CN110408053A - A kind of high toughness antifreeze and heat-resistant polyacrylamide organic hydrogel and preparation method thereof - Google Patents

Abstract

The invention discloses a high-strength, frost-resistant and heat-resistant polyacrylamide organic hydrogel and a preparation method thereof. The polyacrylamide organic hydrogel is prepared by soaking the polyacrylamide hydrogel in polypropylene glycol. Polypropylene glycol and water molecules convert free water into non-freezing water or freezable water through hydrogen bonding. At low temperatures, a small amount of free water and freezable water form tiny ice crystals embedded in the polyacrylamide network, and the tiny ice crystals increase the gel strength. And endow the gel with tensile deformability through shear yielding. Polypropylene glycol also has a physical entanglement with polyacrylamide macromolecular chains to play a strengthening role, making it exhibit excellent mechanical properties at high temperatures of 25°C and 60°C. Therefore, the high strength and toughness antifreeze polyacrylamide organohydrogels provided by the present invention not only exhibit excellent mechanical properties at 25°C and 60°C at high temperatures, but also have high deformation and Fracture toughness has broad application prospects in a wide temperature range.

Description

A kind of high toughness antifreeze and heat-resistant polyacrylamide organic hydrogel and preparation method thereof

technical field

The invention relates to the field of functional polymer materials, in particular to a high-strength, frost-resistant and heat-resistant polyacrylamide organic hydrogel and a preparation method thereof.

Background technique

Hydrogel is a kind of polymer material with a three-dimensional network structure containing a large amount of water. It has important application prospects in tissue engineering, drug controlled release carriers, electronic skin, soft robots and other fields. It has attracted great attention from researchers in recent years. focus on. However, the high water content of conventional hydrogels makes them soft and brittle, low in mechanical strength, sensitive to the environment, and poor in weather resistance. At low temperatures, hydrogels will freeze and lose their flexibility, affecting normal use. Therefore, designing hydrogels with high strength and good flexibility at low temperature is of great value.

The water in the hydrogel exists in three states: the first is non-freezing water, which forms non-freezing water or a monomolecular hydration layer through hydrogen bonding with the hydroxyl groups on the polymer macromolecular chain, and it will not cool down to -100°C. Crystallization; the second is freezable water, non-freezable water can absorb water molecules to form a secondary or tertiary hydration layer, that is, freezable water, and its obvious feature is that the phase transition temperature is between -45°C and -25°C, lower than The phase transition temperature of pure water or free water; the third is free water, the rest of the water is free water, and its characteristic phase transition temperature is around -18°C. Because the water content in the hydrogel system is more than 70%, the free water in the hydrogel network will freeze at low temperature and lose fluidity, thereby causing the hydrogel to harden and lose flexibility.

The conventional way to prepare antifreeze hydrogel is to introduce small molecule polyalcohol antifreeze agents such as ethylene glycol and glycerin (commonly known as glycerin), which can be miscible with water in any proportion, changing the vapor temperature of cooling water. Press to lower the freezing point and achieve antifreeze. For example, the Luxiong research group of Southwest Jiaotong University used glycerol-water as a binary solvent, and ultraviolet light triggered the copolymerization of acrylic acid and acrylamide monomers, and compounded with polydopamine-modified carbon nanotubes to prepare antifreeze hydrogels, which can The quality is stable for a long time in the temperature range of -20°C to 60°C (Adv. Funct. Mater. 2018, 28, 1704195). However, the tensile strength (<100KPa) and maximum tensile deformation (<800%) of the hydrogel prepared by this method are not high. Zhou Xuechang of Shenzhen University et al. soaked the prepared calcium alginate/polyacrylamide double network hydrogel in glycerin, and used glycerin to replace part of the water in the gel to obtain a freeze-resistant and non-drying double network hydrogel. Its tensile stress is about 250KPa, and the maximum deformation is about 1500%, which does not provide the performance of gel at low temperature. (Angew. Chem. Int. Ed. 2018, 57, 6568-6571). Patent CN201811482152.4 discloses a preparation method of a high-strength, tough, viscous, weather-resistant polyvinyl alcohol-based double network hydrogel, using polyvinyl alcohol as a starting material, heating and dissolving it in deionized water to make a polyvinyl alcohol aqueous solution, Add glycerin, sodium chloride, acrylamide, acrylic acid, crosslinking agent N,N'-methylene bisacrylamide and initiator Irgacure 2959 to the obtained polyvinyl alcohol aqueous solution, and then undergo photoinitiation under ultraviolet light to obtain chemical crosslinking. The polyacrylamide-acrylic acid cross-linked structure is used to construct a double-network high-strength polyvinyl alcohol-based hydrogel. The tensile strength is about 1 MPa, and the elongation at break is about 1000%, which does not provide the performance of gel at low temperature.

The preparation method of the antifreeze hydrogel of aforementioned report all is to reduce the loss of water by means of small molecule polyalcohol antifreeze agent such as glycerol, ethylene glycol, sorbitol or its blend and water miscibility in the hydrogel. freezing point. However, small molecular polyols have no reinforcing effect on the hydrogel system, and the improvement of mechanical properties is mainly achieved by introducing nano-fillers (such as carbon nanotubes) or constructing a double network structure. The preparation process of introducing nanofillers or constructing a double network structure is complex, so a simple and easy method is urgently needed to obtain polyacrylamide hydrogels that maintain large deformability and toughness at low temperatures far below 0 °C.

Contents of the invention

The object of the present invention is to provide a high-strength, frost-resistant and heat-resistant polyacrylamide organohydrogel and its preparation method, which overcomes the current problem that the hydrogel system needs to be enhanced by introducing complex methods such as nano fillers.

For reaching this purpose, the present invention adopts following technical scheme:

The invention discloses a high-strength, antifreeze and heat-resistant polyacrylamide organic hydrogel, which is prepared by soaking the polyacrylamide hydrogel in polypropylene glycol.

Optionally, the number average molecular weight of the polypropylene glycol is 200-2000, and the soaking time is 5-180 min.

Optionally, the number average molecular weight of the polypropylene glycol is 500, and the soaking time is 30 minutes.

Optionally, the polyacrylamide hydrogel is prepared by polymerization of polymer monomers, and the polymer monomers are acrylamide monomers;

The polymerization reaction is carried out in the presence of solvent, crosslinking agent, initiator and catalyst.

Optionally, the solvent is water, the crosslinking agent is N,N'-methylenebisacrylamide, the initiator is ammonium persulfate, and the catalyst is tetramethylethylenediamine.

Optionally, the mass of the crosslinking agent is 0.02%-0.18% of the mass of the polymer monomer; the mass of the initiator is 0.1%-0.2% of the mass of the polymer monomer.

Optionally, the ratio of the polymer monomer, solvent, crosslinking agent, initiator and catalyst is 13.8g: 46-56mL: 2.76-24.84mg: 13.8-41.4mg: 22-44μL.

Optionally, the ratio of the polymer monomer, solvent, crosslinking agent, initiator and catalyst is 13.8g: 46mL: 4mg: 32.2mg: 22μL.

A method for preparing the aforementioned high-strength, frost-resistant and heat-resistant polyacrylamide organic hydrogel, comprising the following steps:

The polyacrylamide hydrogel is soaked in polypropylene glycol to obtain a high-strength antifreeze and heat-resistant polyacrylamide organic hydrogel.

Optionally, the polyacrylamide hydrogel is prepared according to the following steps:

Disperse the acrylamide monomer and crosslinking agent in water first, then add the initiator, then drop the catalyst, and stir to obtain a mixed solution;

Ultrasonic defoaming is performed on the mixed solution; the reaction temperature of the mixed solution after ultrasonic defoaming is controlled at 25° C. and kept for 4-24 hours to obtain a polyacrylamide hydrogel.

Compared with the prior art, the present invention has the following beneficial effects:

The high-strength, toughness, frost-resistant and heat-resistant polyacrylamide organic hydrogel provided by the present invention is prepared by soaking polyacrylamide hydrogel in polypropylene glycol. Polypropylene glycol is an oligomer with terminal hydroxyl groups, which can be combined with Water molecules change free water into non-freezing water or freezable water through hydrogen bonding. Slurry gel composed of mixture with polypropylene glycol solution. On the one hand, these tiny ice crystals increase the strength of the gel, and on the other hand, they can endow the gel with a large tensile deformation ability through shear yielding. The strengthening mechanism is similar to that of rigid nanoparticles reinforcing the elastomer. In addition, polypropylene glycol can physically entangle with polyacrylamide macromolecular chains to play a strengthening role, making it exhibit excellent mechanical properties at room temperature such as around 30°C and high temperature such as around 60°C.

Therefore, the high strength and toughness antifreeze polyacrylamide organohydrogels provided by the present invention not only exhibit excellent mechanical properties at room temperature and high temperature of 60°C, but also have high deformation and fracture at temperatures far below 0°C Toughness, excellent mechanical properties in a wide temperature range. After testing, the tensile deformation of the high-strength and tough antifreeze polyacrylamide organic hydrogel can exceed 5000% at room temperature of 30°C, and the tensile deformation can still exceed 2000% after being frozen at -20°C for 24 hours, and the tensile strength It can reach 1MPa, and the tensile deformation can still exceed 1000% at a high temperature of 60°C, and the tensile strength exceeds 180KPa. In a wide temperature range, the physical properties are better than those soaked in glycerin, especially at low temperature -20°C and high temperature 60°C. It is the existing small molecule polyol modified hydraulic gel Glue can not achieve. The high-strength and toughness antifreeze polyacrylamide organohydrogel greatly broadens the use temperature range of the polyacrylamide hydrogel material, and its excellent performance has broad application prospects in the fields of tissue engineering and the like.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. For those skilled in the art, other drawings can also be obtained according to these drawings on the premise of not paying creative efforts.

Fig. 1 is the DSC curve of cooling and heating of polyacrylamide hydrogel soaked in polypropylene glycol 500 for different time provided by Example 4 of the present invention.

Fig. 2 is the tensile property curve at 30° C. of the polyacrylamide hydrogel soaked in polypropylene glycol 500 for different time provided by Example 4 of the present invention.

Fig. 3 is the tensile property curve at -20°C of the polyacrylamide hydrogel soaked in polypropylene glycol 500 for different time provided by Example 4 of the present invention.

Fig. 4 is the tensile property curve at -60°C of polyacrylamide hydrogel soaked in polypropylene glycol 500 for different time provided by Example 4 of the present invention.

Fig. 5 is the DSC curves of polyacrylamide hydrogel soaked in different molecular weight polypropylene glycols provided by Example 5 of the present invention during cooling and heating.

Detailed ways

In order to make the object of the present invention, features, and advantages more obvious and understandable, the technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments. Obviously, the embodiments described below are only the present invention. Some embodiments, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

The invention provides a high-strength, toughness, frost-resistant and heat-resistant polyacrylamide organic hydrogel, which is prepared by soaking polyacrylamide hydrogel in polypropylene glycol .

Polypropylene glycol, also known as propylene glycol polyether, is a colorless transparent oily viscous liquid at 25°C. Polypropylene glycol is an oligomer with terminal hydroxyl groups, and its molecular weight is much larger than that of small molecule polyols such as ethylene glycol and glycerin. Polypropylene glycol can interact with water molecules through hydrogen bonds to change free water into non-freezing water or freezable water. At low temperatures, small ice crystals formed by a small amount of free water and freezable water in the polyacrylamide hydrogel system form a A slurry gel consisting of a mixture of tiny ice crystals and a solution of polypropylene glycol. On the one hand, these tiny ice crystals increase the strength of the gel, and on the other hand, they can endow the gel with high tensile deformation capacity through shear yielding. The strengthening mechanism is similar to that of rigid nanoparticles reinforcing the elastomer. In addition, polypropylene glycol can physically entangle with polyacrylamide macromolecular chains to play a strengthening role, so that it can exhibit excellent mechanical properties at room temperature such as around 30°C and high temperature such as around 60°C. Therefore, the high-strength, toughness, frost-resistant and heat-resistant polyacrylamide organohydrogel provided by the present invention greatly broadens the use temperature range of the polyacrylamide hydrogel material.

In the embodiment of the present invention, the number average molecular weight of the polypropylene glycol is 200-2000, and the soaking time is 5-180 min.

The selection of the molecular weight of polypropylene glycol needs to be considered in many aspects. On the one hand, the higher the molecular weight of polypropylene glycol, the more physical entanglement with polyacrylamide macromolecular chains, and the more obvious the strengthening effect. On the other hand, the miscibility of polypropylene glycol and water decreases with the increase of molecular weight, the polypropylene glycol of lower molecular weight can be dissolved in water, and the polypropylene glycol of higher molecular weight is only slightly soluble in water; and the viscosity of polypropylene glycol with higher molecular weight increases The larger the size, the slower the diffusion and the longer the soaking time required. Therefore, it is very important to choose polypropylene glycol with appropriate molecular weight.

In the embodiment of the present invention, the number average molecular weight of the polypropylene glycol is specifically selected from one of 400, 500, 600, 1000, 1500 and 2000, preferably 500.

When the molecular weight of the polypropylene glycol is 500, the corresponding soaking time is preferably 30 minutes. In the process of immersing polypropylene glycol, the diffusion rate of polypropylene glycol into polyacrylamide hydrogel was relatively fast at the beginning, then gradually slowed down after 30 minutes, and basically reached equilibrium in 180 minutes.

The polyacrylamide hydrogel of the present invention is prepared from polymer monomers through polymerization, and the polymerization is carried out under the conditions of the presence of a solvent, a crosslinking agent, an initiator and a catalyst.

Wherein, the polymer monomer is an acrylamide monomer, the solvent is water, the crosslinking agent is N,N'-methylenebisacrylamide, the initiator is ammonium persulfate, and the catalyst For tetramethylethylenediamine.

The mass of the crosslinking agent is 0.02%-0.18% of the mass of the polymer monomer; the mass of the initiator is 0.1%-0.3% of the mass of the polymer monomer. The proportion of the polymer monomer, solvent, crosslinking agent, initiator and catalyst is 13.8g: 46-56mL: 2.76-24.84mg: 13.8-41.4mg: 22-44μL.

The present invention also provides a preparation method of a high-strength, frost-resistant and heat-resistant polyacrylamide organic hydrogel, comprising the following steps:

The polyacrylamide hydrogel is soaked in polypropylene glycol to obtain a high-strength antifreeze and heat-resistant polyacrylamide organic hydrogel.

Wherein, the polyacrylamide hydrogel is prepared according to the following steps:

Disperse the acrylamide monomer and crosslinking agent in water first, then add the initiator, then drop the catalyst, and stir to obtain a mixed solution;

Ultrasonic defoaming is performed on the mixed solution; the reaction temperature of the mixed solution after ultrasonic defoaming is controlled at 25° C. and kept for 4-24 hours to obtain a polyacrylamide hydrogel.

The preparation method is based on the same inventive concept as the aforementioned high-strength, toughness, freeze-resistant, and heat-resistant polyacrylamide organic hydrogel, and the high-strength, freeze-resistant, and heat-resistant polyacrylamide organic hydrogel obtained by the preparation method has the aforementioned high-strength, toughness, and heat-resistant polyacrylamide organic hydrogels. Properties and effects of freeze- and heat-resistant polyacrylamide organohydrogels. The selection and proportioning of cross-linking agent, initiator and catalyst in the preparation method, as well as the molecular weight and soaking time of polypropylene glycol, etc., are the same as those described above, and will not be repeated here.

After testing, the tensile deformation of the high-strength, frost-resistant and heat-resistant polyacrylamide organic hydrogel provided by the present invention can exceed 5000% at room temperature; The tensile strength can reach 1MPa; the tensile deformation can still exceed 1000% at a high temperature of 60°C, and the tensile strength can exceed 180KPa. The high-strength, frost-resistant and heat-resistant polyacrylamide organohydrogel has better physical properties than samples soaked in glycerol in a wide temperature range, especially the high strength and toughness at low temperatures, and is an existing small molecule polyacrylamide hydrogel. Alcohol-modified hydrogels cannot be realized, which greatly broadens the temperature range of polyacrylamide hydrogel materials, and its excellent performance has broad application prospects in tissue engineering and other fields.

The invention is described in further detail below with specific examples.

In all following examples and comparative examples, the test of the tensile properties of the hydrogel is carried out on a universal material testing machine, and the test sample is a standard sample cut by a dumbbell-shaped cutter, with a length of 75 mm and a width of 4 ± 0.1 mm in the middle. mm, the thickness is 2±0.2mm, and the tensile rate is 100mm/min. Three samples were tested for each sample to obtain the average value.

Example 1

A method for preparing a high-strength, frost-resistant and heat-resistant polyacrylamide organic hydrogel, specifically comprising the following steps:

Weigh 13.8g of acrylamide monomer, dissolve it in 46ml of deionized water, then add 4.0mg of N,N'-methylenebisacrylamide, stir magnetically at room temperature to disperse evenly, then add 32.2mg of ammonium persulfate, and continue stirring Obtain a homogeneous solution, then use a pipette gun to take 22uL tetramethylethylenediamine dropwise into the above mixed solution and keep stirring evenly. After the solution is ultrasonically defoamed, it is introduced into a molding mold and reacted at room temperature for 4 hours to obtain a polyacrylamide hydrogel. Soak the prepared polyacrylamide hydrogel in polypropylene glycol 500 for 30 minutes to obtain a high-strength, freeze-resistant and heat-resistant polyacrylamide organic hydrogel.

The tensile performance test results are as follows: the tensile strain of the high-strength, toughness, frost-resistant and heat-resistant polyacrylamide organic hydrogel exceeds 5000% (the sample is not broken) at 30 °C, and the tensile strength of the spline is about 380KPa. After being frozen at -20°C for 24 hours, the polyacrylamide organic hydrogel still has good flexibility, the elongation at break is about 2200%, and the tensile strength is 1.05 MPa. The tensile strength of the polyacrylamide organohydrogel at 60°C is about 330KPa, and the elongation at break is about 1600%.

Example 2

The preparation of a high-strength antifreeze and heat-resistant polyacrylamide organic hydrogel specifically comprises the following steps:

Weigh 13.8g of acrylamide monomer, dissolve it in 46ml of deionized water, then add 8.0mg of N,N'-methylenebisacrylamide, stir it with magnetic force at room temperature to disperse evenly, then add 32.2mg of ammonium persulfate, and continue stirring Obtain a homogeneous solution, then use a pipette gun to take 44uL tetramethylethylenediamine dropwise into the above mixed solution and keep stirring evenly. After the solution is ultrasonically defoamed, it is introduced into a molding mold and reacted at room temperature for 6 hours to obtain a polyacrylamide hydrogel. Soak the prepared polyacrylamide hydrogel in polypropylene glycol 600 for 1 hour to obtain a high-strength, freeze-resistant and heat-resistant polyacrylamide organic hydrogel.

The tensile performance test results are as follows: the tensile strain of the high-strength, toughness, frost-resistant and heat-resistant polyacrylamide organic hydrogel exceeds 5000% (the sample is not broken) at 30 °C, and the tensile strength of the spline is about 480KPa. After being frozen at -20°C for 24 hours, the polyacrylamide organohydrogel has a breaking elongation of about 2100% and a tensile strength of about 930KPa. The tensile strength of the polyacrylamide organohydrogel at 60°C is about 220KPa, and the elongation at break is about 1100%.

Example 3

The preparation of a high-strength antifreeze and heat-resistant polyacrylamide organic hydrogel specifically comprises the following steps:

Weigh 13.8g of acrylamide monomer, dissolve it in 46ml of deionized water, then add 6.0mg of N,N'-methylenebisacrylamide, stir it with magnetic force at room temperature to disperse evenly, then add 41.4mg of ammonium persulfate, and continue stirring Obtain a homogeneous solution, then use a pipette gun to take 22uL tetramethylethylenediamine dropwise into the above mixed solution and keep stirring evenly. After the solution is ultrasonically defoamed, it is introduced into a molding mold and reacted at room temperature for 12 hours to obtain a polyacrylamide hydrogel. Soak the prepared polyacrylamide hydrogel in polypropylene glycol 2000 for 2 hours to obtain a high-strength, freeze-resistant and heat-resistant polyacrylamide organic hydrogel.

The tensile performance test results are as follows: the tensile strain of the high-strength, toughness, freeze-resistant and heat-resistant polyacrylamide organic hydrogel exceeds 5000% (the sample is not broken) at 30 °C, and the tensile strength of the spline is about 700KPa. After being frozen at -20°C for 24 hours, the polyacrylamide organohydrogel had a breaking elongation of about 3500% and a tensile strength of about 1.27 MPa. The tensile strength of the polyacrylamide organohydrogel at 60°C is about 260KPa, and the elongation at break is about 1300%.

Comparative example 1

Weigh 13.8g of acrylamide monomer, dissolve it in 46ml of deionized water, then add 6.0mg of N,N'-methylenebisacrylamide, stir it with magnetic force at room temperature to disperse evenly, then add 32.2mg of ammonium persulfate, and continue stirring Obtain a homogeneous solution, then use a pipette gun to take 44uL tetramethylethylenediamine dropwise into the above mixed solution and keep stirring evenly. After the solution was ultrasonically defoamed, it was introduced into a molding mold and reacted at room temperature for 4 hours to obtain a polyacrylamide hydrogel as comparative sample 1.

The tensile property test results are as follows: the tensile strength of the polyacrylamide hydrogel at 30° C. is about 140 KPa, and the elongation at break is about 1000%. After being frozen at -20°C for 24 hours, the polyacrylamide hydrogel sample was in a white frozen state, with a tensile strength of about 170KPa and an elongation at break of about 2000%. The tensile strength of the polyacrylamide hydrogel at 60°C is about 70KPa, and the elongation at break is about 800%.

Comparative example 2

Weigh 13.8g of acrylamide monomer, dissolve it in 46ml of deionized water, then add 6.0mg of N,N'-methylenebisacrylamide, stir it with magnetic force at room temperature to disperse evenly, then add 32.2mg of ammonium persulfate, and continue stirring Obtain a homogeneous solution, then use a pipette gun to take 44uL tetramethylethylenediamine dropwise into the above mixed solution and keep stirring evenly. After the solution is ultrasonically defoamed, it is introduced into a molding mold and reacted at room temperature for 4 hours to obtain a polyacrylamide hydrogel. Soak the prepared polyacrylamide hydrogel in glycerol (glycerin) for 30 minutes, and compare the polyacrylamide hydrogel with sample 2.

The tensile property test results are as follows: the tensile strength of the polyacrylamide hydrogel at 30°C is about 330KPa, and the elongation at break is about 1500%. After being frozen at -20°C for 24 hours, the polyacrylamide hydrogel sample still maintained good toughness, the tensile strength was about 450KPa, and the elongation at break was about 2500%. The tensile strength of the polyacrylamide hydrogel at 60°C is about 80KPa, and the elongation at break is about 700%.

The present invention also explores the influence of soaking time on polyacrylamide hydrogel.

Embodiment 4: Soaking time contrast

For Example 1, this example only changed the soaking time, and obtained polyacrylamide organic hydrogel soaked in polypropylene glycol 500 for different times (0min; 5min; 10min; 30min; 60min; 120min).

In this embodiment, DSC (differential scanning calorimetry) curves of various polyacrylamide organohydrogels were obtained through testing. Fig. 1 is the DSC curve of polyacrylamide organohydrogel soaked in polypropylene glycol 500 for different periods of time in cooling (upward heat release) and temperature rise (downward heat absorption). Among them, the curves 1-6 represent that the samples soaked in PPG500 for 0min, 5min, 10min, 30min, 60min and 120min respectively. It can be seen from Figure 1 that when the polyacrylamide hydrogel without soaking polypropylene glycol 500 is below -20°C, a large amount of free water will freeze, causing the hydrogel to become hard and brittle, and lose flexibility. The time of 500 is prolonged, the content of polypropylene glycol in the polyacrylamide hydrogel system increases, the proportion of freezable water and non-freezable water increases, and the proportion of free water decreases. The amount of ice crystals is reduced.

In this example, the tensile property curves of each polyacrylamide organohydrogel at 30°C, -20°C and 60°C were obtained through testing. Figure 2 is the tensile property curve of polyacrylamide organohydrogel soaked in polypropylene glycol 500 for different times at 30°C, and Figure 3 is the polyacrylamide organohydrogel soaked in polypropylene glycol 500 for different times at - Tensile property curve after freezing at 20°C for 24h. Fig. 4 is the tensile property curve of polyacrylamide organohydrogel soaked in polypropylene glycol 500 for different time at 60°C. As shown in the figure, at low temperature (-20 °C), room temperature (30 °C) and high temperature (60 °C), the tensile properties of polyacrylamide organohydrogel soaked in polypropylene glycol 500 were better than those of unsoaked polypropylene glycol 500 For polyacrylamide hydrogel, the comprehensive performance of polyacrylamide organohydrogel is the best when the soaking time is 30min.

The present invention also explores the influence of the molecular weight of polypropylene glycol on polyacrylamide organic hydrogel.

Embodiment 5: polypropylene glycol molecular weight comparison

For Example 1, this example only changes the molecular weight of polypropylene glycol, and obtains polyacrylamide hydrogel soaked in polypropylene glycol 500, polypropylene glycol 600 and polypropylene glycol 2000 for 2 hours, and tests to obtain the polyacrylamide hydrogels DSC curves of hydrogels.

Fig. 5 is the DSC curve of the polyacrylamide hydrogel soaked in different molecular weight polypropylene glycols in cooling (upward heat release) and temperature rise (downward heat absorption). It can be seen from Figure 5 that the polyacrylamide organohydrogel soaked in different molecular weight polypropylene glycols for the same time has different free water content. Among them, after soaking in polypropylene glycol 500 and polypropylene glycol 600, the free water in the polyacrylamide hydrogel basically disappeared, while there was still some free water in the hydrogel after soaking in polypropylene glycol 2000.

As can be seen from the above examples, the high-strength, freeze-resistant and heat-resistant polyacrylamide organic hydrogel provided by the present invention is prepared by soaking polyacrylamide hydrogel in polypropylene glycol. The molecular weight of polypropylene glycol is preferably 500, and the soaking time Preferably it is 30 minutes. The high-strength, toughness, frost-resistant and heat-resistant polyacrylamide organic hydrogel provided by the present invention has excellent mechanical properties no matter at low temperature or at room temperature, and the tensile deformation at normal temperature can exceed 5000%; The tensile deformation can still exceed 2000%, and the tensile strength can reach 1MPa; the tensile deformation can still exceed 1000% at a high temperature of 60°C, and the strength can reach 300KPa, which are better than samples soaked in glycerin. The high-strength, freeze-resistant and heat-resistant polyacrylamide organic hydrogel exhibits extremely high strength and toughness at low temperatures, and does not become soft at high temperatures, thereby greatly expanding the use temperature range of the polyacrylamide hydrogel.

As mentioned above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: it can still understand the foregoing The technical solutions recorded in each embodiment are modified, or some of the technical features are replaced equivalently; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims (10)

1. a kind of high tough freeze proof heat-resistance polypropylene amide organic hydrogels, which is characterized in that the tough freeze proof resistance to hot polymerization of height Acrylamide organic hydrogels are impregnated in polypropylene glycol by polyacrylamide hydrogel and are made.

2. the tough freeze proof heat-resistance polypropylene amide organic hydrogels of height according to claim 1, which is characterized in that described poly- The number-average molecular weight of propylene glycol is 200~2000, and the soaking time is 5~180min.

3. the tough freeze proof heat-resistance polypropylene amide organic hydrogels of height according to claim 2, which is characterized in that described poly- The number-average molecular weight of propylene glycol is 500, and the soaking time is 30min.

4. the tough freeze proof heat-resistance polypropylene amide organic hydrogels of height according to claim 1, which is characterized in that described poly- Acrylamide gel is made by the aggregated reaction of polymer monomer, and the polymer monomer is acrylamide monomer；

It is carried out under the conditions of the polymerization reaction is existing for solvent, crosslinking agent, initiator and the catalyst.

5. the tough freeze proof heat-resistance polypropylene amide organic hydrogels of height according to claim 4, which is characterized in that described molten Agent is water, and the crosslinking agent is N, and N '-methylene-bisacrylamide, the initiator is ammonium persulfate, and the catalyst is four Methyl ethylenediamine.

6. the tough freeze proof heat-resistance polypropylene amide organic hydrogels of height according to claim 5, which is characterized in that the friendship The quality of connection agent is the 0.02%~0.18% of the quality of the polymer monomer；The quality of the initiator is the polymer The 0.1%~0.2% of the quality of monomer.

7. the tough freeze proof heat-resistance polypropylene amide organic hydrogels of height according to claim 4, which is characterized in that described poly- Monomer adduct, solvent, crosslinking agent, initiator and catalyst proportion be 13.8g:46~56mL:2.76~24.84mg:13.8 The μ of~41.4mg:22~44 L.

8. the tough freeze proof heat-resistance polypropylene amide organic hydrogels of height according to claim 7, which is characterized in that described poly- Monomer adduct, solvent, crosslinking agent, initiator and catalyst proportion be 13.8g:46mL:4mg:32.2mg:22 μ L.

9. a kind of tough freeze proof heat-resistance polypropylene amide organic hydrogels of height as described in claim 1-8 any claim Preparation method, which comprises the following steps:

Polyacrylamide hydrogel is impregnated in polypropylene glycol, obtains the high tough freeze proof organic water-setting of heat-resistance polypropylene amide Glue.

10. the preparation method of the tough freeze proof heat-resistance polypropylene amide organic hydrogels of height according to claim 9, feature It is, the poly- propionamide hydrogel is made according to the following steps:

Acrylamide monomer and crosslinking agent are first dispersed in water, initiator is added, instills catalyst later, stirring to obtain is mixed Close solution；

Mixed solution is subjected to ultrasonic defoaming；It is 25 DEG C by the reaction temperature control of the mixed solution after ultrasound defoaming, and keeps 4 ~for 24 hours, obtain polyacrylamide hydrogel.