Reinforced modified magnetic anti-sticking silicone rubber and preparation method thereof
The enhanced magnetic silicon rubber method addresses mechanical weaknesses in silicon rubber by forming a dense crosslinked network with physical interlinking points, improving mechanical and adhesive properties for applications in aerospace engines.
Patent Information
- Application Number
- CN202510651110.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-20
- Publication Date
- 2025-07-15
AI Technical Summary
The existing polydimethylsiloxane (PDMS)-based silicone rubber has fragile mechanical properties in dynamic load scenarios, and traditional enhancement methods have problems such as poor dispersion, high cost and complex process, which is difficult to meet the needs of industrial applications.
Using a one-step synthesis process, enhanced modified magnetic anti-adhesive silicone rubber is prepared through mechanical mixing and low-temperature curing, magnetic Fe3O4 nanoparticles and hydrogen-containing silicone oil are used to form a dense crosslinking network with platinum catalyst, and dimethyl silicone oil is added as a self-sacrificing oil layer to improve mechanical properties and anti-adhesive properties.
It significantly improves the Shore hardness and tensile strength of silicone rubber, imparts magnetic anti-stick performance, reduces production costs and time, and expands the application range to large equipment such as aircraft engines and turbine engines.
Smart Images
Figure CN120310271A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of silicone rubber preparation, and specifically, to a reinforced and modified magnetic anti-adhesive silicone rubber and a preparation method thereof. Background Art
[0002] Polydimethylsiloxane (PDMS)-based silicone rubber has attracted much attention in the fields of electronic packaging, biomedicine, flexible sensors, and anti-adhesive materials due to its excellent chemical stability, low surface energy, biocompatibility, and wide temperature range applicability. However, its inherently fragile mechanical properties (such as low tear strength, tensile strength, and fatigue resistance) severely limit its application in dynamic load scenarios. The reason is that the flexibility of the PDMS molecular chain results in a low melting point (-40°C), making it impossible to achieve self-reinforcement through strain-induced crystallization, and cracks are easily initiated and propagated due to stress concentration in the crosslinked network. Therefore, reinforcement and modification have become the key path to improving the mechanical properties of silicone rubber, especially silicone rubber for ultra-low adhesion.
[0003] Traditional reinforcement strategies usually focus on adding reinforcing fillers for compounding and crosslinking optimization. As a classic reinforcing filler (10 - 60 wt%), silica (SiO2) can orientedly anchor molecular chains and effectively increase the modulus through hydrogen bonding and van der Waals interactions between the surface hydroxyl groups and the PDMS matrix. However, the hydroxyl groups on the silica surface are prone to form aggregates, resulting in poor dispersion in silicone rubber and affecting the reinforcement effect. At the same time, surface modification treatment (such as hydrophobic modification) is required to improve its dispersion and compatibility in silicone rubber. In addition, using carbon nanotubes as a reinforcing filler can also effectively improve the mechanical strength of silicone rubber by improving the preparation process. However, its reinforcement effect is limited, the cost is high, and the process is complex, and it needs to be mixed with other reinforcing fillers to achieve a better reinforcement effect. In terms of crosslinking optimization, using crosslinking agents can form a three-dimensional network structure in silicone rubber, significantly improving the mechanical properties and thermal stability of silicone rubber. Currently, widely used crosslinking agents include peroxide crosslinking agents, organotin crosslinking agents, etc. Compared with traditional filler reinforcement, the use of crosslinking agents has the advantages of good dispersion and no agglomeration phenomenon, and can still better maintain the original properties of silicone rubber (such as light transmittance, etc.) while significantly improving the mechanical properties of silicone rubber. However, it also faces potential deficiencies such as high-temperature vulcanization, complex process, easy phase separation, and biocompatibility.
[0004] Therefore, there is an urgent need for a reinforcement and modification method that is simple in process, low in cost, and applicable to magnetic anti-adhesive silicone rubber, which can significantly improve the mechanical properties and anti-adhesive properties of silicone rubber to meet the urgent needs in industrial production and practical applications. Summary of the Invention
[0005] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a preparation method for a reinforced and modified magnetic anti-adhesive silicone rubber. The preparation method includes the following steps: Prepare a prepolymer for enhanced modified magnetic anti - sticking silicone rubber; mix Dow Corning polydimethylsiloxane prepolymer, hydrogen - containing silicone oil, and magnetic Fe3O4 nanoparticles in proportion, stir and disperse ultrasonically, then add a certain proportion of platinum catalyst and dimethyl silicone oil and stir evenly again, and obtain the enhanced modified magnetic anti - sticking silicone rubber prepolymer through vacuum degassing; Prepare enhanced modified magnetic anti - sticking silicone rubber; pour the prepared enhanced modified magnetic anti - sticking silicone rubber prepolymer into a tetrafluoro template, degas it in a vacuum drying oven, and then cure it in an oven at 60 - 150 °C for 30 - 180 minutes to form enhanced modified magnetic anti - sticking silicone rubber.
[0006] Preferably, the mass ratio of the Dow Corning polydimethylsiloxane prepolymer to the hydrogen - containing silicone oil is 100:(5 - 20), and the addition amount of the magnetic Fe3O4 nanoparticles is 3 - 8% of the addition amount of the Dow Corning polydimethylsiloxane prepolymer; the mass ratio of the platinum catalyst to the dimethyl silicone oil is 1:(5 - 10), and the addition amount of the platinum catalyst is 5% of the addition amount of the Dow Corning polydimethylsiloxane prepolymer.
[0007] Preferably, the hydrogen content of the hydrogen - containing silicone oil is 0.5 - 1.5%, and the viscosity of the hydrogen - containing silicone oil is 50 - 120 mm 2 / s; the particle size of the magnetic Fe3O4 nanoparticles is 10 - 100 nm; the platinum content of the platinum catalyst is 0.1 - 2 wt%, and the viscosity of the dimethyl silicone oil is 5 - 500 cSt.
[0008] Preferably, the stirring time is 0.5 - 2 h, the stirring temperature is 20 - 40 °C, the frequency of ultrasonic dispersion is 75 kHz, the power is 600 W, and the time is 30 minutes; the vacuum degree of vacuum degassing is 1 - 100 Pa, and the degassing time is 10 - 60 minutes.
[0009] Preferably, during the process of pouring the enhanced modified magnetic anti - sticking silicone rubber prepolymer into the tetrafluoro template, the height of the poured enhanced modified magnetic anti - sticking silicone rubber prepolymer is flush with the height of the tetrafluoro template.
[0010] Preferably, the specifications of the tetrafluoro template are one of 20 mm×20 mm×10 mm and 60 mm×60 mm×10 mm.
[0011] Preferably, the vacuum degree of the vacuum drying oven is 1 - 100 Pa, and the degassing time of the vacuum drying oven is 5 - 30 minutes.
[0012] Preferably, the curing process adopts a step - by - step heating method, first curing at 60 - 100 °C for 30 - 120 minutes, and then curing at 100 - 150 °C for 30 - 60 minutes.
[0013] On the other hand, the present invention provides a reinforced and modified magnetic anti-sticking silicone rubber prepared by the above preparation method.
[0014] Preferably, the Shore hardness of the reinforced and modified magnetic anti-sticking silicone rubber is greater than or equal to 35.
[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. The present invention adopts a one-step synthesis process. Through mechanical mixing and low-temperature curing, a magnetic anti-sticking silicone rubber with both anti-sticking performance and excellent mechanical properties is manufactured, making up for the shortcoming of poor strength of traditional anti-sticking silicone rubber, endowing the silicone rubber with magnetism, and greatly reducing the production cost and time.
[0016] 2. By introducing magnetic Fe3O4 nanoparticles, the present invention causes a hydrosilylation reaction between hydrogen-containing silicone oil and SYLGARD 184 prepolymer (Dow Corning polydimethylsiloxane prepolymer), controls the number of Si-H bonds, and forms a denser and more stable cross-linked network compared to SYLGARD 184 B component as a cross-linking agent. The introduced magnetic Fe3O4 nanoparticles, while endowing the anti-sticking material with magnetism, will form many physical cross-linking points in the silicone rubber cross-linked network. Through the synergistic effect of hydrogen-containing silicone oil and magnetic Fe3O4 nanoparticles, the mechanical properties of the magnetic anti-sticking silicone rubber are greatly improved. The Shore hardness (Shore A) of the silicone rubber synergistically enhanced by the two reaches 70.5, which is significantly higher than that of traditional AB component PDMS (Shore A: 43), greatly increasing its use value and application value. Its magnetism endows the silicone rubber with better bonding force and can be widely used in special processing, magnetic sealing and other fields, enabling it to be used as a self-lubricating magnetic sealing material and widely applied to large equipment such as aero engines and turbine engines, providing new ideas for the development and utilization of new multifunctional materials in the aviation industry.
[0017] 3. By introducing dimethyl silicone oil into the cross-linked network, the present invention endows the silicone rubber with a continuous and rich sacrificial oil layer, greatly increasing the anti-sticking performance of the silicone rubber; through a step-by-step curing process (curing at 60~150°C for 30~120 minutes), the formation of the interface layer is eliminated, and the addition ratio of magnetic nanoparticles is appropriate and evenly dispersed. After curing, the mechanical properties and anti-sticking performance of the silicone rubber are greatly improved, significantly enhancing the service life and stability of the silicone rubber. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings of the embodiments will be briefly described below. It should be understood that the following described drawings only relate to some embodiments of the present disclosure and do not limit the present disclosure, where: Figure 1Schematic diagram of a sample with the enhanced and modified magnetic anti-stick silicone rubber coated on a 304 stainless steel substrate provided in Embodiment 1 of the present invention.
[0019] Figure 2 Sample diagrams of the enhanced and modified bulk silicone rubber provided in Embodiments 1-3 and Comparative Examples 1-2 of the present invention, where (a) is the silicone rubber sample diagram of Comparative Example 1, (b) is the silicone rubber sample diagram of Embodiment 1, (c) is the silicone rubber sample diagram of Embodiment 2, (d) is the silicone rubber sample diagram of Comparative Example 2, and (e) is the silicone rubber sample diagram of Embodiment 3.
[0020] Figure 3 Shore hardness comparison diagram of the silicone rubber provided by the present invention.
[0021] Figure 4 Peeling force test curve diagram of the silicone rubber provided by the present invention.
[0022] Figure 5 Peeling strength comparison diagram of the silicone rubber provided by the present invention.
[0023] Figure 6 Tensile strength comparison diagram of the silicone rubber provided by the present invention. Detailed implementation manners
[0024] In order to make the objectives, technical solutions, and advantages of the embodiments of the present disclosure clearer, the technical solutions of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are some but not all of the embodiments of the present disclosure. All other embodiments obtained by those skilled in the art based on the described embodiments of the present disclosure without creative efforts also fall within the scope of protection of the present disclosure.
[0025] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those skilled in the art to which the subject matter of the present disclosure belongs. It will be further understood that terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the specification and the relevant technology, and will not be interpreted in an idealized or overly formal form unless otherwise clearly defined herein. As used herein, the statement of joining or coupling two or more parts together shall mean that these parts are directly joined together or joined through one or more intermediate components.
[0026] As used herein, the term "embodiment" means that the specific features, structures, or characteristics described in connection with the embodiment may be included in at least one embodiment of the present application. The phrase "embodiment" appearing at various positions in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein may be combined with other embodiments.
[0027] The present invention provides an enhanced modified magnetic anti-sticking silicone rubber and a preparation method thereof, comprising the following steps: Preparing an enhanced modified magnetic anti-sticking silicone rubber prepolymer: Mixing SYLGARD 184 (Dow Corning polydimethylsiloxane) prepolymer, hydrogen-containing silicone oil, and magnetic Fe3O4 nanoparticles in proportion, stirring, and subjecting to ultrasonic dispersion, then adding a certain proportion of platinum catalyst and dimethyl silicone oil, stirring evenly, and then obtaining an enhanced modified magnetic anti-sticking silicone rubber prepolymer with uniformly dispersed particles, no agglomeration phenomenon, and no bubbles after vacuum degassing.
[0028] Among them, the mass ratio of SYLGARD 184 prepolymer to hydrogen-containing silicone oil is preferably 100:(5 - 20), for example, it can be 100:5, 100:8, 100:10, 100:12, 100:15, 100:18, 100:20, etc., more preferably 100:10; the mass ratio of platinum catalyst to dimethyl silicone oil is 1:(5 - 10), for example, it can be 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, and the addition amount of platinum catalyst is 5% of the addition amount of SYLGARD 184 prepolymer; the viscosity of the SYLGARD 184 prepolymer is 5100 mPa·s; the hydrogen content of the hydrogen-containing silicone oil is preferably 0.5 - 1.5%, for example, it can be 0.5%, 0.75%, 1.0%, 1.25%, 1.5%, more preferably 1.0%; it should be noted that the change in the hydrogen content of the hydrogen-containing silicone oil has a certain effect on the enhancement and modification of the silicone rubber; the viscosity of the hydrogen-containing silicone oil is preferably 50 - 120 mm 2 / s, for example, it can be 50 mm 2 / s, 60 mm 2 / s, 70 mm 2 / s, 80 mm 2 / s, 90 mm 2 / s, 100 mm 2 / s, 110 mm 2 / s, 120 mm 2 / s, more preferably 100 mm 2 / s; the particle size of the magnetic Fe3O4 nanoparticles is 10 - 100 nm. For example, it can be 10 nm, 20 nm, 50 nm, 80 nm, 100 nm, and more preferably 20 nm; the addition amount of the magnetic Fe3O4 nanoparticles is 3 - 8% of the addition amount of the SYLGARD 184 prepolymer. Too little will affect the enhancement effect and magnetism, and too much will cause difficulty in dispersion and easy agglomeration, thus affecting the enhancement effect; the platinum content of the platinum catalyst is preferably 0.1 - 2 wt%. For example, it can be 0.1 wt%, 0.5 wt%, 1.0 wt%, 1.5 wt%, 2.0 wt%, and more preferably 0.5 wt%; the viscosity of the dimethyl silicone oil is preferably 5 - 500 cSt. For example, it can be 5 cSt, 10 cSt, 50 cSt, 100 cSt, 200 cSt, 500 cSt, and more preferably 50 cSt.
[0029] In the present invention, the temperature of stirring during the mixing process is preferably 20 - 40 °C. For example, it can be 20 °C, 25 °C, 30 °C, 35 °C, 40 °C, and the stirring time is preferably 0.5 - 2 hours. For example, it can be 0.5 hours, 1.0 hours, 1.5 hours, 2 hours; the frequency of ultrasonic dispersion is 75 kHz, the power is 600 W, and the time is 30 minutes; the vacuum degree of vacuum degassing is 1 - 100 Pa, and the degassing time is preferably 10 - 60 minutes. For example, it can be 10 minutes, 20 minutes, 30 minutes, 40 minutes, 50 minutes, 60 minutes.
[0030] Prepare the enhanced modified magnetic anti - sticking silicone rubber: After pouring the enhanced modified anti - sticking prepolymer into a customized polytetrafluoroethylene template, place it in an oven and cure it at 60 - 150 °C for 30 - 180 minutes; for example, the curing temperature can be 60 °C, 70 °C, 80 °C, 90 °C, 100 °C, 110 °C, 120 °C, 130 °C, 140 °C, 150 °C; the curing time can be 30 minutes, 45 minutes, 60 minutes, 75 minutes, 90 minutes, 105 minutes, 120 minutes, 150 minutes, 180 minutes; a magnetic anti - sticking silicone rubber with a certain hardness after enhanced modification is formed in the template.
[0031] Among them, during the curing process, the temperature can be raised in stages. Specifically, first cure it at 60 - 100 °C for 30 - 120 minutes, and then cure it at 100 - 150 °C for 30 - 60 minutes.
[0032] In the present invention, during the process of pouring the enhanced modified prepolymer into the polytetrafluoroethylene template, after pouring, the template can be placed in an environment with a vacuum degree of 1 - 100 Pa for degassing, preferably for 5 - 30 minutes. For example, it can be 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, 30 minutes.
[0033] In the present invention, the hydrogen-containing silicone oil can undergo a hydrosilylation reaction with the SYLGARD 184 prepolymer. By reasonably controlling the addition amount of the hydrogen-containing silicone oil and the number of Si-H bonds, a crosslinked network that is denser and more stable than the SYLGARD 184 B component can be formed. At the same time, the addition of magnetic Fe3O4 nanoparticles not only imparts magnetism to the anti-adhesive material but also forms many physical crosslinking points in the silicone rubber crosslinked network. After ultrasonic dispersion, the obtained physical crosslinking points are evenly dispersed and there is no agglomeration phenomenon. The synergistic effect of the hydrogen-containing silicone oil and the magnetic Fe3O4 nanoparticles greatly improves the mechanical properties of the silicone rubber. In addition, by controlling the addition amounts of the hydrogen-containing silicone oil and the magnetic Fe3O4 nanoparticles, their synergistic enhancement effect not only greatly improves the mechanical properties of the anti-adhesive silicone rubber but also endows the material with more application values. Its magnetism imparts better bonding strength to the silicone rubber, enabling it to be widely used in encapsulation materials. At the same time, its good biocompatibility allows it to be applied in the medical field, showing great potential.
[0034] The following is an illustration with specific examples: Example 1
[0035] A preparation method of an enhanced modified magnetic anti-adhesive silicone rubber, the method comprising the following steps: S1: Preparation of an enhanced modified magnetic anti-adhesive silicone rubber prepolymer Weigh 15 g of the SYLGARD 184 prepolymer, weigh 1 g of a hydrogen-containing silicone oil with a viscosity of 70 mm 2 / s and a hydrogen content of 0.75%, weigh 1 g of magnetic Fe3O4 nanoparticles with a particle size of 20 nm. After stirring them evenly, put them into an ultrasonic machine, set the frequency to 75 kHz, and ultrasonicate for 30 minutes at a power of 600 W to uniformly disperse the magnetic Fe3O4 nanoparticles in the SYLGARD 184 prepolymer. Subsequently, add 0.5 g of a platinum catalyst with a platinum content of 0.5 wt%, such that the ratio of SYLGARD prepolymer: hydrogen-containing silicone oil: magnetic Fe3O4 nanoparticles: platinum catalyst is 15:1:1:0.5. Another 5 g of dimethyl silicone oil with a viscosity of 5 cSt is weighed and added to the above components, and they are mechanically stirred and mixed evenly. The uniformly stirred mixture is placed in a vacuum drying oven, and degassed for 30 minutes at a vacuum degree of 50 Pa to remove all bubbles in the mixture, obtaining an enhanced modified magnetic anti-adhesive silicone rubber prepolymer.
[0036] S2: Preparation of an enhanced modified magnetic anti-adhesive silicone rubber Pour the enhanced modified magnetic anti-adhesive silicone rubber prepolymer prepared in S1 into a customized polytetrafluoroethylene template (specification: 20 mm * 20 mm * 10 mm), pour it to a height flush with the template without obvious concave surfaces, and then put it into a vacuum drying oven (vacuum degree of 50 Pa) for 10 minutes of degassing to further eliminate the tiny bubbles in the prepolymer and ensure the denseness and flatness of the silicone rubber.
[0037] The degassed sample was placed in an oven and cured at 100 °C for 120 minutes first, and then at 120 °C for 60 minutes. Through stepwise curing, the hydrosilicone oil and SYLGARD 184 prepolymer underwent a hydrosilylation reaction under the action of a platinum catalyst to form a dense cross-linked elastomer network. The magnetic Fe3O4 nanoparticles served as fillers to form physical cross-linking points, restricting the movement of molecular chains and thus improving the strength of the silicone rubber. Synergistically with the cross-linked network formed by the enhancement of the hydrosilicone oil, an excellent enhancement effect was achieved. At the same time, the low-viscosity and low-molecular-weight dimethyl silicone oil was evenly distributed in the cross-linked network, acting as a self-sacrificial oil layer to enhance its anti-sticking performance. After curing was completed, the obtained sample was demolded to obtain a bulk magnetic anti-sticking silicone rubber elastomer after enhancement and modification, as Figure 2 shown; and the obtained enhanced and modified magnetic anti-sticking silicone rubber was coated on a 304 stainless steel substrate, and the result was as Figure 1 shown.
[0038] S3: Rubber property evaluation The Shore hardness (Shore A) of the bulk silicone rubber sample obtained in S2 was measured using a Shore hardness tester. The average value was taken after five measurements at different points, and the measured hardness was 42.3, which was nearly three times higher than that of the non-enhanced anti-sticking PDMS (Shore A: 15.5). The obtained result was as Figure 3 shown; the prepolymer was prepared into a standard tensile sample (compliant with ASTM D412 standard), and its tensile properties were measured on a universal testing machine. The measured tensile strength was 2.47 MPa, and the elongation at break was 176.16%; the tape peeling test was carried out on the obtained sample. The prepared sample was subjected to a 90° peeling test with 3M-VHB tape, and the measured average peeling strength was 1.525 gf / cm, which was less than that of common anti-sticking materials such as polytetrafluoroethylene (28.777 gf / cm), PDMS (4.616 gf / cm), etc. The obtained result was as Figure 5 shown, indicating that the enhanced and modified magnetic anti-sticking silicone rubber prepared in Example 1 had a good anti-sticking effect.
[0039] In summary, the sample prepared in Example 1 had a significant enhancement in anti-sticking effect while its mechanical properties were greatly improved.
[0040] Example 2: S1: Preparation of enhanced and modified magnetic anti-sticking silicone rubber prepolymer Weigh 20 g of SYLGARD 184 prepolymer and weigh 2 g of the one with a viscosity of 100 mm 2 / s, hydrogen-containing silicone oil with a hydrogen content of 1.2%. Weigh 1 g of magnetic Fe3O4 nanoparticles with a particle size of 50 nm. After stirring evenly, put them into an ultrasonic machine, control the frequency at 75 kHz and the power at 600 W, and ultrasonicate for 30 minutes to make the magnetic Fe3O4 nanoparticles evenly dispersed in the SYLGARD 184 prepolymer. Subsequently, add 1 g of a platinum catalyst with a platinum content of 2.0 wt%, so that the ratio of SYLGARD prepolymer: hydrogen-containing silicone oil: magnetic Fe3O4 nanoparticles: platinum catalyst is 20:2:1:1. Finally, weigh 10 g of dimethyl silicone oil with a viscosity of 10 cSt and add it to the above components. Put all the above components into a clean beaker, set the temperature at 25 °C on a magnetic stirrer and stir for 30 minutes to make all components mix evenly. Place the well-stirred mixture in a vacuum drying oven, set the vacuum degree at 90 Pa and degas for 30 minutes to remove all the bubbles in the mixture, and obtain an enhanced and modified magnetic anti-adhesive silicone rubber prepolymer.
[0041] S2: Preparation of enhanced and modified magnetic anti-adhesive silicone rubber Pour the enhanced and modified magnetic anti-adhesive silicone rubber prepolymer prepared in S1 into a customized polytetrafluoroethylene template (specification: 60 mm * 60 mm * 10 mm), pour it to a height flush with the template without obvious concave surface, and then put it into a vacuum drying oven (vacuum degree of 90 Pa) and degas for 30 minutes to further eliminate the tiny bubbles in the prepolymer and ensure the density and flatness of the silicone rubber.
[0042] Put the degassed sample into an oven, cure it at 100 °C for 120 minutes first, and then cure it at 120 °C for 60 minutes. Through step-by-step curing, the hydrosilylation reaction occurs between the hydrogen-containing silicone oil and the SYLGARD 184 prepolymer under the action of the platinum catalyst at 100 °C, initially forming a cross-linked elastomer network. Then, the cross-linked network is further cured at 120 °C. The added magnetic Fe3O4 nanoparticles form physical cross-linking points as fillers, restrict the movement of molecular chains, thereby improving the strength of the silicone rubber, synergize with the cross-linked network formed by the enhancement of the hydrogen-containing silicone oil, achieve an excellent enhancement effect, and at the same time endow the silicone rubber with good magnetism. Meanwhile, the dimethyl silicone oil with a small molecular weight and a viscosity of 100 cSt is evenly distributed in the cross-linked network, serving as a self-sacrificing oil layer to enhance the anti-adhesive performance of the silicone rubber. After curing is completed, demold the obtained sample to obtain a bulk magnetic anti-adhesive silicone rubber elastomer after enhancement and modification.
[0043] S3: Rubber property evaluation The Shore hardness (Shore A) of the bulk silicone rubber sample obtained from S2 was measured using a Shore hardness tester. The average value was taken after five measurements at different points, and the measured hardness was 35.5, which was more than twice the hardness of the non-reinforced anti-adhesive PDMS (Shore A: 15.5). The prepolymer was prepared into a standard tensile sample (compliant with ASTM D412 standard), and its tensile properties were measured on a universal testing machine. The measured tensile strength was 2.35 MPa, and the elongation at break was 150.87%. Its tensile properties were significantly enhanced, and the results are as Figure 6 shown; the tape peeling test was carried out on the obtained sample. The prepared sample was subjected to a 90° peeling test with 3M-VHB tape, and the measured average peeling strength was only 2.415 gf / cm, which was much smaller than common anti-adhesive materials such as polytetrafluoroethylene (28.777 gf / cm), PDMS (4.616 gf / cm), etc., indicating that the magnetic anti-adhesive silicone rubber prepared in Example 2 had excellent anti-adhesive effect. In summary, the sample prepared in Example 2 had greatly enhanced anti-adhesive ability while maintaining good mechanical properties.
[0044] Example 3: S1: Preparation of reinforced and modified magnetic anti-adhesive silicone rubber prepolymer Weigh 10 g of SYLGARD 184 prepolymer, weigh 1 g of hydrogen-containing silicone oil with a viscosity of 85 mm 2 / s and a hydrogen content of 1.20%, weigh 0.3 g of magnetic Fe3O4 nanoparticles with a particle size of 60 nm. After stirring evenly, put them into an ultrasonic machine, control the frequency at 75 kHz and the power at 600 W, and ultrasonicate for 25 minutes to make the magnetic Fe3O4 nanoparticles evenly dispersed in the SYLGARD 184 prepolymer; then add 0.5 g of a platinum catalyst with a platinum content of 1.2 wt%, so that the ratio of SYLGARD prepolymer: hydrogen-containing silicone oil: magnetic Fe3O4 nanoparticles: platinum catalyst is 10:1:0.3:0.5; finally, weigh 5 g of dimethyl silicone oil with a viscosity of 100 cSt and add it to the above components. Put all the above components into a clean beaker and stir with a mechanical stirrer at 25 °C for 25 minutes to make all components evenly mixed. Place the evenly stirred mixture in a vacuum drying oven, set the vacuum degree to 90 Pa, and degas for 30 minutes to remove all bubbles in the mixture, obtaining a reinforced and modified magnetic anti-adhesive silicone rubber prepolymer.
[0045] S2: Preparation of reinforced and modified magnetic anti-adhesive silicone rubber Pour the enhanced and modified prepolymer prepared in S1 into a customized polytetrafluoroethylene template (specification: 20mm * 20mm * 10mm), and pour it to a height flush with the template without obvious concave surface. Then place it in a vacuum drying oven (vacuum degree: 90 Pa) for degassing for 20 minutes to further eliminate the tiny bubbles in the prepolymer and ensure the density and flatness of the silicone rubber.
[0046] Put the degassed sample into an oven, cure it at 100 °C for 120 minutes first, and then cure it at 120 °C for 60 minutes. Through step-by-step curing, at 100 °C, the hydrosiloxane and SYLGARD 184 prepolymer undergo a hydrosilylation reaction under the action of a platinum catalyst to initially form a cross-linked elastomer network. Then at 120 °C, the cross-linked network is further cured. The added magnetic Fe3O4 nanoparticles form physical cross-linking points as fillers, restricting the movement of molecular chains to improve the strength of the silicone rubber. They cooperate with the cross-linked network formed by the enhancement of hydrosiloxane to achieve excellent enhancement effects and endow the silicone rubber with good magnetism. At the same time, dimethyl silicone oil with a small molecular weight and a viscosity of 100 cSt is evenly distributed in the cross-linked network as a self-sacrificing oil layer to improve the anti-sticking performance of the silicone rubber. After curing is completed, demold the obtained sample to obtain a bulk magnetic anti-sticking silicone rubber elastomer after enhancement and modification.
[0047] S3: Rubber property evaluation Use a Shore hardness tester to measure the Shore hardness (Shore A) of the bulk magnetic anti-sticking silicone rubber sample obtained in S2. Take the average value after five different-point measurements. The measured hardness is 44.3, which is greatly improved compared with the unenhanced anti-sticking PDMS (Shore A: 15.5). Prepare the prepolymer into a standard tensile sample (compliant with ASTM D412 standard), and measure its tensile properties on a universal testing machine. The measured tensile strength is 1.79 MPa, and the elongation at break is 148.11%. Its tensile properties are greatly improved. Conduct a tape peeling test on the obtained sample. Conduct a 90° peeling test on the prepared sample and 3M-VHB tape. The measured average peeling strength is only 1.139 gf / cm, which is much smaller than common anti-sticking materials such as polytetrafluoroethylene (28.777 gf / cm), PDMS (4.616 gf / cm), etc., indicating that the anti-sticking effect of the anti-sticking silicone rubber prepared in Example 3 is greatly improved. In summary, the enhanced and modified magnetic anti-sticking sample prepared in Example 3 has significantly improved mechanical properties and greatly increased anti-sticking characteristics.
[0048] Comparative Example 1: S1: Prepare SYLGARD 184 prepolymer added with low molecular weight silicone oil Weigh 10 g of SYLGARD 184 prepolymer component A, weigh 1 g of SYLGARD 184 curing agent component B, and 10 g of low molecular weight dimethyl silicone oil with a viscosity of 5 cSt. Put the above three components into a clean beaker and stir with a mechanical stirrer for 20 minutes at 25 °C to make all components mix evenly. Place the well-stirred mixture in a vacuum drying oven, set the vacuum degree to 80 Pa and degas for 30 minutes to remove all air bubbles in the mixture, and obtain SYLGARD 184 prepolymer added with low molecular weight silicone oil.
[0049] S2: Prepare SYLGARD 184-based silicone rubber added with low molecular weight silicone oil Same as S2 in Example 1, prepare block silicone rubber.
[0050] S3: Silicone rubber performance evaluation Use a Shore hardness tester to measure the Shore hardness (Shore A) of the block silicone rubber sample obtained in Comparative Example 1. Take the average value after five different point measurements, and the measured hardness is 15.5. The results are as Figure 3 shown. Prepare the prepolymer into a standard tensile sample (meeting ASTM D412 standard), measure its tensile properties on a universal testing machine, and the measured tensile strength is only 1.25 MPa. Conduct a peel force test on the obtained sample, conduct a 90° peel test on the prepared sample and 3M-VHB tape, and the measured peel strength is 1.629 gf / cm, which is less than that of common non-stick materials such as polytetrafluoroethylene (28.777 gf / cm), PDMS (4.616 gf / cm), etc. It shows that in Comparative Example 1, hydrogen-containing silicone oil and magnetic Fe3O4 nanoparticles were not added, resulting in a significant decrease in the mechanical properties of the silicone rubber, and it does not have application and use value.
[0051] Comparative Example 2: S1: Prepare an enhanced modified magnetic non-stick silicone rubber prepolymer Weigh 20 g of SYLGARD 184 prepolymer, weigh 2 g of viscosity 55 mm 2 / s, hydrogen-containing silicone oil with a hydrogen content of 1.25%. Weigh 1 g of magnetic Fe3O4 nanoparticles with a particle size of 20 nm. After stirring evenly, put them into an ultrasonic machine, control the frequency at 75 kHz and the power at 600 W, and ultrasonicate for 30 minutes to make the magnetic Fe3O4 nanoparticles evenly dispersed in the SYLGARD 184 prepolymer; then add 1 g of a platinum catalyst with a platinum content of 1.0 wt%, so that the ratio of SYLGARD prepolymer: hydrogen-containing silicone oil: magnetic Fe3O4 nanoparticles: platinum catalyst is 20:2:1:1; finally, weigh 20 g of dimethyl silicone oil with a viscosity of 100 cSt and add it to the above components. Put all the above components into a clean beaker and stir with a mechanical stirrer at 25 °C for 30 minutes to make all components mix evenly. Place the evenly stirred mixture in a vacuum drying oven, set the vacuum degree to 100 Pa and degas for 45 minutes to remove all the bubbles in the mixture, and obtain an enhanced modified magnetic anti-adhesive silicone rubber prepolymer.
[0052] S2: Preparation of enhanced modified magnetic anti-adhesive silicone rubber Pour the enhanced modified magnetic silicone rubber prepolymer prepared in S1 into a customized polytetrafluoroethylene template (specification: 20 mm * 20 mm * 10 mm), pour it to a height level with the template without obvious concave surface, and then put it into a vacuum drying oven (vacuum degree is 100 Pa) and degas for 30 minutes to further eliminate the tiny bubbles in the prepolymer and ensure the density and flatness of the silicone rubber.
[0053] Put the degassed sample into an oven, cure it at 80 °C for 150 minutes first, and then cure it at 120 °C for 60 minutes. After step-by-step curing, the hydrosilylation reaction occurs between the hydrogen-containing silicone oil and the SYLGARD 184 prepolymer under the action of the platinum catalyst at 80 °C, initially forming a cross-linked elastomer network, and then the cross-linked network is further cured at 120 °C. After curing is completed, demold the obtained sample to obtain a bulk magnetic anti-adhesive silicone rubber elastomer after enhanced modification, as Figure 2 shown.
[0054] S3: Rubber property evaluation The Shore hardness (Shore A) of the bulk silicone rubber sample obtained from S2 was measured using a Shore hardness tester. The average value was taken after five measurements at different points, and the measured hardness was only 18.5, which was not much different from that of the un-reinforced PDMS (Shore A: 15.5). The prepolymer was prepared into a standard tensile sample (compliant with ASTM D412 standard), and its tensile properties were measured on a universal testing machine. The measured tensile strength was only 0.77 MPa, but the elongation at break still remained at 150.73%, indicating that its mechanical properties had not been improved significantly. The tape peeling test was carried out on the obtained sample. The prepared sample was subjected to a 90° peeling test with 3M-VHB tape, and the measured average peeling strength was 2.099 gf / cm, which was much smaller than that of common non-stick materials such as polytetrafluoroethylene (28.777 gf / cm) and PDMS (4.616 gf / cm), indicating that the non-stick silicone rubber prepared in this comparative example had good non-stick effect.
[0055] In summary, when the amount of dimethyl silicone oil added is excessive, the mechanical properties of the reinforced modified magnetic non-stick silicone rubber will decline, and it only has non-stick effect.
[0056] Comparative Example 3: S1: Preparation of a silicone rubber prepolymer reinforced with hydrogen-containing silicone oil and magnetic Fe3O4 nanoparticles Weigh 10 g of SYLGARD 184 prepolymer, 1 g of hydrogen-containing silicone oil with a viscosity of 100 mm 2 / s and a hydrogen content of 1.2%, and 0.5 g of magnetic Fe3O4 nanoparticles with a particle size of 50 nm. After stirring evenly, put them into an ultrasonic machine, control the frequency at 75 kHz and the power at 600 W, and ultrasonicate for 30 minutes to make the magnetic Fe3O4 nanoparticles evenly dispersed in the SYLGARD 184 prepolymer; then add 0.5 g of a platinum catalyst with a platinum content of 2.0 wt%, so that the ratio of SYLGARD prepolymer: hydrogen-containing silicone oil: magnetic Fe3O4 nanoparticles: platinum catalyst is 10:1:0.5:0.5. Put all the above components into a clean beaker, set the temperature at 25 °C on a magnetic stirrer and stir for 30 minutes to make all components mix evenly. Place the evenly stirred mixture in a vacuum drying oven, set the vacuum degree at 90 Pa and degas for 30 minutes to remove all the bubbles in the mixture, and obtain a reinforced modified magnetic non-stick silicone rubber prepolymer.
[0057] S2: Preparation of a silicone rubber reinforced with hydrogen-containing silicone oil and magnetic Fe3O4 nanoparticles Same as S2 in Comparative Example 2, prepare a bulk silicone rubber reinforced with hydrogen-containing silicone oil and magnetic Fe3O4 nanoparticles.
[0058] S3: Rubber property evaluation The Shore hardness (Shore A) of the bulk silicone rubber sample obtained from S2 was measured using a Shore hardness tester. The average value was taken after five measurements at different points, and the measured hardness was 70.5. Compared with the unenhanced anti - sticking PDMS (Shore A: 15.5), its hardness increased by 354.8%, resulting in extremely excellent hardness and having the potential for machining. The results are as Figure 3 shown. Its tensile properties were measured on a universal testing machine, and the measured tensile strength was 2.53 MPa, with a significant improvement in its tensile properties. The results are as Figure 6 shown; the tape peeling test was carried out on the obtained sample. The prepared sample was subjected to a 90° peeling test with 3M - VHB tape, and the measured peeling strength was 28.78 gf / cm, which is greater than that of common anti - sticking materials such as polytetrafluoroethylene (28.777 gf / cm), PDMS (4.616 gf / cm), etc., indicating that the mechanical properties of the magnetic anti - sticking silicone rubber prepared in Comparative Example 3 were improved, but its anti - sticking performance decreased significantly.
[0059] Comparative Example 4: S1: Preparation of a hydrogen - containing silicone oil - enhanced modified silicone rubber prepolymer Weigh 10 g of the SYLGARD 184 prepolymer component A, 1 g of hydrogen - containing silicone oil with a hydrogen content of 1.2% and a viscosity of 60 mm 2 / s, and 0.5 g of a platinum catalyst with a platinum content of 0.5 wt%, so that the ratio of SYLGARD prepolymer: hydrogen - containing silicone oil: platinum catalyst is 10:1:0.5; finally, weigh 5 g of dimethyl silicone oil with a viscosity of 100 cSt and add it to the above components. Put all the above components into a clean beaker and stir with a mechanical stirrer at 25 °C for 25 minutes to make all components mix evenly. Place the well - stirred mixture in a vacuum drying oven, set the vacuum degree to 90 Pa and degas for 30 minutes to remove all the bubbles in the mixture, obtaining an enhanced modified silicone rubber prepolymer without adding magnetic Fe3O4 nanoparticles.
[0060] S2: Preparation of the enhanced modified silicone rubber is the same as S2 in Example 3.
[0061] S3: Silicone rubber performance evaluation The Shore hardness (Shore A) of the bulk silicone rubber sample obtained in this comparative example was measured using a Shore hardness tester. The average value was taken after five measurements at different points, and the measured hardness was 26, which was significantly lower than that of Example 3. The peel strength of the obtained sample was tested. The prepared sample was subjected to a 90° peel test with 3M-VHB tape, and the measured average peel strength was 1.078 gf / cm, which was much smaller than that of the common anti-adhesive materials polytetrafluoroethylene (28.777 gf / cm) and PDMS silicone rubber (4.616 gf / cm). Therefore, when magnetic Fe3O4 nanoparticles were not introduced in this comparative example, its mechanical properties decreased significantly while the anti-adhesive property improved.
[0062] In summary, the enhanced modification method provided by the present invention can significantly improve the mechanical properties such as hardness and tensile strength of the anti-adhesive silicone rubber. The addition of hydrogen-containing silicone oil can well retain the inherent performance advantages of SYLGARD 184. While the addition of magnetic Fe3O4 nanoparticles forms physical crosslinking points to improve the mechanical properties of the silicone rubber, it also endows the silicone rubber with magnetism, further improving the mechanical properties and application value of the anti-adhesive silicone rubber. The reasonable introduction of low-molecular-weight dimethyl silicone oil can significantly improve the anti-adhesive performance of the silicone rubber. The introduction of the sacrificial oil layer can not only achieve a good anti-adhesive effect but also provide a useful reference for the development and application of future weak adhesion materials. Its excellent anti-adhesive performance can be applied in various fields such as biomedicine and marine anti-fouling, providing a new idea for the development of new multifunctional anti-adhesive materials.
[0063] The above embodiments are only used to illustrate the technical solutions of the present application, and are not intended to limit them. Although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. These modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present application.
Claims
1. A preparation method of an enhanced modified magnetic anti-sticking silicone rubber, characterized in that, The preparation method comprises the following steps: Prepare a prepolymer of enhanced modified magnetic anti-sticking silicone rubber; mix Dow Corning polydimethylsiloxane prepolymer, hydrogen-containing silicone oil, and magnetic Fe3O4 nanoparticles in proportion, stir and disperse ultrasonically, then add a certain proportion of platinum catalyst and dimethyl silicone oil and stir evenly again, and obtain the enhanced modified magnetic anti-sticking silicone rubber prepolymer through vacuum degassing; Prepare the enhanced modified magnetic anti-sticking silicone rubber; pour the prepared enhanced modified magnetic anti-sticking silicone rubber prepolymer into a tetrafluoro template, degas it in a vacuum drying oven, and then cure it in an oven at 60 - 150 °C for 30 - 180 minutes to form the enhanced modified magnetic anti-sticking silicone rubber.
2. The preparation method of a reinforced and modified magnetic anti-sticking silicone rubber according to claim 1, characterized in that, The mass ratio of the Dow Corning polydimethylsiloxane prepolymer to the hydrogen-containing silicone oil is 100:(5 - 20), and the addition amount of the magnetic Fe3O4 nanoparticles is 3 - 8% of the addition amount of the Dow Corning polydimethylsiloxane prepolymer; the mass ratio of the platinum catalyst to the dimethyl silicone oil is 1:(5 - 10), and the addition amount of the platinum catalyst is 5% of the addition amount of the Dow Corning polydimethylsiloxane prepolymer.
3. The preparation method of a reinforced and modified magnetic anti-sticking silicone rubber according to claim 1, wherein, The hydrogen content of the hydrogen-containing silicone oil is 0.5 to 1.5%, and the viscosity of the hydrogen-containing silicone oil is 50 to 120 mm 2 / s; the particle size of the magnetic Fe3O4 nanoparticles is 10 to 100 nm; the platinum content of the platinum catalyst is 0.1 to 2 wt%, and the viscosity of the dimethyl silicone oil is 5 to 500 cSt.
4. The preparation method of a reinforced and modified magnetic anti-sticking silicone rubber according to claim 1, characterized in that, The stirring time is 0.5 - 2 h, the stirring temperature is 20 - 40 °C, the ultrasonic dispersion frequency is 75 kHz, the power is 600 W, and the time is 30 minutes; the vacuum degree of the vacuum degassing is 1 - 100 Pa, and the degassing time is 10 - 60 minutes.
5. The preparation method of an enhanced modified magnetic anti-sticking silicone rubber according to claim 1, wherein During the process of pouring the enhanced modified magnetic anti-sticking silicone rubber prepolymer into the tetrafluoro template, the height of the poured enhanced modified magnetic anti-sticking silicone rubber prepolymer is flush with the height of the tetrafluoro template.
6. The preparation method of an enhanced modified magnetic anti-sticking silicone rubber according to claim 5, characterized in that, The specifications of the tetrafluoro template are one of 20 mm × 20 mm × 10 mm and 60 mm × 60 mm × 10 mm.
7. The preparation method of a reinforced modified magnetic anti-sticking silicone rubber according to claim 1, characterized in that, The vacuum degree of the vacuum drying oven is 1 - 100 Pa, and the degassing time of the vacuum drying oven is 5 - 30 minutes.
8. The preparation method of a reinforced modified magnetic anti-sticking silicone rubber according to claim 1, characterized in that, The curing process adopts a way of stepwise heating. First, cure it at 60 - 100 °C for 30 - 120 minutes, and then cure it at 100 - 150 °C for 30 - 60 minutes.
9. An enhanced modified magnetic anti-sticking silicone rubber prepared by the preparation method according to any one of claims 1 - 8.
10. An enhanced modified magnetic anti-sticking silicone rubber according to claim 9, characterized in that, The Shore hardness of the enhanced modified magnetic anti-sticking silicone rubber is greater than or equal to 35.