Polyrotaxane silicone rubber elastomer and preparation method thereof

Abstract

The invention discloses a polyrotaxane silicone rubber elastomer and a preparation method thereof, and relates to the technical field of high polymer materials. The rubber elastomer is obtained by cross-linking and curing gamma-cyclodextrin / vinyl-terminated polydimethylsiloxane pseudorotaxane (PR) and a hydrogen-containing silicone oil copolymer, and the molar ratio of vinyl in the gamma-cyclodextrin / vinyl-terminated polydimethylsiloxane pseudorotaxane to silicon hydrogen in the hydrogen-containing silicone oil copolymer is (1: 10)-(1: 2). The proportion of a methylhydrosiloxane block in the hydrogen-containing silicone oil copolymer is not higher than 30% in percentage by mass. The invention also provides a preparation method and application of the rubber elastomer. The polyrotaxane silicone rubber elastomer provided by the invention is excellent in performance, the elongation at break can be higher than 400%, and the tensile strength can be higher than 0.6 MPa.

Description

Technical Field

[0001] The invention relates to the technical field of polymer materials, and in particular to a polyrotaxane silicone rubber elastomer and a preparation method thereof. Background Art

[0002] Silicone rubber has a series of advantages such as heat resistance, low temperature resistance, insulation and chemical inertness, so it plays an irreplaceable and important role in daily life and the defense industry. Unreinforced silicone rubber materials have low strength and limited application value due to the low intermolecular force of silicone rubber. In order to improve the strength of silicone rubber materials, the prior art often adds white carbon black and MQ resin to the preparation of silicone rubber elastomers, and utilizes the residual silanol groups in white carbon black and MQ resin to interact with polydimethylsiloxane molecular chains in an adsorption manner to achieve the reinforcement of silicone rubber materials and significantly increase mechanical properties. However, this method has limited reinforcing effect on silicone rubber materials, especially for the optimization of the elongation at break of silicone rubber materials, which makes it difficult to apply to more demanding application scenarios.

[0003] Pulley ring materials are a type of polymer composite material with a new type of network structure. This type of material is prepared by chemically cross-linking polyrotaxane. Polyrotaxane consists of a polymer axis and a small molecule pulley ring that runs through the axis polymer. The most common axis polymer in the polyrotaxane materials reported so far is polyethylene glycol (PEG) terminated with a steric group, and the pulley ring is cyclodextrin. The pulley ring material obtained by curing the system by cross-linking cyclodextrin has a lower Young's modulus and a higher elongation at break because the cross-linking points can move freely within a certain range on the polymer axis. Although polydimethylsiloxane (PDMS) has good physical and chemical properties, there are few reports on pulley ring materials based on PDMS. Kato et al. reported a method for preparing pulley ring hydrogels based on PDMS axis (Macromolecules 42, 7129-7136). The preparation method includes multiple steps such as compounding, end-capping, acetylation and curing. The preparation method is complicated and therefore inefficient. Tran reported another method for preparing polyrotaxane PDMS elastomer (Bioinspiration&Biomimetics 16, 025002). In the preparation method, polyrotaxane was first prepared using PEG and cyclodextrin as raw materials. After the polyrotaxane was hydroxypropylated, vinyl chlorosilane reacted to obtain a polyrotaxane containing a vinyl group, which was then reacted with vinyl silicone oil to obtain an elastomer. The test results showed that the obtained elastomer had a lower Young's modulus and a higher elongation at break, but a lower tensile strength (0.2MPa). Summary of the invention

[0004] The object of the present invention is to provide a polyrotaxane silicone rubber elastomer, which is obtained by cross-linking γ-cyclodextrin / vinyl-terminated polydimethylsiloxane pseudorotaxane with a hydrogen-containing silicone oil copolymer, and has not only high elongation at break and tensile strength, but also obvious heat resistance, aging resistance and damping properties.

[0005] Another object of the present invention is to provide a method for preparing a polyrotaxane silicone rubber elastomer, which is simple and easy to implement and can be easily promoted and used.

[0006] The present invention is achieved through the following technical solutions: In a first aspect, the present invention provides a polyrotaxane silicone rubber elastomer, which is obtained by cross-linking and curing a γ-cyclodextrin / vinyl-terminated polydimethylsiloxane pseudorotaxane and a hydrogen-containing silicone oil copolymer under the action of a catalyst, wherein the molar ratio of vinyl in the γ-cyclodextrin / vinyl-terminated polydimethylsiloxane pseudorotaxane to silicon-hydrogen in the hydrogen-containing silicone oil copolymer is 1:10~1:2, and the proportion of methyl hydrogen siloxane blocks in the hydrogen-containing silicone oil copolymer is not higher than 30% by mass fraction.

[0007] Furthermore, in some embodiments of the present application, the curing temperature of the copolymer of γ-cyclodextrin / vinyl-terminated polydimethylsiloxane pseudorotaxane and hydrogen-containing silicone oil is 20-120°C.

[0008] Furthermore, in some embodiments of the present application, the amount of the catalyst added is 0.01 wt%-0.2 wt% of the mass of the γ-cyclodextrin / vinyl-terminated polydimethylsiloxane pseudorotaxane in terms of mass fraction.

[0009] Furthermore, in some embodiments of the present application, the catalyst is an inorganic metal catalyst or an organic metal catalyst.

[0010] Furthermore, in some embodiments of the present application, the catalyst is an organic metal catalyst containing metal platinum.

[0011] Furthermore, in some embodiments of the present application, the γ-cyclodextrin / vinyl-terminated polydimethylsiloxane pseudorotaxane is obtained by reacting γ-cyclodextrin with vinyl polydimethylsiloxane; in the γ-cyclodextrin / vinyl-terminated polydimethylsiloxane pseudorotaxane, the mass fraction of the γ-cyclodextrin is less than 45 wt%.

[0012] Further, in some embodiments of the present application, the chemical structural formula of the vinyl polydimethylsiloxane is as shown in Formula I:

[0013] Wherein, the value ranges of m and n are independently selected from 60-1500, and R is vinyl.

[0014] Furthermore, in some embodiments of the present application, the hydrogen-containing silicone oil copolymer is a polymethyl hydrogen siloxane having the following structure:

[0015] Wherein the value ranges of x and y are independently selected from 8-200; The molar fraction of the repeating unit hydrogen methyl siloxane in the hydrogen-containing silicone oil copolymer is 8 wt % to 30 wt %.

[0016] Furthermore, in some embodiments of the present application, the elongation at break of the polyrotaxane silicone rubber elastomer is greater than 400%, and the tensile strength is greater than 0.6 MPa.

[0017] In a second aspect, the present invention also provides a method for preparing the polyrotaxane silicone rubber elastomer described in the first aspect, comprising the following steps: S1: obtaining vinyl-terminated vinyl polydimethylsiloxane, and providing γ-cyclodextrin, hydrogen-containing silicone oil copolymer and catalyst; S2: using vinyl polydimethylsiloxane and γ-cyclodextrin to react to form γ-cyclodextrin / vinyl-terminated polydimethylsiloxane pseudorotaxane; S3: Mix γ-cyclodextrin / vinyl-terminated polydimethylsiloxane pseudorotaxane and hydrogenated silicone oil copolymer, add a catalyst, mix and cure at 20-120° C. for 0.5 h-48 h to obtain a polyrotaxane silicone rubber elastomer.

[0018] Furthermore, in some embodiments of the present application, in step S2, the mass ratio of the vinyl polydimethylsiloxane to γ-cyclodextrin is 95:5-55:45.

[0019] Furthermore, in some embodiments of the present application, in step S2, the solvent in the reaction system of vinyl polydimethylsiloxane and γ-cyclodextrin is water, and the reaction conditions are ultrasonic treatment at a frequency of 100 Hz for 5 min to 0.5 h.

[0020] Furthermore, in some embodiments of the present application, in step S3, the mass ratio of the γ-cyclodextrin / vinyl-terminated polydimethylsiloxane pseudorotaxane and the hydrogenated silicone oil copolymer is 1:10 to 1:2.

[0021] Further, in some embodiments of the present application, the curing includes a first curing stage and a second curing stage; the first curing stage is curing at a temperature of 20-45 °C for 2 h-24 h, and the second curing stage is curing at a temperature of 80 °C-100 °C for 24-38 h.

[0022] Compared with the prior art, the present invention has the following advantages and beneficial effects: The present invention provides a polyrotaxane silicone rubber elastomer, which utilizes a hydrogen-containing silicone oil copolymer with a low hydrogen-silicon bond content and a γ-cyclodextrin / vinyl-terminated polydimethylsiloxane pseudorotaxane containing a vinyl end group, and controls the molar ratio of the vinyl end group and the hydrogen-silicon bond within a specific range, so that it is cross-linked and cured, and the amount of cross-linking points formed by cross-linking is controlled, so that the polyrotaxane silicone rubber elastomer formed not only has a high elongation at break, but also has significantly optimized tensile strength, and also has the heat resistance, aging resistance and solvent resistance of silicone rubber. In addition, it also has the damping characteristics of strain rate sensitive materials, showing a significant Mullins effect, and can be used as a filling material in the field of precision electrical components and human sports protection. The elongation at break of the polyrotaxane silicone rubber elastomer provided by the present invention can reach more than 400%, and the tensile strength can reach more than 0.6 MPa.

[0023] The preparation method of the polyrotaxane silicone rubber elastomer provided in the present application is different from the steps of compounding, end-capping, acetylation and curing commonly used in the existing pulley silicone rubber material preparation method. In this method, an elastomer material with high elongation at break and excellent tensile strength can be obtained through two simple chemical reactions (compounding and curing). The preparation method is simple and easy to promote and apply. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A schematic diagram of the preparation process of the polyrotaxane silicone rubber elastomer provided in this application; Figure 2 This is an infrared spectrum of the γ-cyclodextrin / vinyl-terminated polydimethylsiloxane pseudorotaxane prepared in Example 1 provided in the present application; Figure 3 : is an infrared spectrum of the γ-cyclodextrin / vinyl-terminated polydimethylsiloxane pseudorotaxane prepared in Example 2 provided in the present application; Figure 4 : is an infrared spectrum of the γ-cyclodextrin / vinyl-terminated polydimethylsiloxane pseudorotaxane prepared in Example 3 provided in the present application; Figure 5 : is a thermogravimetric curve of the γ-cyclodextrin / vinyl-terminated polydimethylsiloxane pseudorotaxane prepared in Example 1 provided in the present application; Figure 6 : is a thermogravimetric curve of the γ-cyclodextrin / vinyl-terminated polydimethylsiloxane pseudorotaxane prepared in Example 2 provided in the present application; Figure 7 : is a thermogravimetric curve of the γ-cyclodextrin / vinyl-terminated polydimethylsiloxane pseudorotaxane prepared in Example 3 provided in the present application; Figure 8: is a thermal weight loss curve of the silicone rubber elastomer prepared in Comparative Example 1 provided in the present application; Fig. 9 : 1H MAS NMR spectrum of the γ-cyclodextrin / vinyl-terminated polydimethylsiloxane pseudorotaxane prepared in Example 1 provided in the present application; Fig.10 1H MAS NMR spectrum of the γ-cyclodextrin / vinyl-terminated polydimethylsiloxane pseudorotaxane prepared in Example 2 provided in the present application; Fig.11 : 1H MAS NMR spectrum of the γ-cyclodextrin / vinyl-terminated polydimethylsiloxane pseudorotaxane prepared in Example 3 provided in the present application; Fig.12 : 1H MAS NMR spectrum of the polyrotaxane silicone rubber elastomer prepared in Example 1 provided in the present application; Fig.13 : 1H MAS NMR spectrum of the polyrotaxane silicone rubber elastomer prepared in Example 2 provided in the present application; Fig.14 : 1H MAS NMR spectrum of the polyrotaxane silicone rubber elastomer prepared in Example 3 provided in the present application; Fig.15 : Cyclic stretching curves of the polyrotaxane silicone rubber elastomers prepared in Examples 1-6 provided in the present application and the rubber elastomer obtained in Comparative Example 1; Fig.16 : is a stress-strain curve diagram of the polyrotaxane silicone rubber elastomer prepared in Examples 1-6 provided in the present application. DETAILED DESCRIPTION

[0025] The technical solution of the present application will be described clearly and completely below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0026] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as generally understood by those skilled in the art to which this application belongs. It should also be understood that terms such as those defined in common dictionaries should be understood to have meanings consistent with the meanings in the context of the prior art, and will not be interpreted with idealized or overly formal meanings unless specifically defined as here.

[0027] Those skilled in the art will appreciate that, unless otherwise stated, the singular forms "a", "an", "said" and "the" used herein may also include plural forms. It should be further understood that the term "comprising" used in the specification of the present application refers to the presence of the features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof. The term "and / or" used herein includes all or any unit and all combinations of one or more associated listed items.

[0028] The invention provides a polyrotaxane silicone rubber elastomer, which is obtained by crosslinking and curing a γ-cyclodextrin / vinyl-terminated polydimethylsiloxane pseudorotaxane and a hydrogen-containing silicone oil copolymer under the action of a catalyst, wherein the molar ratio of vinyl groups in the γ-cyclodextrin / vinyl-terminated polydimethylsiloxane pseudorotaxane to silicon-hydrogen bonds in the hydrogen-containing silicone oil copolymer is 1:10-1:2, preferably 1:9-1:3, and more preferably 1:7-1:5, so that the final cured product is cured more completely.

[0029] The proportion of the methyl hydrogen siloxane block in the hydrogen-containing silicone oil copolymer is not higher than 30% and not lower than 8% by mass.

[0030] In this scheme, the vinyl groups in the γ-cyclodextrin / vinyl-terminated polydimethylsiloxane pseudorotaxane react with the hydrogen-silicone bonds in the hydrogen-containing silicone oil copolymer to form crosslinking points, and the molar ratio of the two is controlled within a specific range, which is beneficial for controlling the number and distribution of crosslinking points, and further controlling the properties of the formed elastomer.

[0031] Wherein, the hydrogen-containing silicone oil copolymer is a polymethyl hydrogen siloxane having the following structure:

[0032] Wherein, the value ranges of x and y are independently selected from 8-200; The molar fraction of the repeating unit hydrogen methyl siloxane in the hydrogen-containing silicone oil copolymer is 8 wt % to 30 wt %.

[0033] Preferably, the value ranges of x and y are independently selected from 8 to 200; the mole fraction of the repeating unit hydrogen methyl siloxane in the hydrogen-containing silicone oil copolymer is 10wt%-28wt%; more preferably: the value ranges of x and y are independently selected from 8 to 125; the mole fraction of the repeating unit hydrogen methyl siloxane in the hydrogen-containing silicone oil copolymer is 12wt%-15wt%, and the operating time of the reactants is extended on the basis of ensuring complete curing.

[0034] The γ-cyclodextrin / vinyl-terminated polydimethylsiloxane pseudorotaxane is obtained by reacting γ-cyclodextrin with vinyl polydimethylsiloxane; in the γ-cyclodextrin / vinyl-terminated polydimethylsiloxane pseudorotaxane, the mass fraction of the γ-cyclodextrin is less than 45 wt%, more preferably less than 35%, so that the final elastomer has a higher elongation at break.

[0035] Wherein, the chemical structural formula of the vinyl polydimethylsiloxane is as shown in Formula I:

[0036] Formula I Wherein, the value ranges of m and n are independently selected from 60-1500, and R is vinyl.

[0037] Among them, vinyl polydimethylsiloxane can be purchased directly, and can also be obtained by using conventional dimethylsiloxane and a vinyl-containing end-capping material through an end-capping reaction. Vinyl end-capping of dimethylsiloxane is an existing technology, so it will not be described in detail in this scheme.

[0038] In some embodiments, the curing temperature of the γ-cyclodextrin / vinyl-terminated polydimethylsiloxane pseudorotaxane and hydrogenated silicone oil copolymer is 20-120°C, and the curing time is 0.5 h-48 h. The curing temperature is preferably 20-100 °C, and the curing time is preferably 10 h-48 h, so that the curing is more thorough.

[0039] In some embodiments, the amount of the catalyst added is 0.01 wt%-0.2 wt% of the mass of the γ-cyclodextrin / vinyl-terminated polydimethylsiloxane pseudorotaxane, preferably 0.01 wt%~0.5 wt%, and more preferably 0.02 wt%~0.3 wt%, to extend the operation time while ensuring complete curing.

[0040] In some embodiments, the catalyst is an inorganic metal catalyst or an organic metal catalyst, such as metal platinum or a platinum-containing organic catalyst. Preferably, the catalyst is a compound containing zero-valent platinum, such as a cascade catalyst, the structural formula of which is shown below:

[0041] In a second aspect, the present invention also provides a method for preparing the polyrotaxane silicone rubber elastomer described in the first aspect, comprising the following steps: S1: obtaining vinyl-terminated vinyl polydimethylsiloxane, and providing γ-cyclodextrin, hydrogen-containing silicone oil copolymer and catalyst; S2: using vinyl polydimethylsiloxane and γ-cyclodextrin to react to form γ-cyclodextrin / vinyl-terminated polydimethylsiloxane pseudorotaxane; S3: Mix γ-cyclodextrin / vinyl-terminated polydimethylsiloxane pseudorotaxane and hydrogenated silicone oil copolymer, add a catalyst, mix and cure at 20-120° C. for 0.5 h-48 h to obtain a polyrotaxane silicone rubber elastomer.

[0042] Wherein, in the step S2, the mass ratio of the vinyl polydimethylsiloxane to γ-cyclodextrin is 95:5-50:50.

[0043] Wherein, in the step S2, the solvent in the reaction system of vinyl polydimethylsiloxane and γ-cyclodextrin is water, and the reaction conditions are ultrasonic treatment at a frequency of 100 Hz for 5 min to 0.5 h, so that the vinyl polydimethylsiloxane and γ-cyclodextrin are complexed to form γ-cyclodextrin / vinyl-terminated polydimethylsiloxane pseudorotaxane, and a white γ-cyclodextrin / vinyl-terminated polydimethylsiloxane pseudorotaxane is obtained.

[0044] Preferably, the γ-cyclodextrin is dissolved in a solvent and then vinyl-terminated vinyl polydimethylsiloxane is added, and the vinyl polydimethylsiloxane is slowly added while the γ-cyclodextrin is stirred, and ultrasonic treatment is performed for 5 min to 0.5 h after the addition to obtain a white suspension, which is filtered and washed to obtain a white γ-cyclodextrin / vinyl-terminated polydimethylsiloxane pseudorotaxane.

[0045] In the step S3, the mass ratio of the γ-cyclodextrin / vinyl-terminated polydimethylsiloxane pseudorotaxane to the hydrogen-containing silicone oil copolymer is 1:10 to 1:2.

[0046] Among them, in the step S3, the catalyst is added after the γ-cyclodextrin / vinyl-terminated polydimethylsiloxane pseudorotaxane and the hydrogenated silicone oil copolymer are evenly mixed, and stirring is continued to make them evenly mixed, the temperature is raised to the curing temperature, and the temperature is kept to cure to obtain a milky white cured product.

[0047] Among them, according to the desired configuration of the cured product, the reaction system with the catalyst added can be injected or poured into a specific structural part, such as a base plate or a mold, and then heated and cured to make the configuration of the obtained elastomer into the desired configuration.

[0048] Further, the curing and crosslinking of the γ-cyclodextrin / vinyl-terminated polydimethylsiloxane pseudorotaxane and hydrogenated silicone oil copolymer is a staged curing, which includes a first curing stage and a second curing stage; the first curing stage is cured at a temperature of 20 ° C to 45 ° C for 2 h to 24 h, and the second curing stage is cured at a temperature of 70 ° C to 100 ° C for 2 h to 40 h. Preferably, the first curing stage is cured at a temperature of 20 ° C to 40 ° C for 10 to 24 h, and the second curing stage is cured at a temperature of 80 ° C to 100 ° C for 24 to 38 h.

[0049] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0050] Among them, γ-cyclodextrin was purchased from MacLean Chemical Reagent Company with a purity of 97%; Vinyl-terminated polydimethylsiloxane was purchased from Gelest Company with molecular weights of 25 KDa and 62 KDa; Karl-Förster catalyst was purchased from McLean Chemicals, 2 wt% xylene solution; Polymethylhydrogensiloxane-copolydimethylsiloxane was purchased from Gelest Company, molecular weight 15 KDa; The hydrogenated silicone copolymer was purchased from Aladdin Chemical Reagent Company with a viscosity of 15-40 mPa·s.

[0051] Example 1 Preparation of γ-cyclodextrin / vinyl-terminated polydimethylsiloxane pseudorotaxane PR1 Weigh 1.2 g (15.1 mmol) of γ-cyclodextrin, add it to a reaction container, add 100 ml of deionized water, and sonicate to dissolve. Take another reaction container and add 10 g of vinyl-terminated polydimethylsiloxane (PDMS) with a molecular weight of 25 KDa. Add the cyclodextrin aqueous solution to the PDMS under stirring, and then sonicate for 20 min. After the sonication is completed, stir at room temperature for 24 h to obtain a white suspension.

[0052] The reaction mixture was filtered, and the residue was washed with water three times and freeze-dried to obtain a white paste solid PR1.

[0053] Preparation of polyrotaxane silicone rubber elastomer Take a reaction container, add 5.2 g PR1 and 50 mg of polymethylhydrogensiloxane-copolydimethylsiloxane with a molecular weight of 15KDa (methylhydrogensiloxane molar fraction of 10%), stir evenly, add 0.25 μL of Carfghan catalyst, continue to stir evenly, pour it onto a PTFE plate, cure it at room temperature for 2 hours, and then cure it in an oven at 80°C for 48 hours to obtain a milky white elastic film ER1.

[0054] Example 2 Preparation of γ-cyclodextrin / vinyl-terminated polydimethylsiloxane pseudorotaxane PR2 Weigh 2.4 g (15.1 mmol) of γ-cyclodextrin, add it to a reaction container, add 100 ml of deionized water, and sonicate to dissolve. Take another reaction container and add 10 g of vinyl-terminated polydimethylsiloxane with a molecular weight of 25 KDa. Add the cyclodextrin aqueous solution to PDMS under stirring, and then sonicate for 20 min. After the sonication is completed, stir at room temperature for 24 h to obtain a white suspension.

[0055] The reaction mixture was filtered, and the residue was washed with water three times and freeze-dried to obtain a white paste solid PR2.

[0056] Preparation of polyrotaxane silicone rubber elastomer Take a reaction container, add 5.2 g PR2 and 50 mg of polymethylhydrogensiloxane-copolydimethylsiloxane with a molecular weight of 15KDa (methylhydrogensiloxane molar fraction of 10%), stir evenly, add 0.5 μL of Carfghan catalyst, continue to stir evenly, pour it onto a PTFE plate, cure it at room temperature for 2 h, and then cure it in an oven at 80°C for 2 days to obtain a milky white elastic film ER2.

[0057] Example 3 Preparation of γ-cyclodextrin / vinyl-terminated polydimethylsiloxane pseudorotaxane PR3 Weigh 3.6 g (15.1 mmol) of γ-cyclodextrin, add it to a reaction container, add 100 ml of deionized water, and sonicate to dissolve. Take another reaction container and add 10 g of vinyl-terminated polydimethylsiloxane with a molecular weight of 25 KDa. Add the cyclodextrin aqueous solution to PDMS under stirring, and then sonicate for 20 min. After the sonication is completed, stir at room temperature for 24 h to obtain a white suspension.

[0058] The reaction mixture was filtered, and the residue was washed with water three times and freeze-dried to obtain a white paste solid PR3.

[0059] Preparation of polyrotaxane silicone rubber elastomer Take a reaction container, add 5.2 g PR3 and 50 mg of polymethylhydrogensiloxane-copolydimethylsiloxane with a molecular weight of 15KDa (methylhydrogensiloxane molar fraction of 10%), stir evenly, add 0.8 μL of Carfghan catalyst, continue to stir evenly, pour it on a PTFE plate, cure at room temperature for 24 h, and then cure in an oven at 80 °C for 2 days to obtain a milky white elastic film ER3.

[0060] Example 4 Preparation of γ-cyclodextrin / vinyl-terminated polydimethylsiloxane pseudorotaxane PR4 Weigh 10.0 g (15.1 mmol) of γ-cyclodextrin, add it to a reaction container, add 100 ml of deionized water, and sonicate to dissolve. Take another reaction container and add 11 g of vinyl-terminated polydimethylsiloxane with a molecular weight of 62 KDa. Add the cyclodextrin aqueous solution to PDMS under stirring, and then sonicate for 20 min. After the sonication is completed, stir at room temperature for 24 h to obtain a white suspension.

[0061] The reaction mixture was filtered, and the residue was washed with water three times and freeze-dried to obtain a white paste solid PR4.

[0062] Preparation of polyrotaxane silicone rubber elastomer Take a reaction container, add 5.2 g PR4 and 50 mg of polymethylhydrogensiloxane-copolydimethylsiloxane with a molecular weight of 15KDa (methylhydrogensiloxane molar fraction of 10%), stir evenly, add 1.1 μL of Carfghan catalyst, continue to stir evenly, pour it onto a PTFE plate, cure it at room temperature for 8 h, and then cure it in an oven at 80 °C for 2 days to obtain a milky white elastic film ER4.

[0063] Example 5 Preparation of γ-cyclodextrin / vinyl-terminated polydimethylsiloxane pseudorotaxane PR5 Weigh 5.6 g (15.1 mmol) of γ-cyclodextrin, add it to a reaction container, add 100 ml of deionized water, and sonicate to dissolve. Take another reaction container and add 10 g of vinyl-terminated polydimethylsiloxane with a molecular weight of 62 KDa. Add the cyclodextrin aqueous solution to PDMS under stirring, and then sonicate for 20 min. After the sonication is completed, stir at room temperature for 24 h to obtain a white suspension.

[0064] The reaction mixture was filtered, and the residue was washed with water three times and freeze-dried to obtain a white paste solid PR5.

[0065] Preparation of polyrotaxane silicone rubber elastomer Take a reaction container, add 5.2 g PR5 and 50 mg of polymethylhydrogensiloxane-copolydimethylsiloxane with a molecular weight of 15KDa (methylhydrogensiloxane molar fraction of 10%), stir evenly, add 0.8 μL of Carfghan catalyst, continue to stir evenly, pour it onto a PTFE plate, cure it at room temperature for 2 h, and then cure it in an oven at 80 °C for 2 days to obtain a milky white elastic film ER5.

[0066] Example 6 Preparation of γ-cyclodextrin / vinyl-terminated polydimethylsiloxane pseudorotaxane PR6 Weigh 5.6 g (15.1 mmol) of γ-cyclodextrin, add it to a reaction container, add 100 ml of deionized water, and sonicate to dissolve. Take another reaction container and add 10 g of vinyl-terminated polydimethylsiloxane with a molecular weight of 62 KDa. Add the cyclodextrin aqueous solution to PDMS under stirring, and then sonicate for 20 min. After the sonication is completed, stir at room temperature for 24 h to obtain a white suspension.

[0067] The reaction mixture was filtered, and the residue was washed with water three times and freeze-dried to obtain a white paste solid PR6.

[0068] Preparation of polyrotaxane silicone rubber elastomer Take a reaction container, add 5.2 g PR6 and 50 mg of polymethylhydrogensiloxane-copolydimethylsiloxane with a molecular weight of 15 KDa (methylhydrogensiloxane molar fraction of 30%), stir evenly, add 0.5 μL of Carfghan catalyst, continue to stir evenly, pour it onto a PTFE plate, cure it at room temperature for 8 h, and then cure it in an oven at 80 °C for 3 days to obtain a milky white elastic film ER6.

[0069] Comparative Example 1 Take a reaction container, add 5.2 g of vinyl-terminated polydimethylsiloxane with a molecular weight of 24 KDa and 50 mg of polymethylhydrogensiloxane-copolydimethylsiloxane with a molecular weight of 15 KDa (methylhydrogensiloxane molar fraction of 10%), stir evenly, add 0.5 μL of Carfghan catalyst, continue to stir evenly, pour it on a PTFE plate, cure it at room temperature for 2 h, and then cure it in an oven at 80 °C for 2 days to obtain a transparent elastic film CR.

[0070] Comparative Example 2 Take a reaction container, add 5.2 g PR5 and 50 mg hydrogenated silicone oil copolymer (polymethylhydrogensiloxane) with a viscosity of 15-40 mPa·s, stir evenly, then add 0.5 μL of Carfghan catalyst and stir. The product foams rapidly to obtain a porous material with irregular pore size.

[0071] The intermediates obtained in the above examples and comparative examples: γ-cyclodextrin / vinyl-terminated polydimethylsiloxane pseudorotaxane, the product (polyrotaxane silicone rubber elastomer) and the comparative sample (elastomer) were subjected to infrared spectroscopy, thermogravimetric analysis, 1HMAS NMR detection, and cyclic tensile and stress-strain curve tests. The detection and test results are shown in FIG. Figures 1 to 16 shown.

[0072] From Figures 1 to 16, it can be seen that the polyrotaxane silicone rubber elastomer provided by the present application has excellent tensile strength and elongation at break, and the tensile strength and elongation of the elastomer can be adjusted by adjusting the molar ratio of vinyl and silicon-hydrogen bonds in the γ-cyclodextrin / vinyl-terminated polydimethylsiloxane pseudorotaxane and hydrogen-containing silicone oil copolymer, and the content of methylhydrogensiloxane in the hydrogen-containing silicone oil copolymer, so that it can be suitable for different application requirements. The foam material prepared by the method of the present invention has both the heat-resistant and aging-resistant properties of silicone foam and the damping properties of strain rate sensitive materials, and can be used as a filling material in the fields of precision electrical components and human motion protection. Figure 6 As shown, by comparing the examples and comparative example 1, it can be seen that the introduction of cyclodextrin into the elastomer has an effect on improving the tensile strength and elongation at break of the elastomer. Figure 5 As shown, the polyrotaxane silicone rubber elastomer obtained in the example exhibits a significant Mullins effect.

[0073] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A polyrotaxane silicone rubber elastomer, characterized in that: The method is obtained by cross-linking and curing a copolymer of γ-cyclodextrin / vinyl-terminated polydimethylsiloxane pseudorotaxane and hydrogen-containing silicone oil under the action of a catalyst, wherein the molar ratio of vinyl in the γ-cyclodextrin / vinyl-terminated polydimethylsiloxane pseudorotaxane to silicon-hydrogen in the hydrogen-containing silicone oil copolymer is 1:10-1:2; The proportion of methyl hydrogen siloxane blocks in the hydrogen-containing silicone oil copolymer is no more than 30% by mass.

2. The polyrotaxane silicone rubber elastomer according to claim 1, characterized in that: The curing temperature of the copolymer of gamma-cyclodextrin / vinyl-terminated polydimethylsiloxane pseudorotaxane and hydrogen-containing silicone oil is 20-120°C.

3. The polyrotaxane silicone rubber elastomer according to claim 1 or 2, characterized in that: The amount of the catalyst added is 0.01 wt%-0.2 wt% of the mass of the γ-cyclodextrin / vinyl-terminated polydimethylsiloxane pseudorotaxane in terms of mass fraction; and / or The catalyst is an inorganic metal catalyst or an organic metal catalyst.

4. The polyrotaxane silicone rubber elastomer according to claim 3, characterized in that: The catalyst is an organic metal catalyst containing metal platinum.

5. The polyrotaxane silicone rubber elastomer according to claim 1, characterized in that: The γ-cyclodextrin / vinyl-terminated polydimethylsiloxane pseudorotaxane is obtained by reacting γ-cyclodextrin with vinyl polydimethylsiloxane; in the γ-cyclodextrin / vinyl-terminated polydimethylsiloxane pseudorotaxane, the mass fraction of the γ-cyclodextrin is less than 45 wt%.

6. The polyrotaxane silicone rubber elastomer according to claim 5, characterized in that: The chemical structural formula of the vinyl polydimethylsiloxane is shown in Formula I: ， Wherein, the value ranges of m and n are independently selected from 60-1500, and R is vinyl.

7. The polyrotaxane silicone rubber elastomer according to claim 5, characterized in that: The hydrogen-containing silicone oil copolymer is a polymethyl hydrogen siloxane having the following structure: ， Wherein, the value ranges of x and y are independently selected from 8-200; The molar fraction of the repeating unit hydrogen methyl siloxane in the hydrogen-containing silicone oil copolymer is 8 wt % to 30 wt %.

8. The polyrotaxane silicone rubber elastomer according to claim 1, characterized in that: The polyrotaxane silicone rubber elastomer has an elongation at break greater than 400%, and a tensile strength greater than 0.6 MPa.

9. The method for preparing a polyrotaxane silicone rubber elastomer according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1: obtaining vinyl-terminated vinyl polydimethylsiloxane, and providing γ-cyclodextrin, hydrogen-containing silicone oil copolymer and catalyst; S2: using vinyl polydimethylsiloxane and γ-cyclodextrin to react to form γ-cyclodextrin / vinyl-terminated polydimethylsiloxane pseudorotaxane; S3: Mix γ-cyclodextrin / vinyl-terminated polydimethylsiloxane pseudorotaxane and hydrogenated silicone oil copolymer, add a catalyst, mix and cure at 20-120° C. for 0.5 h-48 h to obtain a polyrotaxane silicone rubber elastomer.

10. The method for preparing a polyrotaxane silicone rubber elastomer according to claim 9, characterized in that: In the step S2, the mass ratio of the vinyl polydimethylsiloxane to γ-cyclodextrin is 95:5 to 5:5:45; and / or In the step S2, the solvent in the reaction system of vinyl polydimethylsiloxane and γ-cyclodextrin is water, and the reaction conditions are ultrasonic treatment at a frequency of 100 Hz for 5 min to 0.5 h; and / or In the step S3, the mass ratio of the γ-cyclodextrin / vinyl-terminated polydimethylsiloxane pseudorotaxane and hydrogen-containing silicone oil copolymer is 1:10 to 1:2; and / or The curing includes a first curing stage and a second curing stage; the first curing stage is curing at a temperature of 20°C to 45°C for 2 h to 24 h, and the second curing stage is curing at a temperature of 80°C to 100°C for 24 h to 38 h.

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