Preparation method of high-performance hyperbranched concrete modifier based on controllable degradation of waste resin

Abstract

The application discloses a preparation method of a high-performance hyperbranched concrete modifier based on controllable degradation of waste resin, and particularly relates to the field of concrete modifiers, and is applicable to low-carbon high-strength concrete materials. The waste epoxy resin is swelled and pretreated in a good solvent to improve its reaction activity and act as a catalyst for the next reaction, and in the presence of a polyamine, partial degradation of the polymer is realized through low-temperature swelling treatment and high-temperature partial degradation. The surface hyperbranched structure of the waste is constructed through chemical reaction of the amino groups and hydroxyl groups on the surface of the partial degradation product with the multi-functional borate hydroxyl groups, and the prepared concrete high-performance modifier has a water-reducing rate of greater than or equal to 30%. The method for constructing the hyperbranched structure after partial degradation has the advantages of mild method conditions, simple steps, low cost, avoidance of key difficulties such as complex synthesis of the cement high-performance modifier and high carbon emission, and the product greatly improves the mechanical properties of concrete, and has a wide application in the field of low-carbon high-strength concrete.

Description

Technical Field

[0001] This invention belongs to the field of concrete modifier technology, and specifically relates to a method for preparing a high-performance hyperbranched concrete modifier based on the controllable degradation of waste resin. Background Technology

[0002] Concrete, as the most important building material, is widely used in civil engineering, water conservancy, and national defense construction due to its excellent mechanical properties and durability. my country's "Outline for Building a Quality Powerhouse," issued in 2023, explicitly proposes promoting the application of high-performance concrete as a green building material and emphasizing the comprehensive utilization of solid waste resources to achieve green carbon reduction.

[0003] Modifiers, such as water-reducing agents, are essential components of modern high-performance concrete because they can improve the mechanical properties of concrete while enhancing its workability and fluidity. Hyperbranched modifiers, in particular, have attracted widespread attention due to their excellent water-reducing capabilities resulting from their near-spherical three-dimensional molecular shape and high-density reactive groups. However, hyperbranched modifiers typically face bottlenecks such as low molecular weight, uncontrollable structure, product value failing to cover manufacturing costs, and high carbon emissions, hindering their practical application.

[0004] Therefore, developing hyperbranched modifiers from waste materials to achieve efficient water reduction and effectively enhance the mechanical properties of cement is of great significance to the development of the cement industry. Summary of the Invention

[0005] To address the above-mentioned problems, this invention provides a method for preparing a high-performance hyperbranched concrete modifier based on the controllable degradation of waste resin, aiming to solve the technical problems encountered in the application of existing high-performance concrete modifiers. Its features are:

[0006] Waste epoxy resin was pretreated by swelling in a good solvent to enhance its reactivity and act as a catalyst for the next reaction. In the presence of polyamines, the polymer was partially degraded through low-temperature swelling followed by high-temperature partial degradation. The strong interaction between the amino and hydroxyl groups on the surface of the partially degraded product and the hydroxyl groups in borate was utilized to construct a hyperbranched structure on the waste surface. The polyhydroxyl and polyamine structures resulting from the hyperbranched structure allow the modifier to form a solvation film with water molecules, effectively reducing the sliding resistance of cement particles and thus improving the fluidity of concrete.

[0007] Based on the tribranched structure and electron-deficient effect of boron, by controlling the polyamines, their types, and group densities, the molecular weight and branching modification of the resulting partially degraded waste can be adjusted, which can effectively improve the fluidity required for concrete construction and significantly increase the strength of concrete.

[0008] To solve the above-mentioned technical problems, the present invention is achieved through the following technical means: a method for preparing a high-performance hyperbranched concrete modifier based on the controllable degradation of waste resin, comprising the following steps:

[0009] (1) Keep the waste epoxy resin in a good solvent at a certain stirring rate and stir at room temperature for 24-72 hours. After the polymer is completely swollen, dry it to obtain the pretreated waste epoxy resin.

[0010] (2) Add the pretreated waste epoxy resin to the polyamine, heat and stir thoroughly for 2-6 hours until the solution viscosity reaches 500-1000 Pa·s and then stop the reaction.

[0011] (3) Add the above solution dropwise to 500 ml of ethanol, and sonicate at 200-600 W for 1 h at room temperature, and then centrifuge at 9000 r / min for 5 min;

[0012] (4) Add the precipitate after centrifugation to N,N-dimethylformamide and stir until dissolved. Then add boric acid and stir at room temperature for 4-8 hours. Then heat to 80°C until completely dried and cooled to obtain high-performance hyperbranched concrete modifier.

[0013] Furthermore, the good solvent is at least one of dichloromethane, chloroform, acetic acid, acetone, and dimethyl carbonate.

[0014] Furthermore, the polyamine is at least one of ethylenediamine, diethylenetriamine, and triethylenetetramine.

[0015] The present invention also discloses a high-performance hyperbranched concrete modifier based on the controllable degradation of waste resin, prepared according to any of the above preparation methods.

[0016] The present invention also discloses the application of the above-mentioned high-performance hyperbranched concrete modifier based on the controllable degradation of waste resin in the preparation of low-carbon high-strength concrete.

[0017] Furthermore, by mixing high-performance hyperbranched concrete modifier with cement aggregate at a mass ratio of 1:100, low-carbon high-strength concrete is obtained.

[0018] Compared with existing technologies, the concrete modifier prepared by the controlled degradation and hyperbranching modification of waste epoxy resin described in this application has the following characteristics:

[0019] 1. This invention prepares a high-performance concrete modifier based on epoxy resin materials derived from waste, avoiding the problems of high cost and excessive carbon emissions caused by the complex synthesis of high-performance modifiers.

[0020] 2. By controlling the polyamines, their types, group densities, and reaction temperature during degradation, the molecular weight and branched modified group density of the resulting partially degraded waste can be adjusted, making it suitable for applications in different grades and types of concrete.

[0021] 3. The waste partial degradation and hyperbranching method established by this invention has simple steps, controllable product structure, high-performance modifier water reduction rate ≥30%, and significantly improved concrete mechanical properties. Attached Figure Description

[0022] Figure 1 This refers to the chemical change process in the material preparation method described in Example 1 of this application.

[0023] Figure 2 This is the molecular weight GPC diagram of the epoxy resin after partial degradation as described in Example 1 of this application.

[0024] Figure 3 This is the Raman spectrum of the hydration rate of the concrete before and after the addition of the modifier as described in Example 1 of this application.

[0025] Figure 4 The concrete flexural strength and compressive strength described in Embodiment 1 of this application are as follows. Detailed Implementation

[0026] The present invention will be specifically described below through embodiments. It should be noted that the following embodiments are only for further explanation of the present invention and should not be construed as limiting the scope of protection of the present invention. Those skilled in the art can make some non-essential improvements and adjustments to the present invention based on the above content.

[0027] Example 1:

[0028] Take 30g of waste anhydride-cured epoxy resin and 100ml of dichloromethane, stir at 500r / min for 24h until the polymer is completely swollen, then dry and collect for later use. Accurately weigh 80ml of diethylenetriamine, slowly add it to the swollen epoxy resin, stir at 500r / min and heat to 160℃, then cool to terminate the reaction after 2h. Add the resulting high-viscosity solution to 500ml of ethanol, sonicate at 200W for 1h at room temperature, then centrifuge at 9000r / min for 5min. Add the centrifuged precipitate to 100ml of N,N-dimethylformamide and stir for 20min until dissolved. Add 5g of boric acid to the above solution, stir at room temperature for 4-8h, then heat to 80℃, dry completely after 4h, and cool to obtain the high-performance hyperbranched concrete modifier.

[0029] The obtained modifier is mixed with cement aggregate at a ratio of 1:100, which greatly accelerates the cement hydration rate, reduces the water content by ≥30%, increases the flexural strength of concrete by more than 15%, and increases the compressive strength by more than 20%. Figure 2 This is the molecular weight GPC diagram of the epoxy resin after partial degradation as described in Example 1 of this application. According to... Figure 2 The results showed that the molecular weight of the degradation product was 2034 and the molecular weight distribution index was 1.878, indicating that the epoxy resin had been successfully degraded in a controlled manner. Therefore, the method proposed in this application can achieve the controlled degradation of epoxy resin. Figure 3 This is the Raman spectrum of the hydration rate of concrete before and after adding the modifier, as described in Example 1 of this application. Figure 3 The results show that the peak intensity of calcium silicate hydrate in cement increased significantly after the addition of the modifier. This indicates that the hydration rate of cement is greatly increased after the addition of the modifier. Figure 4 The flexural strength and compressive strength of the concrete described in Embodiment 1 of this application are based on... Figure 4 The results show that after adding the modifier, the flexural strength of the concrete increased by more than 15%, and the compressive strength increased by more than 20%. Therefore, the method proposed in this application can effectively improve the flexural and compressive strength of concrete.

[0030] Example 2:

[0031] Take 30g of waste anhydride-cured epoxy resin and 100ml of dichloromethane, stir at 500r / min for 24h until the polymer is completely swollen, then dry and collect for later use. Accurately weigh 80ml of diethylenetriamine, slowly add it to the swollen epoxy resin, stir at 500r / min and heat to 160℃, then cool down to terminate the reaction after 2h. Add the resulting high-viscosity solution to 500ml of ethanol, sonicate at 600W for 1h at room temperature, then centrifuge at 9000r / min for 5min. Add the centrifuged precipitate to 100ml of N,N-dimethylformamide and stir for 20min until dissolved. Add 5g of boric acid to the above solution, stir at room temperature for 4-8h, then heat to 80℃ and dry for 4h until completely dry. Cool to obtain the high-performance hyperbranched concrete modifier.

[0032] The obtained modifier is mixed with cement aggregate at a ratio of 1:100, which greatly accelerates the cement hydration rate, reduces the water content by ≥20%, increases the flexural strength of concrete by more than 10%, and increases the compressive strength by more than 15%.

[0033] The above are merely preferred embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1.A method for preparing a high-performance hyperbranched concrete modifier based on controllable degradation of waste resin, comprising: (1) stirring the waste anhydride-cured epoxy resin in a good solvent, and drying after the polymer is completely swelled to obtain the pretreated waste anhydride-cured epoxy resin; (2) adding the pretreated waste anhydride-cured epoxy resin to a polyamine, heating, and fully stirring for 2-6 hours, and stopping the reaction according to the change in the viscosity of the solution; (3) adding the solution obtained in step (2) dropwise into 500 ml of ethanol, and ultrasonically treating at room temperature, and then centrifuging; (4) adding the precipitate after centrifugation in step (3) into 100 ml of N, N-dimethylformamide and stirring until dissolved, then adding boric acid and stirring, heating and drying, and cooling to obtain the high-performance hyperbranched concrete modifier; wherein: the good solvent is at least one of dichloromethane, trichloromethane, acetic acid, acetone, and dimethyl carbonate; the polyamine is at least one of ethylenediamine, diethylenetriamine, and triethylenetetramine. 2.The method according to claim 1, wherein: in step (1), the mass-volume ratio of the waste anhydride-cured epoxy resin to the good solvent is 30 g: 100 ml. 3.The method according to claim 1, wherein: in step (1), the stirring speed is 500 r / min, and the stirring time is 24 h. 4.The method according to claim 1, wherein: in step (2), the amount of the polyamine is 80 ml. 5.The method according to claim 1, wherein: in step (2), the temperature is raised to 160-180℃; the stopping point of the reaction is until the viscosity of the solution is raised to 500-1000 Pa·s. 6.The method according to claim 1, wherein: in step (3), the ultrasonic treatment power is 200-600 W, and the ultrasonic treatment time is 1 h; the centrifugation rate is 9000 r / min, and the centrifugation time is 5 min. 7.The method according to claim 1, wherein: in step (4), the stirring time is 4-8 h; the heating and drying temperature is 80℃. 8.A high-performance hyperbranched concrete modifier based on controllable degradation of waste resin, prepared by the method according to any one of claims 1-7. 9.The application of the high-performance hyperbranched concrete modifier based on controllable degradation of waste resin according to claim 8 in the preparation of low-carbon high-strength concrete. 10.The application according to claim 9, wherein: the mass ratio of the high-performance hyperbranched concrete modifier based on controllable degradation of waste resin to cement aggregate is 1: 100, and the low-carbon high-strength concrete is obtained.

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