Ultra-high toughness multifunctional self-assembled c-s-h gel material and preparation method thereof

Abstract

This invention discloses an ultra-high toughness multifunctional self-assembled C-S-H gel material and its preparation method. The ultra-high toughness multifunctional self-assembled C-S-H gel material includes a stacked core-shell structure layer, which is composed of core-shell structure particles. The core-shell structure particles have hydrated calcium silicate nanoparticles as the core and polyacrylic acid-acrylamide copolymer as the shell. The obtained ultra-high toughness multifunctional self-assembled C-S-H gel material has high toughness, good tensile deformation properties, and temperature-sensitive effect.

Description

Technical Field

[0001] This invention relates to the field of building materials technology, and in particular to an ultra-high toughness multifunctional self-assembled CSH gel material and its preparation method. Background Technology

[0002] Functional materials refer to high-tech materials that possess excellent electrical, magnetic, optical, thermal, acoustic, mechanical, chemical, and biomedical properties, as well as special physical, chemical, and biological effects. They can achieve interconversion of functions and are primarily used to manufacture various functional components, thus finding widespread application in various high-tech fields. Functional ceramics and functional polymers are the most researched, and these two materials have been widely used in electronics, sensing, laser, optoelectronics, infrared, biotechnology, and environmental science. However, in the construction field, cement-based functional materials are more prevalent. Due to the relatively late start of research and development in cement-based functional materials, current applications mainly focus on cement-based conductive composites, cement-based dielectric composites, cement-based piezoelectric composites, and cement-based electromagnetic shielding composites, resulting in relatively limited functional applications for cement-based materials. Modern architecture presents new challenges to cement-based composites, requiring not only high strength, high toughness, and high durability, but also light- or temperature-sensing functions to meet the needs of multifunctional and intelligent buildings.

[0003] Calcium silicate hydrate (CSH) gel is a major product of cement hydration and the most important cementitious phase in cement-based materials. Improving the structure and properties of CSH gel can affect the functionality of cement-based materials. Among related technologies, the most effective way to improve the toughness of CSH gel is currently considered to be by introducing flexible materials into the CSH gel structure to construct CSH / organic hybrids at the nano-microscale.

[0004] However, in previous studies on organic-toughened CSH gels, the organics were mostly introduced directly during the synthesis of CSH gels. This meant that the toughening potential of the organics had not been fully realized, and their toughening effect was not significant. In addition, research on the functional modification of CSH gels by organics is relatively lacking. Therefore, it is necessary to propose a hydrated calcium silicate gel material to improve its toughness and endow it with a temperature-sensitive effect, so as to adapt it to the application of cement-based functional composite materials. Summary of the Invention

[0005] In view of this, this application provides an ultra-high toughness multifunctional self-assembled CSH gel material and its preparation method, which has high toughness, good tensile deformation properties and temperature-sensitive effect.

[0006] To achieve the above technical objectives, this application adopts the following technical solution:

[0007] In a first aspect, this application provides an ultra-tough, multifunctional self-assembled CSH gel material, which includes a stacked core-shell structure layer composed of core-shell structure particles; the core-shell structure particles have hydrated calcium silicate nanoparticles as the core and polyacrylic acid-acrylamide copolymer as the shell.

[0008] Preferably, the hydrated calcium silicate nanoparticles are needle-shaped or rod-shaped hydrated calcium silicate nanoparticles.

[0009] Preferably, the mass of the polyacrylic acid-acrylamide copolymer accounts for 10-30% of the total mass of the ultra-tough multifunctional self-assembled CSH gel material.

[0010] Secondly, this application provides a method for preparing an ultra-high toughness multifunctional self-assembled CSH gel material, comprising the following steps:

[0011] S1. Obtain a suspension of hydrated calcium silicate;

[0012] S2. After mixing and stirring acrylic acid, acrylamide, ionic solvent, photoinitiator and crosslinking agent, add them to a suspension of hydrated calcium silicate to obtain CSH-AA-AAM slurry;

[0013] S3. By irradiating CSH-AA-AAM slurry with ultraviolet light, in-situ polymerization and self-assembly reactions are carried out to obtain ultra-tough multifunctional self-assembled CSH gel material.

[0014] Preferably, the specific process of step S1 is as follows: dissolve sodium silicate nonahydrate in deionized water to obtain sodium silicate solution, dissolve calcium nitrate tetrahydrate in deionized water to obtain calcium nitrate solution; add calcium nitrate solution dropwise to sodium silicate solution, stir and react to obtain a suspension of hydrated calcium silicate.

[0015] Preferably, the ionic solvent is 1-ethyl-3-methylimidazolium ethyl sulfate, and the mass ratio of the sum of acrylic acid and acrylamide to the ionic solvent is 3.3-4:1.

[0016] Preferably, the photoinitiator is 2-hydroxy-4-(2-hydroxyethoxy)-2-methylphenylacetone, and the mass ratio of the sum of acrylic acid and acrylamide to the mass of the photoinitiator is 100:0.5-1.

[0017] Preferably, the crosslinking agent is N,N-methylenebenzene-acrylamide, and the mass ratio of the sum of the masses of acrylic acid and acrylamide to the mass of the crosslinking agent is 100:0.5-1.

[0018] Preferably, the mass ratio of acrylic acid to acrylamide is 1:4-5.

[0019] Thirdly, this application provides a cement-based material for ultra-high toughness, multifunctional self-assembled CSH gel materials.

[0020] The beneficial effects of this application are as follows:

[0021] 1. This invention constructs a core (CSH) / shell (polymer) crosslinking network with a unique core-shell structure by in-situ polymerization of acrylic acid and acrylamide, two reactive monomers, on CSH nanoparticles. Then, through the self-assembly between polymer molecules, a highly ordered layered self-assembled CSH gel is formed.

[0022] 2. The self-assembled CSH gel material produced by this invention has ultra-high toughness and excellent tensile deformation capacity, providing a new approach for the toughening design of cement-based materials at the nano / micro scale.

[0023] 3. The self-assembled CSH gel material of this invention has special shape memory function and temperature-sensitive effect, which provides a very promising application path for the multi-functional application of traditional cement-based materials in the future. Attached Figure Description

[0024] Figure 1 These are transmission electron microscope (TEM) images of the material from Example 1 under different illumination times;

[0025] Figure 2 A comparison of the finished product images of different materials.

[0026] Figure 3 This is the process flow diagram for this scheme.

[0027] Figure 4 The tensile stress curves of the material in Example 1 at different temperatures are shown. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0029] This application provides an ultra-tough, multifunctional self-assembled CSH gel material, which includes a stacked core-shell structure layer composed of core-shell structure particles; the core-shell structure particles have hydrated calcium silicate nanoparticles as the core and polyacrylic acid-acrylamide copolymer as the shell.

[0030] The ultra-high toughness multifunctional self-assembled CSH gel material of this application has ultra-high toughness, excellent tensile deformation ability, and good temperature sensitivity.

[0031] The hydrated calcium silicate nanoparticles are needle-shaped and rod-shaped.

[0032] The mass of polyacrylic acid-acrylamide copolymer accounts for 10-30% of the total mass of ultra-high toughness multifunctional self-assembled CSH gel material.

[0033] like Figure 3 As shown, this application provides a method for preparing an ultra-high toughness multifunctional self-assembled CSH gel material, comprising the following steps:

[0034] S1. Obtain a suspension of hydrated calcium silicate;

[0035] S2. After mixing and stirring acrylic acid, acrylamide, ionic solvent, photoinitiator and crosslinking agent, add them to a suspension of hydrated calcium silicate to obtain CSH-AA-AAM slurry;

[0036] S3. By irradiating CSH-AA-AAM slurry with ultraviolet light, in-situ polymerization and self-assembly reactions are carried out to obtain ultra-tough multifunctional self-assembled CSH gel material.

[0037] This application utilizes in-situ polymerization to prepare stretchable and deformable self-assembled CSH gels. The core material is CSH (calcium silicate hydrate) nanoparticles as the dispersed phase, in which reactive monomers and a catalyst are added. Then, by adjusting the polymerization conditions, photoinitiation is used to induce the polymerization of reactive monomers (acrylic acid, acrylamide) on the CSH nanoparticles. Through in-situ polymerization on the CSH nanoparticles, a CSH / organic cross-linked network with a unique core-shell structure is constructed. Subsequently, through the self-assembly of polymer molecules attracting and aggregating, a highly ordered layered CSH structure is formed, and the CSH nanoparticles are transformed into needle-like rod-shaped calcium silicate hydrate nanoparticles within the CSH gel material. This self-assembled CSH gel exhibits unique shape memory properties and temperature-sensitive characteristics.

[0038] The specific process of step S1 is as follows: Sodium silicate nonahydrate is dissolved in deionized water to obtain a sodium silicate solution; calcium nitrate tetrahydrate is dissolved in deionized water to obtain a calcium nitrate solution; the calcium nitrate solution is added dropwise to the sodium silicate solution, and the mixture is stirred to react, thus obtaining a suspension of hydrated calcium silicate. It can be understood that in the preparation of the CSH solution, the calcium source is analytical grade calcium nitrate tetrahydrate, and the silicon source is analytical grade sodium silicate nonahydrate. Suitable, but not limiting, molar ratios of calcium nitrate tetrahydrate to sodium silicate nonahydrate are 3:2-1.

[0039] The ionic solvent is 1-ethyl-3-methylimidazolium ethyl sulfate, and the mass ratio of the sum of acrylic acid and acrylamide to the ionic solvent is 3.3-4:1. This ionic solvent is used to simultaneously dissolve both acrylic acid and acrylamide monomers, thereby carrying out the polymerization reaction.

[0040] The photoinitiator is 2-hydroxy-4-(2-hydroxyethoxy)-2-methylphenylacetone, and the mass ratio of the sum of acrylic acid and acrylamide to the photoinitiator is 100:0.5-1. The crosslinking agent is N,N-methylenebenzene-acrylamide, and the mass ratio of the sum of acrylic acid and acrylamide to the crosslinking agent is 100:0.5-1. The photoinitiator of this application provides free radicals to open the olefinic double bonds of acrylic acid, resulting in carbocations. The carbocations attack one of the double bonds, and simultaneously, the crosslinking agent N,N-methylenebenzene-acrylamide, which can be attacked by the carbocations, is added, thereby forming a three-dimensional spatial network structure between the single chains of polymethacrylic acid.

[0041] The mass ratio of acrylic acid to acrylamide is 1:4-5. The acrylic acid structural units mainly give the self-assembled CSH gel a certain degree of flexibility, while the acrylamide structural units give the self-assembled CSH gel a certain degree of rigidity and strength. Exceeding the limits of this application will lead to problems such as excessive surface cracks or inability to form.

[0042] Thirdly, this application provides a cement-based material of ultra-high toughness, multifunctional self-assembled CSH gel. The application temperature of the cement-based material of this application is 0-100℃.

[0043] Example 1

[0044] A high-toughness, multifunctional self-assembled CSH gel material comprises a stacked core-shell structure layer composed of core-shell structure particles. These particles have a core of needle-like, rod-shaped hydrated calcium silicate nanoparticles and a shell of polyacrylic acid-acrylamide copolymer. The polyacrylic acid-acrylamide copolymer accounts for 15% of the total mass of the high-toughness, multifunctional self-assembled CSH gel material.

[0045] A method for preparing an ultra-tough, multifunctional self-assembled CSH gel material:

[0046] S1. Dissolve 28.4g of sodium silicate nonahydrate in 60ml of deionized water at 40℃ to obtain a sodium silicate solution. Dissolve 35.42g of calcium nitrate tetrahydrate in 60ml of deionized water to obtain a calcium nitrate solution. Add the calcium nitrate solution dropwise to the sodium silicate solution and stir to react, thus obtaining a suspension of hydrated calcium silicate.

[0047] S2. Mix 2g acrylic acid, 8g acrylamide, 3.3g ionic solvent, 0.05g photoinitiator, and 0.05g crosslinking agent, then add the mixture to the calcium silicate hydrate suspension from step S1 and stir for 60 minutes to obtain CSH-AA-AAM slurry.

[0048] S3. Pour the CSH-AA-AAM slurry into a mold and irradiate it with ultraviolet light to carry out in-situ polymerization and self-assembly reaction, thereby obtaining an ultra-tough multifunctional self-assembled CSH gel material.

[0049] like Figure 1 The image shown is a transmission electron microscope image under different illumination times. Figure 1 (A) and Figure 1 (E) Morphology of CSH without light exposure; (A) and (E) are morphologies of CSH gel materials taken from different locations. Figure 1 (B) and Figure 1 (F) CSH morphology after 5 minutes of illumination (B) and (F) correspond to (A) and (E) respectively; Figure 1 (C) and Figure 1 (G) CSH morphology after 10 minutes of illumination Figure 1 (C) and Figure 1 (G) corresponds to (A) and (E) respectively; Figure 1 (D) and Figure 1 (H) Morphology of CSH after 15 minutes of illumination; (D) and (H) correspond to (A) and (E), respectively. This demonstrates that within 5-10 minutes, driven by the polymerization reaction, individual CSH nanoparticles are individually coated by the polymer, forming distinct spherical aggregates with a clear core-shell structure. Then, with prolonged illumination, the spherical CSH nanoparticles within these aggregates gradually grow into needle-like or rod-shaped CSH nanoparticles. Figure 1 D、 Figure 1 H). Finally, through self-assembly between polymers, the core-shell structured CSH is assembled into a highly ordered layered CSH.

[0050] Example 2

[0051] A high-toughness, multifunctional self-assembled CSH gel material is described, with the same contents as in Example 1, except that the mass of the polyacrylic acid-acrylamide copolymer accounts for 30% of the total mass of the high-toughness, multifunctional self-assembled CSH gel material.

[0052] Example 3

[0053] A high-toughness, multifunctional self-assembled CSH gel material is described. The contents are the same as in Example 2, except that in step S2, 2g of acrylic acid, 8g of acrylamide, 2.5g of ionic solvent, 0.1g of photoinitiator, and 0.1g of crosslinking agent are mixed and stirred, and then added to a suspension of hydrated calcium silicate. The mixture is stirred for 60 minutes to obtain CSH-AA-AAM slurry.

[0054] Comparative Example 1

[0055] A CSH gel material is prepared as follows:

[0056] Dissolve 28.4g of sodium silicate nonahydrate in 60ml of deionized water at 40℃ to obtain a sodium silicate solution. Dissolve 35.42g of calcium nitrate tetrahydrate in 60ml of deionized water to obtain a calcium nitrate solution. Add the calcium nitrate solution dropwise to the sodium silicate solution and stir to react, thus obtaining a suspension of hydrated calcium silicate.

[0057] Pour a suspension of hydrated calcium silicate into a mold and irradiate it with ultraviolet light to obtain CSH gel material.

[0058] Comparative Example 2

[0059] A method for preparing CSH gel material:

[0060] Dissolve 28.4g of sodium silicate nonahydrate in 60ml of deionized water at 40℃ to obtain a sodium silicate solution. Dissolve 35.42g of calcium nitrate tetrahydrate in 60ml of deionized water to obtain a calcium nitrate solution. Add the calcium nitrate solution dropwise to the sodium silicate solution and stir to react, thus obtaining a suspension of hydrated calcium silicate.

[0061] 10g of polyacrylic acid-acrylamide copolymer, 3.3g of ionic solvent, 0.05g of photoinitiator, and 0.05g of crosslinking agent were mixed and stirred to obtain the polyacrylic acid-acrylamide copolymer polymer solvent. The polyacrylic acid-acrylamide copolymer was added to a suspension of hydrated calcium silicate and stirred for 60 minutes to obtain a mixture. The mixture was poured into a mold and irradiated with ultraviolet light to obtain the CSH gel material.

[0062] Evaluation Test

[0063] like Figure 2 As shown, Figure 2 C Figure 2 D shows the morphology of the CSH gel material obtained by this invention from different angles, illustrating the feasibility of this method; as... Figure 2 A and B correspond to the materials obtained in Comparative Example 1 and Comparative Example 2, respectively. The results show that the CSH gel materials obtained in Comparative Example 1 and 2 do not form.

[0064] The CSH gel material obtained in Example 1 was functionally tested. After kneading the CSH gel material, it was placed in deionized water. Within 20 seconds, the kneaded and bent CSH gel material could recover to its original shape before being kneaded and bent, indicating that the self-assembled CSH gel prepared by the present invention has shape memory function.

[0065] The toughness and tensile deformation capacity of the CSH gel material obtained in Example 1 were tested, such as... Figure 4 As shown, tensile tests were conducted at 0°C, room temperature, and 100°C until fracture, measuring the maximum stretchable length of the material. The results show that at 0°C, the CSH gel material can be stretched to nearly twice its original length; at room temperature, it can be stretched to more than twice its original length; and at 100°C, the deformation is very small. This indicates that the material of Example 1 exhibits different properties at different temperatures, demonstrating a temperature-sensitive effect. This demonstrates that the self-assembled CSH gel prepared by this invention has excellent tensile properties and temperature sensitivity.

[0066] This invention proposes a method for preparing an ultra-tough, multifunctional self-assembled CSH gel using in-situ polymerization. This self-assembled CSH gel exhibits unique shape memory and temperature-sensitive effects, displaying exceptional toughness and excellent tensile deformation capacity. In the preparation process, CSH nanoparticles serve as the core material, with acrylic acid, acrylamide, and a catalyst added. The polymerization conditions are then adjusted, and photoinitiation is used to induce polymerization of the reactive monomers on the CSH nanoparticles. Through in-situ polymerization on CSH nanoparticles, a CSH / organic crosslinked network with a unique core-shell structure is constructed. Then, through the self-assembly of polymer molecules, a highly ordered layered self-assembled CSH gel is formed. This invention not only provides a new approach for toughening cement-based materials at the nano / microscale but also offers a highly promising application pathway for the future multifunctionalization of traditional cement-based materials.

[0067] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing an ultra-high toughness multifunctional self-assembled CSH gel material, characterized in that, Includes the following steps: S1. Obtain a suspension of hydrated calcium silicate; S2. After mixing and stirring acrylic acid, acrylamide, ionic solvent, photoinitiator and crosslinking agent, add them to the suspension of hydrated calcium silicate to obtain CSH-AA-AAM slurry; S3. The CSH-AA-AAM slurry is irradiated with ultraviolet light to carry out in-situ polymerization and self-assembly reactions, thereby obtaining the ultra-high toughness multifunctional self-assembled CSH gel material; The photoinitiator is 2-hydroxy-4-(2-hydroxyethoxy)-2-methylphenylacetone, and the mass ratio of the sum of the mass of the acrylic acid and acrylamide to the mass of the photoinitiator is 100:0.5-1; The mass ratio of acrylic acid to acrylamide is 1:4-5.

2. The method for preparing the ultra-high toughness multifunctional self-assembled CSH gel material according to claim 1, characterized in that, The specific process of step S1 is as follows: dissolve sodium silicate nonahydrate in deionized water to obtain sodium silicate solution, dissolve calcium nitrate tetrahydrate in deionized water to obtain calcium nitrate solution; add the calcium nitrate solution dropwise into the sodium silicate solution, stir and react to obtain the suspension of hydrated calcium silicate.

3. The method for preparing the ultra-high toughness multifunctional self-assembled CSH gel material according to claim 1, characterized in that, The ionic solvent is 1-ethyl-3-methylimidazolium ethyl sulfate, and the mass ratio of the sum of the masses of the acrylic acid and acrylamide to the mass of the ionic solvent is 3.3-4:

1.

4. The method for preparing the ultra-high toughness multifunctional self-assembled CSH gel material according to claim 1, characterized in that, The crosslinking agent is N,N-methylenebenzene-acrylamide, and the mass ratio of the sum of the mass of acrylic acid and acrylamide to the mass of the crosslinking agent is 100:0.5-1.

5. A high-toughness, multifunctional self-assembled CSH gel material prepared by the method of claim 1, characterized in that, It comprises a stacked core-shell structure layer, which is composed of core-shell structure particles; the core-shell structure particles have hydrated calcium silicate nanoparticles as the core and polyacrylic acid-acrylamide copolymer as the outer shell; the hydrated calcium silicate nanoparticles are needle-shaped hydrated calcium silicate nanoparticles.

6. The ultra-high toughness multifunctional self-assembled CSH gel material according to claim 5, characterized in that, The mass of the polyacrylic acid-acrylamide copolymer accounts for 10-30% of the total mass of the ultra-high toughness multifunctional self-assembled CSH gel material.

7. A cement-based material comprising an ultra-high toughness multifunctional self-assembled CSH gel material obtained by the preparation method according to any one of claims 1-4.

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