Hierarchical hydrogen bond and rigid chain segment enhanced polyurea as well as preparation method and application thereof

Abstract

The invention discloses graded hydrogen bond and rigid chain segment enhanced polyurea as well as a preparation method and application thereof.The polyurea is prepared from a component A, a component B and a component C. The component A comprises the following components in parts by mass: 10-24 parts of a flatting agent, 10-24 parts of a defoaming agent and 150-156 parts of modified MD I; the component B is prepared from 559 to 618 parts of benzocaine modified polytetrahydrofuran; the component C is prepared from the following components in parts by weight: 5 to 12 parts of 5-(2-hydroxyethyl)-6-methyl-2-aminouracil and 10 to 24 parts of N, N-dimethylformamide. The prepared polyurea has good strength, toughness and wear resistance, and can resist puncture and drop hammer impact.

Description

Technical Field

[0001] The invention relates to the technical field of impact-resistant coatings, and in particular to a hierarchical hydrogen bond and rigid segment reinforced polyurea and a preparation method and application thereof. Background Art

[0002] In the context of the increasingly complex global security environment, extreme events such as explosions pose challenges to military and civilian protection safety. Traditional protective measures are to use steel plates and reinforce building components and military equipment. However, in actual applications, the overall weight increases significantly, and the cost is high and the construction is difficult. As the requirements for efficient and lightweight impact-resistant protective structures become higher and higher, more and more polymer materials are being applied to the design in order to improve protection performance, reduce costs, and expand the scope of application. Therefore, the application of high-performance impact-resistant materials is of great significance to the field of protection.

[0003] With the development of spray polyurea elastomer technology, polyurea has become the research focus in the protection field due to its advantages such as impact resistance, fast curing, strong adhesion, adjustable performance and excellent dynamic mechanical response. Chinese patent CN116253983A "An impact-resistant polyurea elastomer composite material and its preparation method" discloses an impact-resistant polyurea elastomer composite material and its preparation method. The raw material components of the composite material, measured by the amount of substances, include 1 part polyurea elastomer, 1 part asphalt-based carbon fiber and 1 part polyacrylic acid side chain triphenylene liquid crystal. The raw material components of the polyurea elastomer include component A and component B; its preparation method includes: taking the raw materials of component A, mixing and heating to 60°C, stirring for 2 hours, and obtaining component A of the polyurea elastomer; taking the raw materials of component B, mixing and stirring at 50°C for 3 hours, and obtaining component B of the polyurea elastomer; spraying the component A and component B of the polyurea elastomer on the asphalt-based carbon fiber modified by the polyacrylic acid side chain triphenylene liquid crystal in proportion with a spray gun, and then continuing to cure at room temperature for 10 hours to obtain the impact-resistant polyurea elastomer composite material; the impact-resistant polyurea elastomer composite material of the invention has high impact resistance, high strength, and high elongation, and can resist shock waves and fragments generated by explosions. Therefore, it is necessary to conduct in-depth research on the application of polyurea in the field of impact resistance and to improve the strength and toughness of polyurea elastomers.

[0004] At present, in terms of improving the strength and toughness of polyurea elastomers, researchers believe that introducing multiple hydrogen bonds into the polyurea network is an effective way. Chinese patent CN117924649A "A method for preparing a hydrogen-bonded boron-containing supramolecular polyurea elastomer" discloses a method for preparing a hydrogen-bonded boron-containing supramolecular polyurea elastomer. Through segment design and synthesis process, a controllable molecular sequence of multiple hydrogen bonds and dynamic covalent bonds is constructed, which solves the problems of chaotic molecular structure and weakened mechanical properties of traditional cross-linked polyurea elastomers, while taking into account good thermoplastic reprocessing capabilities. However, in order to meet the needs of instantaneous high-energy impact protection, the strength and toughness of polyurea elastomers need to be further improved. Summary of the invention

[0005] In view of this, the object of the present invention is to provide a hierarchical hydrogen bond and rigid segment reinforced polyurea and a preparation method and application thereof, wherein the polyurea has good strength, toughness and wear resistance and can resist puncture and drop hammer impact.

[0006] The technical solutions adopted are:

[0007] The hierarchical hydrogen bond and rigid segment reinforced polyurea of ​​the present invention is prepared by mixing component A, component B and component C, wherein each component is calculated by weight.

[0008] The A component comprises:

[0009] 10-24 parts of leveling agent, 10-24 parts of defoamer and 150-156 parts of modified MDI;

[0010] The B component includes:

[0011] 559-618 parts of benzocaine-modified polytetrahydrofuran;

[0012] The C component includes:

[0013] 5-(2-hydroxyethyl)-6-methyl-2-aminouracil 5-12 parts, N,N-dimethylformamide 10-24 parts.

[0014] Furthermore, the modified MDI is MDI-100LL.

[0015] MDI-100LL is commercially available MDI-100LL. It is MDI-100LL of Wanhua Chemical Group Co., Ltd. MDI-100LL is carbodiimide-uretonimine-modified 4,4'-diphenylmethane diisocyanate, and is a light yellow liquid at room temperature.

[0016] Furthermore, the leveling agent is an acrylic leveling agent, and the defoaming agent is a silicone defoaming agent.

[0017] Furthermore, the benzocaine-modified polytetrahydrofuran is obtained by mixing benzocaine, polytetrahydrofuran diol, an organic metal catalyst and an auxiliary alcohol and performing a staged reaction;

[0018] And / or, the 5-(2-hydroxyethyl)-6-methyl-2-aminouracil is obtained by reacting α-acetyl-γ-butyrolactone, guanidine carbonate, anhydrous ethanol and triethylamine, filtering and drying.

[0019] A method for preparing the above-mentioned hierarchical hydrogen bond and rigid segment reinforced polyurea of ​​the present invention comprises the following steps:

[0020] S1. Mixing a leveling agent, a defoamer and modified MDI to obtain component A;

[0021] S2. mixing benzocaine, polytetrahydrofuran diol, an organic metal catalyst and an auxiliary alcohol for a staged reaction to obtain a component B;

[0022] S3. α-acetyl-γ-butyrolactone, guanidine carbonate, anhydrous ethanol and triethylamine were reacted in a mass ratio of 2:3:16:4, filtered and dried to obtain a white powder 5-(2-hydroxyethyl)-6-methyl-2-aminouracil, and 5-(2-hydroxyethyl)-6-methyl-2-aminouracil and N,N-dimethylformamide were mixed to obtain component C;

[0023] S4. The three components A, B and C are mixed in a mass ratio of 85:293:12 to obtain polyurea.

[0024] Further, in S2, the staged reaction includes a first heating reaction, a second heating reaction, a third heating reaction and a fourth heating reaction;

[0025] The temperature of the first heating reaction is 50-60°C, and the insulation time is 1-2h;

[0026] The temperature of the second heating reaction is 130-150°C, and the insulation time is 16-24h;

[0027] The temperature of the third heating reaction is 170-190°C, and the insulation time is 18-24h;

[0028] The temperature of the fourth heating reaction is 200-230° C., and the insulation time is 18-24 hours.

[0029] Further, in S2, the organic metal catalyst includes one or more of dibutyltin dilaurate, butyl titanate and dibutyltin diacetate;

[0030] And / or, in S2, the auxiliary alcohol includes one or more of n-butanol, isopropanol, ethanol, propanol, methanol, isopentanol and pentanol.

[0031] Further, in S3, the reaction stage is: stirring and reflux at 80°C for 12h, and the suspension is yellow and turbid;

[0032] and / or, in S3, the filtration stage is: after cooling, adjusting the pH to 6-7 using an aqueous HCl solution, filtering and washing the solid with ethanol;

[0033] And / or, in S3, the drying stage is: drying in an oven at 80° C. for 9 hours.

[0034] Further, in S4, component B and component C are dispersed at a high speed of 2000 r / min, and then component A is added and dispersed at a high speed of 2000 r / min, and then transferred to a polytetrafluoroethylene mold, cured at room temperature for 1 hour, and then transferred to an 80°C oven for further curing for 12 hours to obtain polyurea.

[0035] The above-mentioned hierarchical hydrogen bond and rigid segment reinforced polyurea of ​​the present invention is used in the field of impact protection, for example, in the preparation of impact protection equipment.

[0036] The beneficial effects of the present invention are:

[0037] The polyurea prepared by the invention has graded hydrogen bonds and rigid segment reinforcement, and the prepared polyurea has good strength, toughness and wear resistance, and can resist puncture and drop hammer impact. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 The tensile strength diagram of the hierarchical hydrogen bond and rigid segment reinforced polyurea explosion-proof coating prepared in Examples 1 to 3 of the present invention. Examples 1 to 3 correspond to samples APU-UPy-8, APU-UPy-10 and APU-UPy-12, respectively.

[0039] Figure 2 The puncture performance test diagram of the polyurea elastomer and the unmodified blank sample in Example 1 of the present invention and the corresponding force and displacement curve. Example 1 corresponds to sample APU-UPy-8.

[0040] Figure 3 This is a drop weight performance test diagram of the polyurea elastomer and the unmodified blank sample in Example 1 of the present invention.

[0041] Figure 4 This is a diagram showing the damage of a composite plate formed of a polyurea elastomer and a steel plate by a projectile in Example 1 of the present invention. Example 1 corresponds to sample APU-UPy-8.

[0043] Figure 5 Schematic diagram of the structure of polyurea with hierarchical hydrogen bonds and rigid chain segment reinforcement.

[0044] Figure 6 This is an explanatory diagram of hierarchical hydrogen bonding. DETAILED DESCRIPTION

[0045] The present invention is described in detail below through specific embodiments, but these exemplified uses and purposes are only used to illustrate the present invention and do not constitute any form of limitation on the actual protection scope of the present invention, and do not limit the protection scope of the present invention to these.

[0046] Example 1

[0047] This embodiment prepares hierarchical hydrogen bond and rigid segment reinforced polyurea, comprising the following steps:

[0048] S1. Add 16 parts of leveling agent, 16 parts of defoamer and 154 parts of MDI-100LL to a high-speed disperser and disperse at a speed of 1000 r / min for 1 min to obtain component A;

[0049] S2. 33 g of benzocaine and 100 g of polytetrahydrofuran diol (PTMG-1000) were dispersed in a three-necked flask, and 14.43 g of n-butanol was evenly dispersed in the resulting solution, and 0.12 g of tetrabutyl titanate was added dropwise under stirring. The reactant changed from milky white to yellow and eventually to yellowish brown. After 62 h, the reaction was completed to obtain benzocaine-modified polytetrahydrofuran, and 573 parts were taken to obtain component B;

[0050] S3. α-Acetyl-γ-butyrolactone (6.41 g) and guanidine carbonate (9.04 g) were stirred evenly in anhydrous ethanol (60 mL). Triethylamine (15.6 mL) was added and stirred and refluxed at 80 ° C for 12 hours, and the suspension was turbid yellow. After cooling, the pH was adjusted to 6-7 using HCl aqueous solution. After filtering, the solid was fully washed with ethanol and dried in an oven at 80 ° C for 9 hours to finally obtain a white powder 5-(2-hydroxyethyl)-6-methyl-2-aminouracil. Take 8 parts of 5-(2-hydroxyethyl)-6-methyl-2-aminouracil and 16 parts of N, N-dimethylformamide and mix them to obtain component C.

[0051] S4. Components B and C were dispersed at a high speed of 2000 r / min for 1 min, and then component A was added and dispersed at a high speed of 2000 r / min for 1 min. The mixture was then transferred to a polytetrafluoroethylene mold and cured at room temperature for 1 hour. The mixture was then transferred to an oven at 80°C and continued to cure for 12 hours to obtain a polyurea elastomer, which was recorded as APU-UPy-8.

[0052] Example 2

[0053] This example prepares hierarchical hydrogen bond and rigid segment reinforced polyurea, referring to Example 1. The difference from Example 1 is that in S1 of this example, the leveling agent of component A is 20 parts, the defoamer is 20 parts, and the MDI-100LL is 154 parts; the component C is 10 parts of 5-(2-hydroxyethyl)-6-methyl-2-aminouracil and 20 parts of N,N-dimethylformamide. The rest of the steps remain unchanged. The obtained polyurea elastomer is recorded as APU-UPy-10.

[0054] Example 3

[0055] This example prepares hierarchical hydrogen bond and rigid segment reinforced polyurea, referring to Example 1. The difference from Example 1 is that in S1 of this example, the leveling agent of component A is 24 parts, the defoamer is 24 parts, and the MDI-100LL is 154 parts; the component C is 12 parts of 5-(2-hydroxyethyl)-6-methyl-2-aminouracil and 24 parts of N,N-dimethylformamide. The rest of the steps remain unchanged. The obtained polyurea elastomer is recorded as APU-UPy-12.

[0056] Comparative Example 1

[0057] Referring to Example 1, the difference from the example is that the C component consisting of 5-(2-hydroxyethyl)-6-methyl-2-aminouracil and N,N-dimethylformamide is not added in this comparative example, and the other steps remain unchanged. The obtained product is recorded as APU-UPy-0.

[0058] Performance Test:

[0059] The mechanical property test results of the hierarchical hydrogen bond and rigid segment reinforced polyurea elastomers obtained in Examples 1-3 are shown in Table 1.

[0060] Table 1 Test results of mechanical properties of polyurea elastomer

[0061]

[0062] Figure 1 This is a graph of the tensile strength of the hierarchical hydrogen bond and rigid segment reinforced polyurea explosion-proof coatings prepared in Examples 1-3 of the present invention. Examples 1-3 correspond to samples APU-UPy-8, APU-UPy-10 and APU-UPy-12, respectively. Among them, the maximum tensile strength of APU-UPy-8 is as high as 50.25MPa, and the elongation at break is 1435.09%

[0063] Figure 2It is the puncture performance test graph of the polyurea elastomer and the unmodified blank sample in Example 1 of the present invention and the corresponding force and displacement curve. Example 1 corresponds to sample APU-UPy-8, and the unmodified sample corresponds to APU-UPy-0. The puncture needle with a diameter of 500μm is lowered at a rate of 5mm / min until the film sample with a thickness of 1mm is completely punctured. Compared with the APU-UPy-0 elastomer film, the APU-UPy-8 elastomer has significantly stronger puncture resistance. According to the obtained puncture force-displacement curve, it can be seen that the puncture force of the APU-UPy-8 elastomer is 94.05N, and the maximum displacement reaches 13.06mm. The puncture force of the APU-UPy-0 elastomer film is 89.39N, and the maximum displacement is only 10.72mm.

[0064] Figure 3 The composite plate formed by the polyurea elastomer and the steel plate in Example 1 of the present invention is damaged by a drop hammer impact. Example 1 corresponds to sample APU-UPy-8. The steel plate without polyurea coating forms a large through hole at the central impact point, and the surrounding steel plates are petal-shaped, showing obvious flipping, with the opening facing outward. The steel plate coated with polyurea limits the deformation of the steel plate and shows less damage.

[0065] Figure 4 The curve of the drop hammer impact force and time corresponding to the drop hammer impact test of the polyurea elastomer and the unmodified blank sample in Example 1 of the present invention. The presence of the polyurea coating significantly reduces the peak impact force and plays a buffering role. This is due to the good fluidity of the polymer chain and the energy dissipation by hydrogen bonding. The polyurea molecular chain changes from a curled state to an extended state and extends in the tensile direction, thereby dissipating energy. Among them, the peak impact force of APU-UPy-8 is lower than that of APU-UPy-0. More hydrogen bonds consume a large amount of impact energy in elastic deformation, which has a certain protective effect on the structure and shows a better impact protection effect.

[0066] Figure 5 The schematic diagram of the structure of the polyurea prepared in Examples 1-3 with hierarchical hydrogen bonds and rigid segment reinforcement; Figure 6 This is an explanatory diagram of hierarchical hydrogen bonding. Figure 5 It can be seen that the prepared polyurea has an enhanced rigid segment. The graded hydrogen bonds are that the prepared polyurea has weak hydrogen bonds and strong hydrogen bonds. The graded hydrogen bonds are graded according to their strength.

[0067] The series of detailed descriptions listed above are only specific descriptions of feasible embodiments of the present invention. They are not intended to limit the scope of protection of the present invention. All equivalent embodiments or changes that do not deviate from the technical spirit of the present invention should be included in the scope of protection of the present invention.

Claims

1. A hierarchical hydrogen bond and rigid segment reinforced polyurea, characterized in that: It is prepared by mixing components A, B and C, and each component is calculated by weight. The A component comprises: 10-24 parts of leveling agent, 10-24 parts of defoaming agent and 150-156 parts of modified MDI; The B component includes: 559-618 parts of benzocaine-modified polytetrahydrofuran; The C component includes: 5-(2-hydroxyethyl)-6-methyl-2-aminouracil 5-12 parts, N,N-dimethylformamide 10-24 parts.

2. The hierarchical hydrogen bond and rigid segment reinforced polyurea according to claim 1, characterized in that: The modified MDI is MDI-100LL.

3. The hierarchical hydrogen bond and rigid segment reinforced polyurea according to claim 1, characterized in that: The leveling agent is an acrylic leveling agent, and the defoaming agent is an organosilicon defoaming agent.

4. The hierarchical hydrogen bond and rigid segment reinforced polyurea according to claim 1, characterized in that: The benzocaine-modified polytetrahydrofuran is obtained by mixing benzocaine, polytetrahydrofuran diol, an organic metal catalyst and an auxiliary alcohol and performing a stepwise reaction; And / or, the 5-(2-hydroxyethyl)-6-methyl-2-aminouracil is obtained by reacting α-acetyl-γ-butyrolactone, guanidine carbonate, anhydrous ethanol and triethylamine, filtering and drying.

5. A method for preparing the hierarchical hydrogen bond and rigid segment reinforced polyurea according to any one of claims 1 to 4, characterized in that: The following steps are involved: S1. Mixing a leveling agent, a defoamer and modified MDI to obtain component A; S2. mixing benzocaine, polytetrahydrofuran diol, an organic metal catalyst and an auxiliary alcohol for a staged reaction to obtain a component B; S3. α-acetyl-γ-butyrolactone, guanidine carbonate, anhydrous ethanol and triethylamine were reacted in a mass ratio of 2:3:16:4, filtered and dried to obtain a white powder 5-(2-hydroxyethyl)-6-methyl-2-aminouracil, and 5-(2-hydroxyethyl)-6-methyl-2-aminouracil and N,N-dimethylformamide were mixed to obtain component C; S4. The three components A, B and C are mixed in a mass ratio of 85:293:12 to obtain polyurea.

6. The method for preparing hierarchical hydrogen bond and rigid segment reinforced polyurea according to claim 5, characterized in that: In S2, the staged reaction includes a first heating reaction, a second heating reaction, a third heating reaction and a fourth heating reaction; The temperature of the first heating reaction is 50-60°C, and the insulation time is 1-2h; The temperature of the second heating reaction is 130-150°C, and the insulation time is 16-24h; The temperature of the third heating reaction is 170-190°C, and the insulation time is 18-24h; The temperature of the fourth heating reaction is 200-230° C., and the insulation time is 18-24 hours.

7. The method for preparing hierarchical hydrogen bond and rigid segment reinforced polyurea according to claim 5, characterized in that: In S2, the organic metal catalyst includes one or more of dibutyltin dilaurate, butyl titanate and dibutyltin diacetate; And / or, in S2, the auxiliary alcohol includes one or more of n-butanol, isopropanol, ethanol, propanol, methanol, isopentanol and pentanol.

8. The method for preparing hierarchical hydrogen bond and rigid segment reinforced polyurea according to claim 5, characterized in that: In S3, the reaction stages are: stirring and reflux at 80°C for 12 h, and the suspension becomes yellow and turbid; and / or, in S3, the filtration stage is: after cooling, adjusting the pH to 6-7 using an aqueous HCl solution, filtering and washing the solid with ethanol; And / or, in S3, the drying stage is: drying in an oven at 80° C. for 9 hours.

9. The method for preparing hierarchical hydrogen bond and rigid segment reinforced polyurea according to claim 5, characterized in that: In S4, component B and component C are dispersed at a high speed of 2000 r / min, and then component A is added and dispersed at a high speed of 2000 r / min, and then transferred to a polytetrafluoroethylene mold, cured at room temperature for 1 hour, and then transferred to an 80°C oven for further curing for 12 hours to obtain polyurea.

10. Use of the hierarchical hydrogen bond and rigid segment reinforced polyurea according to any one of claims 1 to 4 in the field of impact protection.

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