A multi-arm polyethylene glycol gel and preparation method thereof

Abstract

The present invention relates to a multi-arm polyethylene glycol gel and a preparation method thereof, and belongs to the technical field of gel preparation. The preparation method of the multi-arm polyethylene glycol gel of the present invention is to form an anhydride structure by DCC condensation and dehydration of multi-arm polyethylene glycol acetic acid. The multi-arm polyethylene glycol gel of the present invention is a gel of a new structure, with a carboxylic acid group at the end, and is prepared in a non-aqueous phase system, so there is no situation where the active end loses its reactivity, and the prepared gel has good mechanical properties, stable chemical properties, and a wide range of applications. The preparation method of the multi-arm polyethylene glycol gel provided by the present invention has a non-aqueous phase reaction system and a fast gelation rate.

Description

Technical Field

[0001] The invention relates to the technical field of gel preparation, and in particular to a multi-arm polyethylene glycol gel and a preparation method thereof. Background Art

[0002] Polyethylene glycol (PEG) is a common water-soluble polymer. The hydrogel obtained by it is non-toxic and has good biocompatibility. It is widely used in biomedicine and pharmaceutical fields. In addition, there are functional group hydroxyls at both ends of the PEG molecular chain, which are easy to modify and easy to chemically react. PEG is also easy to crystallize. Therefore, it has significant advantages to prepare hydrogels with uniform structure using PEG. However, most of the PEG active ends selected by common PEG hydrogels are NHS esters, and its reaction system is generally in an aqueous phase system. In this reaction system, the active end NHS ester of PEG will have a certain degree of hydrolysis, and the terminal active groups after hydrolysis have lost their reactivity, thereby reducing the cross-linking degree of PEG hydrogel. Summary of the invention

[0003] The present invention aims to solve the technical problem that the active terminal NHS ester of PEG hydrogel in the aqueous phase system loses its reactivity due to hydrolysis, thereby reducing the crosslinking degree of the PEG hydrogel, and provides a multi-arm polyethylene glycol gel and a preparation method thereof. The terminal of the multi-arm polyethylene glycol gel of the present invention is a carboxylic acid group, and it is prepared in a non-aqueous phase system, so there is no situation where the active terminal loses its reactivity.

[0004] In order to achieve the above object, the technical solution of the present invention is as follows:

[0005] The present invention provides a multi-arm polyethylene glycol gel, which is an anhydride structure formed by condensing and dehydrating multi-arm polyethylene glycol acetic acid through dicyclohexylcarbodiimide (DCC);

[0006] The multi-arm polyethylene glycol acetic acid structural formula is one of the structures shown below:

[0007]

[0008] Among them, the value of n is 55-110;

[0009] The structural formula of DCC is as follows:

[0010]

[0011] The degree of polymerization of the acid anhydride structure is 1-20.

[0012] In the above technical solution, it is preferred that: the multi-arm polyethylene glycol acetic acid has the following structural formula:

[0013] The present invention also provides a method for preparing a multi-arm polyethylene glycol gel, comprising the following steps:

[0014] The multi-arm polyethylene glycol acetic acid is subjected to DCC condensation and dehydration to form an anhydride structure to prepare the multi-arm polyethylene glycol gel;

[0015] The multi-arm polyethylene glycol acetic acid structural formula is one of the structures shown below:

[0016]

[0017] Among them, the value of n is 55-110;

[0018] The structural formula of DCC is as follows:

[0019]

[0020] The degree of polymerization of the acid anhydride structure is 1-20.

[0021] In the above technical solution, preferably, the multi-arm polyethylene glycol acetic acid is four-arm polyethylene glycol acetic acid, and its molecular weight is 10000-20000.

[0022] In the above technical solution, preferably, the dicyclohexylcarbodiimide can also be replaced by 1-ethyl-(3-dimethylaminopropyl)carbodiimide (EDC) or N-diisopropylcarbodiimide (DIC).

[0023] In the above technical solution, preferably, the molar ratio of the multi-arm polyethylene glycol acetic acid to dicyclohexylcarbodiimide is 1:13.2-20.

[0024] In the above technical solution, it is further preferred that the molar ratio of the multi-arm polyethylene glycol acetic acid to dicyclohexylcarbodiimide is 1:13.2 or 1:20.

[0025] In the above technical solution, preferably, a specific implementation of the preparation method is:

[0026] The raw material multi-arm polyethylene glycol acetic acid is dissolved with 5 times dichloromethane. When the raw material is completely dissolved, the dissolved raw material liquid is placed in an ice water bath and begins to cool down. When the temperature drops below 5°C, dicyclohexylcarbodiimide is added. After the reaction is complete, the multi-arm polyethylene glycol gel is obtained.

[0027] In the above technical solution, it is further preferred that when the temperature drops to 3°C, dicyclohexylcarbodiimide is added.

[0028] In the above technical solution, preferably, a specific implementation of the preparation method is:

[0029] The raw material multi-arm polyethylene glycol acetic acid is dissolved with 5 times dichloromethane. When the raw material is completely dissolved, dicyclohexylcarbodiimide is added, and the multi-arm polyethylene glycol gel is obtained after the reaction is completed at room temperature of 25 degrees Celsius.

[0030] The beneficial effects of the present invention are:

[0031] The multi-arm polyethylene glycol gel provided by the present invention is a gel with a novel structure prepared by condensing and dehydrating multi-arm polyethylene glycol acetic acid through dicyclohexylcarbodiimide, and its terminal is a carboxylic acid group. Moreover, the gel is prepared in a non-aqueous phase system, so there is no situation where the active terminal loses its reaction activity. The prepared gel has good mechanical properties, stable chemical properties, and a wide range of applications.

[0032] The gelling mechanism of the multi-arm polyethylene glycol gel provided by the present invention is that two or more carboxylic acid groups at the end of PEG are dehydrated by DCC condensation to form anhydride structures, which cause the polymerization of PEG, thereby forming a gel.

[0033] The method for preparing the multi-arm polyethylene glycol gel provided by the invention has a non-aqueous phase reaction system and a fast gelling rate.

[0034] The multi-arm polyethylene glycol gel provided by the present invention has the advantages of fast solidification, non-volatility, stable chemical properties and good insulation, and can therefore be used for insulating equipment and rapid repair of electrical equipment leakage.

[0035] The multi-arm polyethylene glycol gel provided by the present invention has good insulation, stable chemical properties and shock absorption effect, so it plays a good role in protecting the outer skin of new energy vehicle batteries.

[0036] The multi-arm polyethylene glycol gel provided by the present invention can be used for preparing molds and can also be used for sealing valuable items such as handicrafts because of its fast solidification, non-volatility and stable chemical properties.

[0037] The multi-arm polyethylene glycol gel provided by the present invention can also be applied to 3D printing, such as concept car design, large sculptures and even cement building molds. The advantages of this process in concrete construction are also increasingly evident, including the production of concrete casting molds and full-size templates. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0039] Figure 1 This is the H-NMR spectrum of the four-arm polyethylene glycol gel prepared in Example 1 of the present invention.

[0040] Figure 2 This is an electron micrograph of the four-arm polyethylene glycol gel prepared in Example 1 of the present invention.

[0041] Figure 3 This is the H-NMR spectrum of the two-arm polyethylene glycol gel prepared in Example 5 of the present invention.

[0042] Figure 4 This is the NMR carbon spectrum of the two-arm polyethylene glycol gel prepared in Example 5 of the present invention. DETAILED DESCRIPTION

[0043] The present invention is further described below through specific embodiments, but the specific details of the embodiments are only for illustrating the present invention and do not represent all the technical solutions conceived by the present invention. Therefore, they should not be understood as limiting the overall technical solution of the present invention. Some non-substantial additions and modifications that do not deviate from the present invention in the eyes of technical personnel, such as simple replacement or substitution of technical features with the same or similar effects, all fall within the scope of protection of the present invention.

[0044] The reagents used in the following examples are all commercially available products.

[0045] Example 1

[0046] The raw material four-arm polyethylene glycol acetic acid (molecular weight 20000) is dissolved with 5 times dichloromethane. When the raw material is completely dissolved, the dissolved raw material liquid is placed in an ice water bath and the temperature is lowered. When the temperature drops to 3°C, dicyclohexylcarbodiimide (DCC) is added, and gelation can be achieved in about 1 minute. The molar ratio of four-arm polyethylene glycol acetic acid to dicyclohexylcarbodiimide is 1:20, and the four-arm polyethylene glycol gel is obtained. The obtained four-arm polyethylene glycol gel is an anhydride structure, a white gel, and is elastic.

[0047] The multi-arm polyethylene glycol acetic acid structural formula is as follows:

[0048]

[0049] The structural formula of the DCC is as follows:

[0050]

[0051] The degree of polymerization of the anhydride structure is 10.

[0052] Figure 1 This is the H-NMR spectrum of the obtained four-arm polyethylene glycol gel. Due to the molecular weight, the peak of the anhydride is weaker at 4.24. It can be seen from the figure that the multi-arm polyethylene glycol gel was successfully prepared in this example.

[0053] The four-arm polyethylene glycol gel of the present invention has a honeycomb porous structure, and the pores are connected and evenly distributed. Figure 2 .

[0054] The four-arm polyethylene glycol gel of this embodiment has a fast gelling speed, does not volatilize after being placed at room temperature for two days, has no active groups in the structure, is chemically stable, and has good non-conductive insulation properties.

[0055] Example 2

[0056] The raw material four-arm polyethylene glycol acetic acid (molecular weight 20000) is dissolved in 5 times dichloromethane. When the raw material is completely dissolved, dicyclohexylcarbodiimide (DCC) is added to form a gel at room temperature of 25 degrees Celsius for about 1 minute. The molar ratio of four-arm polyethylene glycol acetic acid to dicyclohexylcarbodiimide is 1:20 to obtain the four-arm polyethylene glycol gel. The obtained four-arm polyethylene glycol gel is an anhydride structure, a white gel, and is elastic.

[0057] The multi-arm polyethylene glycol acetic acid structural formula is as follows:

[0058]

[0059] The structural formula of the DCC is as follows:

[0060]

[0061] The degree of polymerization of the anhydride structure is 10.

[0062] Example 3

[0063] The raw material four-arm polyethylene glycol acetic acid (molecular weight 20000) is dissolved in 5 times dichloromethane. When the raw material is completely dissolved, dicyclohexylcarbodiimide (DCC) is added to form a gel at room temperature of 25 degrees Celsius for about 1 minute. The molar ratio of four-arm polyethylene glycol acetic acid to dicyclohexylcarbodiimide is 1:13.2 to obtain the four-arm polyethylene glycol gel. The obtained four-arm polyethylene glycol gel is an anhydride structure, a white gel, and is elastic.

[0064] The multi-arm polyethylene glycol acetic acid structural formula is as follows:

[0065]

[0066] The structural formula of the DCC is as follows:

[0067]

[0068] The degree of polymerization of the anhydride structure is 16.

[0069] Example 4

[0070] The raw material four-arm polyethylene glycol acetic acid (molecular weight 10000) is dissolved in 5 times dichloromethane. When the raw material is completely dissolved, dicyclohexylcarbodiimide (DCC) is added to form a gel at room temperature of 25 degrees Celsius for about 1 minute. The molar ratio of four-arm polyethylene glycol acetic acid to dicyclohexylcarbodiimide is 1:13.2 to obtain the four-arm polyethylene glycol gel. The obtained four-arm polyethylene glycol gel is an anhydride structure, a white gel, and is elastic.

[0071] The multi-arm polyethylene glycol acetic acid structural formula is as follows:

[0072]

[0073] The structural formula of the DCC is as follows:

[0074]

[0075] The degree of polymerization of the anhydride structure is 12.

[0076] Example 5

[0077] The raw material two-arm polyethylene glycol acetic acid (molecular weight 5000) is dissolved in 5 times dichloromethane. When the raw material is completely dissolved, dicyclohexylcarbodiimide (DCC) is added to form a gel at room temperature of 25 degrees Celsius for about 1 minute. The molar ratio of the two-arm polyethylene glycol acetic acid to the dicyclohexylcarbodiimide is 1:20, and the two-arm polyethylene glycol gel is obtained. The obtained two-arm polyethylene glycol gel is an anhydride structure, a white gel, and is elastic.

[0078] The multi-arm polyethylene glycol acetic acid structural formula is as follows:

[0079]

[0080] The structural formula of the DCC is as follows:

[0081]

[0082] The degree of polymerization of the anhydride structure is 10.

[0083] Figure 3 This is the H-NMR spectrum of the two-arm polyethylene glycol gel prepared in Example 5. The peak position of the anhydride is at 4.31. The peak position of the anhydride can be clearly seen, and it can be determined that the connection position group of the gel is the anhydride. Figure 4 This is the NMR carbon spectrum of the two-arm polyethylene glycol gel prepared in Example 5. 166.22 is the carbonyl peak of acetic anhydride, which can also prove that the connecting group is anhydride.

[0084] The multi-arm polyethylene glycol acetic acid raw material used in the above embodiments can also be replaced by six-arm polyethylene glycol acetic acid or eight-arm polyethylene glycol acetic acid, and dicyclohexylcarbodiimide can also be replaced by EDC or DIC. The gel with the technical effect described in the present invention can also be obtained, and examples are not given one by one here.

[0085] Example 6

[0086] The mechanical properties of the multi-arm polyethylene glycol gel prepared in Examples 1-5 were tested as follows:

[0087] With reference to the national standard, a universal mechanical testing machine was used to carry out mechanical tensile and compression tests on the multi-arm polyethylene glycol gels prepared in Examples 1-5.

[0088] Tensile test: Sample specifications: width 8.0mm, thickness 1.5mm, length 25mm, test gauge length 15mm; test conditions: room temperature, tensile rate 50mm / min. Multiple tests were averaged and the results are shown in Table 1.

[0089] Compression modulus determination: Sample specifications: Use a mold to make a cylinder with a diameter of 8 mm and a height of 6 mm, demold, and then test the compression modulus of the gel. The compression rate during the test is 4 mm / min, and the average value is taken from multiple tests. The results are shown in Table 1.

[0090] Table 1

[0091] Group Example 1 Example 2 Example 3 Example 4 Example 5 Elongation 92％ 90％ 85％ 80％ 82％ Compression modulus 185Kpa 182Kpa 175Kpa 170Kpa 172Kpa

[0092] From the results in Table 1, it can be seen that the compression moduli of the multi-arm polyethylene glycol gel prepared in Examples 1-5 of the present invention are 185 Kpa, 182 Kpa, 175 Kpa, 170 Kpa, and 172 Kpa, respectively, and the elongation rates are 92%, 90%, 85%, 80%, and 82%, respectively, indicating that the multi-arm polyethylene glycol gel of the present invention has good mechanical properties.

[0093] In summary, the multi-arm polyethylene glycol gel provided by the present invention is a gel of a novel structure prepared by condensing and dehydrating multi-arm polyethylene glycol acetic acid through cyclohexylcarbodiimide, and its terminal is a carboxylic acid group, and it is prepared in a non-aqueous phase system, so there is no situation where the active terminal loses its reactivity, and the prepared gel has good mechanical properties, stable chemical properties, and a wide range of applications. The preparation method of the multi-arm polyethylene glycol gel provided by the present invention has a non-aqueous phase reaction system and a fast gelation rate.

[0094] The multi-arm polyethylene glycol gel provided by the present invention has the advantages of fast solidification, non-volatility, stable chemical properties, good insulation, shock absorption, etc., and therefore has broad application prospects in the fields of rapid repair of insulation equipment and electrical equipment leakage, mold preparation, sealing of handicrafts and valuables, 3D printing, etc.

[0095] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A multi-arm polyethylene glycol gel, characterized in that: It is a gel containing anhydride structure formed by condensation and dehydration of multi-arm polyethylene glycol acetic acid through dicyclohexylcarbodiimide (DCC); The multi-arm polyethylene glycol acetic acid structural formula is one of the structures shown below: Among them, the value of n is 55-110; The structural formula of the DCC is as follows: The degree of polymerization of the gel containing anhydride structure is 1-20.

2. The multi-arm polyethylene glycol gel according to claim 1, characterized in that The multi-arm polyethylene glycol acetic acid structural formula is as follows:

3. A method for preparing the multi-arm polyethylene glycol gel according to claim 1, characterized in that: The following steps are involved: The multi-arm polyethylene glycol acetic acid is subjected to DCC condensation and dehydration to form a gel containing anhydride structure, thereby preparing the multi-arm polyethylene glycol gel; The multi-arm polyethylene glycol acetic acid structural formula is one of the structures shown below: Among them, the value of n is 55-110; The structural formula of the DCC is as follows: The degree of polymerization of the gel containing anhydride structure is 1-20.

4. The method for preparing the multi-arm polyethylene glycol gel according to claim 3, characterized in that: The multi-arm polyethylene glycol acetic acid is four-arm polyethylene glycol acetic acid, and its molecular weight is 10000-20000.

5. The method for preparing the multi-arm polyethylene glycol gel according to claim 3, characterized in that: The dicyclohexylcarbodiimide is replaced by 1-ethyl-(3-dimethylaminopropyl)carbodiimide or N-diisopropylcarbodiimide.

6. The method for preparing the multi-arm polyethylene glycol gel according to claim 3, characterized in that: The molar ratio of the multi-arm polyethylene glycol acetic acid to dicyclohexylcarbodiimide is 1:13.2-20.

7. The method for preparing the multi-arm polyethylene glycol gel according to claim 3, characterized in that: The molar ratio of the multi-arm polyethylene glycol acetic acid to dicyclohexylcarbodiimide is 1:13.2 or 1:

20.

8. The method for preparing the multi-arm polyethylene glycol gel according to any one of claims 3, 4, 6 and 7, characterized in that: A specific implementation of the preparation method is: The raw material multi-arm polyethylene glycol acetic acid is dissolved with 5 times dichloromethane. When the raw material is completely dissolved, the dissolved raw material liquid is placed in an ice water bath and begins to cool down. When the temperature drops below 5°C, dicyclohexylcarbodiimide is added. After the reaction is complete, the multi-arm polyethylene glycol gel is obtained.

9. The method for preparing the multi-arm polyethylene glycol gel according to claim 8, characterized in that: When the temperature dropped to 3°C, dicyclohexylcarbodiimide was added.

10. The method for preparing the multi-arm polyethylene glycol gel according to any one of claims 3, 4, 6 and 7, characterized in that: A specific implementation of the preparation method is: The raw material multi-arm polyethylene glycol acetic acid is dissolved with 5 times dichloromethane. When the raw material is completely dissolved, dicyclohexylcarbodiimide is added, and the multi-arm polyethylene glycol gel is obtained after the reaction is completed at room temperature of 25 degrees Celsius.

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