Hydrogel with high mechanical property and preparation method thereof
A high-mechanical-performance hydrogel was prepared by crosslinking hyperbranched polysiloxane with acrylamide, which solved the problem of insufficient mechanical properties of traditional hydrogels, and achieved high-density crosslinking and strength enhancement. It is suitable for fields such as sensors, capacitors, fluid control and intelligent machinery.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- TIANJIN BOHAI VOCATIONAL TECHN COLLEGE
- Filing Date
- 2026-01-23
- Publication Date
- 2026-05-15
AI Technical Summary
The mechanical properties of existing hydrogels are poor and have not been effectively improved.
Cross-linked hyperbranched polysiloxanes were prepared by using hyperbranched polysiloxane prepolymers and cross-linking agents, and then co-prepared with acrylamide to form hydrogels with high mechanical properties. Cross-linking was carried out by thermally initiated free radical polymerization.
It significantly improves the crosslinking network density and strength of hydrogels, enhances their mechanical properties, and has a simple preparation method that is easy to scale up for production.
Abstract
Description
Technical Field
[0001] This invention belongs to the field of polymer material preparation, specifically relating to a high-mechanical-performance hydrogel and its preparation method. Background Technology
[0002] Hydrogels are a class of polymeric materials with a three-dimensional network structure. They are rich in water, allowing them to swell significantly in water while maintaining their structural integrity without dissolving. This unique "wet and soft" property makes them highly similar to biological tissues in structure and properties, thus earning them the reputation of being "ideal candidate materials for artificial tissues." Hydrogels can be classified according to their components into natural polymer hydrogels, synthetic polymer hydrogels, and inorganic hybrid composite hydrogels. Polyacrylamide hydrogel is a three-dimensional network polymeric functional material prepared through free radical copolymerization. Its main polymerization process involves the chain polymerization of water-soluble monomer acrylamide under the action of an initiator, while the linear polymer chains are linked together by the bifunctional chemical crosslinking agent N,N′-methylenebisacrylamide, forming a network structure that is insoluble in water but can absorb and retain a large amount of water.
[0003] Hyperbranched polysiloxanes are unique organic-inorganic hybrid polymers with a structure intermediate between ordinary linear polymers and symmetrical dendritic macromolecules, possessing numerous terminal functional groups and a three-dimensional structure. Hyperbranched polysiloxanes can be used as multifunctional crosslinking agents or nanofillers in hydrogels. Their three-dimensional spherical structure and abundant surface functional groups can serve as multifunctional crosslinking points, chemically bonding with acrylamide and acrylic acid. Hyperbranched polysiloxanes themselves possess the properties of organosilicon materials and can act as reinforcing nanofillers in hydrogels. Researchers have already investigated their application in hydrogels. CN113278188A discloses a high-strength, high-toughness, strain-responsive graphene oxide conductive hydrogel, which uses a hyperbranched polysiloxane containing epoxy, vinyl, and alkyl groups simultaneously. The resulting hydrogel exhibits excellent mechanical properties and strain response characteristics; however, this application specifies that the hyperbranched polysiloxane must contain multiple functional groups simultaneously. CN105037629A discloses a highly resilient silicone hydrogel formed by reacting a mixture of silicon-containing monomers with hydrophilic monomers and a crosslinking agent. The resilience of the polymer hydrogel is enhanced by the combination of two different silicon-containing monomers. Furthermore, the inventor's previous patent CN115819680A first prepared a polysiloxane prepolymer, then reacted it with aniline and graphene oxide to form a hyperbranched polyaniline-graphene composite, which simultaneously improved the mechanical and electrical properties of the hydrogel.
[0004] Currently, there is not much research on hyperbranched polysiloxanes in hydrogels. There is also limited research on the modification of hyperbranched polysiloxane prepolymers, their composites, and their applications in hydrogels. In particular, there are no reports on how their crosslinking reactions improve mechanical properties. Summary of the Invention
[0005] The purpose of this invention is to provide a hydrogel with high crosslinking degree and high mechanical properties, and its preparation method. Addressing the problem of poor mechanical properties in traditional hydrogels, this invention first prepares a crosslinked hyperbranched polysiloxane using a hyperbranched polysiloxane prepolymer and a crosslinking agent, and then co-prepares it with acrylamide to prepare a hydrogel with high mechanical properties. This hydrogel can be practically applied in fields such as sensors, capacitors, fluid control, and intelligent machinery.
[0006] To achieve the above objectives, the present invention adopts the following technical solution:
[0007] A method for preparing a hydrogel with high mechanical properties includes the following steps:
[0008] (1) Preparation of hyperbranched polysiloxane prepolymer: γ-methacryloxypropyltrimethoxysilane was added to dilute hydrochloric acid and stirred at high temperature. The reaction was carried out by rotary evaporation to obtain hyperbranched polysiloxane prepolymer. The molar ratio of water to siloxane in dilute hydrochloric acid was controlled to be 1.1-1.5:1.
[0009] (2) Pre-crosslinking of hyperbranched polysiloxane: The polysiloxane prepolymer prepared in step (1) is added to an ethanol aqueous solution and stirred. The crosslinking agent and initiator are added and pre-reacted for 1-2 hours. Then, the crosslinked hyperbranched polysiloxane is obtained by rotary evaporation. The mass ratio of the added crosslinking agent, initiator and polysiloxane prepolymer is 0.1-0.5:0.01-0.1:10.
[0010] (3) Preparation of high mechanical property hydrogel: First, the cross-linked hyperbranched polysiloxane prepared in step (2) is soaked and swollen in water. Then, acrylamide, water, cross-linking agent and initiator are added. After ultrasonic stirring, the reaction is carried out to obtain a high degree of cross-linking hydrogel. The hydrogel is then soaked in sodium chloride solution to obtain a high mechanical property hydrogel. The mass ratio of acrylamide, cross-linked hyperbranched polysiloxane, cross-linking agent and water is 1:0.01-0.1:0.01-0.1:10-20.
[0011] Furthermore, in step (1), the reaction temperature is 30-60℃ and the reaction time is 4-6h.
[0012] Furthermore, the crosslinking agent in step (2) includes one or more of polyethylene glycol diacrylate and trimethylolpropane triacrylate.
[0013] Furthermore, in step (2), the crosslinking agent is polyethylene glycol diacrylate and trimethylolpropane triacrylate in a mass ratio of 4-6:4-6.
[0014] Furthermore, in step (2), the initiator is ammonium persulfate, and the reaction temperature is 60-70℃.
[0015] Furthermore, the volume percentage concentration of the ethanol aqueous solution in step (2) is 60%.
[0016] Furthermore, in step (3), the initiator is ammonium persulfate, the reaction time is 4-6 hours, and the reaction temperature is 60-80℃.
[0017] Furthermore, the crosslinking agent in step (3) is N,N-methylenebisacrylamide.
[0018] A hydrogel with high mechanical properties was prepared by the method described above.
[0019] The significant advantages of this invention are:
[0020] (1) The hyperbranched polysiloxane prepared in this invention contains end double bonds and can be used with difunctional or trifunctional crosslinking agents to prepare crosslinked hyperbranched polysiloxane. When reacted with acrylamide and crosslinking agents, crosslinked hydrogels can be obtained, which significantly improves the density and strength of the hydrogel crosslinking network, thereby improving mechanical properties.
[0021] (2) This invention uses thermally initiated free radical polymerization, which does not require special equipment. The preparation method is simple and the conditions are mild. The main raw materials are all commercially available chemicals, which are easy to achieve large-scale production and have high industrialization potential. Detailed Implementation
[0022] To provide a clearer understanding of the technical approach and beneficial effects of the present invention, the technical solution described in the present invention will be further explained below in conjunction with specific embodiments. The tensile properties are tested on a universal tensile testing machine according to the ASTM D412 test standard. The test specimen is 50 mm long, 6 mm wide, and 3 mm thick, and the tensile rate is set to 50 mm / min.
[0023] Example 1
[0024] A method for preparing a hydrogel with high mechanical properties includes the following steps:
[0025] (1) Preparation of hyperbranched polysiloxane prepolymer: Take γ-methacryloxypropyltrimethoxysilane, add dilute hydrochloric acid, heat to 50℃ and stir for 5h, and rotary evaporate to obtain hyperbranched polysiloxane prepolymer. Control the molar ratio of water to siloxane in dilute hydrochloric acid to be 1.3:1.
[0026] (2) Pre-crosslinking of hyperbranched polysiloxane: 10g of the polysiloxane prepolymer prepared in step (1) was added to an ethanol aqueous solution and stirred. 0.5g of a crosslinking agent composed of polyethylene glycol denenoate and trimethylolpropane triacrylate (mass ratio 5:5) and 0.05g of ammonium persulfate were added. After pre-reaction at 70°C for 1h, the crosslinked hyperbranched polysiloxane was obtained by rotary evaporation.
[0027] (3) Preparation of high mechanical properties hydrogel: First, 0.5g of the cross-linked hyperbranched polysiloxane prepared in step (2) was soaked and swollen in water. Then, 10g of acrylamide, 100mL of water, 0.1g of N,N-methylenebisacrylamide and 0.1g of ammonium persulfate were added. After ultrasonic stirring, the mixture was reacted at 80℃ for 5h to obtain a high degree of cross-linking hydrogel. The hydrogel was then soaked in sodium chloride solution to obtain a high mechanical properties hydrogel.
[0028] After testing, the tensile strength of the high mechanical properties hydrogel prepared in Example 1 was 1.07 MPa.
[0029] Example 2
[0030] A method for preparing a hydrogel with high mechanical properties includes the following steps:
[0031] (1) Preparation of hyperbranched polysiloxane prepolymer: γ-methacryloxypropyltrimethoxysilane was added to dilute hydrochloric acid and heated to 50°C and stirred for 5 hours. The hyperbranched polysiloxane prepolymer was obtained by rotary evaporation. The molar ratio of water to siloxane in dilute hydrochloric acid was controlled to be 1.3:1.
[0032] (2) Pre-crosslinking of hyperbranched polysiloxane: 10g of the polysiloxane prepolymer prepared in step (1) was added to an ethanol aqueous solution and stirred. 0.5g of polyethylene glycol diacrylate and 0.05g of ammonium persulfate were added. After pre-reaction at 70°C for 1h, the crosslinked hyperbranched polysiloxane was obtained by rotary evaporation.
[0033] (3) Preparation of high mechanical properties hydrogel: First, 0.5g of the cross-linked hyperbranched polysiloxane prepared in step (2) was soaked and swollen in water. Then, 10g of acrylamide, 100mL of water, 0.1g of N,N-methylenebisacrylamide and 0.1g of ammonium persulfate were added. After ultrasonic stirring, the mixture was reacted at 80℃ for 5h to obtain a high degree of cross-linking hydrogel. The hydrogel was then soaked in sodium chloride solution to obtain a high mechanical properties hydrogel.
[0034] After testing, the tensile strength of the high mechanical properties hydrogel prepared in Example 2 was found to be 0.97 MPa.
[0035] Example 3
[0036] A method for preparing a hydrogel with high mechanical properties includes the following steps:
[0037] (1) Preparation of hyperbranched polysiloxane prepolymer: γ-methacryloxypropyltrimethoxysilane was added to dilute hydrochloric acid and heated to 50°C and stirred for 5 hours. The hyperbranched polysiloxane prepolymer was obtained by rotary evaporation. The molar ratio of water to siloxane in dilute hydrochloric acid was controlled to be 1.3:1.
[0038] (2) Pre-crosslinking of hyperbranched polysiloxane: 10g of the polysiloxane prepolymer prepared in step (1) was added to an ethanol aqueous solution and stirred. 0.5g of trimethylolpropane trimenoate and 0.05g of ammonium persulfate were added. After pre-reaction at 70°C for 1h, the crosslinked hyperbranched polysiloxane was obtained by rotary evaporation.
[0039] (3) Preparation of high mechanical properties hydrogel: First, 0.5g of the cross-linked hyperbranched polysiloxane prepared in step (2) was soaked and swollen in water. Then, 10g of acrylamide, 100mL of water, 0.1g of N,N-methylenebisacrylamide and 0.1g of ammonium persulfate were added. After ultrasonic stirring, the mixture was reacted at 80℃ for 5h to obtain a high degree of cross-linking hydrogel. The hydrogel was then soaked in sodium chloride solution to obtain a high mechanical properties hydrogel.
[0040] After testing, the tensile strength of the high mechanical properties hydrogel prepared in Example 3 was found to be 0.95 MPa.
[0041] Example 4
[0042] A method for preparing a hydrogel with high mechanical properties includes the following steps:
[0043] (1) Preparation of hyperbranched polysiloxane prepolymer: Y-methacryloxypropyltrimethoxysilane was added to dilute hydrochloric acid and stirred at 50°C for 5 hours. The hyperbranched polysiloxane prepolymer was obtained by rotary evaporation. The molar ratio of water to siloxane in dilute hydrochloric acid was controlled to be 1.2:1.
[0044] (2) Pre-crosslinking of hyperbranched polysiloxane: 10g of the polysiloxane prepolymer prepared in step (1) was added to an ethanol aqueous solution and stirred. 0.3g of a crosslinking agent composed of polyethylene glycol diacrylate and trimethylolpropane triacrylate (mass ratio 4:6) and 0.05g of ammonium persulfate were added. After pre-reaction at 70°C for 1h, the crosslinked hyperbranched polysiloxane was obtained by rotary evaporation.
[0045] (3) Preparation of high mechanical properties hydrogel: First, 0.4g of the cross-linked hyperbranched polysiloxane prepared in step (2) was soaked and swollen in water. Then, 10g of acrylamide, 100mL of water, 0.1g of N,N-methylenebisacrylamide and 0.1g of ammonium persulfate were added. After ultrasonic stirring, the mixture was reacted at 75℃ for 6h to obtain a high degree of cross-linking hydrogel. The hydrogel was then soaked in sodium chloride solution to obtain a high mechanical properties hydrogel.
[0046] After testing, the tensile strength of the high mechanical properties hydrogel prepared in Example 4 was found to be 0.92 MPa.
[0047] Example 5
[0048] A method for preparing a hydrogel with high mechanical properties includes the following steps:
[0049] (1) Preparation of hyperbranched polysiloxane prepolymer: γ-methacryloxypropyltrimethoxysilane was added to dilute hydrochloric acid and stirred at 40°C for 5 hours. The hyperbranched polysiloxane prepolymer was obtained by rotary evaporation. The molar ratio of water to siloxane in dilute hydrochloric acid was controlled to be 1.2:1.
[0050] (2) Pre-crosslinking of hyperbranched polysiloxane: 10g of the polysiloxane prepolymer prepared in step (1) was added to an ethanol aqueous solution and stirred. 0.4g of a crosslinking agent composed of polyethylene glycol diacrylate and trimethylolpropane triacrylate (mass ratio 6:4) and 0.05g of ammonium persulfate were added. After pre-reaction at 70℃ for 2h, the crosslinked hyperbranched polysiloxane was obtained by rotary evaporation.
[0051] (3) Preparation of high mechanical properties hydrogel: First, 0.2g of cross-linked hyperbranched polysiloxane prepared in step (2) was soaked and swollen in water. Then, 10g of acrylamide, 100mL of water, 0.1g of N,N-methylenebisacrylamide and 0.1g of ammonium persulfate were added. After ultrasonic stirring, the mixture was reacted at 70℃ for 5h to obtain a high degree of cross-linking hydrogel. The hydrogel was then soaked in sodium chloride solution to obtain a high mechanical properties hydrogel.
[0052] After testing, the tensile strength of the high mechanical properties hydrogel prepared in Example 5 was found to be 0.87 MPa.
[0053] Example 6
[0054] A method for preparing a hydrogel with high mechanical properties includes the following steps:
[0055] (1) Preparation of hyperbranched polysiloxane prepolymer: γ-methacryloxypropyltrimethoxysilane was added to dilute hydrochloric acid and stirred at 40°C for 6 hours. The hyperbranched polysiloxane prepolymer was obtained by rotary evaporation. The molar ratio of water to siloxane in dilute hydrochloric acid was controlled to be 1.2:1.
[0056] (2) Pre-crosslinking of hyperbranched polysiloxane: 10g of the polysiloxane prepolymer prepared in step (1) was added to an ethanol aqueous solution and stirred. 0.3g of a crosslinking agent composed of polyethylene glycol diacrylate and trimethylolpropane triacrylate (mass ratio 4:6) and 0.05g of ammonium persulfate were added. After pre-reaction at 70°C for 1h, the crosslinked hyperbranched polysiloxane was obtained by rotary evaporation.
[0057] (3) Preparation of high mechanical properties hydrogel: First, 0.3g of the cross-linked hyperbranched polysiloxane prepared in step (2) was soaked and swollen in water. Then, 10g of acrylamide, 100mL of water, 0.1g of N,N-methylenebisacrylamide and 0.1g of ammonium persulfate were added. After ultrasonic stirring, the mixture was reacted at 80℃ for 5h to obtain a high degree of cross-linking hydrogel. The hydrogel was then soaked in sodium chloride solution to obtain a high mechanical properties hydrogel.
[0058] After testing, the tensile strength of the high mechanical properties hydrogel prepared in Example 6 was found to be 0.90 MPa.
[0059] Comparative Example 1
[0060] The difference between this comparative example and Example 1 is that the crosslinking step of the hyperbranched polysiloxane is omitted. The specific steps are as follows:
[0061] A method for preparing a hydrogel with high mechanical properties includes the following steps:
[0062] (1) Preparation of hyperbranched polysiloxane prepolymer: γ-methacryloxypropyltrimethoxysilane was added to dilute hydrochloric acid and heated to 50°C and stirred for 5 hours. The hyperbranched polysiloxane prepolymer was obtained by rotary evaporation. The molar ratio of water to siloxane in dilute hydrochloric acid was controlled to be 1.3:1.
[0063] (2) Preparation of high mechanical properties hydrogel: First, 0.5g of the hyperbranched polysiloxane prepolymer prepared in step (1) was soaked and swollen in water. Then, 10g of acrylamide, 100mL of water, 0.1g of N,N-methylenebisacrylamide and 0.1g of ammonium persulfate were added. After ultrasonic stirring, the mixture was reacted at 80℃ for 5h to obtain hydrogel. The hydrogel was then soaked in sodium chloride solution to obtain high mechanical properties hydrogel.
[0064] After testing, the tensile strength of the high mechanical properties hydrogel prepared in Comparative Example 1 was found to be 0.74 MPa.
[0065] Comparative Example 2
[0066] This comparative example omits the preparation and crosslinking steps of hyperbranched polysiloxanes. The specific steps are as follows:
[0067] A method for preparing a hydrogel includes the following steps: mixing 10g of acrylamide with 100mL of water, 0.1g of N,N-methylenebisacrylamide, and 0.1g of ammonium persulfate, ultrasonically stirring until homogeneous, and reacting at 80℃ for 5h to obtain a hydrogel, which is then immersed in a sodium chloride solution to obtain the hydrogel.
[0068] After testing, the tensile strength of the hydrogel prepared in Comparative Example 2 was found to be 0.56 MPa.
[0069] Comparative Example 3
[0070] In this comparative example, the reaction time for the second pre-crosslinking step was increased. The specific steps are as follows:
[0071] A method for preparing a hydrogel with high mechanical properties includes the following steps:
[0072] (1) Preparation of hyperbranched polysiloxane prepolymer: Take γ-methacryloxypropyltrimethoxysilane, add dilute hydrochloric acid, heat to 50℃ and stir for 5h, and rotary evaporate to obtain hyperbranched polysiloxane prepolymer. Control the molar ratio of water to siloxane in dilute hydrochloric acid to be 1.3:1.
[0073] (2) Pre-crosslinking of hyperbranched polysiloxane: 10g of the polysiloxane prepolymer prepared in step (1) was added to an ethanol aqueous solution and stirred. 0.5g of a crosslinking agent composed of polyethylene glycol diacrylate and trimethylolpropane triacrylate (mass ratio 5:5) and 0.05g of ammonium persulfate were added. After pre-reaction at 70℃ for 5h, the crosslinked hyperbranched polysiloxane was obtained by rotary evaporation.
[0074] (3) Preparation of high mechanical properties hydrogel: First, 0.5g of the cross-linked hyperbranched polysiloxane prepared in step (2) was soaked and swollen in water. Then, 10g of acrylamide, 100mL of water, 0.1g of N,N-methylenebisacrylamide and 0.1g of ammonium persulfate were added. After ultrasonic stirring, the mixture was reacted at 80℃ for 5h to obtain a high degree of cross-linking hydrogel. The hydrogel was then soaked in sodium chloride solution to obtain a high mechanical properties hydrogel.
[0075] After testing, the tensile strength of the high mechanical properties hydrogel prepared in Comparative Example 3 was found to be 0.86 MPa.
[0076] A comparison of Example 1 and Comparative Examples 1-2 shows that adding hyperbranched polysiloxanes, especially cross-linked hyperbranched polysiloxanes, can enhance the cross-linking degree and strength of the hydrogel, thereby improving its tensile properties. A comparison of Example 1 and Comparative Example 3 shows that the second-step pre-cross-linking reaction time should not be too long; otherwise, the number of polymerizable functional groups in the cross-linked hyperbranched polysiloxane will decrease, ultimately reducing the cross-linking density of the hydrogel and leading to a decline in mechanical properties. Furthermore, according to Examples 1-3, the combined use of the bifunctional cross-linking agent polyethylene glycol diacrylate and the trifunctional cross-linking agent trimethylolpropane triacrylate yields the best results.
[0077] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made within the scope of the claims of the present invention should be included in the scope of the present invention.
Claims
1. A method for preparing a hydrogel with high mechanical properties, comprising the following steps: (1) Preparation of hyperbranched polysiloxane prepolymer: Take γ-methacryloxypropyltrimethoxysilane, add dilute hydrochloric acid, heat and stir to react, and rotary evaporate to obtain hyperbranched polysiloxane prepolymer; (2) Pre-crosslinking of hyperbranched polysiloxane: The polysiloxane prepolymer prepared in step (1) is added to an ethanol aqueous solution and stirred. A crosslinking agent and an initiator are added and the reaction is carried out for 1-2 hours. Then, the crosslinked hyperbranched polysiloxane is obtained by rotary evaporation. (3) Preparation of high mechanical properties hydrogel: First, the cross-linked hyperbranched polysiloxane prepared in step (2) is soaked and swollen in water, and then acrylamide, water, cross-linking agent and initiator are added. After ultrasonic stirring, the reaction is carried out to obtain a high degree of cross-linking hydrogel. The hydrogel is then soaked in sodium chloride solution to obtain a high mechanical properties hydrogel.
2. The method for preparing a high-mechanical-performance hydrogel according to claim 1, characterized in that: In step (1), the molar ratio of water to siloxane in dilute hydrochloric acid is controlled to be 1.1-1.5:
1.
3. The method for preparing a high-mechanical-performance hydrogel according to claim 1, characterized in that: In step (2), the mass ratio of crosslinking agent, initiator, and polysiloxane prepolymer is 0.1-0.5:0.01-0.1:
10.
4. The method for preparing a high-mechanical-performance hydrogel according to claim 1, characterized in that: In step (3), the mass ratio of acrylamide, crosslinked hyperbranched polysiloxane, crosslinking agent, and water is 1:0.01-0.1:0.01-0.1:10-20.
5. The method for preparing a high-mechanical-performance hydrogel according to claim 1, characterized in that: The reaction temperature in step (1) is 30-60℃ and the reaction time is 4-6h.
6. The method for preparing a high-mechanical-performance hydrogel according to claim 1, characterized in that: The crosslinking agent in step (2) includes one or more of polyethylene glycol diacrylate and trimethylolpropane triacrylate.
7. The method for preparing a high-mechanical-performance hydrogel according to claim 1, characterized in that: In step (2), the crosslinking agent is polyethylene glycol diacrylate and trimethylolpropane triacrylate in a mass ratio of 4-6:4-6.
8. The method for preparing a high-mechanical-performance hydrogel according to claim 1, characterized in that: In step (2), the initiator is ammonium persulfate, the reaction temperature is 60-70℃, and the volume percentage concentration of the ethanol aqueous solution is 60%.
9. The method for preparing a high-mechanical-performance hydrogel according to claim 1, characterized in that: In step (3), the crosslinking agent is N,N-methylenebisacrylamide, the initiator is ammonium persulfate, the reaction time is 4-6 hours, and the reaction temperature is 60-80℃.
10. A high-mechanical-performance hydrogel prepared by the preparation method according to any one of claims 1-9.