A method of preparing a material having acetone detection and self-healing properties

Abstract

The application belongs to the field of intelligent materials, and specifically discloses a preparation method of a material with acetone detection and self-healing property. First, salicylaldehyde Schiff base ligand is formed by reacting salicylaldehyde with 3-aminopropyl dimethoxymethyl silane, then zinc acetate is added and reacted to form a siloxane metal complex, and finally the siloxane metal complex is poured into a mold, dried in an oven, and the solvent is removed to obtain a polysiloxane self-healing material, which is the material with acetone detection and self-healing property. The preparation process is simple, safe, and the selected material is low in toxicity, cheap and easy to obtain. The prepared material can not only be self-healed through a special metal coordination bond, but also can have a color reaction with acetone to detect the presence of acetone, and has good selectivity.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of intelligent materials, and relates to a preparation method of a material with acetone detection and self-healing properties. BACKGROUND

[0002] Digital technology and intelligent systems are changing our lives through the Internet of Things (IoT). Therefore, with the potential growth of smart lifestyles, the application of intelligent materials such as sensors and actuators in the future has attracted great attention in the past few decades. Due to its unique stimulus response characteristics, intelligent materials have always played an important role in the realization of intelligent systems. However, the service life of intelligent materials still needs to be improved, so the durability and safety of intelligent materials can be enhanced by self-repairing properties. There are still some challenges in preparing intelligent materials with self-repairing properties.

[0003] Metal-ligand bonding has unique kinetic properties and different association strengths, and is an extremely attractive non-covalent interaction. This uniqueness is due to the interaction between a metal ion, usually called a coordination center, and a molecule in the vicinity, called a ligand. Due to the difference in bond strength, there are many types of coordination complexes. In addition, this strength can be adjusted by adjusting the properties of the coordination center. By carefully selecting the ligand and metal ion group, the bond strength can be adjusted to a weak or dynamic form suitable for self-healing phenomena. Therefore, metal-ligand interactions are an attractive choice in the field of self-healing polymers. Polysiloxane has excellent properties such as high and low temperature resistance, ozone resistance, excellent permeability, low surface energy, and corrosion resistance due to its highly flexible Si-O-Si bond. The use of polysiloxane to prepare intelligent materials can further broaden the application of intelligent materials and enable them to be used in more fields.

[0004] The prior art CN201810768823.7 discloses a preparation method of a self-healing silicone elastomer based on metal coordination bond-hydrogen bond double crosslinking and an elastomer. It uses octamethylcyclotetrasiloxane and 3-aminopropylmethyldimethoxysilane to prepare a polysiloxane containing amino groups by ring-opening polymerization, then grafts a monomer with a pyridine ring with the amino group to obtain a polysiloxane with a pyridine ring, and then uses metal salt and pyridine ring coordination complexation to obtain a metal coordination-hydrogen bond double crosslinked self-healing silicone elastomer, which has high healing efficiency. However, since the patent uses pyridine ligand to coordinate with metal ions, the pyridine ligand cannot activate the carbonyl group of the metal ions to react with acetone, i.e. it cannot produce a color change reaction with acetone, and cannot achieve the effect of detecting acetone. In addition, since a metal coordination-hydrogen bond double crosslinked structure is used, the healing time of the material is relatively long.

[0005] Therefore, the application proposes a preparation method of a material with acetone detection and self-healing property in order to increase the acetone detection capability of polysiloxane self-healing material and shorten the self-healing time. SUMMARY

[0006] The application discloses a preparation method of a material with acetone detection and self-healing property. The amino group on 3-aminopropyl dimethoxymethyl silane is reacted with the aldehyde group on salicylaldehyde to iminize 3-aminopropyl dimethoxymethyl silane into a salicylaldehyde Schiff base ligand, zinc ions are introduced to form a siloxane metal complex, and finally, a polysiloxane self-healing material is prepared by drying a solvent through a sol-gel method, which is an intelligent material with the properties of acetone detection and self-healing. The application can control the molar ratio of salicylaldehyde and zinc acetate to adjust the content of metal coordination bonds of the material, thereby adjusting the self-healing time of the material. The metal coordination bonds can also have a color reaction with acetone, thereby achieving the effect of acetone detection, which expands the application of the intelligent material.

[0007] In order to achieve the purpose of the application, the technical solution adopted is as follows:

[0008] The preparation method of the material with acetone detection and self-healing property comprises the following steps.

[0009] (1) Preparation of a salicylaldehyde Schiff base ligand: tetrahydrofuran is used as a solvent, 3-aminopropyl dimethoxymethyl silane is added and stirred for 10 min, then salicylaldehyde is added, the temperature is raised to 60-80 DEG C, and stirring is performed for 10-14 h, so that the salicylaldehyde Schiff base ligand is obtained.

[0010] Further, the molar ratio of 3-aminopropyl dimethoxymethyl silane to salicylaldehyde is 1:0.8-1:1.6, preferably, the molar ratio of 3-aminopropyl dimethoxymethyl silane to salicylaldehyde is 1:1.2.

[0011] (2) Preparation of a siloxane metal complex: zinc acetate is added to the salicylaldehyde Schiff base ligand, the temperature is raised to 50-70 DEG C, and stirring is performed for 5-7 h, so that the siloxane metal complex is obtained.

[0012] Further, the molar ratio of 3-aminopropyl dimethoxymethyl silane to zinc acetate is 2:1-6:1, preferably, the molar ratio of 3-aminopropyl dimethoxymethyl silane to zinc acetate is 4:1-6:1.

[0013] (3) Preparation of a material with acetone detection and self-healing property: the siloxane metal complex is poured into a mold, and is placed in a vacuum oven to be dried at a temperature of 30-50 DEG C and a vacuum degree of 0.1 MPa for 16-20 h, so that the material with acetone detection and self-healing property is obtained.

[0014] Compared with the prior art, the present application has the following beneficial effects:

[0015] The present application carries out imidization reaction by using -NH2 group on 3-aminopropyl dimethoxymethyl silane and -C=O group on salicylaldehyde, obtains salicylaldehyde Schiff base ligand, and then carries out coordination with Zn 2+ in acetic acid to obtain siloxane metal complex, and finally obtains polysiloxane self-healing material by drying solvent through sol-gel method, that is, a material with acetone detection and self-healing property. 2+ The material not only can self-heal through metal coordination bond, but also can activate carbonyl and acetone and cause electronic rearrangement. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 The structure of the material with acetone detection and self-healing property.

[0017] Figure 2 The Fourier infrared spectrum of salicylaldehyde Schiff base ligand (a) prepared in step (1) and siloxane metal complex (b) prepared in step (2) of Example 1. -1 The characteristic peak of Zn-O bond and the characteristic peak of C-N bond are enhanced compared with the characteristic peak of salicylaldehyde Schiff base ligand at this place. -1 The characteristic peak of Zn-O bond and the characteristic peak of C-N bond are enhanced compared with the characteristic peak of salicylaldehyde Schiff base ligand at this place.

[0018] Figure 3 The UV spectrum of salicylaldehyde Schiff base ligand (a) prepared in step (1) and siloxane metal complex (b) prepared in step (2) of Example 1.

[0019] Figure 4 The self-healing schematic diagram of the material with acetone detection and self-healing property prepared in Example 1.

[0020] Figure 5 The schematic diagram of the material with acetone detection and self-healing property prepared in Example 1 after contacting with acetone. DETAILED DESCRIPTION

[0021] The application will be further described in the following specific examples. The application is not limited to the following specific examples, and those skilled in the art can implement the application in other various specific embodiments according to the disclosure of the application, or any simple changes or modifications made by using the design structure and ideas of the application all fall within the protection scope of the application. It should be noted that the examples in the application and the features in the examples can be combined with each other without conflict.

[0022] Example 1

[0023] (1) Preparation of salicylaldehyde Schiff base ligand

[0024] First, 5 g of 3-aminopropyl dimethoxymethyl silane and 40 mL of tetrahydrofuran were weighed and stirred uniformly at room temperature, then 2.99 g of salicylaldehyde was added, the molar ratio of 3-aminopropyl dimethoxymethyl silane to salicylaldehyde was 1:0.8, the temperature was raised to 70℃, and the stirring reaction was carried out for 12 h at a stirring rate of 200 r / min. After the reaction was completed, the salicylaldehyde Schiff base ligand was obtained.

[0025] (2) Preparation of siloxane metal complex

[0026] 3.36 g of zinc acetate was weighed and added to the salicylaldehyde Schiff base ligand prepared in step (1), the molar ratio of 3-aminopropyl dimethoxymethyl silane to zinc acetate was 2:1, the reaction temperature was reduced to 60℃, and the stirring reaction was carried out for 6 h at a stirring rate of 200 r / min. After the reaction was completed, the siloxane metal complex was obtained.

[0027] (3) Preparation of material with acetone detection and self-healing property

[0028] The siloxane metal complex was poured into a mold, and the mold was placed in a vacuum oven. After drying at a temperature of 40℃ and a vacuum degree of 0.1 MPa for 18 h, the polysiloxane self-healing material was obtained, which was the material with acetone detection and self-healing property.

[0029] Example 2

[0030] Compared with example 1, the difference lies in that the molar ratio of 3-aminopropyl dimethoxymethyl silane to zinc acetate added is 6:1, which is specifically as follows:

[0031] Step (1) is the same as example 1.

[0032] (2) 1.12 g of zinc acetate was weighed and added to the salicylaldehyde Schiff base ligand prepared in step (1), the reaction temperature was reduced to 60℃, and the stirring reaction was carried out for 6 h at a stirring rate of 200 r / min. After the reaction was completed, the siloxane metal complex was obtained.

[0033] Step (3) is the same as Example 1.

[0034] Example 3

[0035] The difference compared with Example 1 is that the molar ratio of 3-aminopropyl dimethoxymethyl silane to salicylaldehyde is 1:1.2, specifically as follows:

[0036] (1) 5g of 3-aminopropyl dimethoxymethyl silane and 40mL of tetrahydrofuran are stirred uniformly at room temperature, then 4.49g of salicylaldehyde is added, the temperature is raised to 70℃, and stirred for 12h at a stirring rate of 200r / min. After the reaction is completed, the salicylaldehyde Schiff base ligand is obtained.

[0037] Step (2) is the same as Example 1.

[0038] Step (3) is the same as Example 1.

[0039] Example 4

[0040] The difference compared with Example 1 is that the molar ratio of 3-aminopropyl dimethoxymethyl silane to salicylaldehyde is 1:1.6, specifically as follows:

[0041] (1) 5g of 3-aminopropyl dimethoxymethyl silane and 40mL of tetrahydrofuran are stirred uniformly at room temperature, then 5.98g of salicylaldehyde is added, the temperature is raised to 70℃, and stirred for 12h at a stirring rate of 200r / min. After the reaction is completed, the salicylaldehyde Schiff base ligand is obtained.

[0042] Step (2) is the same as Example 1.

[0043] Step (3) is the same as Example 1.

[0044] Example 5

[0045] The difference compared with Example 1 is that the molar ratio of 3-aminopropyl dimethoxymethyl silane to salicylaldehyde is 1:1.6, and the molar ratio of 3-aminopropyl dimethoxymethyl silane to zinc acetate is 6:1, specifically as follows:

[0046] (1) 5g of 3-aminopropyl dimethoxymethyl silane and 40mL of tetrahydrofuran are stirred uniformly at room temperature, then 5.98g of salicylaldehyde is added, the temperature is raised to 70℃, and stirred for 12h at a stirring rate of 200r / min. After the reaction is completed, the salicylaldehyde Schiff base ligand is obtained.

[0047] (2) 1.12g of zinc acetate is added to the salicylaldehyde Schiff base ligand prepared in step (1), the reaction temperature is reduced to 60℃, and stirred for 6h at a stirring rate of 200r / min. After the reaction is completed, the siloxane metal complex is obtained.

[0048] Step (3) is the same as Example 1.

[0049] Example 6

[0050] Compared with Example 3, the difference is that the molar ratio of 3-aminopropyl dimethoxymethyl silane to zinc acetate is 4:1, specifically as follows:

[0051] Step (1) is the same as Example 3.

[0052] (2) 1.68 g of zinc acetate was weighed and added to the salicylaldehyde Schiff base ligand prepared in step (1), the reaction temperature was reduced to 60°C, and the stirring reaction was carried out for 6 h at a stirring rate of 200 r / min. After the reaction was completed, the siloxane metal complex was obtained.

[0053] Step (3) is the same as Example 3.

[0054] Example 7

[0055] Compared with Example 3, the difference is that the molar ratio of 3-aminopropyl dimethoxymethyl silane to zinc acetate is 6:1, specifically as follows:

[0056] Step (1) is the same as Example 3.

[0057] (2) 1.12 g of zinc acetate was weighed and added to the salicylaldehyde Schiff base ligand prepared in step (1), the reaction temperature was reduced to 60°C, and the stirring reaction was carried out for 6 h at a stirring rate of 200 r / min. After the reaction was completed, the siloxane metal complex was obtained.

[0058] Step (3) is the same as Example 3.

[0059] Example 8

[0060] Compared with Example 6, the difference is that the reaction temperature, reaction time, drying temperature and drying time are different, specifically as follows:

[0061] (1) 5 g of 3-aminopropyl dimethoxymethyl silane and 40 mL of tetrahydrofuran were first weighed and stirred uniformly at room temperature, then 4.49 g of salicylaldehyde was added, the temperature was raised to 60°C, and the stirring reaction was carried out for 10 h at a stirring rate of 200 r / min. After the reaction was completed, the salicylaldehyde Schiff base ligand was obtained.

[0062] (2) 1.68 g of zinc acetate was weighed and added to the salicylaldehyde Schiff base ligand prepared in step (1), the reaction temperature was reduced to 50°C, and the stirring reaction was carried out for 5 h at a stirring rate of 200 r / min. After the reaction was completed, the siloxane metal complex was obtained.

[0063] (3) Pour the silicone metal complex into the mold, and place the mold into a vacuum oven, and dry at a temperature of 30℃ and a vacuum degree of 0.1 MPa for 16 h to obtain a polysiloxane self-healing material, which is an acetone detecting and self-healing material.

[0064] Example 9

[0065] Compared with Example 6, the difference lies in different reaction temperature, reaction time, drying temperature and drying time, specifically as follows:

[0066] (1) First, 5 g of 3-aminopropyl dimethoxymethyl silane and 40 mL of tetrahydrofuran are stirred uniformly at room temperature, then 4.49 g of salicylaldehyde is added, the temperature is raised to 80℃, and stirring is performed at a stirring rate of 200 r / min for 14 h, and after the reaction is completed, a salicylaldehyde Schiff base ligand is obtained.

[0067] (2) 1.68 g of zinc acetate is added to the salicylaldehyde Schiff base ligand prepared in step (1), the reaction temperature is reduced to 70℃, and stirring is performed at a stirring rate of 200 r / min for 7 h, and after the reaction is completed, a silicone metal complex is obtained.

[0068] (3) Pour the silicone metal complex into the mold, and place the mold into a vacuum oven, and dry at a temperature of 50℃ and a vacuum degree of 0.1 MPa for 20 h to obtain a polysiloxane self-healing material, which is an acetone detecting and self-healing material.

[0069] Comparative Example 1

[0070] Compared with Example 1, the difference lies in that the molar ratio of 3-aminopropyl dimethoxymethyl silane to salicylaldehyde is 1:2, specifically as follows:

[0071] (1) First, 5 g of 3-aminopropyl dimethoxymethyl silane and 40 mL of tetrahydrofuran are stirred uniformly at room temperature, then 4.49 g of salicylaldehyde is added, the temperature is raised to 80℃, and stirring is performed at a stirring rate of 200 r / min for 14 h, and after the reaction is completed, a salicylaldehyde Schiff base ligand is obtained.

[0072] Step (2) is the same as Example 1.

[0073] Step (3) is the same as Example 1.

[0074] Comparative Example 2

[0075] Compared with Example 6, the difference lies in that 3-aminopropyl dimethoxymethyl silane is replaced by 3-aminopropyl triethoxysilane, specifically as follows:

[0076] (1) 5 g of 3-aminopropyltrimethoxysilane and 40 mL of tetrahydrofuran were stirred uniformly at room temperature, then 4.49 g of salicylaldehyde was added, the temperature was raised to 70°C, and stirring was carried out for 12 h at a stirring rate of 200 r / min. After the reaction was completed, the salicylaldehyde Schiff base ligand was obtained.

[0077] Step (2) is the same as in Example 6.

[0078] Step (3) is the same as in Example 6.

[0079] Comparative Example 3

[0080] Compared with Example 6, the difference is that the salicylaldehyde Schiff base ligand is directly prepared without adding zinc acetate, and the preparation is as follows:

[0081] (1) 5 g of 3-aminopropyltrimethoxysilane and 40 mL of tetrahydrofuran were stirred uniformly at room temperature, then 4.49 g of salicylaldehyde was added, the temperature was raised to 70°C, and stirring was carried out for 12 h at a stirring rate of 200 r / min. After the reaction was completed, the salicylaldehyde Schiff base ligand was obtained.

[0082] (2) The salicylaldehyde Schiff base ligand was poured into a mold, and the mold was placed in a vacuum oven and dried at a temperature of 40°C and a vacuum degree of 0.1 MPa for 18 h to obtain a polysiloxane self-healing material without zinc ions.

[0083] Self-healing test method: The material was cut and then spliced together, and then placed in a 50°C oven at normal pressure for heating. After a period of time, the surface wound of the material was observed under a microscope to determine whether the healing was complete. If there was no fracture after slight pulling and observation under a microscope, it was proved that the healing was complete.

[0084] Color change reaction test method: 1-2 drops of acetone, cyclohexanone, methyl isobutyl ketone, isoflurone or ethanol, toluene were directly added to the surface of the material, and whether the material would turn red was observed.

[0085] The self-healing and color change reaction test data of the materials prepared in Examples 1 to 9 and Comparative Examples 1 to 3 are shown in Table 1.

[0086] Table 1

[0087]

[0088]

[0089] From Table 1, it can be seen that when the molar ratio of 3-aminopropyltrimethoxysilane to salicylaldehyde is 1:1.2, the self-repairing time is the shortest. The reason is that the self-healing effect of the material is highly related to the number of coordination bonds in the network, and the number of salicylaldehyde Schiff base ligands in the material reaches the optimal value at this molar ratio, which can be coordinated with Zn 2+The ion coordination generates appropriate metal coordination bonds to promote the self-healing effect.

[0090] As can be seen from Example 1, when the molar ratio of 3-aminopropyl dimethoxymethyl silane to salicylaldehyde is 1:0.8, the self-repairing time is longer than that of Example 3 with a molar ratio of 1:1.2. The possible reason is that the decrease of salicylaldehyde leads to the decrease of metal coordination bonds, and the self-healing property of the material mainly depends on the reversible repair of metal coordination bonds, so when the metal coordination bonds decrease, the self-repairing time also increases. The reason why the self-repairing time of Example 2 cannot be measured is that the Schiff base ligand of salicylaldehyde and Zn 2+ The decrease of ions leads to too few metal coordination bonds and too low crosslinking density, so the product prepared is a viscous liquid, and thus the self-repairing time cannot be measured.

[0091] As can be seen from Example 4, when the molar ratio of 3-aminopropyl dimethoxymethyl silane to salicylaldehyde is 1:1.6, the self-repairing time is longer than that of Example 3 with a molar ratio of 1:1.2. The possible reason is that too much salicylaldehyde leads to too many metal coordination bonds, so the crosslinking density of the system is too large, the molecular chain movement in the material is hindered, the ligand exchange reaction is slowed down, and the self-repairing time is increased. The same reason also leads to the longer self-repairing time of Example 5 than that of Example 3. Comparative Example 1 is even too hard and brittle due to too much salicylaldehyde, and the self-healing effect is extremely poor.

[0092] As can be seen from Example 3, when the molar ratio of 3-aminopropyl dimethoxymethyl silane to salicylaldehyde is 1:1.2, the self-healing time is the shortest, so the experiment is continued to verify that under the condition of a molar ratio of 1:1.2, the molar ratio of 3-aminopropyl dimethoxymethyl silane to zinc acetate is changed, as shown in the self-repairing time data of Example 6 and Example 7 in Table 1. Under the condition of a molar ratio of 3-aminopropyl dimethoxymethyl silane to salicylaldehyde of 1:1.2 and a molar ratio of 3-aminopropyl dimethoxymethyl silane to zinc acetate of 4:1 (Example 6), the material can achieve the best self-healing effect.

[0093] Example 6 is used to contact different substances to observe whether a color change reaction occurs, and the test results are shown in Table 2.

[0094] Table 2

[0095] Cyclohexanone Methyl isobutyl ketone Isoflurokete Ethanol Toluene Discoloration No No No No No

[0096] As can be seen from Table 2, the polysiloxane self-healing material does not produce a color change reaction with other different substances, and has good selectivity.

[0097] The above merely describes preferred embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can make equivalent substitutions or changes according to the technical solutions and concepts of the present application within the technical scope disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A method for preparing a material with acetone detection and self-healing properties, characterized in that: Includes the following steps: (1) Preparation of salicylaldehyde Schiff base ligand: 3-aminopropyldimethoxymethylsilane and tetrahydrofuran were stirred evenly at room temperature, and then salicylaldehyde was added. After heating and reaction, salicylaldehyde Schiff base ligand was obtained; wherein, the molar ratio of 3-aminopropyldimethoxymethylsilane to salicylaldehyde was 1:0.8~1:1.

6. (2) Preparation of siloxane metal complex: Zinc acetate was added to salicylaldehyde Schiff base ligand and heated to react, and siloxane metal complex was obtained; wherein the molar ratio of 3-aminopropyldimethoxymethylsilane to zinc acetate was 2:1~6:

1. (3) Preparation of materials with acetone detection and self-healing properties: The siloxane metal complex is poured into a mold and dried to obtain materials with acetone detection and self-healing properties; The heating reaction temperature in step (1) is 60~80℃, and the time is 10~14h; The heating reaction temperature in step (2) is 30~50℃ and the time is 16~20h.

2. The method for preparing a material with acetone detection and self-healing properties according to claim 1, characterized in that: The molar ratio of 3-aminopropyldimethoxymethylsilane to salicylaldehyde in step (1) is 1:1.

2.

3. The method for preparing a material with acetone detection and self-healing properties according to claim 1, characterized in that: The molar ratio of 3-aminopropyldimethoxymethylsilane to zinc acetate in step (2) is 4:1 to 6:

1.

4. A material with acetone detection and self-healing properties prepared by the method according to any one of claims 1 to 3.

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