Anti-freezing gel and preparation method thereof

Abstract

The invention relates to the field of high polymer materials, and provides anti-freezing gel and a preparation method thereof.The preparation method of the anti-freezing gel comprises the steps that an organic solvent and water are mixed into a binary solvent; the preparation method comprises the following steps: mixing an acrylamide monomer, an acrylic monomer and a binary solvent to obtain a prepolymerization solution; and initiating the pre-polymerization solution to be subjected to cross-linking copolymerization by adopting a thermal initiator so as to form the anti-freezing gel. The anti-freezing gel network is constructed through the acrylamide monomer and the acrylic acid monomer, the monomers are thermally initiated to polymerize to form the anti-freezing gel, and the obtained anti-freezing gel is relatively excellent in anti-freezing effect.

Description

Technical Field

[0001] The present application relates to the field of polymer materials, and in particular to an antifreeze gel and a preparation method thereof. Background Art

[0002] Different from traditional rigid substrate sensors and metal semiconductor material sensors, gel has good flexibility, Young's modulus similar to human tissue, and biocompatibility. Based on these characteristics, gel is gradually developed as a flexible sensor device and widely used in various life scenarios.

[0003] Although gel has great development potential, it faces many problems in practical application. For example, in the cold winter, gel will freeze in low temperature environment, which will greatly reduce its mechanical properties or even disappear, making it difficult to achieve stable application under low temperature conditions. Summary of the invention

[0004] In order to solve the above technical problems, the purpose of the present application is to provide an antifreeze gel and a preparation method thereof. The preparation method is safe and simple, the raw materials are easily available, and the obtained antifreeze gel has excellent antifreeze effect. At low temperatures, the mechanical properties of the antifreeze gel are still relatively excellent.

[0005] In a first aspect, the present application provides a method for preparing an antifreeze gel, which comprises: mixing an organic solvent and water to form a binary solvent; mixing acrylamide monomers, acrylic acid monomers and the binary solvent to form a prepolymer solution; and using a thermal initiator to initiate crosslinking copolymerization of the prepolymer solution to form an antifreeze gel.

[0006] In any embodiment of the first aspect of the present application, the organic solvent includes at least one of a sulfoxide solvent or a solvent containing a hydroxyl group, wherein the sulfoxide solvent includes at least one of dimethyl sulfoxide, diethyl sulfoxide or methyl ethyl sulfoxide; the solvent containing a hydroxyl group includes at least one of glycerol or ethylene glycol.

[0007] In any embodiment of the first aspect of the present application, the mass fraction of the organic solvent is greater than 0% and less than 100%, and can be optionally 30% to 90%, based on the total mass of the binary solvent.

[0008] In any embodiment of the first aspect of the present application, based on the total mass of the prepolymerization solution, the sum of the mass fraction of the acrylamide monomer and the mass fraction of the acrylic acid monomer is 11% to 13%.

[0009] In any embodiment of the first aspect of the present application, the ratio of the mass fraction of the acrylamide monomer to the mass fraction of the acrylic acid monomer is 1:9 to 9:1.

[0010] In any embodiment of the first aspect of the present application, the acrylamide monomer includes at least one of acrylamide, dimethylacrylamide, diethylacrylamide or N-isopropylacrylamide.

[0011] In any embodiment of the first aspect of the present application, based on the total mass of the prepolymerization solution, the mass fraction of the acrylamide monomer is greater than 0% and less than 12.6%.

[0012] In any embodiment of the first aspect of the present application, the acrylic monomer includes at least one of acrylic acid, methacrylic acid, hydroxyethyl acrylate or hydroxypropyl acrylate.

[0013] In any embodiment of the first aspect of the present application, based on the total mass of the prepolymerization solution, the mass fraction of the acrylic acid monomer is greater than 0% and less than 12.6%.

[0014] In any embodiment of the first aspect of the present application, the thermal initiator includes at least one of ammonium persulfate, potassium persulfate or sodium persulfate.

[0015] In any embodiment of the first aspect of the present application, the mass fraction of the thermal initiator is 3.2% to 3.6% based on the total mass of the prepolymerization solution.

[0016] In any embodiment of the first aspect of the present application, the step of mixing the organic solvent and water into a binary solvent includes: mixing the organic solvent and water at room temperature and stirring them evenly to prepare a binary solvent.

[0017] In any embodiment of the first aspect of the present application, the step of mixing acrylamide monomers, acrylic acid monomers and a binary solvent to form a prepolymerization solution includes: adding acrylamide monomers and acrylic acid monomers to a binary solvent at room temperature and stirring to dissolve to prepare a prepolymerization solution.

[0018] In any embodiment of the first aspect of the present application, the step of using a thermal initiator to initiate cross-linking copolymerization of the pre-polymer solution to form an antifreeze gel includes: adding the thermal initiator to the pre-polymer solution and stirring to dissolve at room temperature, and forming the antifreeze gel by thermally initiating free radical polymerization at 45°C to 55°C.

[0019] In a second aspect, the present application provides an antifreeze gel, which is prepared by the preparation method of the first aspect of the present application.

[0020] In any embodiment of the second aspect of the present application, the freezing point of the antifreeze gel ranges from 0°C to -80°C, optionally from -10°C to -60°C, and further optionally from -15°C to -25°C. When the antifreeze gel is placed in a low temperature environment, it exhibits good antifreeze properties.

[0021] The present application constructs an antifreeze gel network through acrylamide monomers and acrylic acid monomers, and thermally initiates monomer polymerization to form antifreeze gel. The polymer formed by acrylamide monomers and acrylic acid monomers has a strong ability to bind to water molecules, which is beneficial to increase the content of bound water in the antifreeze gel and improve the antifreeze performance. During the preparation process, the organic solvent can form a strong hydrogen bond interaction with water molecules, disrupting the hydrogen bond network of water, which can further improve the antifreeze property of the antifreeze gel, and can improve the dispersion of polymer chains and the mechanical properties of the gel. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the implementation methods of the present application, the drawings required for use in the implementation methods of the present application will be briefly introduced below. Obviously, the drawings described below are only some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on the drawings without paying creative work.

[0023] Figure 1 This is an infrared spectrum test chart of the raw material and antifreeze gel of Example 1 of the present application.

[0024] Figure 2 Physical pictures of gels formed at 20°C, -20°C and -80°C at different monomer ratios and different binary solvent ratios provided for the examples and comparative examples of the present application.

[0025] Figure 3 The differential scanning calorimetry diagram of the antifreeze gel formed at different monomer ratios provided in the examples and comparative examples of the present application.

[0026] Figure 4 The Raman spectra of the antifreeze gels formed at different monomer ratios provided in the examples and comparative examples of the present application are shown.

[0027] Figure 5 This is a single compression stress-strain curve diagram of the antifreeze gel provided in Example 1 of the present application at different temperatures. DETAILED DESCRIPTION

[0028] In order to make the application purpose, technical solution and beneficial technical effect of this application clearer, the application is described in detail below in conjunction with specific embodiments. It should be understood that the embodiments described in this specification are only for explaining this application, not for limiting this application.

[0029] For simplicity, only some numerical ranges are explicitly disclosed herein. However, any lower limit can be combined with any upper limit to form an unambiguous range; and any lower limit can be combined with other lower limits to form an unambiguous range, and any upper limit can be combined with any other upper limit to form an unambiguous range. In addition, although not explicitly stated, each point or single value between the range endpoints is included in the range. Thus, each point or single value can be combined with any other point or single value as its own lower limit or upper limit or with other lower limits or upper limits to form an unambiguous range.

[0030] In the description of this article, it should be noted that, unless otherwise specified, “above” and “below” are inclusive of the number itself, and “multiple” in “one or more” means more than two.

[0031] The above application content of the present application is not intended to describe each disclosed embodiment or each implementation in the present application. The following description more specifically illustrates exemplary embodiments. In many places throughout the application, guidance is provided by a series of examples, which can be used in various combinations. In each example, enumeration is only used as a representative group and should not be interpreted as exhaustive.

[0032] The present application has conducted extensive research on the antifreeze properties of antifreeze gels, and has studied whether acrylamide monomers and acrylic acid monomers can be used as polymerization monomers to prepare antifreeze gels with excellent antifreeze properties.

[0033] Therefore, in a first aspect, the present application provides a method for preparing an antifreeze gel, the method comprising: a step S100 of preparing a binary solvent, a step S200 of mixing acrylamide monomers, acrylic acid monomers and the binary solvent to form a prepolymer solution, and a step S300 of using a thermal initiator to initiate cross-linking copolymerization of the prepolymer solution to form an antifreeze gel.

[0034] In step S100, an organic solvent and water are stirred at room temperature.

[0035] In the present application, room temperature refers to the ambient temperature of the system, for example, it can be 20°C-35°C.

[0036] At 20°C-35°C, the organic solvent and water can be quickly and evenly mixed to obtain a homogeneous solvent system without the need for additional heating, which is convenient for industrial production.

[0037] In some embodiments, the organic solvent includes at least one of a sulfoxide solvent or a solvent containing a hydroxyl group. The sulfoxide group and / or hydroxyl group contained in the above organic solvent can form a strong hydrogen bond interaction with water molecules to enhance the antifreeze performance of the antifreeze gel.

[0038] The sulfoxide solvent includes at least one of dimethyl sulfoxide, diethyl sulfoxide or methyl ethyl sulfoxide.

[0039] The solvent containing a hydroxyl group includes at least one of glycerol or ethylene glycol.

[0040] In some embodiments, the mass fraction of the organic solvent is greater than 0% and less than 100% based on the total mass of the binary solvent. Exemplarily, the mass fraction of the organic solvent substance is 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% or a range consisting of any two of the above values. Optionally, the mass fraction of the organic solvent is 30% to 90%, further optionally 30% to 70%, and further optionally 50% to 70%. The mass fraction of the organic solvent within the above range is conducive to making the antifreeze gel have excellent antifreeze properties.

[0041] In step S200 , at least acrylamide monomers, acrylic acid monomers and a binary solvent are mixed to form a prepolymerization solution.

[0042] In some embodiments, based on the total mass of the pre-polymerization solution, the mass fraction of the acrylamide monomer is greater than 0% and less than 12.6%. Exemplarily, the mass fraction of the acrylamide monomer is 1%, 1.26%, 2.52%, 3.78%, 5.04%, 6.3%, 7.56%, 8.82%, 10.08%, 11.34%, 12%, or a range consisting of any two of the above values.

[0043] In some embodiments, based on the total mass of the pre-polymerization solution, the mass fraction of the acrylic monomer is greater than 0% and less than 12.6%. Exemplarily, the mass fraction of the acrylic monomer is 1%, 1.26%, 2.52%, 3.78%, 5.04%, 6.3%, 7.56%, 8.82%, 10.08%, 11.34%, 12%, or a range consisting of any two of the above values.

[0044] In some embodiments, the ratio of the mass fraction of acrylamide monomers to the mass fraction of acrylic acid monomers is 1:9 to 9:1, and can be 3:7 to 9:1. When the ratio of the mass fraction of acrylamide monomers to the mass fraction of acrylic acid monomers is within the above range, the gel network and polymer chain length of the antifreeze gel formed are optimal, which is more conducive to improving the antifreeze performance, mechanical properties, etc. of the antifreeze gel. By adjusting the ratio of the two monomers, the performance of the antifreeze gel can be further improved.

[0045] As the concentration of acrylic acid monomers increases, the ability of the formed polymer chains to bind water molecules increases, the content of bound water in the gel increases, and the antifreeze performance of the gel is significantly improved. As the mass fraction of acrylamide monomers increases, the ability of the formed polymer chains to bind water molecules weakens, the content of bound water in the gel decreases, and the antifreeze performance of the gel decreases. The electronegativity of the carboxyl group is stronger than that of the amide group, so when the concentration of acrylic acid monomers increases, the proportion of carboxyl groups on the polymer chain increases, which enhances its ability to hydrogen bond with water molecules.

[0046] In some embodiments, based on the total mass of the prepolymerization solution, the sum of the mass fraction of the acrylamide monomer and the mass fraction of the acrylic acid monomer is 11%-13%, optionally 12.0% to 13%, for example 12.6%.

[0047] When the sum of the mass fractions of acrylamide monomers and acrylic acid monomers is within the above range, the gel network and polymer chain length of the antifreeze gel formed are optimal, which is more conducive to improving the antifreeze performance and mechanical properties of the antifreeze gel. When the monomer sum is greater than 12.6%, the excessively high monomer concentration will lead to a too fast polymerization reaction rate, causing a violent polymerization phenomenon, making the gel structure uneven, and causing local excessive cross-linking. When the monomer sum is less than 12.6%, due to the insufficient number of monomers, the formed polymer network structure is not perfect, the interaction between the molecular chains is weak, and the strength and stability of the gel will be significantly affected.

[0048] The present application has found that, while keeping the total concentration of acrylamide monomers and acrylic acid monomers substantially unchanged, changing the ratio of acrylamide monomers to acrylic acid monomers can more effectively improve the antifreeze performance of the antifreeze gel formed; specifically, as the content of acrylic acid monomers increases, the corresponding content of acrylamide monomers decreases, so that the carboxyl groups on the copolymerized polymer chains increase and the amide groups decrease, so that it has a stronger interaction with water molecules, thereby enhancing the antifreeze performance of the gel. For example, when the sum of the mass fraction of acrylamide monomers and the mass fraction of acrylic acid monomers is 12.6%, when the mass fraction of acrylic acid monomers increases from greater than 0% to less than 12.6%, the mass fraction of acrylamide monomers will correspondingly decrease from less than 12.6% to greater than 0%.

[0049] In some embodiments, the acrylamide monomer includes at least one of acrylamide, dimethylacrylamide, diethylacrylamide or N-isopropylacrylamide. The above materials all contain amide groups, which can interact strongly with water molecules; and the above chain length groups such as methyl, ethyl and isopropyl have a certain steric hindrance effect, which restricts the movement of polymer chains and enhances the interaction between chains.

[0050] In some embodiments, the acrylic monomer includes at least one of acrylic acid, methacrylic acid, hydroxyethyl acrylate, or hydroxypropyl acrylate. In addition to the carboxyl group of the above materials, which has a strong interaction with water molecules to improve the antifreeze effect of the antifreeze gel, the methyl group has a steric hindrance effect, which affects the flexibility of the gel; and the hydroxyethyl and hydroxypropyl groups have a certain degree of hydrophilicity, and to a certain extent increase the distance between the molecular chains, adjusting the balance between the flexibility and rigidity of the gel.

[0051] For example, acrylamide monomers may include acrylamide, and acrylic acid monomers may include acrylic acid. For another example, acrylamide monomers may include acrylamide and dimethylacrylamide, and acrylic acid monomers may include acrylic acid and methacrylic acid. The copolymerization forms the skeleton of the antifreeze gel network, so that it has a strong hydrogen bond interaction with water molecules in a low temperature environment, thereby achieving excellent antifreeze performance.

[0052] In step S300, a thermal initiator is used to initiate cross-linking copolymerization of the prepolymer solution to form an antifreeze gel.

[0053] In some embodiments, the mass fraction of the thermal initiator is 3.2% to 3.6% based on the total mass of the prepolymer solution and the thermal initiator. For example, the mass fraction of the thermal initiator is 3.2%, 3.3%, 3.4%, 3.5%, 3.6% or a range consisting of any two of the above values.

[0054] The system before copolymerization can be understood as a prepolymerization solution. For example, the total mass of the raw materials (organic solvent, monomer, etc.) in the system is taken as the total mass of the prepolymerization solution.

[0055] In some embodiments, the prepolymer solution is thermally initiated to crosslink and polymerize at a reaction condition of 45° C. to 55° C. for 18 to 22 min.

[0056] In some embodiments, the thermal initiator includes at least one of ammonium persulfate, sodium persulfate or potassium persulfate, which is used to thermally initiate the generation of free radicals, thereby initiating free radical polymerization between acrylamide monomers and acrylic acid monomers.

[0057] According to the embodiments of the present application, an antifreeze gel is obtained by using acrylamide monomers and acrylic acid monomers through a thermally initiated free radical copolymerization mechanism. As the content of acrylic acid monomers increases, the antifreeze property of the formed gel increases, because the amide groups on the formed polymer chains are replaced by carboxyl groups, which enhances its ability to bind water molecules, increases the content of bound water in the gel, and reduces the content of free water, thereby improving the antifreeze property of the gel.

[0058] The antifreeze gel provided according to the embodiments of the present application has excellent antifreeze performance, and the freezing point range of the antifreeze gel is 0°C to -80°C; optionally -10°C to -60°C; further optionally -15°C to -25°C, for example -20°C.

[0059] The antifreeze gel provided in the embodiments of the present application has good mechanical properties under the condition of -20°C.

[0060] In some embodiments, at -20°C, the antifreeze gel has a high mechanical resilience, measured using an electronic universal testing machine, and the shape of the gel sample in the compression test is cylindrical with a diameter of 15 mm and a height of 10 mm.

[0061] The compression rate of the compression test, cyclic progressive compression test and cyclic compression test is 50 mm / min. The compression response time and recovery time are both 318 ms~319 ms. Under the compression test, it can reach 80% strain and recover the original shape, with excellent fatigue resistance, and can achieve about 1000 compression cycle tests, 1000 compression cycles under 50% strain conditions, and can achieve progressive compression from 10% to 80% strain. The above results show that the antifreeze gel has excellent mechanical properties in low temperature environment, laying a foundation for the application of flexible antifreeze gel at low temperature.

[0062] The above test parameters can be tested using test equipment and test methods known in the art, or tested with reference to national standards.

[0063] Example Preparation of Antifreeze Gel

[0064] The following examples describe the disclosure of the present application in more detail, and these examples are intended for illustrative purposes only, as it will be apparent to those skilled in the art that various modifications and variations may be made within the scope of the disclosure of the present application. Unless otherwise stated, all fractions, percentages, and ratios reported in the following examples are by weight, and all reagents used in the examples are commercially available or synthesized according to conventional methods and can be used directly without further processing, and the instruments used in the examples are commercially available.

[0065] Example 1

[0066] In this embodiment, dimethyl sulfoxide and water are used as raw materials to prepare a binary solvent, acrylamide and acrylic acid are used as monomers to be mixed and dissolved with the binary solvent, and polymerization is initiated by a thermal initiator to prepare an antifreeze gel, which specifically includes the following steps:

[0067] (1) Preparation of binary solvent: Accurately weigh dimethyl sulfoxide: water in a mass ratio of 7:3, i.e. 3.5 g of dimethyl sulfoxide and 1.5 g of water, mix them, and stir at room temperature for 5 min at a stirring speed of 500 rpm to fully and evenly dissolve dimethyl sulfoxide and water. Based on the total mass of the binary solvent, the mass fraction of the organic solvent is 70% and the mass fraction of water is 30%.

[0068] (2) Preparation of prepolymer solution: Accurately weigh acrylamide: acrylic acid in a mass ratio of 7:3, i.e., 0.525 g acrylamide and 0.225 g acrylic acid, add the binary solvent in (1) above to the weighed monomers, stir and dissolve at room temperature, and finally add 0.2 g ammonium persulfate to prepare a prepolymer solution. The mass fraction of acrylamide is 8.82% and the mass fraction of acrylic acid is 3.78%, based on the total mass of the prepolymer solution.

[0069] (3) Preparation of antifreeze gel: The prepolymer solution was initiated at 50 °C for 20 min to form an antifreeze gel.

[0070] Figure 1 The infrared spectra of the antifreeze gel prepared in Example 1 and various monomers and solvents are shown. From the comparison of the infrared spectra of acrylamide and acrylic acid monomers with the spectrum of the antifreeze gel in the figure, it can be found that the polymerization mechanism of the antifreeze gel is a free radical polymerization mechanism initiated by heat. Figure 1 As can be seen, 1611cm -1 and 1634 cm -1 The peaks at 1016cm belong to the stretching vibration of the C=C double bond in acrylamide and the stretching vibration of the C=C double bond in acrylic acid. However, there is no stretching vibration peak of the C=C double bond in the formed gel, indicating that the monomer is polymerized into gel by free radicals under thermal initiation conditions, and the characteristic peak disappears. -1 and 952cm -1 The stretching absorption peak at is the S=O characteristic peak of dimethyl sulfoxide, which is also observed in the formed gel, indicating that dimethyl sulfoxide was successfully introduced.

[0071] Example 2

[0072] The antifreeze gel was prepared by a method similar to that in Example 1. The difference from Example 1 was that the masses of dimethyl sulfoxide and water were adjusted in Example 2. Specifically, the steps were as follows:

[0073] (1) Preparation of binary solvent: Accurately weigh dimethyl sulfoxide (DMSO) and water in a mass ratio of 3:7, i.e., 1.5 g DMSO and 3.5 g water. Mix them and stir at room temperature for 5 min at a stirring speed of 500 rpm to ensure that the DMSO and water are fully and evenly dissolved.

[0074] (2) Preparation of prepolymer solution: Accurately weigh acrylamide and acrylic acid in a ratio of 7:3, i.e., 0.525 g acrylamide and 0.225 g acrylic acid, add the binary solvent in (1) above to the weighed monomers, stir to dissolve, and finally add 0.2 g ammonium persulfate to prepare a prepolymer solution. The mass fraction of acrylamide is 8.82% and the mass fraction of acrylic acid is 3.78%, based on the total mass of the prepolymer solution.

[0075] (3) Preparation of antifreeze gel: The prepolymer solution was initiated at 50 °C for 20 min to form an antifreeze gel.

[0076] Example 3

[0077] The antifreeze gel was prepared by a method similar to that of Example 1. The difference from Examples 1 and 2 is that the quality of dimethyl sulfoxide and water was adjusted in Example 3. Specifically, the steps are as follows:

[0078] (1) Preparation of binary solvent: Accurately weigh dimethyl sulfoxide (DMSO) and water in a mass ratio of 5:5, i.e., 2.5 g DMSO and 2.5 g water. Mix them and stir at room temperature for 5 min at a stirring speed of 500 rpm to ensure that the DMSO and water are fully and evenly dissolved.

[0079] (2) Preparation of prepolymer solution: Accurately weigh acrylamide and acrylic acid in a ratio of 7:3, i.e., 0.525 g acrylamide and 0.225 g acrylic acid, add the binary solvent in (1) above to the weighed monomers, stir to dissolve, and finally add 0.2 g ammonium persulfate to prepare a prepolymer solution. The mass fraction of acrylamide is 8.82% and the mass fraction of acrylic acid is 3.78%, based on the total mass of the prepolymer solution.

[0080] (3) Preparation of antifreeze gel: The prepolymer solution was initiated at 50 °C for 20 min to form an antifreeze gel.

[0081] Example 4

[0082] The antifreeze gel was prepared by a method similar to that in Example 1. The difference from Example 1 was that the masses of acrylamide and acrylic acid were adjusted in Example 4. Specifically, the steps were as follows:

[0083] (1) Preparation of binary solvent: accurately weigh dimethyl sulfoxide and water in a ratio of 7:3, i.e., 3.5 g of dimethyl sulfoxide and 1.5 g of water, mix them, and stir at room temperature for 5 min at a stirring speed of 500 rpm to allow dimethyl sulfoxide and water to be fully and evenly dissolved. Based on the total mass of the binary solvent, the mass fraction of the organic solvent is 70% and the mass fraction of water is 30%.

[0084] (2) Preparation of prepolymer solution: Accurately weigh acrylamide and acrylic acid in a ratio of 1:9, i.e., 0.075 g acrylamide and 0.675 g acrylic acid, add the binary solvent in (1) above to the weighed monomers, stir to dissolve, and finally add 0.2 g ammonium persulfate to prepare a prepolymer solution. The mass fraction of acrylamide is 1.26% and the mass fraction of acrylic acid is 11.34%, based on the total mass of the prepolymer solution.

[0085] (3) Preparation of antifreeze gel: The prepolymer solution was initiated at 50 °C for 20 min to form an antifreeze gel.

[0086] Example 5

[0087] The antifreeze gel was prepared by a method similar to that of Example 1. The difference from Example 1 and Example 4 is that the masses of acrylamide and acrylic acid were adjusted in Example 5. Specifically, the steps are as follows:

[0088] (1) Preparation of binary solvent: accurately weigh dimethyl sulfoxide and water in a ratio of 7:3, i.e., 3.5 g of dimethyl sulfoxide and 1.5 g of water, mix them, and stir at room temperature for 5 min at a stirring speed of 500 rpm to allow dimethyl sulfoxide and water to be fully and evenly dissolved. Based on the total mass of the binary solvent, the mass fraction of the organic solvent is 70% and the mass fraction of water is 30%.

[0089] (2) Preparation of prepolymer solution: Accurately weigh acrylamide and acrylic acid in a ratio of 2:8, i.e., 0.15 g acrylamide and 0.6 g acrylic acid, add the binary solvent in (1) above to the weighed monomers, stir to dissolve, and finally add 0.2 g ammonium persulfate to prepare a prepolymer solution. The mass fraction of acrylamide is 2.52% and the mass fraction of acrylic acid is 10.08%, based on the total mass of the prepolymer solution.

[0090] (3) Preparation of antifreeze gel: The prepolymer solution was initiated at 50 °C for 20 min to form an antifreeze gel.

[0091] Example 6

[0092] The antifreeze gel was prepared by a method similar to that of Example 1. The difference from Examples 1, 4 and 5 is that the masses of acrylamide and acrylic acid were adjusted in Example 6. Specifically, the steps are as follows:

[0093] (1) Preparation of binary solvent: accurately weigh dimethyl sulfoxide and water in a ratio of 7:3, i.e., 3.5 g of dimethyl sulfoxide and 1.5 g of water, mix them, and stir at room temperature for 5 min at a stirring speed of 500 rpm to allow dimethyl sulfoxide and water to be fully and evenly dissolved. Based on the total mass of the binary solvent, the mass fraction of the organic solvent is 70% and the mass fraction of water is 30%.

[0094] (2) Preparation of prepolymerization solution: Accurately weigh acrylamide and acrylic acid in a ratio of 3:7, i.e., 0.225 g acrylamide and 0.525 g acrylic acid, add the binary solvent in (1) above to the weighed monomers, stir to dissolve, and finally add 0.2 g ammonium persulfate to prepare a prepolymerization solution. The mass fraction of acrylamide is 3.78% and the mass fraction of acrylic acid is 8.82%, based on the total mass of the prepolymerization solution.

[0095] (3) Preparation of antifreeze gel: The prepolymer solution was initiated at 50 °C for 20 min to form an antifreeze gel.

[0096] Example 7

[0097] The antifreeze gel was prepared by a method similar to that of Example 1. The difference from Examples 1, 4, 5 and 6 was that the masses of acrylamide and acrylic acid were adjusted in Example 7. Specifically, the steps were as follows:

[0098] (1) Preparation of binary solvent: accurately weigh dimethyl sulfoxide and water in a ratio of 7:3, i.e., 3.5 g of dimethyl sulfoxide and 1.5 g of water, mix them, and stir at room temperature for 5 min at a stirring speed of 500 rpm to allow dimethyl sulfoxide and water to be fully and evenly dissolved. Based on the total mass of the binary solvent, the mass fraction of the organic solvent is 70% and the mass fraction of water is 30%.

[0099] (2) Preparation of prepolymerization solution: Accurately weigh acrylamide and acrylic acid in a ratio of 4:6, i.e., 0.3 g acrylamide and 0.45 g acrylic acid, add the binary solvent in (1) above to the weighed monomers, stir to dissolve, and finally add 0.2 g ammonium persulfate to prepare a prepolymerization solution. The mass fraction of acrylamide is 5.04% and the mass fraction of acrylic acid is 7.56%, based on the total mass of the prepolymerization solution.

[0100] (3) Preparation of antifreeze gel: The prepolymer solution was initiated at 50 °C for 20 min to form an antifreeze gel.

[0101] Example 8

[0102] The antifreeze gel was prepared by a method similar to that of Example 1. The difference from Examples 1, 4, 5, 6 and 7 was that the masses of acrylamide and acrylic acid were adjusted in Example 8. Specifically, the steps were as follows:

[0103] (1) Preparation of binary solvent: accurately weigh dimethyl sulfoxide and water in a ratio of 7:3, i.e., 3.5 g of dimethyl sulfoxide and 1.5 g of water, mix them, and stir at room temperature for 5 min at a stirring speed of 500 rpm to allow dimethyl sulfoxide and water to be fully and evenly dissolved. Based on the total mass of the binary solvent, the mass fraction of the organic solvent is 70% and the mass fraction of water is 30%.

[0104] (2) Preparation of prepolymerization solution: Accurately weigh acrylamide and acrylic acid in a ratio of 5:5, i.e., 0.375 g acrylamide and 0.375 g acrylic acid, add the binary solvent in (1) above to the weighed monomers, stir to dissolve, and finally add 0.2 g ammonium persulfate to prepare a prepolymerization solution. The mass fraction of acrylamide is 6.3% and the mass fraction of acrylic acid is 6.3%, based on the total mass of the prepolymerization solution.

[0105] (3) Preparation of antifreeze gel: The prepolymer solution was initiated at 50 °C for 20 min to form an antifreeze gel.

[0106] Example 9

[0107] The antifreeze gel was prepared by a method similar to that of Example 1. The difference from Examples 1, 4, 5, 6, 7 and 8 was that the masses of acrylamide and acrylic acid were adjusted in Example 9. Specifically, the steps were as follows:

[0108] (1) Preparation of binary solvent: accurately weigh dimethyl sulfoxide and water in a ratio of 7:3, i.e., 3.5 g of dimethyl sulfoxide and 1.5 g of water, mix them, and stir at room temperature for 5 min at a stirring speed of 500 rpm to allow dimethyl sulfoxide and water to be fully and evenly dissolved. Based on the total mass of the binary solvent, the mass fraction of the organic solvent is 70% and the mass fraction of water is 30%.

[0109] (2) Preparation of prepolymerization solution: Accurately weigh acrylamide and acrylic acid in a ratio of 6:4, i.e., 0.45 g acrylamide and 0.3 g acrylic acid, add the binary solvent in (1) above to the weighed monomers, stir to dissolve, and finally add 0.2 g ammonium persulfate to prepare a prepolymerization solution. The mass fraction of acrylamide is 7.56% and the mass fraction of acrylic acid is 5.04%, based on the total mass of the prepolymerization solution.

[0110] (3) Preparation of antifreeze gel: The prepolymer solution was initiated at 50 °C for 20 min to form an antifreeze gel.

[0111] Example 10

[0112] The antifreeze gel was prepared by a method similar to that of Example 1. The difference from Examples 1, 4, 5, 6, 7, 8 and 9 was that the masses of acrylamide and acrylic acid were adjusted in Example 10, which specifically included the following steps:

[0113] (1) Preparation of binary solvent: accurately weigh dimethyl sulfoxide and water in a ratio of 7:3, i.e., 3.5 g of dimethyl sulfoxide and 1.5 g of water, mix them, and stir at room temperature for 5 min at a stirring speed of 500 rpm to allow dimethyl sulfoxide and water to be fully and evenly dissolved. Based on the total mass of the binary solvent, the mass fraction of the organic solvent is 70% and the mass fraction of water is 30%.

[0114] (2) Preparation of prepolymerization solution: Accurately weigh acrylamide and acrylic acid in a ratio of 8:2, i.e., 0.6 g acrylamide and 0.15 g acrylic acid, add the binary solvent in (1) above to the weighed monomers, stir to dissolve, and finally add 0.2 g ammonium persulfate to prepare a prepolymerization solution. The mass fraction of acrylamide is 10.08% and the mass fraction of acrylic acid is 2.52%, based on the total mass of the prepolymerization solution.

[0115] (3) Preparation of antifreeze gel: The prepolymer solution was initiated at 50 °C for 20 min to form an antifreeze gel.

[0116] Embodiment 11

[0117] The antifreeze gel was prepared by a method similar to that of Example 1. The difference from Examples 1, 4, 5, 6, 7, 8, 9 and 10 was that the masses of acrylamide and acrylic acid were adjusted in Example 11, which specifically included the following steps:

[0118] (1) Preparation of binary solvent: accurately weigh dimethyl sulfoxide and water in a ratio of 7:3, i.e., 3.5 g of dimethyl sulfoxide and 1.5 g of water, mix them, and stir at room temperature for 5 min at a stirring speed of 500 rpm to allow dimethyl sulfoxide and water to be fully and evenly dissolved. Based on the total mass of the binary solvent, the mass fraction of the organic solvent is 70% and the mass fraction of water is 30%.

[0119] (2) Preparation of prepolymerization solution: Accurately weigh acrylamide and acrylic acid in a ratio of 9:1, i.e., 0.675 g acrylamide and 0.075 g acrylic acid, add the binary solvent in (1) above to the weighed monomers, stir to dissolve, and finally add 0.2 g ammonium persulfate to prepare a prepolymerization solution. The mass fraction of acrylamide is 11.34% and the mass fraction of acrylic acid is 1.26%, based on the total mass of the prepolymerization solution.

[0120] (3) Preparation of antifreeze gel: The prepolymer solution was initiated at 50 °C for 20 min to form an antifreeze gel.

[0121] Example 12

[0122] The antifreeze gel was prepared by a method similar to that of Example 1. The difference from Example 1 was that the types of acrylamide monomers and acrylic acid monomers were adjusted in Example 12. Specifically, the steps included:

[0123] (1) Preparation of binary solvent: accurately weigh dimethyl sulfoxide and water in a ratio of 7:3, i.e., 3.5 g of dimethyl sulfoxide and 1.5 g of water, mix them, and stir at room temperature for 5 min at a stirring speed of 500 rpm to allow dimethyl sulfoxide and water to be fully and evenly dissolved. Based on the total mass of the binary solvent, the mass fraction of the organic solvent is 70% and the mass fraction of water is 30%.

[0124] (2) Preparation of prepolymer solution: Accurately weigh acrylamide: dimethylacrylamide: acrylic acid: methacrylic acid to be 3:4:2:1. Using multiple monomers can better adjust the performance of the antifreeze gel and optimize the preparation process, that is, 0.225 g acrylamide, 0.3 g dimethylacrylamide, 0.15 g acrylic acid and 0.075 g methacrylic acid. Add the binary solvent in (1) above to the weighed monomers, stir to dissolve, and finally add 0.2 g ammonium persulfate to form a prepolymer solution. Among them, based on the total mass of the prepolymer solution, the mass fraction of acrylamide is 3.78%, the mass fraction of dimethylacrylamide is 5.04%, the mass fraction of acrylic acid is 2.52%, and the mass fraction of methacrylic acid is 1.26%.

[0125] (3) Preparation of antifreeze gel: The prepolymer solution was initiated at 50 °C for 20 min to form an antifreeze gel.

[0126] Example 13

[0127] The antifreeze gel was prepared by a method similar to that of Example 1. The difference from Example 1 and Example 14 was that the types of acrylamide monomers and acrylic acid monomers were adjusted in Example 13. Specifically, the steps were as follows:

[0128] (1) Preparation of binary solvent: accurately weigh dimethyl sulfoxide and water in a ratio of 7:3, i.e., 3.5 g of dimethyl sulfoxide and 1.5 g of water, mix them, and stir at room temperature for 5 min at a stirring speed of 500 rpm to allow dimethyl sulfoxide and water to be fully and evenly dissolved. Based on the total mass of the binary solvent, the mass fraction of the organic solvent is 70% and the mass fraction of water is 30%.

[0129] (2) Preparation of prepolymer solution: Accurately weigh acrylamide: diethylacrylamide: acrylic acid: hydroxyethyl acrylate in a ratio of 3:4:2:1, i.e., 0.225 g acrylamide, 0.3 g diethylacrylamide, 0.15 g acrylic acid and 0.075 g hydroxyethyl acrylate, add the binary solvent in (1) above to the weighed monomers, stir to dissolve, and finally add 0.2 g ammonium persulfate to prepare a prepolymer solution. Based on the total mass of the prepolymer solution, the mass fraction of acrylamide is 3.78%, the mass fraction of diethylacrylamide is 5.04%, the mass fraction of acrylic acid is 2.52%, and the mass fraction of hydroxyethyl acrylate is 1.26%.

[0130] (3) Preparation of antifreeze gel: The prepolymer solution was initiated at 50 °C for 20 min to form an antifreeze gel.

[0131] Comparative Example 1

[0132] The antifreeze gel was prepared by a method similar to that in Example 1. The difference from Example 1 is that acrylic acid was not used in Comparative Example 1. The method specifically comprises the following steps:

[0133] (1) Preparation of binary solvent: accurately weigh dimethyl sulfoxide and water in a ratio of 7:3, i.e. 3.5 g of dimethyl sulfoxide and 1.5 g of water, mix them, and stir at room temperature for 5 min at a stirring speed of 500 rpm to allow dimethyl sulfoxide and water to be fully and evenly dissolved. Based on the total mass of the binary solvent, the mass fraction of the organic solvent is 70% and the mass fraction of water is 30%.

[0134] (2) Preparation of prepolymerization solution: Accurately weigh acrylamide: acrylic acid at a ratio of 10:0, i.e., 0.75 g of acrylamide, add the binary solvent in (1) above to the weighed monomers, stir to dissolve, and finally add 0.2 g of ammonium persulfate to prepare a prepolymerization solution. The mass fraction of acrylamide is 12.6% and the mass fraction of acrylic acid is 0%, based on the total mass of the prepolymerization solution.

[0135] (3) Preparation of antifreeze gel: The prepolymer solution was initiated at 50 °C for 20 min to form an antifreeze gel.

[0136] Comparative Example 2

[0137] The antifreeze gel was prepared by a method similar to that of Example 1. The difference from Example 1 is that acrylamide was not used in Comparative Example 2, which specifically comprises the following steps:

[0138] (1) Preparation of binary solvent: accurately weigh dimethyl sulfoxide and water in a ratio of 7:3, i.e. 3.5 g of dimethyl sulfoxide and 1.5 g of water, mix them, and stir at room temperature for 5 min at a stirring speed of 500 rpm to allow dimethyl sulfoxide and water to be fully and evenly dissolved. Based on the total mass of the binary solvent, the mass fraction of the organic solvent is 70% and the mass fraction of water is 30%.

[0139] (2) Preparation of prepolymer solution: Accurately weigh acrylamide: acrylic acid at a ratio of 0:10, i.e., 0.75 g acrylic acid, add the binary solvent in (1) above to the weighed monomers, stir to dissolve, and finally add 0.2 g ammonium persulfate to prepare a prepolymer solution. The mass fraction of acrylamide is 0% and the mass fraction of acrylic acid is 12.6%, based on the total mass of the prepolymer solution.

[0140] (3) Preparation of antifreeze gel: The prepolymer solution was initiated at 50 °C for 20 min to form an antifreeze gel.

[0141] Figure 2 The following are the actual pictures of gels formed under different monomer ratios and different binary solvent ratios at 20 ℃, -20 ℃ and -80 ℃. The test method is to place the prepared gel at 20 ℃, -20 ℃ and -80 ℃ for 48 hours, and observe the change in gel color to determine whether the gel is antifreeze.

[0142] The images show that at 20 °C, the gels formed at all ratios are clear and transparent. At -20 °C and -80 °C, the antifreeze performance of the gel first increases and then decreases with the increase of dimethyl sulfoxide. When the dimethyl sulfoxide: water ratio is 7:3, the antifreeze performance of the series of gels formed is the best; at the same time, the antifreeze performance of the gel will also show a trend of continuous enhancement with the increase of acrylic acid.

[0143] The antifreeze performance of the gel in comparative example 1 is far inferior to that of the gel in the embodiment of the present application; the antifreeze performance of the gel in comparative example 2 is not much different from that of the gel in the embodiment, but its flexibility is greatly reduced. This shows that the desired antifreeze gel can only be obtained by including two types of monomers.

[0144] Figure 3 The differential scanning calorimetry diagram of the antifreeze gel formed at different monomer ratios. The antifreeze property of the gel in the range of -100~0 ℃ was measured using differential scanning calorimetry (DSC). During the cooling process, the crystallization peak temperature gradually decreased with the increase of acrylic acid concentration, proving that the antifreeze property of the gel will continue to improve with the increase of acrylic acid concentration. When the acrylic acid: acrylamide ratio is greater than 7:3, no crystallization peak is observed during the cooling process, indicating that the gel does not form ice crystals in this temperature range.

[0145] Figure 4 The Raman spectra of the antifreeze gel formed under different monomer ratios are shown in Figure 2. Different types of water molecules in the gel were studied using Raman spectroscopy. The Raman spectrum of the gel was fitted with a Gaussian function to obtain four peaks at 3240, 3344, 3426, and 3574 cm -1 The free water peaks are located at 3240 and 3344 cm -1 , the bound water peaks are located at 3426 and 3574 cm -1 By comparing the peak areas, it can be clearly seen that with the increase of acrylic acid concentration, the bound water content in the gel increases and the free water content decreases. This further proves that the antifreeze performance of the antifreeze gel is continuously enhanced with the increase of acrylic acid.

[0146] Figure 5 The single compression stress-strain curves of the antifreeze gel of Example 1 at different temperatures are shown in Figure 1. In order to test the mechanical properties of the gel at different low temperatures, the gel was subjected to a single compression test at 20°C, -20°C, -40°C, -60°C, and -80°C. As can be seen from the figure, even when the temperature drops to -80°C, the gel can still achieve 80% deformation, which proves that the gel has good antifreeze properties.

Claims

1. A method for preparing an antifreeze gel, characterized in that: include: Mixing an organic solvent with water to form a binary solvent; Mixing acrylamide monomers, acrylic acid monomers and the binary solvent to form a prepolymerization solution; A thermal initiator is used to initiate crosslinking and copolymerization of the prepolymer solution to form an antifreeze gel.

2. The method for preparing the antifreeze gel according to claim 1, characterized in that: The organic solvent includes at least one of a sulfoxide solvent or a solvent containing a hydroxyl group, wherein the sulfoxide solvent includes at least one of dimethyl sulfoxide, diethyl sulfoxide or methyl ethyl sulfoxide; the solvent containing a hydroxyl group includes at least one of glycerol or ethylene glycol; and / or Based on the total mass of the binary solvent, the mass fraction of the organic solvent is greater than 0% and less than 100%.

3. The method for preparing the antifreeze gel according to claim 1, characterized in that: Based on the total mass of the prepolymer solution, the sum of the mass fraction of the acrylamide monomer and the mass fraction of the acrylic acid monomer is 11% to 13%.

4. The method for preparing the antifreeze gel according to any one of claims 1 to 3, characterized in that: The acrylamide monomer includes at least one of acrylamide, dimethylacrylamide, diethylacrylamide or N-isopropylacrylamide; and / or Based on the total mass of the prepolymerization solution, the mass fraction of the acrylamide monomer is greater than 0% and less than 12.6%.

5. The method for preparing the antifreeze gel according to any one of claims 1 to 3, characterized in that: The acrylic monomer comprises at least one of acrylic acid, methacrylic acid, hydroxyethyl acrylate or hydroxypropyl acrylate; and / or Based on the total mass of the prepolymerization solution, the mass fraction of the acrylic monomer is greater than 0% and less than 12.6%.

6. The method for preparing the antifreeze gel according to claim 1, characterized in that: The thermal initiator comprises at least one of ammonium persulfate, potassium persulfate or sodium persulfate; and / or Based on the total mass of the prepolymerization solution, the mass fraction of the thermal initiator is 3.2% to 3.6%.

7. The method for preparing the antifreeze gel according to claim 1, characterized in that: The step of mixing the organic solvent and water to form a binary solvent comprises: The organic solvent and water are mixed and stirred evenly at room temperature to prepare a binary solvent.

8. The method for preparing the antifreeze gel according to claim 1, characterized in that: The step of mixing acrylamide monomers, acrylic acid monomers and a binary solvent to form a prepolymerization solution comprises: The acrylamide monomer and the acrylic acid monomer are added into a binary solvent and stirred to dissolve at room temperature to prepare a prepolymerization solution.

9. The method for preparing the antifreeze gel according to claim 1, characterized in that: The step of using a thermal initiator to initiate cross-linking copolymerization of the prepolymer solution to form an antifreeze gel comprises: A thermal initiator is added to the prepolymerization solution at room temperature and stirred to dissolve, and an antifreeze gel is formed by thermally initiating free radical polymerization at 45° C. to 55° C.

10. An antifreeze gel, characterized in that: The antifreeze gel is prepared by the preparation method of any one of claims 1 to 9.

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