A preparation method and product of a natural biomass chitin-modified single-component water-soluble polyurethane chemical grouting material

Abstract

The present invention discloses a method for preparing a natural biomass chitosan modified single-component water-soluble polyurethane chemical grouting material and its product. The method uses N-ether chitosan polyol oligomers to replace chemical polyether polyols, broadens the application field of natural chitosan polymer materials, increases the use of biomass chitosan, and reduces the cost of raw materials; improves the compatibility and uniformity of the modified single-component water-soluble polyurethane chemical grouting material; reduces the use of organic solvents, and realizes the green environmental protection of the chemical grouting material production process; the use of stabilizers improves the long-term storage stability of the single-component water-soluble polyurethane chemical grouting material. The natural biomass chitosan modified single-component water-soluble polyurethane chemical grouting material has better storage stability, greater water content, volume expansion rate, curing time, better elastomer compressive strength and other application properties.

Description

Technical Field

[0001] The invention relates to a preparation method of a natural biomass chitin-modified single-component water-soluble polyurethane chemical grouting material and a product thereof, and belongs to the field of biomass material recycling and repair material preparation. Background Art

[0002] Concrete is the most common civil engineering material in the world because of its wide range of raw material sources, high strength, high toughness, easy compaction, non-segregation, and ability to maintain performance for a long time in complex environments. It is widely used in civil engineering construction such as high-rise buildings, highways, high-speed railways, urban rail transit, dams, ports, bridges, etc. Concrete is a non-homogeneous composite material composed of cement, mineral admixtures, coarse and fine aggregates, admixtures, and mixing water. Cracks and damage will occur during the preparation and use of concrete. The causes and formation mechanisms of cracks are complex, including both the material itself and the influence of construction technology, as well as environmental factors. Related research shows that when fresh concrete hardens, the deformation of cement paste and coarse aggregate and fine aggregate in the concrete material is inconsistent, which will produce mutually constrained initial stress, and fine cracks will appear between the bonding surface of cement paste and aggregate or between the cement paste bodies; during the concrete hardening process, the concrete loses water and dries, and tensile stress is generated inside the concrete. When the tensile stress exceeds the tensile strength limit of the concrete, shrinkage cracks will appear in the concrete; concrete also has the property of thermal expansion and contraction. The heat released by the hydration of cement during concrete hardening causes the volume of the concrete to expand, while the external concrete shrinks as the temperature drops. The internal concrete expansion and external contraction Mutual constraints produce tensile stress. When the tensile stress inside the concrete exceeds the tensile strength limit of the concrete, temperature cracks will occur in the concrete. During the use of cement concrete bridge decks and road surfaces, the tensile strength and bending strength of the concrete are reduced due to dynamic loads, static loads, and uneven settlement, which easily forms cracks in the tensile zone of the concrete. Water, oxygen, carbon dioxide, sulfate, and chloride ion media in the external environment invade the concrete structure during service, react with the cement hydration products and steel bars of the concrete to expand the volume of the concrete, and the resulting expansion squeezes the concrete to produce tensile stress. When the tensile stress exceeds the bearing capacity of the concrete, longitudinal cracks will occur on the surface of the concrete. The generation of cracks not only affects the appearance of civil engineering structures, but also small cracks will accelerate the expansion into through cracks, reducing the overall stiffness and integrity of the structure, resulting in a decrease in the bearing capacity of the structure. As a channel for harmful ion erosion, cracks will accelerate water seepage and dissolution of engineering structures and induce steel corrosion, reducing the durability and service life of civil engineering structures. According to statistics, the proportion of cracks on the roofs and basements of existing high-rise buildings in my country is as high as 95.33% and 57.51% respectively; in 2010, the mileage of cement concrete pavement in my country reached 6,000 kilometers, of which 25-32% needed to be repaired due to cracks; more than 60 concrete dams with a length of more than 70 meters and 600km concrete lined tunnels all had cracks to varying degrees; newly built concrete bridges cracked after 3-5 years of use, and some of them had cracks exceeding the allowable crack width before being put into use, which brought great challenges to the structural safety of civil engineering. Concrete cracks are the most concerned topic for technicians in the field of civil engineering.In order to ensure the quality and normal use of civil engineering structures, concrete cracks must be properly repaired to isolate the cracks from the corrosive environment, which is of great significance to improving the durability of structural concrete.

[0003] At present, the repair methods of concrete cracks mainly include surface repair treatment method, filling method, structural reinforcement method, self-repair method, chemical grouting method, etc. The chemical grouting method is to prepare organic and inorganic materials into a true solution. Under the action of the chemical grouting pump, the grouting material is squeezed into the concrete gap to make it diffuse, gel and solidify to increase the strength of the concrete structure, reduce the permeability of the concrete and prevent the deformation of the concrete, so as to achieve the purpose of improving the overall performance of the concrete structure. The chemical grouting method has the characteristics of good groutability, can effectively fill fine cracks, and quickly consolidate within a controllable time range. The solidified body has both anti-seepage and plugging effects and a certain bearing capacity. It is the most commonly used and main means to treat cracks in concrete structures. Commonly used chemical grouting materials include water glass, epoxy resin, acrylamide, methyl methacrylate, and polyurethane. The water glass grout material is composed of water glass solution and salt and acid gelling agents. After being poured into the cracks, it generates silicate gel, fills the pores and cracks of the concrete, and plays a role in consolidation and anti-seepage and plugging. Water glass chemical grouting materials are characterized by abundant sources and low prices. However, water glass slurry uses calcium chloride as a gelling agent. Calcium chloride reacts quickly with water glass, and its gel time is short and its slurry viscosity is large. The diffusion distance in concrete is short, and the durability of water glass chemical slurry gel is poor. These shortcomings limit the promotion and application of water glass chemical grouting materials. Epoxy resin grouting materials are composed of epoxy resin as the main agent, amine curing agent, diluent and toughening agent and other auxiliary agents. Linear epoxy resin and curing agent are cross-linked to form a spatial network structure to play a role in consolidation and reinforcement. Epoxy resin chemical grouting materials have the characteristics of low cost, strong compressive and tensile strength of the consolidated body, good chemical stability, and resistance to acid and alkali medium erosion. However, the viscosity of epoxy resin grouting materials is large, and it is difficult to pour into fine cracks. Although adding diluents can reduce the viscosity of the grouting materials, the addition of diluents will reduce the curing effect of the product. Amine curing agents have high reaction activity at room temperature and low reaction activity at low temperature. The curing speed and strength performance of epoxy resin grouting materials decrease at low temperatures. Amine curing agents also have certain toxicity. The adhesion of epoxy resin grouting materials to structural concrete is poor in a humid environment. These disadvantages limit the application of epoxy resin grouting materials in the repair of cracks in civil engineering structures. Acrylamide grouting materials are composed of acrylamide slurry as the main agent, N, N-methylenebisacrylamide as a cross-linking agent, and promoters and initiators. When the acrylamide grouting material slurry is poured into the concrete cracks, free radical polymerization occurs between acrylamide molecules under the action of the initiator to obtain a water-insoluble, linear long-chain structure and certain elastic water-containing gel. Acrylamide slurry has the characteristics of low viscosity, good pourability and strong permeability, and is suitable for filling fine cracks in structural concrete. The gel time of acrylamide slurry can be adjusted by changing the amount of inhibitor, so that the acrylamide slurry forms a gel within a few minutes to a few hours.However, the consolidation strength of acrylamide grouting materials is not high, and the polymerized monomer acrylamide has certain toxicity. If the slurry is improperly prepared or mixed insufficiently during construction, it will pollute the surrounding water environment. Many countries in the world have banned the use of acrylamide grouting materials. Methyl methacrylate methyl chemical grouting materials undergo free radical polymerization under the action of an initiator to form a solid body to seal concrete cracks. Methyl methacrylate grouting materials have the advantages of low viscosity, good fluidity, ability to fill microcracks, good mechanical properties of the solid body, high adhesion to concrete structure, and ability to better restore the overall performance of cracked concrete. However, the solid body formed by methyl methacrylate grouting materials lacks elasticity, and the volume shrinkage of the solid body will cause local decompression between the solid body and the gap, resulting in poor crack repair effect, and its use is limited. Polyurethane grouting materials are new chemical grouting materials that have emerged after water glass, epoxy resin, acrylamide, and methyl methacrylate. Polyurethane grouting materials are composed of isocyanate-terminated prepolymers obtained by the reaction of polyisocyanates and polyether polyols, catalysts, retarders, surfactants, and plasticizers. The polyurethane grouting material is pressed into the cracks of the concrete, and the isocyanate-terminated prepolymer undergoes a chain extension and cross-linking reaction with the water in the cracks, and expands and solidifies into a gel-like solid body with a certain strength in the concrete gap. The polyurethane solid body has a strong bonding force with the concrete, which plays a role in repairing cracks and improving the strength of the concrete. Compared with traditional water glass, epoxy resin, acrylamide, and methyl methacrylate chemical grouting materials, polyurethane grouting materials have the advantages of convenient storage, low slurry viscosity, strong fluidity, controllable gelation time according to needs, compact solid body structure, excellent mechanical properties, good impermeability, and simple construction process. Polyurethane material is one of the chemical grouting materials with the best performance, the widest range of use, and broad application prospects.

[0004] Polyurethane chemical grouting materials can be divided into oil-soluble and water-soluble polyurethane grouting materials according to the hydrophilicity of the raw materials. Oil-soluble polyurethane grouting materials are mainly composed of prepolymers, acetone, plasticizers, surfactants, and catalyst additives obtained by the reaction of polyisocyanates and non-water-soluble polyether polyols. Oil-soluble polyurethane grouting materials can effectively reinforce concrete structures while plugging concrete cracks. Water-soluble polyurethane grouting materials are mainly composed of prepolymers, acetone, and plasticizers generated by the reaction of toluene diisocyanate and hydrophilic polyether polyols. Water-soluble chemical grouting materials undergo polymerization reactions when they come into contact with water to generate CO2 gas. The pressure generated causes the slurry to enter small cracks and form a consolidation body with the surrounding cement slurry and coarse and fine aggregates. It is suitable for grouting and plugging concrete cracks in low temperature, humidity, and large filling areas. In addition, polyurethane grouting materials can be divided into single-component and two-component polyurethane grouting materials according to the different composition methods of polyurethane slurry. The one-component polyurethane grouting material is obtained by the reaction of polyol ether compounds and isocyanate to obtain a polyurethane prepolymer. After adding a diluent, a catalyst, a retarder and a plasticizer to the polyurethane prepolymer, it is sealed and stored, and can be used directly when grouting is needed. The two-component polyurethane grouting material is obtained by the reaction of polyol ether compounds and isocyanate compounds to obtain a prepolymer (component A), and a mixture of a diluent, a catalyst, a retarder and a plasticizer is used as component B. When used, component A and component B are mixed in proportion for chemical grouting. Compared with the two-component polyurethane chemical grouting material, the one-component water-soluble polyurethane chemical grouting material has the advantages of low viscosity, strong penetration, no use of solvents, long storage time, simple preparation, and easy use. It has become the most used chemical grouting material in the field of crack repair.

[0005] At present, most polyether polyols used in the preparation of one-component water-soluble polyurethane chemical grouting materials are petrochemicals. With the intensification of the global energy crisis and the consumption of oil resources, the production of artificial chemical polyether polyols has decreased, and the price of materials has risen rapidly; the release of toxic solvents in the preparation process of polyether polyols is large, which will cause serious harm and pollution to the bodies of production workers and the surrounding environment; traditional one-component water-soluble polyurethane chemical grouting materials are non-degradable polymer materials, and large-scale use will have a negative impact on soil and groundwater; in the preparation process of traditional one-component water-soluble polyurethane chemical grouting materials, triethylamine catalyst will reduce the mechanical strength of water-soluble polyurethane elastomers and the long-term storage of slurry is poor. Modifying natural biomass materials to replace polyether polyol chemicals, researching and developing a one-component water-soluble polyurethane chemical grouting material with a wide source of raw materials, low cost, good storage stability, good elasticity of the consolidated body, high compressive strength of the elastomer, easy biodegradation, and environmentally friendly is an important way to achieve sustainable development of the polyurethane industry.

[0006] Chitin is a natural biomass polymer compound, which is widely found in the cell walls of fungi, mushrooms, and algae; in the bones of arthropods; in snails, horned clams, and squid mollusks; in amoebas and paramecium protozoa; in tube hydras, moon jellyfish, and nematodes coelenterates; and in earthworms and hornworm annelids. Chitin polymer is the most abundant natural biomass material on earth after cellulose. The amount of chitin synthesized in nature is as high as 100 billion tons per year. The chitin molecule is composed of four elements: C, H, O, and N, and the chemical formula is (C8H 13 NO5) n The chitin molecule is composed of N-acetyl-2-amino-2-deoxy-D-glucose connected by β-(l,4) glycosidic bonds to form a linear natural polymer amino polysaccharide structure. The 2-carbon in the chitin molecule is acetyl, the 3-carbon is hydroxyl, and the 5-carbon is hydroxymethyl. The presence of a large number of hydroxyl groups leads to strong polar hydrogen bonds between chitin molecules, forming an ordered, highly crystalline molecular structure. Chitin is insoluble in water, and is also insoluble in dilute acid, concentrated alkali and organic solvents. However, under the action of strong acids such as hydrochloric acid, phosphoric acid and formic acid, the main chain of the linear chitin polymer will break and degrade, the molecular weight will decrease and the water solubility will increase. The acetyl, hydroxyl and hydroxymethyl in the chitin polymer have certain chemical reactivity. The active groups in the chitin molecule are degraded, hydrolyzed, oxidized, halogenated, etherified, esterified, grafted and cross-linked to introduce functional groups, and water-soluble chitin derivatives with different functions can be obtained. Chemical modification of chitin polymers to prepare environmentally friendly water-soluble polyurethane materials can reduce the use of artificial chemicals in polyurethane materials and reduce environmental pollution caused by the non-degradability of polymer materials. This has become a development trend in the polyurethane field at home and abroad.

[0007] At present, there are reports on the use of natural chitin to modify waterborne polyurethane materials. Zeng Ming (Structure and properties of chitin derivatives / polyurethane composite materials, doctoral dissertation, Wuhan University: Wuhan, 2004); Li Aiping (Study on the structure and properties of chitin whiskers / waterborne polyurethane composite materials, master's thesis, China University of Geosciences: Wuhan, 2007) blended carboxymethyl chitosan with waterborne polyurethane to modify waterborne polyurethane and found that carboxymethyl chitosan and waterborne polyurethane are not completely compatible, but compared with pure waterborne polyurethane, the addition of carboxymethyl chitosan can significantly improve the mechanical properties, thermal stability, and organic solvent resistance of waterborne polyurethane blends. The addition of triethylamine catalyst can improve the compatibility of carboxymethyl chitosan and waterborne polyurethane blends, but reduce the mechanical strength of the blends. Yu Jiahui et al. (Preparation method of chitin whisker modified waterborne polyurethane, Chinese invention patent, CN 201110005529.9) discloses a method for preparing polyurethane resin modified by emulsification of chitin whisker, wherein polyisocyanate and polyester polyol / polyether polyol are used as raw materials to prepare polyurethane prepolymer, small molecule chain extender is added to reduce viscosity, acid hydrolysis is performed to obtain chitin whisker, and then chitin whisker is added to waterborne polyurethane emulsion to obtain chitin whisker modified waterborne polyurethane material. The chitin-modified waterborne polyurethane prepared by this method not only ensures that the product has a higher elongation at break, but also improves the tensile strength and Young's modulus of the elastomer. Jia Xudong et al. (Preparation method of chitosan-polyurethane ion complex elastomer material, Chinese invention patent, CN20091002835) proposed to deacylate natural chitin, dissolve it with dilute acid to obtain a cationic chitosan aqueous solution, react anionic polyurethane emulsion with cationic chitosan aqueous solution to form a chitosan-polyurethane ion complex emulsion, and dry and solidify it to obtain a chitosan-polyurethane ion complex elastomer material. The chitosan-modified waterborne polyurethane prepared by this method has the advantages of thermodynamic stability, mechanical properties, oil resistance, water resistance, good degradability, etc. Jia Xudong et al. (Novel blood compatible water borne polyurethane using chitosan as an extender. Journal of Applied Polymer Science, 2008, 109 (1), 240-246) also prepared -NCO terminated prepolymer using polybutylene adipamide oxide diol, isophorone diisocyanate (IPDI) and dimethylol propionic acid as reaction monomers, and used triethylamine to neutralize low molecular weight water-soluble chitosan as a chain extender to prepare waterborne polyurethane / chitosan block copolymer by self-emulsification method. The results showed that although the waterborne polyurethane / chitosan block copolymer contained hydrophilic groups, the cross-linking effect reduced the solubility of the block copolymer.At present, there are studies on the use of natural chitin to modify waterborne polyurethane materials, but the relevant technologies are mainly concentrated on the physical blending and emulsification modification of natural chitin and waterborne polyurethane. When natural chitin is blended and modified with waterborne polyurethane, the proportion of natural chitin is small, the blend is not completely compatible, and the uniformity is poor. It is necessary to use an ultrasonic treatment method to improve the compatibility of natural chitin and waterborne polyurethane, which increases the production steps and time of natural chitin modified waterborne polyurethane. The natural chitin emulsion copolymerization method is used to prepare modified waterborne polyurethane. The addition of emulsion exacerbates the reaction difficulty and controllability of the polymerization process and increases the production cost. At the same time, the existing natural chitin modified waterborne polyurethane technology cannot effectively reduce the use of artificial chemical polyether polyols, which leads to the high cost of use of natural chitin modified waterborne polyurethane materials and poor market acceptance, making it difficult to promote and apply them on a large scale in engineering. Therefore, it is necessary to find other methods for preparing natural chitin-modified one-component water-soluble polyurethane chemical grouting materials with low cost, simple process, good product compatibility, high polyether polyol chemical replacement ratio, high hydroxyl reaction activity, good mechanical properties and environmental friendliness. Summary of the invention

[0008] Purpose of the invention: The technical problem to be solved by the present invention is to provide a method for preparing a single-component water-soluble polyurethane chemical grouting material modified by natural biomass chitosan.

[0009] The technical problem that the present invention also aims to solve is to provide a natural biomass chitin-modified single-component water-soluble polyurethane chemical grouting material prepared by the method.

[0010] Technical solution: To solve the above technical problems, the present invention provides a method for preparing a natural biomass chitosan-modified single-component water-soluble polyurethane chemical grouting material, comprising the following steps:

[0011] (1) placing chitosan polymer and water in a reaction vessel equipped with a stirrer, a thermometer, a dropping funnel, and a reflux condenser, heating to 85-90° C., rapidly stirring, and dispersing the chitosan polymer in the water to obtain a chitosan polymer suspension solution;

[0012] (2) heating the chitosan polymer suspension solution to 85-90° C., adding a sodium hydroxide solution, and stirring for 16-24 hours to obtain an amino-containing chitosan polymer suspension solution;

[0013] (3) adding ferrous sulfate as a catalyst to the amino-containing chitosan polymer suspension solution, placing the solution in a polytetrafluoroethylene tank in a stainless steel high-pressure reaction vessel, and reacting the solution at 155-160° C. for 18-20 hours in a sealed state; after the reaction, taking out the degraded amino-containing chitosan polymer solution, keeping the temperature of the degraded amino-containing chitosan polymer solution at 80-85° C., slowly adding hydrogen peroxide and ammonium persulfate composite oxidant dropwise over 25-30 minutes, raising the temperature to 90-95° C., and reacting the solution at this temperature for 6-8 hours to obtain an amino-containing chitosan oligomer solution;

[0014] (4) adjusting the pH value of the mixed solution of polyethylene glycol and epichlorohydrin, maintaining the temperature at 45-50° C., adding the catalyst tetra-n-butylammonium bromide dropwise within 20-40 minutes, raising the temperature to 50-60° C., and continuously stirring and reacting at this temperature for 2-3 hours to obtain an epoxy-terminated polyethylene glycol glycidyl ether liquid; adjusting the system pH value to 1-2 with dilute sulfuric acid, and hydrolyzing at room temperature for 2-3 hours to obtain an epoxy-terminated polyethylene glycol glycidyl ether hydrolyzed solution;

[0015] (5) adding the amino-containing chitosan oligomer solution obtained in step (3) to the hydrolyzed solution of epoxy-terminated polyethylene glycol glycidyl ether, maintaining the temperature at 45-50° C., slowly adding tetrafluoroboric acid as a catalyst over a period of 20-30 minutes, raising the temperature to 80-85° C., reacting at this temperature for 4-5 hours, and obtaining an N-ether chitosan polyol oligomer solution;

[0016] (6) placing polytetrahydrofuran ether diol and N-ether chitosan polyol oligomer into a reaction vessel equipped with a stirrer, a thermometer, a dropping funnel, and a reflux condenser, heating to 95-100° C., dehydrating at a vacuum degree of 0.01-0.02 MPa for 8-10 hours, and stopping vacuuming when the water content of the mixed polyether polyol is less than 0.03%; cooling to 50-55° C., nitrogen protection, slowly adding toluene diisocyanate solution dropwise, and after the toluene diisocyanate solution is added, heating to 75-85° C., reacting for 2-3 hours, and adding stabilizer benzoyl chloride to obtain a prepolymer terminated with an -NCO group;

[0017] (7) Mixing the prepolymer terminated with -NCO groups, stannous oleate and dioctyl sebacate, vacuum dehydrating at 95-100° C. and 0.01-0.02 MPa for 2-3 hours, and cooling to 20-30° C. after releasing the vacuum, to obtain a one-component water-soluble polyurethane chemical grouting material.

[0018] Wherein, in step (1), the mass ratio of chitosan polymer to water is 1:2-2.1.

[0019] Wherein, in step (2), the mass ratio of the chitosan polymer suspension solution to the sodium hydroxide solution is 1.875-2:1.

[0020] Wherein, the amount of the catalyst ferrous sulfate used in step (3) is 0.10-0.15% of the weight of the amino-containing chitosan polymer suspension solution.

[0021] Wherein, the amount of the mixed solution of hydrogen peroxide and ammonium persulfate composite oxidant in step (3) is 1.0-1.5% of the weight of the amino-containing chitosan polymer suspension solution.

[0022] Wherein, in step (4), the mass ratio of polyethylene glycol to epichlorohydrin is 3-3.4:1; the pH value of the mixed solution of polyethylene glycol and epichlorohydrin is 12-13; and the mass ratio of the mixed solution of polyethylene glycol and epichlorohydrin to the tetra-n-butylammonium bromide catalyst is 106-115:1.

[0023] Wherein, in step (5), the mass ratio of the epoxy-terminated polyethylene glycol glycidyl ether liquid to the amino-containing chitosan oligomer solution is 1:25.7-27.5; and the mass ratio of the epoxy-terminated polyethylene glycol glycidyl ether liquid to the tetrafluoroboric acid catalyst is 24-26:1.

[0024] Wherein, in step (6), the mass ratio of polytetrahydrofuran ether diol to N-ether-based chitosan polyol oligomer solution is 1:6.0-6.4; the mass ratio of polytetrahydrofuran ether diol and N-ether-based chitosan polyol oligomer to toluene diisocyanate solution is 9.5-10.0:1; and the amount of benzoyl chloride stabilizer is 0.045-0.05% of the total weight of polytetrahydrofuran ether diol and N-ether-based chitosan polyol oligomer.

[0025] Wherein, in step (7), the mass ratio of the -NCO group-terminated prepolymer to dioctyl sebacate is 4.0-4.2:1, and the stannous oleate is 0.25-0.30% of the total weight of the -NCO group-terminated prepolymer and dioctyl sebacate.

[0026] The invention also provides a single-component water-soluble polyurethane chemical grouting material prepared by the method.

[0027] Reaction mechanism: The present invention is based on the fact that natural chitin has multiple hydroxyl groups, and its molecular structure is similar to that of organic synthetic chemical polyols, and the molecular chemical structure of chitin is more regular, and the hydroxyl reaction activity can be improved by high temperature and oxidative degradation. First, the chitin polymer is deacylated under high temperature and strong alkaline conditions, and the chitin polymer is degraded into chitosan oligomers with -CH2OH, -OH, and -NH2 groups by high temperature catalysis and strong oxidation. Then, polyethylene glycol and epichlorohydrin are polymerized to form an epoxy-terminated polyethylene glycol glycidyl ether hydrolysis solution. Subsequently, amino-containing chitosan oligomers and epoxy-terminated polyethylene glycol glycidyl ethers are subjected to ring-opening etherification reaction to obtain N-ether chitosan polyol oligomers. Finally, N-ether chitosan polyol oligomers partially replace synthetic chemical polyether polyols, and the mixed ether alcohols are subjected to high temperature vacuum dehydration, and the mixed ether alcohols and polyisocyanates are subjected to polymerization reaction in the case of excessive isocyanate to obtain -NCO group-terminated prepolymers. The prepolymer, curing agent and plasticizer are mixed and vacuum dehydrated to prepare a natural biomass chitosan modified single-component water-soluble polyurethane chemical grouting material.

[0028] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages:

[0029] 1. In the preparation process of water-soluble polyurethane chemical grouting materials, N-ether-based chitosan polyol oligomers replace chemical polyether polyols to prepare single-component water-soluble polyurethane chemical grouting materials, which broadens the application field of natural chitin polymer materials, increases the use of biomass chitin, consumes a large amount of natural chitin materials, and reduces the material use cost in the preparation process of single-component water-soluble polyurethane chemical grouting materials. For every ton of natural biomass chitin-modified single-component water-soluble polyurethane chemical grouting materials produced, the cost of synthetic chemical polyether polyol materials can be saved by 7.58 yuan;

[0030] 2. Compared with the preparation method of biomass chitin physical blending modified waterborne polyurethane material, the natural biomass chitin etherification modified single-component water-soluble polyurethane chemical grouting material improves the compatibility and uniformity of the modified single-component water-soluble polyurethane chemical grouting material;

[0031] 3. The one-component water-soluble polyurethane chemical grouting material prepared by the method of the present invention reduces the use of organic solvents, avoids the negative impact of organic solvents on the environment and the health of operators, realizes the green and environmental protection of the production process of chemical grouting materials, and can generate an economic benefit of 3.43 yuan per ton of product;

[0032] 4. The use of stabilizers improves the long-term storage stability of single-component water-soluble polyurethane chemical grouting materials, and each ton of single-component water-soluble polyurethane chemical grouting materials can generate an economic benefit of 2.13 yuan;

[0033] 5. The natural biomass chitosan modified one-component water-soluble polyurethane chemical grouting material has better storage stability than the traditional one-component water-soluble polyurethane chemical grouting material. Under the same water usage and foaming conditions, the natural biomass chitosan modified one-component water-soluble polyurethane chemical grouting material has a larger water content, volume expansion rate, curing time, and better elastomer compressive strength;

[0034] 6. The natural biomass chitin modified single-component water-soluble polyurethane is biodegradable, avoiding the environmental pollution problem caused by the non-degradability of traditional polyurethane materials;

[0035] 7. The use of natural biomass chitosan to modify and prepare a single-component water-soluble polyurethane chemical grouting material can produce good technical, economic, social and environmental benefits;

[0036] In summary, according to Example 1 of the present invention, if 4,000 tons of such biomass chitin modified single-component water-soluble polyurethane chemical grouting material is produced annually, 44,000 yuan of chemical polyether polyol and organic solvent raw material costs can be saved. The economic benefits of 24,300 yuan can be brought about by reducing the investment in production equipment, simplifying the process, increasing the production time and improving the storage time. If 4,000 tons of single-component biomass chitin modified water-soluble polyurethane chemical grouting material is produced annually, 5.56×10 6 Compared with the traditional one-component water-soluble polyurethane chemical grouting material, the same crack repair effect can save 68,900 yuan in chemical grouting material usage fees. The production of 4,000 tons of biomass chitin modified one-component water-soluble polyurethane chemical grouting material can generate 137,200 yuan in economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 The present invention is a preparation flow chart of biomass chitin modified single-component water-soluble polyurethane chemical grouting material;

[0038] Figure 2 The -NCO content of two one-component water-soluble polyurethane chemical grouting materials changes with storage time;

[0039] Figure 3 It is the water content of two single-component water-soluble polyurethane chemical grouting materials under different water contents;

[0040] Figure 4 is the volume expansion rate of two single-component water-soluble polyurethane chemical grouting materials under different water amounts;

[0041] Figure 5 It is the curing time of two one-component water-soluble polyurethane chemical grouting materials under different water amounts;

[0042] Figure 6is the compressive strength of two single-component water-soluble polyurethane elastomers under different water amounts;

[0043] Figure 7 A is the tensile strength of two single-component water-soluble polyurethane elastomers under different water amounts; Figure 7 B is the tensile elongation of two single-component water-soluble polyurethane elastomers under different water amounts. DETAILED DESCRIPTION

[0044] The technical solution of the present invention is further described below in conjunction with the accompanying drawings.

[0045] Raw materials: chitosan polymer (weight average molecular weight 335,400) was produced by Nantong Langshan Xingcheng Biochemical Products Factory; sodium hydroxide (industrial grade, purity 97%) was produced by Hebei Cangzhou Xincheng Chemical Products Co., Ltd.; ferrous sulfate (industrial grade, purity ≥ 90.0%) was produced by Wuxi Kaier Chemical Products Co., Ltd.; hydrogen peroxide (industrial grade, concentration 30%) was produced by Hangzhou Jingxin Chemical Co., Ltd.; ammonium persulfate (industrial grade, purity ≥ 90.0%) was produced by Fujian Zhanhua Chemical Co., Ltd.; polyethylene glycol (PEG-600, weight average molecular weight 600, analytical grade, purity 99%) was produced by Tianjin Dongli District Tianda Chemical Reagent Factory; epichlorohydrin (industrial grade, purity 93%) was produced by Jiangsu Yingte Chemical Co., Ltd.; tetrabutyl bromide Ammonium (industrial grade, purity ≥99%) was produced by Shandong Zibo Mingju Chemical Co., Ltd.; dilute sulfuric acid (industrial grade, concentration 30-32%) was produced by Suzhou Junma Chemical Co., Ltd.; tetrafluoroboric acid (industrial grade, purity 92%) was produced by Jinan Huifengda Chemical Co., Ltd.; polytetramethylene glycol (PTMG3000, weight average molecular weight 3000, industrial grade) was produced by South Korea's PTG Company; toluene diisocyanate (TDI, industrial grade) was produced by Germany's Bayer AG; benzoyl chloride (industrial grade, purity 99%) was produced by Jiangsu Wanlong Chemical Co., Ltd.; stannous oleate (industrial grade, purity 99%) was produced by Hubei Xinhongli Chemical Co., Ltd.; dioctyl sebacate (industrial grade, purity 99%) was produced by Shandong Weifang Hansheng Chemical Co., Ltd.

[0046] Example 1 Preparation of natural biomass chitin modified single-component water-soluble polyurethane chemical grouting material

[0047] Figure 1 The invention relates to the steps for preparing a natural biomass chitin-modified single-component water-soluble polyurethane chemical grouting material.

[0048] 1. Preparation of amino-containing chitosan oligomers

[0049] First, the chitosan polymer suspension solution is prepared: 500 kg of natural chitosan polymer and 1000 kg of water are placed in a reaction kettle equipped with a stirrer, a thermometer, a dropping funnel, and a reflux condenser, the temperature is raised to 85° C., and the mixture is quickly stirred to fully mix the chitosan polymer and the water to obtain a chitosan polymer suspension solution.

[0050] Secondly, preparation of amino-containing chitosan polymer: 750 kg of sodium hydroxide solution (concentration of 40%) was added to 1500 kg of chitosan polymer suspension solution, the temperature of the chitosan polymer suspension solution was 85°C, and stirred for 24 hours to remove the acetyl groups on the chitosan polymer molecules to obtain amino-containing chitosan polymer suspension solution. The deacylation degree of chitosan polymer was 92.58%.

[0051] Finally, the preparation of amino-containing chitosan oligomers: 2.5 kg of ferrous sulfate catalyst was added to the above 2250 kg chitosan polymer suspension containing amino groups, and the mixture was placed in a polytetrafluoroethylene tank in a stainless steel autoclave, and hydrothermally reacted for 20 hours at 155 ° C. After the reaction, the degraded chitosan polymer solution containing amino groups was taken out, and the temperature of the degraded chitosan polymer solution containing amino groups was kept at 85 ° C. In 25 minutes, 24.0 kg of hydrogen peroxide and ammonium persulfate composite oxidant mixed solution (hydrogen peroxide: ammonium persulfate = 1:1) was slowly added dropwise, and the temperature was raised to 95 ° C. At this temperature, the reaction was carried out for 7 hours to obtain 2249.9 kg of chitosan oligomer solution containing amino groups. The weight average molecular weight of the chitosan oligomer containing amino groups was determined to be 4878 by gel permeation chromatography.

[0052] 2. Preparation of Epoxy-Terminated Polyethylene Glycol Glycidyl Ether

[0053] 61.0 kg of polyethylene glycol and 18.7 kg of epichlorohydrin were placed in a reaction kettle equipped with a stirrer, a thermometer, a dropping funnel and a reflux condenser, 14.8 kg of sodium hydroxide solution (concentration of 40%) was added to adjust the pH value of the system to 12.17, the solution temperature was maintained at 50° C., 0.72 kg of catalyst tetra-n-butylammonium bromide was slowly added dropwise over 25 minutes, the temperature was raised to 55° C., and the reaction was continued at this temperature for 3 hours to obtain 91.59 kg of light yellow epoxy-terminated polyethylene glycol glycidyl ether liquid, dilute sulfuric acid was used to adjust the pH value of the system to 1.59, and the epoxy-terminated polyethylene glycol glycidyl ether hydrolyzed solution was obtained by hydrolysis at room temperature for 3 hours.

[0054] 3. Preparation of N-ether chitosan polyol oligomers

[0055] 1938kg of chitosan oligomer solution containing amino groups was added to 73.48kg of epoxy-terminated polyethylene glycol glycidyl ether hydrolyzed solution, and the temperature of the mixed solution was kept at 50°C. Within 25 minutes, 2.89kg of catalyst tetrafluoroboric acid was slowly added dropwise, and the temperature was raised to 85°C. The reaction was carried out at this temperature for 5 hours. The amino groups on the chitosan oligomer reacted with the epoxy groups terminated with polyethylene glycol glycidyl ether to form a ring-opening etherification reaction, and 2006.14kg of N-ether chitosan polyol oligomer solution was obtained.

[0056] 4. Preparation of prepolymer

[0057] 300kg of polytetrahydrofuran ether diol and 1850kg of N-ether chitosan polyol oligomer solution were placed in a reactor equipped with a stirrer, a thermometer, a dropping funnel, and a reflux condenser. The mixture was heated to 95°C and dehydrated under a vacuum of 0.015MPa for 10 hours. When the water content of the mixed polyether polyol was less than 0.03%, the vacuum was stopped. The mixture was cooled to 55°C, nitrogen was protected, and 220kg of toluene diisocyanate solution was slowly added dropwise. After the toluene diisocyanate solution was added, the mixture was heated to 80°C. In the case of excess isocyanate, the mixed polyether polyol and toluene diisocyanate were polymerized for 3 hours. 1.03kg of stabilizer benzoyl chloride was added to obtain 928.23kg of -NCO group-terminated prepolymer, and the -NCO value of the prepolymer was 7.03%.

[0058] 5. Preparation of natural biomass chitin modified single-component water-soluble polyurethane chemical grouting material

[0059] 805kg of -NCO-terminated prepolymer, 2.62kg of stannous oleate, and 195kg of dioctyl sebacate were placed in a reaction kettle equipped with a stirrer, a thermometer, a dropping funnel, and a reflux condenser, and vacuum dehydrated for 3 hours at 95°C and 0.017MPa. After the vacuum was released, the temperature was lowered to 30°C to obtain 997.19kg of a light yellow, viscous, single-component water-soluble polyurethane chemical grouting material. The material was placed in a sealed container and stored at 23°C for later use.

[0060] Example 2

[0061] 1. Preparation of amino-containing chitosan oligomers

[0062] First, the chitosan polymer suspension solution was prepared by placing 510 kg of natural chitosan polymer and 1025 kg of water into a reaction kettle equipped with a stirrer, a thermometer, a dropping funnel, and a reflux condenser, raising the temperature to 90° C. and rapidly stirring the mixture to fully mix the chitosan polymer and the water to obtain a chitosan polymer suspension solution.

[0063] Secondly, preparation of chitosan polymer containing amino groups: 770 kg of sodium hydroxide solution (concentration of 40%) was added to 1525 kg of chitosan polymer suspension solution, the chitosan polymer suspension solution was kept at 90°C and stirred for 20 hours to remove the acetyl groups on the chitosan polymer molecules to obtain a chitosan polymer suspension solution containing amino groups. The deacylation degree of the chitosan polymer was 92.09%.

[0064] Finally, the preparation of chitosan oligomer containing amino group: 2.7kg of catalyst ferrous sulfate was added to the above 2295kg chitosan polymer suspension containing amino group, and the suspension was placed in a polytetrafluoroethylene tank in a stainless steel autoclave, and hydrothermally reacted for 20 hours at 160℃ under high temperature and sealing. After the reaction, the degraded chitosan polymer solution containing amino group was taken out, and the temperature of the degraded chitosan polymer solution containing amino group was kept at 85℃. In 25 minutes, 25.5kg of hydrogen peroxide and ammonium persulfate composite oxidant mixed solution (hydrogen peroxide: ammonium persulfate = 1:1) was slowly added dropwise, and the temperature was raised to 95℃. At this temperature, the reaction was performed for 8 hours to obtain 2297.35kg of chitosan oligomer solution containing amino group. The weight average molecular weight of chitosan oligomer containing amino group was determined to be 4855 by gel permeation chromatography.

[0065] 2. Preparation of Epoxy-Terminated Polyethylene Glycol Glycidyl Ether

[0066] 61.25 kg of polyethylene glycol and 18.75 kg of epichlorohydrin were placed in a reaction kettle equipped with a stirrer, a thermometer, a dropping funnel and a reflux condenser, 14.92 kg of sodium hydroxide solution (concentration of 40%) was added to adjust the pH value of the system to 12.89, the solution temperature was maintained at 50° C., 0.735 kg of catalyst tetra-n-butylammonium bromide was slowly added dropwise over 40 minutes, the temperature was raised to 60° C., and the reaction was continued at this temperature for 3 hours to obtain 94.22 kg of light yellow epoxy-terminated polyethylene glycol glycidyl ether liquid, the pH value of the system was adjusted to 1.76 using dilute sulfuric acid, and the epoxy-terminated polyethylene glycol glycidyl ether hydrolyzed solution was obtained by hydrolysis at room temperature for 3 hours.

[0067] 3. Preparation of N-ether chitosan polyol oligomers

[0068] 1938.5 kg of chitosan oligomer solution containing amino groups was added to 73.5 kg of epoxy-terminated polyethylene glycol glycidyl ether hydrolyzed solution, and the temperature of the mixed solution was kept at 50°C. Within 30 minutes, 2.90 kg of catalyst tetrafluoroboric acid was slowly added dropwise, and the temperature was raised to 85°C. The reaction was carried out at this temperature for 5 hours. The amino groups on the chitosan oligomer reacted with the epoxy groups terminated with polyethylene glycol glycidyl ether to form a ring-opening etherification reaction, and 2007.22 kg of N-ether chitosan polyol oligomer solution was obtained.

[0069] 4. Preparation of prepolymer

[0070] 302.5kg of polytetrahydrofuran ether diol and 1875.5kg of N-ether chitosan polyol oligomer solution were placed in a reactor equipped with a stirrer, a thermometer, a dropping funnel, and a reflux condenser. The temperature was raised to 95°C, and dehydrated under a vacuum degree of 0.019MPa for 9 hours. When the water content of the mixed polyether polyol was less than 0.03%, the vacuum was stopped. The temperature was lowered to 50°C, nitrogen protection was performed, and 222.5kg of toluene diisocyanate solution was slowly added dropwise. After the toluene diisocyanate solution was added, the temperature was raised to 80°C. In the case of excessive isocyanate, the mixed polyether polyol and toluene diisocyanate were polymerized for 3 hours. 1.07kg of stabilizer benzoyl chloride was added to obtain 927.4kg of -NCO group-terminated prepolymer, and the -NCO value of the prepolymer was 6.89%.

[0071] 5. Preparation of natural biomass chitin modified single-component water-soluble polyurethane chemical grouting material

[0072] 805kg of -NCO-terminated prepolymer, 2.78kg of stannous oleate, and 195.5kg of dioctyl sebacate were placed in a reaction kettle equipped with a stirrer, a thermometer, a dropping funnel, and a reflux condenser, and vacuum dehydrated for 3 hours at 95°C and 0.015MPa. After the vacuum was released, the temperature was lowered to 30°C to obtain 995.09kg of a light yellow, viscous, one-component water-soluble polyurethane chemical grouting material. The material was placed in a sealed container and stored at 22°C for later use.

[0073] Example 3

[0074] 1. Preparation of amino-containing chitosan oligomers

[0075] First, the chitosan polymer suspension solution is prepared: 520 kg of natural chitosan polymer and 1050 kg of water are placed in a reaction kettle equipped with a stirrer, a thermometer, a dropping funnel, and a reflux condenser, the temperature is raised to 90° C., and the mixture is quickly stirred to fully mix the chitosan polymer and the water to obtain a chitosan polymer suspension solution.

[0076] Secondly, preparation of chitosan polymer containing amino groups: 780 kg of sodium hydroxide solution (concentration of 40%) was added to 1550 kg of chitosan polymer suspension solution, the suspension solution temperature was 90°C, and stirred for 22 hours to remove the acetyl groups on the chitosan polymer molecules to obtain a chitosan polymer suspension solution containing amino groups. The deacylation degree of chitosan polymer was 93.54%.

[0077] Finally, the preparation of chitosan oligomer containing amino group: 2.83kg of catalyst ferrous sulfate was added to the above 2330kg chitosan polymer suspension containing amino group, and the mixture was placed in a polytetrafluoroethylene tank in a stainless steel autoclave, and hydrothermally reacted for 20 hours at 155-160℃ under high temperature and sealing. After the reaction, the degraded chitosan polymer solution containing amino group was taken out, and the temperature of the degraded chitosan polymer solution containing amino group was kept at 85℃. In 30 minutes, 26.8kg of hydrogen peroxide and ammonium persulfate composite oxidant mixed solution (hydrogen peroxide: ammonium persulfate = 1:1) was slowly added dropwise, and the temperature was raised to 95℃. The mixture was reacted at this temperature for 7 hours to obtain 2322.5kg of chitosan oligomer solution containing amino group. The weight average molecular weight of chitosan oligomer containing amino group was determined to be 4679 by gel permeation chromatography.

[0078] 2. Preparation of Epoxy-Terminated Polyethylene Glycol Glycidyl Ether

[0079] 61.3 kg of polyethylene glycol and 18.92 kg of epichlorohydrin were placed in a reaction kettle equipped with a stirrer, a thermometer, a dropping funnel and a reflux condenser, 14.78 kg of sodium hydroxide solution (concentration of 40%) was added to adjust the pH value of the system to 12.47, the solution temperature was maintained at 50° C., 0.729 kg of catalyst tetra-n-butylammonium bromide was slowly added dropwise over 40 minutes, the temperature was raised to 60° C., and the reaction was continued at this temperature for 2-3 hours to obtain 93.16 kg of light yellow epoxy-terminated polyethylene glycol glycidyl ether liquid, the pH value of the system was adjusted to 1.33 using dilute sulfuric acid, and the epoxy-terminated polyethylene glycol glycidyl ether hydrolyzed solution was obtained by hydrolysis at room temperature for 3 hours.

[0080] 3. Preparation of N-ether chitosan polyol oligomers

[0081] 1939.5 kg of chitosan oligomer solution containing amino groups was added to 73.2 kg of epoxy-terminated polyethylene glycol glycidyl ether hydrolysis solution, and the temperature of the mixed solution was kept at 50°C. Within 30 minutes, 2.90 kg of catalyst tetrafluoroboric acid was slowly added dropwise, and the temperature was raised to 85°C. The reaction was carried out at this temperature for 4.5 hours. The amino groups on the chitosan oligomer reacted with the epoxy groups terminated with polyethylene glycol glycidyl ether to form a ring-opening etherification reaction, and 2011.33 kg of N-ether chitosan polyol oligomer solution was obtained.

[0082] 4. Preparation of prepolymer

[0083] 303.8kg of polytetrahydrofuran ether diol and 1890kg of N-ether chitosan polyol oligomer solution were placed in a reactor equipped with a stirrer, a thermometer, a dropping funnel, and a reflux condenser. The mixture was heated to 95°C and dehydrated under a vacuum of 0.013MPa for 9 hours. When the water content of the mixed polyether polyol was less than 0.03%, the vacuum was stopped. The mixture was cooled to 55°C, nitrogen was protected, and 221.9kg of toluene diisocyanate solution was slowly added dropwise. After the toluene diisocyanate solution was added, the mixture was heated to 85°C. In the case of excess isocyanate, the mixed polyether polyol and toluene diisocyanate were polymerized for 3 hours. 1.06kg of benzoyl chloride stabilizer was added to obtain 929.1kg of -NCO group-terminated prepolymer, and the prepolymer -NCO value was 7.06%.

[0084] 5. Preparation of natural biomass chitin modified single-component water-soluble polyurethane chemical grouting material

[0085] 807.2kg of -NCO-terminated prepolymer, 2.83kg of stannous oleate, and 193.6kg of dioctyl sebacate were placed in a reaction kettle equipped with a stirrer, a thermometer, a dropping funnel, and a reflux condenser, and vacuum dehydrated for 3 hours at 95°C and 0.015MPa vacuum. After the vacuum was released, the temperature was lowered to 30°C to obtain 995.42kg of a light yellow, viscous, one-component water-soluble polyurethane chemical grouting material. The material was placed in a sealed container and stored at 21°C for later use.

[0086] Example 4 Storage stability of natural biomass chitin modified single-component water-soluble polyurethane chemical grouting material

[0087] The storage stability of natural biomass chitin modified one-component water-soluble polyurethane chemical grouting materials is an important performance indicator. After the traditional one-component water-soluble polyurethane chemical grouting material (N-WPU) and the natural biomass chitin modified one-component water-soluble polyurethane chemical grouting material (Chitin-WPU) were placed at room temperature for 0, 30, 60, and 180 days, the isocyanate content in the two chemical grouting materials was determined using the di-n-butylamine-acetone titration method (bromocresol green as an indicator and 0.1 mol / L HCl as a standard solution). The change in isocyanate (-NCO content) in the grout was used to evaluate the storage stability of the two one-component water-soluble polyurethane chemical grouting materials.

[0088] like Figure 2As shown in the figure, with the increase of storage time, the -NCO content in both one-component water-soluble polyurethane chemical grouting materials decreased. During the same storage time, the -NCO content reduction rate of the natural biomass chitosan modified one-component water-soluble polyurethane chemical grouting material was slower than that of the traditional one-component water-soluble polyurethane chemical grouting material. The natural biomass chitosan modified one-component water-soluble polyurethane chemical grouting material had better storage stability than the traditional one-component water-soluble polyurethane chemical grouting material.

[0089] Example 5: Grouting performance test of natural biomass chitin modified single-component water-soluble polyurethane grouting material

[0090] 1. Water content detection

[0091] Under standard test conditions, the chemical grouting material is mixed with a certain amount of water and reacts completely with water. The grouting material solidifies into a gel within 200 seconds and the solidified body has no water seepage. The multiple of the amount of water contained in the solidified body of the chemical grouting material and the amount of the chemical grouting material is called the water content of the grouting material. Weigh 5g of traditional one-component water-soluble polyurethane chemical grouting material (N-WPU) and natural biomass chitin-modified one-component water-soluble polyurethane chemical grouting material (Chitin-WPU), stir and mix with 50g, 55g, and 60g of water, and the chemical grouting material gels and solidifies within the specified time. The water content of the two one-component water-soluble polyurethane chemical grouting materials is tested.

[0092] like Figure 3 As shown in the figure, with the increase of water consumption, the water content of the two one-component water-soluble polyurethane chemical grouting materials increases. Under the same grouting material / water consumption ratio, the natural biomass chitosan modified one-component water-soluble polyurethane chemical grouting material has a higher water content than the traditional one-component water-soluble polyurethane chemical grouting material.

[0093] 2. Volume expansion rate detection

[0094] Referring to the test method of JC / T2041-2010 "Polyurethane Grouting Material", under standard test conditions, 50g of traditional one-component water-soluble polyurethane chemical grouting material (N-WPU) and natural biomass chitin modified one-component water-soluble polyurethane chemical grouting material (Chitin-WPU) were taken and put into a 500ml measuring cup with 70g, 75g, and 80g of water respectively and stirred evenly. When the foaming of the water-soluble polyurethane slurry was completed, the volume of the slurry before and after solidification was recorded. The growth rate of the foamed solid body formed by the two water-soluble polyurethane chemical grouting materials after water foaming relative to the volume of the original slurry solution is defined as the volume expansion rate of the chemical grouting material, expressed as a percentage.

[0095] like Figure 4As shown in the figure, with the increase of water consumption, the volume expansion rate of the two one-component water-soluble polyurethane chemical grouting materials increased. Under the same grouting material / water consumption ratio, the natural biomass chitosan modified one-component water-soluble polyurethane chemical grouting material has a higher volume expansion rate than the traditional one-component water-soluble polyurethane chemical grouting material.

[0096] 3. Curing time

[0097] Referring to the detection method of JC / T2041-2010 "Polyurethane Grouting Materials", under standard test conditions, weigh 20g of traditional one-component water-soluble polyurethane chemical grouting material (N-WPU) and natural biomass chitin modified one-component water-soluble polyurethane chemical grouting material (Chitin-WPU) into a 500ml measuring cup, add 1g, 1.5g, and 2g of water into the 500ml measuring cup and record the time of adding water. Use a glass rod to evenly stir the chemical grouting material. The chemical grouting material foams when it meets water. After the foam stops foaming, it is considered that the chemical grouting material has been completely solidified. The time from the beginning of stirring to the solidification of the grouting material is defined as the solidification time.

[0098] like Figure 5 As shown in the figure, with the increase of water consumption, the curing time of the two one-component water-soluble polyurethane chemical grouting materials increases. Under the same grouting material / water consumption ratio, the natural biomass chitosan modified one-component water-soluble polyurethane chemical grouting material has a longer curing time than the traditional one-component water-soluble polyurethane chemical grouting material.

[0099] 4. Compressive strength of polyurethane elastomer

[0100] According to the test method of JC / T2041-2010 "Polyurethane Grouting Material", under standard test conditions, the traditional one-component water-soluble polyurethane chemical grouting material (N-WPU), the natural biomass chitin modified one-component water-soluble polyurethane chemical grouting material (Chitin-WPU) and water were prepared into slurry at a ratio of 20:1.0, 20:1.5, and 20:2.0, and the prepared slurry was poured into a 70mm×70mm×70mm polytetrafluoroethylene test mold for molding. After demolding, the mold was cured at a constant temperature for 10 hours. After the sample was placed at room temperature for 7 days, the polyurethane elastomer sample was placed on a universal testing machine and continuously loaded at a loading speed of 0.3MPa / s-0.5MPa / s. When the sample was close to failure and began to deform rapidly, the throttle adjustment was stopped until the specimen was destroyed, and the failure load was recorded. The failure load per unit area of ​​the polyurethane elastomer is defined as the compressive strength of the polyurethane elastomer.

[0101] like Figure 6As shown in the figure, with the increase of water consumption, the compressive strength of the two one-component water-soluble polyurethane chemical grouting material elastomers decreased. Under the same grouting material / water consumption ratio, the natural biomass chitosan modified one-component water-soluble polyurethane chemical grouting material elastomer has higher compressive strength than the traditional one-component water-soluble polyurethane chemical grouting material elastomer.

[0102] 5. Tensile strength and tensile elongation of polyurethane elastomer

[0103] According to the test method of JC / T2041-2010 "Polyurethane Grouting Material", under standard test conditions, add 1g, 1.5g, and 2g of water to 20g of traditional one-component water-soluble polyurethane chemical grouting material (N-WPU) and natural biomass chitin modified one-component water-soluble polyurethane chemical grouting material (Chitin-WPU), stir evenly, pour into a polytetrafluoroethylene mold and flatten, put the mold into a vacuum drying oven, and cure it at a set temperature for 10 hours to obtain a polyurethane elastomer sample. The sample is placed at room temperature for 7 days. The polyurethane elastomer film is made into a dumbbell-shaped specimen, and the thickness and width of the specimen are measured respectively, and the average value is taken. During the specified test time, the dumbbell-shaped specimen is loaded with a universal electronic tensile testing machine at a tensile speed of 100mm / min. The maximum tensile stress during the stretching of the specimen to the fracture process is taken as the tensile strength, and the ratio of the maximum tensile length of the specimen to the original length of the specimen is defined as the tensile elongation.

[0104] like Figure 7 As shown in the figure, with the increase of water consumption, the tensile strength and elongation of the two one-component water-soluble polyurethane chemical grouting material elastomers increased. Under the same grouting material / water consumption ratio, the natural biomass chitin modified one-component water-soluble polyurethane chemical grouting material elastomer has slightly lower tensile strength and elongation than the traditional one-component water-soluble polyurethane chemical grouting material elastomer.

Claims

1. A method for preparing a natural biomass chitin-modified single-component water-soluble polyurethane chemical grouting material, characterized in that: The following steps are involved: (1) placing chitosan polymer and water in a reaction vessel equipped with a stirrer, a thermometer, a dropping funnel, and a reflux condenser, heating the reaction vessel to 85-90° C., and rapidly stirring the reaction vessel to disperse the chitosan polymer in the water to obtain a chitosan polymer suspension solution; (2) heating the chitosan polymer suspension solution to 85-90° C., adding a sodium hydroxide solution, and stirring for 16-24 hours to obtain an amino-containing chitosan polymer suspension solution; (3) Adding ferrous sulfate as a catalyst to the amino-containing chitosan polymer suspension solution, placing the solution in a polytetrafluoroethylene tank in a stainless steel high-pressure container, and sealing the tank at 155-160° C. for reaction for 18-20 hours; after the reaction, taking out the degraded amino-containing chitosan polymer solution, keeping the temperature of the degraded amino-containing chitosan polymer solution at 80-85° C., slowly adding hydrogen peroxide and ammonium persulfate composite oxidant dropwise over 25-30 minutes, raising the temperature to 90-95° C., and reacting at this temperature for 6-8 hours to obtain an amino-containing chitosan oligomer solution; (4) adjusting the pH value of the mixed solution of polyethylene glycol and epichlorohydrin, maintaining the temperature at 45-50°C, adding the catalyst tetra-n-butylammonium bromide dropwise within 20-40 minutes, raising the temperature to 50-60°C, and continuously stirring the reaction at this temperature for 2-3 hours to obtain an epoxy-terminated polyethylene glycol glycidyl ether liquid; adjusting the pH value of the system to 1-2 with dilute sulfuric acid, and hydrolyzing at room temperature for 2-3 hours to obtain an epoxy-terminated polyethylene glycol glycidyl ether hydrolyzate solution; (5) adding the amino-containing chitosan oligomer solution obtained in step (3) to the hydrolyzed solution of epoxy-terminated polyethylene glycol glycidyl ether, maintaining the temperature at 45-50° C., slowly adding tetrafluoroboric acid as a catalyst over a period of 20-30 minutes, raising the temperature to 80-85° C., and reacting at this temperature for 4-5 hours to obtain an N-ether chitosan polyol oligomer solution; (6) Place polytetrahydrofuran ether diol and N-ether chitosan polyol oligomer in a reaction vessel equipped with a stirrer, a thermometer, a dropping funnel, and a reflux condenser, raise the temperature to 95-100°C, and dehydrate under a vacuum degree of 0.01-0.02 MPa for 8-10 hours. When the water content of the mixed polyether polyol is less than 0.03%, stop vacuuming; cool down to 50-55 The mixture was stirred at 40 ℃ for 2-3 hours under nitrogen protection, and the toluene diisocyanate solution was slowly added dropwise. After the toluene diisocyanate solution was added, the temperature was raised to 75-85 ℃, and the reaction was carried out for 2-3 hours. Benzoyl chloride as a stabilizer was added to obtain a prepolymer terminated with an -NCO group; the mass ratio of polytetrahydrofuran ether diol to N-ether chitosan polyol oligomer solution was 1:6.0-6.4; the mass ratio of the total mass of polytetrahydrofuran ether diol and N-ether chitosan polyol oligomer to the mass of toluene diisocyanate solution was 9.5-10.0:1; the benzoyl chloride stabilizer was 0.045-0.05% of the total weight of polytetrahydrofuran ether diol and N-ether chitosan polyol oligomer; (7) Mixing the -NCO group-terminated prepolymer, stannous oleate and dioctyl sebacate, vacuum dehydrating the mixture at a temperature of 95-100° C. and a vacuum degree of 0.01-0.02 MPa for 2-3 hours, and cooling the mixture to 20-30° C. after releasing the vacuum to obtain a one-component water-soluble polyurethane chemical grouting material.

2. The method according to claim 1, characterized in that In step (1), the mass ratio of chitosan polymer to water is 1:2-2.

1.

3. The method according to claim 1, characterized in that In step (2), the mass ratio of the chitosan polymer suspension solution to the sodium hydroxide solution is 1.875-2:

1.

4. The method according to claim 1, characterized in that: In step (3), the amount of ferrous sulfate catalyst used is 0.10-0.15% of the weight of the amino-containing chitosan polymer suspension solution.

5. The method according to claim 1, characterized in that: In step (3), the amount of the mixed solution of hydrogen peroxide and ammonium persulfate composite oxidant is 1.0-1.5% by weight of the amino-containing chitosan polymer suspension solution.

6. The method according to claim 1, characterized in that In step (4), the mass ratio of polyethylene glycol to epichlorohydrin is 3-3.4:1; the pH value of the mixed solution of polyethylene glycol and epichlorohydrin is 12-13; the mass ratio of the mixed solution of polyethylene glycol and epichlorohydrin to the catalyst tetra-n-butylammonium bromide is 106-115:

1.

7. The method according to claim 1, characterized in that In step (5), the mass ratio of the epoxy-terminated polyethylene glycol glycidyl ether liquid to the amino-containing chitosan oligomer solution is 1:25.7-27.5; the mass ratio of the epoxy-terminated polyethylene glycol glycidyl ether liquid to the catalyst tetrafluoroboric acid is 24-26:

1.

8. The method according to claim 1, characterized in that: In step (7), the mass ratio of the -NCO group-terminated prepolymer to dioctyl sebacate is 4.0-4.2, and the stannous oleate is 0.25-0.30% of the total weight of the -NCO group-terminated prepolymer and dioctyl sebacate.

9. A one-component water-soluble polyurethane chemical grouting material prepared by the method described in any one of claims 1 to 8.

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