In-situ compounding method of robot skin modified by phenyl poss for HDI polyurethane and polypyrrole

Abstract

This invention discloses an in-situ composite method for phenyl POSS-modified HDI polyurethane and polypyrrole for robotic skin, relating to the technical field of flexible composite material preparation methods. The method includes the following steps: adding phenyl POSS to a polyol, followed by high-speed stirring and ultrasonic dispersion to obtain a uniformly dispersed POSS-polyol mixture; adding HDI aliphatic isocyanate curing agent to the obtained POSS-polyol mixture, maintaining the reaction temperature, and then cooling to obtain a phenyl POSS-modified HDI polyurethane prepolymer; coating the obtained polyurethane prepolymer onto a substrate surface to form a wet film, allowing it to stand at room temperature, and then immersing it in a pyrrole monomer solution, where an oxidant is added to initiate in-situ oxidative polymerization of pyrrole. This invention integrates a continuous in-situ composite method, solving the problems of cumbersome processes, long production cycles, and high costs associated with traditional two-step methods, achieving a 45% to 50% reduction in production cycle time, improving production efficiency, and meeting the needs of mass industrial production of robotic skin.

Description

Technical Field

[0001] This invention relates to the technical field of flexible composite material preparation methods, specifically to an in-situ composite method of phenyl POSS-modified HDI polyurethane and polypyrrole for robot skin. Background Technology

[0002] In the current field of flexible sensing materials, the composite of phenyl POSS-modified HDI polyurethane and polypyrrole is mostly carried out using a two-step method. First, a phenyl POSS-modified HDI polyurethane matrix is ​​prepared, and then the conductive polypyrrole component is added through blending, spraying, or other methods. This method has the following technical drawbacks: The two-step process is cumbersome, has a long production cycle, and is costly, making it unsuitable for the mass industrial production needs of robot skins. 2. The polypyrrole conductive component and the phenyl POSS modified HDI polyurethane substrate are only physically bonded, with weak interfacial bonding. Long-term use can easily lead to delamination and peeling, resulting in continuous degradation of sensing performance. Third, pyrrole monomers are prone to agglomeration when directly blended with polyurethane matrix, making it impossible to form a uniform and continuous conductive network inside the matrix, which greatly reduces the sensing sensitivity and performance stability of robot skin. Fourth, existing composite methods struggle to control the uniform dispersion of phenyl POSS within HDI polyurethane segments, leading to nanoparticle aggregation and consequently affecting the overall mechanical properties and weather resistance of the composite system. Therefore, there is an urgent need to develop an in-situ composite method for phenyl POSS-modified HDI polyurethane and polypyrrole for robotic skin to address these technical challenges. Summary of the Invention

[0003] Technical problems to be solved To address the shortcomings of existing technologies, this invention provides an in-situ composite method for phenyl POSS-modified HDI polyurethane and polypyrrole for robotic skin, which solves the problems mentioned in the background art.

[0004] Technical solution To achieve the above objectives, the present invention provides the following technical solution: an in-situ composite method for phenyl POSS-modified HDI polyurethane and polypyrrole for robotic skin, such as... Figure 1 As shown, it includes the following steps: S1, Phenyl POSS is added to a polyol and subjected to high-speed stirring and ultrasonic dispersion treatment in sequence to obtain a uniformly dispersed POSS-polyol mixture.

[0005] The phenyl POSS is a cage-like polyhedral oligomeric silsesquioxane with multiple phenyl functional groups in its molecular structure, which can form good compatibility with polyurethane segments. At the same time, the cage-like rigid structure can significantly improve the tensile strength, wear resistance and UV aging resistance of the polyurethane matrix. It is the core modifying component for achieving synergistic improvement of the mechanical properties and weather resistance of the composite system.

[0006] The polyol includes at least one type of polyether polyol, whose hydroxyl value can be controlled between 50 mg KOH / g and 100 mg KOH / g. This type of polyether polyol is a commonly used soft segment raw material for polyurethane synthesis. It has moderate viscosity at room temperature and its reactivity matches that of phenyl POSS and HDI isocyanate. The polyurethane matrix formed after curing has excellent flexibility and resilience, which can meet the requirements of large deformation and stretching of robot skin.

[0007] In this step, the mass ratio of phenyl POSS to polyol can be controlled at 0.5–2.5:100; the high-speed stirring temperature can be controlled at 50℃–60℃, and the stirring time can be controlled at 30 min–60 min; the ultrasonic dispersion power can be controlled at 200 W–300 W, and the dispersion time can be controlled at 20 min–30 min. This dual dispersion method combining high-speed stirring and ultrasound effectively breaks down the agglomerates of phenyl POSS nanoparticles, allowing them to be uniformly distributed in the polyol system in a monodisperse state. The stirring temperature of 50℃–60℃ reduces the viscosity of the polyol, improves dispersion efficiency, and avoids oxidation and deterioration of the polyol due to excessively high temperatures. The ultrasonic power of 200 W–300 W ensures effective dispersion without damaging the cage-like molecular structure of phenyl POSS.

[0008] The key points for execution control in this step are as follows: First, preheat the polyol to the set temperature, then slowly add the phenyl POSS powder while stirring to avoid powder clumping; after high-speed stirring, immediately perform ultrasonic dispersion, and control the system temperature to not exceed 65℃ during the dispersion process; the dispersed mixture must be used within 24 hours to avoid phenyl POSS nanoparticles from re-settling and agglomerating.

[0009] After this step, the phenyl POSS nanoparticles are uniformly dispersed in the polyol, which solves the problem of nanoparticle agglomeration caused by the traditional single stirring dispersion method, ensures the consistency of the properties of the subsequent modified polyurethane matrix, and provides uniform nucleation sites for the subsequent in-situ polymerization of pyrrole monomers.

[0010] S2, add HDI aliphatic isocyanate curing agent to the obtained POSS-polyol mixture, keep it at a constant temperature and then cool it down to obtain phenyl POSS modified HDI polyurethane prepolymer.

[0011] The HDI aliphatic isocyanate is hexamethylene diisocyanate, which is the preferred curing agent for synthesizing weather-resistant polyurethane. Its molecular structure does not contain benzene rings, and the polyurethane matrix formed after curing has excellent resistance to yellowing and weathering, which can meet the long-term use requirements of robots in complex outdoor environments.

[0012] In this step, the molar ratio of NCO to OH in the system is controlled to be 1.05 to 1.2; the temperature of the reaction can be controlled at 60℃ to 70℃, and the reaction time can be controlled at 2h to 3h; after the reaction is completed, the temperature is lowered to 30℃ to 40℃.

[0013] A NCO / OH molar ratio of 1.05–1.2 ensures that the prepolymer has a suitable molecular weight and end-group content, avoiding both excessive viscosity and coating difficulties caused by an excessively low molar ratio, and increased matrix brittleness after curing caused by an excessively high molar ratio. A reaction temperature of 60℃–70℃ ensures a stable reaction between isocyanate and hydroxyl groups, preventing explosive polymerization. A reaction time of 2h–3h ensures complete reaction and that the free NCO content in the system remains stable within the design range. Cooling the temperature to 30℃–40℃ after the reaction inhibits further reaction of the prepolymer and extends its pot life.

[0014] The key points for execution control in this step are as follows: continuous low-speed stirring is required during the reaction to ensure uniform mixing of the system; the reaction must be carried out under dry nitrogen protection to avoid the reaction of moisture in the air with isocyanate to generate bubbles; the content of free NCO in the system must be monitored periodically during the reaction, and the reaction should be terminated and the temperature lowered immediately when the content reaches the design value.

[0015] After this step, phenyl POSS is chemically grafted onto the polyurethane molecular chain, forming a chemically cross-linked modified network structure rather than a simple physical blend. This significantly improves the mechanical properties and weather resistance of the polyurethane matrix, while retaining the matrix's good flexibility and processing performance.

[0016] S3, the obtained polyurethane prepolymer is coated on the substrate surface to form a wet film, and after standing at room temperature, it is immersed in a pyrrole monomer solution. An oxidant is added to initiate in-situ oxidative polymerization of pyrrole, forming a polypyrrole conductive network inside the polyurethane matrix.

[0017] The substrate includes at least one of PET substrate and silicone substrate. Both types of substrates are commonly used support substrates in the field of flexible electronics. They have smooth and flat surfaces, good adhesion to polyurethane prepolymer, and can provide stable mechanical support for the composite film. At the same time, substrates with different thicknesses and hardnesses can be selected according to actual usage requirements.

[0018] The pyrrole monomer is a commonly used monomer for synthesizing conductive polymers. It is liquid at room temperature and can quickly penetrate into the incompletely cured polyurethane prepolymer network, undergoing an oxidative polymerization reaction under the action of an oxidant to form a continuous conductive pathway. The oxidant includes at least one of ferric chloride and ammonium persulfate. Both are commonly used and highly efficient oxidants for pyrrole polymerization, capable of stably initiating the polymerization reaction at low temperatures, and the reaction products are easily removed by water washing.

[0019] In this step, the thickness of the wet film can be controlled between 50 μm and 500 μm; the standing time at room temperature can be controlled between 30 min and 60 min; the concentration of the pyrrole monomer solution can be controlled between 0.5 mol / L and 1.5 mol / L; the molar ratio of pyrrole monomer to oxidant is 1:1.2 to 1.5; the temperature of in-situ oxidative polymerization can be controlled between 0℃ and 25℃; and the polymerization time can be controlled between 1 h and 3 h.

[0020] The film thickness range of 50μm to 500μm covers the general application needs from ultra-thin, highly sensitive skin to thick, abrasion-resistant skin; the room temperature standing time of 30min to 60min allows the polyurethane prepolymer to initially crosslink and cure, forming a three-dimensional network structure with a certain strength, while maintaining sufficient porosity to facilitate the penetration of pyrrole monomers; the pyrrole monomer concentration of 0.5mol / L to 1.5mol / L ensures the formation of a continuous and uniform conductive network. Too low a concentration will lead to discontinuous conductive pathways, while too high a concentration will lead to polypyrrole agglomeration, reducing the flexibility of the composite film; A molar ratio of oxidant to monomer of 1:1.2 to 1.5 ensures complete polymerization of pyrrole monomers while avoiding excessive oxidant residue that could affect the performance of the composite film. The low-temperature polymerization method of 0℃ to 25℃ avoids the damage of high temperature to the weather resistance of HDI polyurethane and the cage structure of phenyl POSS, while slowing down the polymerization reaction rate, allowing the polypyrrole molecular chains to grow uniformly and form a denser and more stable conductive network.

[0021] The key control points for this step are as follows: the polyurethane prepolymer can be coated by scraping, rolling, or slot coating to ensure uniform coating thickness; after coating, it should be left to stand in a dust-free environment to avoid dust contamination of the composite film surface; the pyrrole monomer solution should be prepared and used immediately, and the preparation and polymerization process should be carried out in a light-proof environment to avoid self-polymerization of pyrrole monomers; the oxidant should be added slowly to the pyrrole monomer solution while stirring to avoid excessively high local oxidant concentrations that could lead to rapid agglomeration of polypyrrole.

[0022] After this step, the pyrrole monomer undergoes in-situ polymerization inside the polyurethane matrix, forming a polyurethane-polypyrrole interpenetrating network structure. There is no obvious interface between the polypyrrole conductive network and the polyurethane matrix, which completely solves the problem of weak bonding force between the conductive component and the matrix and easy delamination caused by the traditional blending method, and significantly improves the cycle stability and sensing sensitivity of the composite system.

[0023] S4. Take out the polymerized composite membrane, wash to remove unreacted monomers and oxidants, and dry to obtain the composite system for robotic skin.

[0024] This step involves cleaning the composite membrane with deionized water. The number of cleaning cycles can be controlled between 3 and 5. Deionized water can effectively dissolve and remove unreacted pyrrole monomers, oxidants, and reaction byproducts remaining on and inside the composite membrane, thus preventing residual impurities from affecting the electrical properties and biocompatibility of the composite membrane.

[0025] After cleaning, vacuum drying is used for drying. The drying temperature can be controlled between 40℃ and 50℃, and the drying time can be controlled between 12h and 24h. Vacuum drying can quickly remove moisture from the composite film at low temperature, avoiding aging, deformation, and conductivity degradation of the composite film caused by high-temperature drying; the drying temperature of 40℃ to 50℃ can ensure complete removal of moisture without damaging the structure of the polyurethane matrix and polypyrrole conductive network.

[0026] The key points for execution control in this step are: gentle handling is required during the cleaning process to avoid stretching and deformation of the composite film; the composite film must be placed flat on the drying rack during drying to avoid wrinkles; the composite film after drying must be sealed and stored to prevent the absorption of moisture and dust from the air.

[0027] The composite system for robotic skin prepared by this method has a tensile elongation of 150% to 300%, a strain factor GF ≥ 12, a performance degradation of less than 10% after 1000 cycles, and a tensile strength retention rate of more than 90% after 100 hours of UV aging.

[0028] Beneficial effects The present invention has the following beneficial effects: (1) The robot skin uses a phenyl POSS-modified HDI polyurethane and polypyrrole in-situ composite method. Through continuous in-situ composite method integration, it solves the problems of cumbersome process, long production cycle and high cost of traditional two-step method, and achieves a 45% to 50% reduction in production cycle, improves production efficiency and meets the needs of mass industrial production of robot skin.

[0029] (2) The robot skin uses a phenyl POSS modified HDI polyurethane and polypyrrole in situ composite method. By introducing pyrrole in situ oxidative polymerization during the initial curing stage of polyurethane prepolymer, the problem of weak bonding force between conductive components and polyurethane substrate in traditional blending method and easy delamination and shedding is solved. The polypyrrole forms a continuous conductive network inside the polyurethane matrix, and the cycle stability is improved by more than 60%. The performance decay is less than 10% after 1000 tensile cycles.

[0030] (3) The robot skin uses a phenyl POSS-modified HDI polyurethane and polypyrrole in-situ composite method. Through a dual dispersion composite method of high-speed stirring and ultrasound synergy, the problem of easy aggregation and uneven dispersion of phenyl POSS nanoparticles in polyurethane chain segments is solved. The phenyl POSS is uniformly grafted onto the polyurethane molecular chain in a monodisperse state, which effectively ensures the consistency of material mechanical properties and weather resistance. After UV aging for 100h, the tensile strength retention rate is greater than 90%.

[0031] (4) The robot skin uses a phenyl POSS-modified HDI polyurethane and polypyrrole in-situ composite method. Through the synergistic effect of phenyl POSS modification and in-situ polymerization, the problems of easy agglomeration of pyrrole monomers and uneven distribution of conductive network are solved. The uniform growth of polypyrrole molecular chains is achieved, which effectively improves the sensing sensitivity of the composite system. The strain factor is not less than 12, and the tensile elongation can reach 150% to 300%, which meets the requirements of large deformation stretching of robot skin.

[0032] (5) The robot skin uses a phenyl POSS-modified HDI polyurethane and polypyrrole in-situ composite method. Through the whole process of low temperature in-situ composite method, the problem of high temperature reaction destroying the weather resistance of HDI polyurethane and the cage structure of phenyl POSS is solved. The composite system is prepared while retaining the core advantages of the materials. The resulting material has good flexibility, sensing performance, cycle stability and weather resistance, and can be applied to the flexible tactile skin system of various robots.

[0033] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0034] Figure 1 This is a flowchart of the in-situ composite method of phenyl POSS-modified HDI polyurethane and polypyrrole for robot skin according to the present invention. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] Example 1 This embodiment 1 provides a method for in-situ composite of phenyl POSS-modified HDI polyurethane and polypyrrole for robotic skin. The raw materials used, by weight, include: Pre-dispersion system: 0.5 parts phenyl POSS, 100 parts polyether polyol, hydroxyl value of polyether polyol is 50 mg KOH / g Curing agent: HDI aliphatic isocyanate, with the molar ratio of NCO to OH in the system controlled at 1.05. Conductive system: pyrrole monomer, prepared as a 0.5 mol / L aqueous solution; ferric chloride, with a molar ratio of pyrrole to ferric chloride of 1:1.2. Substrate: 50μm thick PET substrate The preparation method is as follows: S1: Preheat the polyether polyol to 50°C, slowly add phenyl POSS powder while stirring, stir at high speed at 50°C for 30 min, then ultrasonically disperse at 200W power for 20 min to obtain a uniformly dispersed POSS-polyol mixture, which should be used within 24 hours. S2: Add HDI aliphatic isocyanate to the obtained mixture, stir continuously at low speed under dry nitrogen protection, keep the reaction at 60℃ for 2h, periodically check the free NCO content until it stabilizes, cool down to 30℃, and obtain phenyl POSS modified HDI polyurethane prepolymer. S3: The polyurethane prepolymer is uniformly coated onto the surface of the PET substrate using a scraping method, and the wet film thickness is controlled to be 50 μm. The substrate is then left to stand at room temperature in a dust-free environment for 30 min. Subsequently, the substrate is immersed in a 0.5 mol / L pyrrole monomer aqueous solution, ferric chloride is slowly added, and the mixture is stirred evenly. The substrate is then reacted at 0°C in the dark for 1 h to initiate the in-situ oxidative polymerization of pyrrole. S4: Take out the composite membrane, wash it 3 times with deionized water to remove unreacted monomers and oxidants, place it flat on a drying rack, and vacuum dry it at 40°C for 12 hours to obtain the composite system for robotic skin.

[0037] Performance testing: Elongation at break 152%, tensile strength 3.2 MPa, strain factor 12.3, initial conductivity 0.08 S / cm, suitable for use in robotic flexible tactile skin.

[0038] Example 2 This embodiment 2 provides a method for in-situ composite of phenyl POSS-modified HDI polyurethane and polypyrrole for robotic skin. The raw materials used, by weight, include: Pre-dispersion system: 2.5 parts phenyl POSS, 100 parts polyether polyol, hydroxyl value of polyether polyol is 100 mg KOH / g Curing agent: HDI aliphatic isocyanate, with the molar ratio of NCO to OH in the system controlled at 1.2. Conductive system: pyrrole monomer, prepared as a 1.5 mol / L aqueous solution; ammonium persulfate, with a molar ratio of pyrrole to ammonium persulfate of 1:1.5. Substrate: 500μm thick silicone substrate The preparation method is as follows: S1: Preheat the polyether polyol to 60°C, slowly add phenyl POSS powder while stirring, stir at high speed at 60°C for 60 min, and then ultrasonically disperse at 300W power for 30 min to obtain a uniformly dispersed POSS-polyol mixture, which should be used within 24 hours. S2: Add HDI aliphatic isocyanate to the obtained mixture, stir continuously at low speed under dry nitrogen protection, keep the reaction at 70℃ for 3h, periodically check the free NCO content until it stabilizes, cool down to 40℃, and obtain phenyl POSS modified HDI polyurethane prepolymer. S3: The polyurethane prepolymer was uniformly coated onto the surface of the silicone substrate using a slot coating method, and the wet film thickness was controlled to be 500 μm. The substrate was then left to stand at room temperature for 60 min in a dust-free environment. Subsequently, the substrate was immersed in a 1.5 mol / L pyrrole monomer aqueous solution, and ammonium persulfate was slowly added. The mixture was stirred until homogeneous and reacted at 25°C in the dark for 3 h to initiate the in-situ oxidative polymerization of pyrrole. S4: Take out the composite membrane, wash it 5 times with deionized water to remove unreacted monomers and oxidants, place it flat on a drying rack, and vacuum dry it at 50°C for 24 hours to obtain the composite system for robotic skin.

[0039] Performance testing: tensile elongation 296%, tensile strength 5.8MPa, strain factor 15.7, initial conductivity 0.21S / cm, suitable for use in robotic flexible tactile skin.

[0040] Comparative Example 1: Phenyl-free POSS-modified group The difference between Comparative Example 1 and Example 2 is that the addition of phenyl POSS in S1 is omitted, and the polyurethane prepolymer is prepared directly using pure polyether polyol. The hydroxyl value of the polyether polyol is 100 mg KOH / g. The dosage of other raw materials and method parameters are completely consistent with those of Example 2.

[0041] Results: Elongation at break 187%, tensile strength 2.9 MPa, strain factor 9.2, initial conductivity 0.17 S / cm.

[0042] Comparative Example 2: Traditional Two-Step Method The difference between Comparative Example 2 and Example 2 is that a fully cured phenyl POSS-modified HDI polyurethane film was prepared first, followed by polypyrrole polymerization. In Example 3, S3 was changed to coating the polyurethane prepolymer into a film, followed by vacuum drying at 50°C for 24 hours to achieve complete curing, and then immersing it in a pyrrole monomer solution with an oxidant for polymerization. The amounts of other raw materials and the method parameters were completely consistent with Example 2.

[0043] Results: Elongation at break 272%, tensile strength 5.5 MPa, strain factor 10.1, initial conductivity 0.12 S / cm.

[0044] Experimental Example 1 Test Objective: To verify the differences in basic mechanical and sensing properties between the example and comparative examples, focusing on the core quality indicators of the composite system. Test Items and Methods: Tensile elongation and tensile strength: measured according to GB / T528-2024 standard for determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber, with a tensile rate of 50 mm / min. Strain factor: The strain factor is calculated by using a universal testing machine in conjunction with a digital source meter to apply a strain of 0 to 50%, record the rate of change of resistance, and calculate the strain factor. The strain factor is equal to the rate of change of resistance divided by the product of the initial resistance and the strain. Initial conductivity: The sheet resistance of the composite film surface was measured using the four-probe method, and the conductivity was calculated.

[0045] The test results are shown in the table below:

[0046] In this experimental example, the overall performance of Examples 1 and 2 is significantly better than that of the comparative example. The tensile strength of the two examples is increased by 81% to 100% compared with Comparative Example 1, and the strain factor is increased by 34% to 71% compared with Comparative Example 1, and by 22% to 55% compared with Comparative Example 2. Comparative Example 1 has insufficient matrix mechanical properties due to the lack of phenyl POSS nano-reinforcement, and lacks polypyrrole nucleation sites, resulting in poor uniformity of the conductive network. Comparative Example 2 adopts the traditional two-step method, in which polypyrrole is polymerized only on the matrix surface, and cannot form an internal interpenetrating conductive network, resulting in a significant reduction in sensing sensitivity. This confirms the necessity of the dual-core method of phenyl POSS modification and in-situ polymerization in the prepolymer stage in this scheme.

[0047] Experiment Example 2 Test Objective: To verify the long-term service stability of the examples and comparative examples, focusing on the core requirements of practical applications of robotic skin. Test Items and Methods: Cyclic stability: 1000 cycles of 0 to 50% reciprocating tensile testing were performed using a universal testing machine at a cycle rate of 100 mm / min. The rate of change in resistance before and after the cycles was tested, and the performance retention rate was calculated. Weather resistance: UV aging was carried out for 100 hours in a UV aging test chamber with a UV wavelength of 313nm and an irradiation intensity of 0.51W / m². The tensile strength before and after aging was tested and the tensile strength retention rate was calculated. Interface adhesion: The adhesion of the conductive layer was tested using the tape peeling method according to the GB / T2792-2023 standard for the determination of peel strength of adhesive tape, and it was observed whether delamination or peeling occurred.

[0048] The test results are shown in the table below:

[0049] In this experiment, the long-term service stability of Examples 1 and 2 is far superior to that of the comparative example. Both examples retained over 90% of their performance after 1000 tensile cycles, and over 90% of their tensile strength after 100 hours of UV aging, demonstrating excellent interfacial bonding. Comparative Example 1, lacking phenyl POSS modification, exhibited poor weather resistance, and its substrate was prone to fatigue fracture after long-term cycling. Comparative Example 2, with its conductive layer only physically bonded to the substrate, was prone to interfacial separation during cycling, leading to a sharp decline in sensing performance. This confirms that the proposed solution, through in-situ polymerization to form an interpenetrating network structure, fundamentally solves the core problem of long-term failure of robotic skin.

[0050] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0051] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for in-situ composite of phenyl POSS-modified HDI polyurethane and polypyrrole for robotic skin, characterized in that, Includes the following steps: Phenyl POSS was added to a polyol and subjected to high-speed stirring and ultrasonic dispersion treatment in sequence to obtain a uniformly dispersed POSS-polyol mixture. HDI aliphatic isocyanate curing agent was added to the obtained POSS-polyol mixture, and the mixture was kept at a constant temperature and then cooled to obtain phenyl POSS modified HDI polyurethane prepolymer. The obtained polyurethane prepolymer was coated on the substrate surface to form a wet film. After standing at room temperature, it was immersed in a pyrrole monomer solution. An oxidant was added to initiate in-situ oxidative polymerization of pyrrole, forming a polypyrrole conductive network inside the polyurethane matrix. The polymerized composite membrane is removed, washed to remove unreacted monomers and oxidants, and dried to obtain the composite system for robotic skin.

2. The method for in-situ composite of phenyl POSS-modified HDI polyurethane and polypyrrole for robotic skin according to claim 1, characterized in that, The mass ratio of phenyl POSS to polyol is 0.5–2.5:100; The temperature of the high-speed stirring is controlled at 50℃~60℃, and the stirring time is 30min~60min; The power of ultrasonic dispersion is controlled at 200W to 300W, and the dispersion time is 20min to 30min.

3. The method for in-situ composite of phenyl POSS-modified HDI polyurethane and polypyrrole for robotic skin according to claim 1, characterized in that, When adding HDI aliphatic isocyanate curing agent to the obtained POSS-polyol mixture, the molar ratio of NCO to OH in the system is controlled to be 1.05 to 1.

2. The temperature of the heat preservation reaction is controlled at 60℃~70℃, and the reaction time is 2h~3h; After the reaction is complete, cool down to 30℃~40℃.

4. The method for in-situ composite of phenyl POSS-modified HDI polyurethane and polypyrrole for robotic skin according to claim 1, characterized in that, The substrate includes at least one of PET substrate and silicone substrate; The thickness of the wet film is controlled between 50 μm and 500 μm; The standing time at room temperature is 30 to 60 minutes.

5. The method for in-situ composite of phenyl POSS-modified HDI polyurethane and polypyrrole for robotic skin according to claim 1, characterized in that, The concentration of the pyrrole monomer solution is 0.5 mol / L to 1.5 mol / L; The molar ratio of pyrrole monomer to oxidant is 1:1.2 to 1.5; The temperature for in-situ oxidative polymerization was controlled between 0℃ and 25℃, and the polymerization time was between 1h and 3h.

6. The method for in-situ composite of phenyl POSS-modified HDI polyurethane and polypyrrole for robotic skin according to claim 1, characterized in that, The cleaning process removes unreacted monomers and oxidants, specifically by cleaning the composite membrane with deionized water, repeating the cleaning process 3 to 5 times. The drying process employs vacuum drying, with the drying temperature controlled between 40℃ and 50℃ and the drying time between 12h and 24h.

7. The method for in-situ composite of phenyl POSS-modified HDI polyurethane and polypyrrole for robotic skin according to claim 1, characterized in that, The polyol includes at least one of the polyether polyols, with a hydroxyl value of 50 mg KOH / g to 100 mg KOH / g.

8. The method for in-situ composite of phenyl POSS-modified HDI polyurethane and polypyrrole for robotic skin according to claim 1, characterized in that, The oxidant includes at least one of ferric chloride and ammonium persulfate.

9. The method for in-situ composite of phenyl POSS-modified HDI polyurethane and polypyrrole for robotic skin according to any one of claims 1 to 8, characterized in that, The prepared composite system was applied to the flexible tactile skin of the robot, with a tensile elongation of 150% to 300% and a strain factor GF ≥ 12.

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