SR and SNTs-3@CNTs/ There is not agglomeration, favorable dispersibility in the SEM photograph of SR composite materials, SNTs@CNTs nano-particles.As it can be seen that SNTs packets After covering, the dispersibilities of CNTs in the composite improve.

Embodiment 1

Step 1：The accurate raw-silastic continuously for weighing 100 parts by weight, is added in appropriate ethyl acetate, 65 DEG C of heating water baths And continue stirring to obtain raw rubber solution.

Step 2：It weighs 4 parts by weight SNTs-1@CNTs nano-particles to be placed in ethyl acetate solution, is ultrasonically treated and obtains Even dispersion liquid.It is added in raw rubber solution made from step 1, stirs evenly, 93 DEG C are evaporated while stirring, 61 DEG C of vacuum drying 48h removes solvent, obtains SNTs-1@CNTs/ raw-silastic continuouslies.

Step 3：By raw rubber made from 100 parts by weight steps 2 in the double roller of temperature 45 C, it is kneaded 5min, makes it uniformly Roll banding.

Step 4：2,5- dimethyl -2,5- di-t-butyl hexane peroxides of 0.6 parts by weight are added, continue to be kneaded 11min, It is kneaded and uniformly obtains rubber compound.

Step 5：Rubber compound prepared by step 4 is fitted into mold, temperature is 180 ± 1 DEG C, heat under conditions of pressure 9MPa 11min sulfidization moldings are pressed, sulfide film is obtained after cooling；

Embodiment 2

Step 1：The accurate raw-silastic continuously for weighing 100 parts by weight, is added in appropriate ethyl acetate, 66 DEG C of heating water baths And continue stirring to obtain raw rubber solution.

Step 2：It weighs 5 parts by weight SNTs-2@CNTs nano-particles to be placed in ethyl acetate solution, is ultrasonically treated and obtains Even dispersion liquid.It is added in raw rubber solution made from step 1, stirs evenly, 94 DEG C are evaporated while stirring, 60 DEG C of vacuum drying 49h removes solvent, obtains SNTs-2@CNTs/ raw-silastic continuouslies.

Step 3：By raw rubber made from 100 parts by weight steps 2 in the double roller of 46 DEG C of temperature, it is kneaded 4min, makes it uniformly Roll banding.

Step 4：2,5- dimethyl -2,5- di-t-butyl hexane peroxides of 0.7 parts by weight are added, continue to be kneaded 12min, It is kneaded and uniformly obtains rubber compound.

Step 5：Rubber compound prepared by step 4 is fitted into mold, temperature is 180 ± 1 DEG C, under conditions of pressure 10MPa Hot pressing 12min sulfidization moldings obtain sulfide film after cooling；

Embodiment 3

Step 1：The accurate raw-silastic continuously for weighing 100 parts by weight, is added in appropriate ethyl acetate, 67 DEG C of heating water baths And continue stirring to obtain raw rubber solution.

Step 2：It weighs 6 mass parts SNTs-3@CNTs nano-particles to be placed in ethyl acetate solution, is ultrasonically treated and obtains Even dispersion liquid.It is added in raw rubber solution made from step 1, stirs evenly, 95 DEG C are evaporated while stirring, 61 DEG C of vacuum drying 48h removes solvent, obtains SNTs@CNTs-3/ raw-silastic continuouslies.

Step 3：By raw rubber made from 100 parts by weight steps 2 in the double roller of 47 DEG C of temperature, it is kneaded 3min, makes it uniformly Roll banding.

Step 4：2,5- dimethyl -2,5- di-t-butyl hexane peroxides of 0.8 mass parts are added, continue to be kneaded 10min, It is kneaded and uniformly obtains rubber compound.

Step 5：Rubber compound prepared by step 4 is fitted into mold, temperature is 180 ± 1 DEG C, under conditions of pressure 11MPa Hot pressing 11min sulfidization moldings obtain sulfide film after cooling；

Embodiment 4

Step 1：The accurate raw-silastic continuously for weighing 100 parts by weight, is added in appropriate ethyl acetate, 68 DEG C of heating water baths And continue stirring to obtain raw rubber solution.

Step 2：It weighs 4 mass parts SNTs-3@CNTs nano-particles to be placed in ethyl acetate solution, is ultrasonically treated and obtains Even dispersion liquid.It is added in raw rubber solution made from step 1, stirs evenly, be evaporated while stirring at 96 DEG C, 60 DEG C of vacuum are dry Dry 49h removes solvent, obtains SNTs@CNTs/ raw-silastic continuouslies.

Step 3：By raw rubber made from 100 parts by weight steps 2 in the double roller of 48 DEG C of temperature, it is kneaded 2min, makes it uniformly Roll banding.

Step 4：2,5- dimethyl -2,5- di-t-butyl hexane peroxides of 0.9 mass parts are added, continue to be kneaded 11min, It is kneaded and uniformly obtains rubber compound.

Step 5：Rubber compound prepared by step 4 is fitted into mold, temperature is 180 ± 1 DEG C, under conditions of pressure 12MPa Hot pressing 12min sulfidization moldings obtain sulfide film after cooling.

Embodiment 5

Step 1：The accurate raw-silastic continuously for weighing 100 parts by weight, is added in appropriate ethyl acetate, 69 DEG C of heating water baths And continue stirring to obtain raw rubber solution.

Step 2：It weighs 5 mass parts SNTs-1@CNTs nano-particles to be placed in ethyl acetate solution, is ultrasonically treated and obtains Even dispersion liquid.It is added in raw rubber solution made from step 1, stirs evenly, be evaporated while stirring at 93 DEG C, 61 DEG C of vacuum are dry Dry 48h removes solvent, obtains SNTs@CNTs/ raw-silastic continuouslies.

Step 3：By raw rubber made from 100 parts by weight steps 2 in the double roller of 49 DEG C of temperature, it is kneaded 5min, makes it uniformly Roll banding.

Step 4：2,5- dimethyl -2,5- di-t-butyl hexane peroxides of 0.7 mass parts are added, continue to be kneaded 11min, It is kneaded and uniformly obtains rubber compound.

Step 5：Rubber compound prepared by step 4 is fitted into mold, temperature is 180 ± 1 DEG C, under conditions of pressure 10MPa Hot pressing 11min sulfidization moldings obtain sulfide film after cooling.

Simultaneously using blank sample is made, each parts by weight are 1g

Step 1：The accurate raw-silastic continuously for weighing 100 parts by weight, is added in appropriate ethyl acetate, 70 DEG C of heating water baths And continue stirring to obtain raw rubber solution.

Step 2：It in raw rubber solution made from step 1, stirs evenly, is evaporated while stirring at 95 DEG C, 60 DEG C of vacuum drying 49h removes solvent, obtains raw-silastic continuously.

Step 3：Raw rubber made from 100 parts by weight steps 2 is mixed in the double roller of temperature 45 C, 5min is kneaded, makes it 2,5- dimethyl -2,5- di-t-butyl hexane peroxides of 0.6 parts by weight are added in even roll banding, continue to be kneaded 10min, are kneaded equal Even acquisition rubber compound.

Step 4：Rubber compound prepared by step 3 is fitted into mold, temperature is 180 ± 1 DEG C, under conditions of pressure 11MPa Hot pressing 12min sulfidization moldings obtain sulfide film after cooling；

According to the formula of embodiment 2, by SNTs-2@CNTs replace with respectively carboxylic carbon nano-tube (CNTs-COOH) and It is standby that three kinds of SNTs@CNTs carry out rubber system.

Sample is subjected to thermal weight loss test, test results are shown in figure 3 for composite material thermal weight loss.The incipient degradation of blank sample Temperature (Ti) is 364 DEG C, and the Ti of CNTs-COOH/SR composite materials is 389 DEG C, improves 25 DEG C；And SNTs@CNTs nanoparticles The addition of son, further improves the incipient degradation temperature of silicon rubber, the incipient degradation temperature of SNTs-2@CNTs/SR composite materials Degree is 405 DEG C, exceeds 41 DEG C of blank sample.Therefore, nano-tube enveloped carbon nanometer tube improves the first of silicon rubber composite material Beginning degradation temperature improves its thermal stability.

Using punching experimental machine, print (after aging) cutting makes it be similar to dumbbell shaped (with reference to GB/T 528-2009).It is trying Two parallel lines easy to identify for not influencing sample physical property are spread in the narrow parallel place of sample, painting, and line and center it is equidistant (25.0 ± 0.5mm).According to GB/T528-2009 and GB/T529-2008 requirements, surveyed with TestometricM350-20KN electronic tensile machines Try the mechanical property of vulcanizate.Sample is placed in the center of clamper, is machined, with the speed tensile batten of 500mm/min And the label of pointers track sample working portion is stretched by surveying.Load data value when each sample is pulled apart is recorded, and is sought average Value.Aging condition is 300 degrees Celsius, under air conditions, aging 12h.According to the formula of embodiment 2, SNTs-2@CNTs are distinguished Replace with carboxylic carbon nano-tube (CNTs-COOH).

Mechanical property after silicon rubber based composites thermo-oxidative ageing

Title	Tensile strength (MPa)	Elongation at break (%)
			Blank	0	0
CNTs-COOH/SR	0.22±0.011	133.22±11.23
			Embodiment 1	0.30±0.013	156.74±10.58
Embodiment 2	0.43±0.017	152.96±9.64
			Embodiment 3	0.45±0.014	153.96±7.64
Embodiment 4	0.42±0.012	153.66±6.64
			Embodiment 5	0.45±0.015	154.86±6.84

After sample burin-in process, blank sample does not have mechanical strength, and CNTs-COOH/SR and SNTs@CNTs/SR are multiple The tensile strength of condensation material still keeps good.The tensile strength of SNTs-2@CNTs/SR composite materials especially after aging, phase Compared with CNTs-COOH/SR, 75% is further improved.The extension at break of SNTs@CNTs/SR composite materials after thermo-oxidative ageing Rate keeps good, compared to CNTs-COOH/SR, improves 18% and 15% respectively, and rubber still has well after illustrating aging Elasticity.Therefore, nano-tube enveloped carbon nanometer tube improves the mechanical property after the thermo-oxidative ageing of silicon rubber composite material, i.e., Improve its thermal stability.

The adjustment of technological parameter is carried out according to the content of present invention can prepare nano-tube enveloped carbon nanometer tube modified silicon rubber Glue simultaneously has good thermal stability.Illustrative description is done to the present invention above, it should which explanation is not departing from this hair In the case of bright core, any simple deformation, modification or other skilled in the art can not spend creative labor Dynamic equivalent replacement each falls within protection scope of the present invention.

Claims (9)

1. a kind of method improving methyl vinyl silicone rubber thermal stability, it is characterised in that steps are as follows：

Step 1, the raw-silastic continuously of 100 mass parts is added in ethyl acetate, 65~70 DEG C of heating water baths simultaneously continue to stir Obtain raw rubber solution；

Step 2, the silicon-carbon composite nano tube for weighing 4~6 mass parts is placed in ethyl acetate solution, is ultrasonically treated and is obtained uniformly Dispersion liquid；Then mixed liquor is added in raw rubber solution made from step 1, stir evenly and at 93~96 DEG C while stirring It is evaporated, SNTs@CNTs/ raw-silastic continuouslies is obtained after being then dried in vacuo；

Step 3, by raw rubber made from 100 mass parts steps 3 in the double roller of 45~50 DEG C of temperature, it is kneaded 2~5min, makes it Even roll banding；Then be added 0.6~1 mass parts 2,5- dimethyl -2,5- di-t-butyl hexane peroxides, continue mixing 10~ 12min is kneaded and uniformly obtains rubber compound；

Step 4, rubber compound prepared by step 3 is fitted into mold, temperature is 180 ± 1 DEG C, heat under conditions of 9~12MPa of pressure 11~12min sulfidization moldings are pressed, sulfide film is obtained after cooling；

The raw-silastic continuously is methyl vinyl silicone rubber；

Silicon dioxide layer is arranged on the outer wall of carbon nanotube using carbon nanotube as inner tube in the silicon-carbon composite nano tube, with Silica Nanotube is formed on the outside of carbon nanotube；In the structure of silicon-carbon composite nano tube, carbon nanotube and silica Nanotube forms coaxial sleeve structure, and inner tube is carbon nanotube, and outer tube is Silica Nanotube；

The preparation method of the silicon-carbon composite nano tube is by the evenly dispersed formation suspension of carboxylic carbon nano-tube and to adjust PH value is alkalinity, then ethyl orthosilicate is added in the suspension of carboxylic carbon nano-tube, is sufficiently mixed and evenly dispersed；Point From solid matter, 550~650 DEG C are heated to from room temperature in an inert atmosphere and are heat-treated, then cooled to room temperature.

2. a kind of method improving methyl vinyl silicone rubber thermal stability according to claim 1, it is characterised in that： In the step 2, carboxylic carbon nano-tube is dispersed in absolute ethyl alcohol and forms suspension, adjusting pH value using ammonium hydroxide is 8~10, it specifically, weighs carboxylic carbon nano-tube and is put into beaker, absolute ethyl alcohol is added, stirring keeps CNTs dispersions abundant. Dispersion liquid is put into ultrasonic cell disrupte machine, ice-bath ultrasonic process 1h, power 500W, working time 3s, the intermittent time is 2s weighs ammonium hydroxide, is added rapidly to adjust pH value in suspension obtained above to be alkalinity 8~10, strong stirring 0.5h is obtained The suspension of carboxylic carbon nano-tube.

3. a kind of method improving methyl vinyl silicone rubber thermal stability according to claim 1, it is characterised in that： In the step 2, ethyl orthosilicate is dispersed in absolute ethyl alcohol, forms the teos solution of stable homogeneous, then Teos solution is added in the suspension of carboxylic carbon nano-tube, specifically, ethyl orthosilicate is weighed, is put into In the absolute ethyl alcohol of 300ml, stirring fully obtains the solution of stable homogeneous.Solution is rapidly joined in suspension, strong stirring 2h obtains mixed liquor, this mixed liquor is put into ultrasonic cell disrupte machine again, ice-bath ultrasonic process 30min, ultrasonic power 500W, Working time is 3s, intermittent time 2s, is taken out after the completion of processing, sealing and standing is for 24 hours.

4. a kind of method improving methyl vinyl silicone rubber thermal stability according to claim 1, it is characterised in that： In the step 2, inert atmosphere is nitrogen, helium or argon gas；It is warming up to from room temperature with 5~10 DEG C/min speed for 20~25 DEG C 550~650 DEG C are heat-treated at least 2 hours, specifically, are filtered after standing, are filtered product and are placed in vacuum drying oven, It is dried at 60~80 DEG C, after dry, ground solid sample to obtain powder with mortar, powder is placed in Muffle furnace and carries out heat Processing.

5. a kind of method improving methyl vinyl silicone rubber thermal stability according to claim 5, it is characterised in that：Institute The heat treatment stated is handled 2~5 hours at 600~650 DEG C.

6. a kind of method improving methyl vinyl silicone rubber thermal stability according to claim 1, it is characterised in that： It is as shown in Fig. 1, bonded using carboxyl and the ethyl orthosilicate realization of carbon nano tube surface in the step 2, then the progress that heats up Heat treatment, so that ethyl orthosilicate is in carbon nano tube surface in-situ preparation silica.Contained by the carboxyl of carbon nano tube surface Amount, the dosage of ethyl orthosilicate adjust the appearance structure of silicon-carbon composite nano tube, can to silicone tube thickness, silicone tube continuity degree etc. Regulated and controled.

7. a kind of method improving methyl vinyl silicone rubber thermal stability according to claim 1, it is characterised in that： In the step 3, vacuum drying condition is that 48~49h is dried in vacuo at 61~62 DEG C.

8. a kind of method improving methyl vinyl silicone rubber thermal stability according to claim 1, it is characterised in that： In the step 3,0.7~0.9 parts by weight 2,5- dimethyl -2,5- di-t-butyl hexane peroxides are chosen.

9. a kind of method improving methyl vinyl silicone rubber thermal stability according to claim 1, it is characterised in that： In the step 4, die size is 140 × 140 × 2mm³, preferably hot pressing under conditions of 180 ± 1 DEG C of temperature, pressure 10MPa 11min sulfidization moldings.