Lightweight thermal-insulation cement mortar and preparation method thereof

Abstract

The invention discloses light-weight thermal-insulation cement mortar and a preparation method thereof, and relates to the technical field of light-weight cement mortar. The polyurea aerogel is added into the mortar to replace part of machine-made sand. The polyurea aerogel is a porous and light material, and the polyurea aerogel is added into the mortar, so that the light weight is ensured, and meanwhile, the thermal insulation property of the cement mortar can be enhanced. The triethanolamine is used for modifying the polyurea aerogel, so that the polyurea aerogel is changed into a hydrophilic substance, the consistency of the mortar is reduced, the dry density is increased, and the strength of the mortar is improved. A copper chloride dihydrate solution is added for further modification, copper ions in copper chloride dihydrate can be subjected to a chelation reaction with triethanolamine, and the loading of copper chloride on the polyurea aerogel is enhanced, so that the mechanical property of the mortar is improved, and the compressive strength is enhanced.

Description

Technical Field

[0001] The invention relates to the technical field of lightweight cement mortar, in particular to a lightweight thermal insulation cement mortar and a preparation method thereof. Background Art

[0002] Cement mortar, a foundation material widely used in construction, possesses excellent bonding and mechanical properties. Among building materials, the quality of thermal insulation directly impacts a building's energy consumption and indoor temperature regulation. Therefore, the development of high-performance thermal insulation cement mortar materials is of great significance. Traditional cement mortar, due to its high density and thermal conductivity, cannot meet the thermal insulation requirements of buildings. To enhance the thermal insulation effect of buildings, existing technologies incorporate various lightweight fillers and thermal insulation materials into cement mortar to improve the mortar's thermal insulation performance. However, the addition of lightweight fillers can lead to a decrease in the mortar's mechanical properties.

[0003] In order to solve the above problems and improve the strength and mechanical properties of mortar, the present invention provides a lightweight thermal insulation cement mortar and a preparation method thereof. Summary of the Invention

[0004] The object of the present invention is to provide a lightweight thermal insulation cement mortar and a preparation method thereof, so as to solve the problems raised in the prior art.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A method for preparing a lightweight thermal insulation cement mortar comprises the following steps:

[0007] Step 1: Take straw fiber and deionized water, ultrasonically disperse for 30-40 minutes, add dopamine, stir for 30-40 minutes, add tris (hydroxymethyl)aminomethane buffer, add hydrochloric acid, adjust the pH, stir for 22-24 hours, add modified polyurea aerogel, stir for 22-24 hours, centrifuge, wash, and dry to obtain polyurea aerogel loaded with straw fiber;

[0008] Step 2: Mixing silicate cement, kaolin, fly ash and silica fume to obtain an inorganic gelling material;

[0009] Step 3: Take epoxidized acrylic emulsion and straw fiber-loaded polyurea aerogel, stir evenly, add acrylic emulsion, machine-made sand, inorganic gelling material, slag, deionized water, redispersible latex powder, water reducer, and hydroxypropyl methyl cellulose ether, stir evenly to obtain lightweight thermal insulation cement mortar.

[0010] More optimally, the inorganic gelling material comprises the following components, by weight: 70-76 parts of Portland cement, 7-9 parts of kaolin, 3-6 parts of silica fume, and 3-4 parts of fly ash.

[0011] More optimally, the lightweight thermal insulation cement mortar includes the following ingredients, by weight: 30-35 parts of acrylic emulsion, 15-20 parts of epoxidized acrylic emulsion, 45-50 parts of straw fiber-loaded polyurea aerogel, 33-35 parts of inorganic gelling material, 30-35 parts of machine-made sand, 10-12 parts of slag, 15-18 parts of deionized water, 2-3 parts of redispersible latex powder, 2-3 parts of water reducer, and 0.7-1 part of hydroxypropyl methylcellulose ether.

[0012] More optimally, the preparation method of the modified polyurea aerogel is as follows: polyurea aerogel and anhydrous ethanol are ultrasonically dispersed for 10-15 minutes, triethanolamine is added, stirred for 20-25 minutes, copper chloride dihydrate solution is added, stirred for 20-25 minutes, washed, and dried to obtain the modified polyurea aerogel.

[0013] More optimally, the preparation method of the polyurea aerogel is as follows: take hexamethylene diisocyanate type polyisocyanate, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, and acetone, stir evenly, add acetone, continue stirring for 10-15 minutes, age for 22-26 hours to obtain a gel material; use tert-butanol to impregnate it, freeze-dry it, and obtain the polyurea aerogel.

[0014] More optimally, the preparation method of the epoxidized acrylic emulsion comprises the following steps:

[0015] S1: Sodium lauryl sulfate, alkylphenol polyoxyethylene ether, acrylamide, butyl acrylate, bisphenol A epoxy resin, styrene, methyl methacrylate, hydroxyethyl methacrylate, glycidyl methacrylate, ethylene glycol dimethacrylate, methacrylic acid, and deionized water are mixed uniformly to obtain a mixture A; sodium bicarbonate, sodium lauryl sulfate, alkylphenol polyoxyethylene ether, and deionized water are mixed uniformly to obtain a mixture B; potassium persulfate and deionized water are mixed uniformly to obtain a mixture C;

[0016] S2: Take mixed material B, add mixed material A, stir evenly, heat to 65-70°C, add mixed material C dropwise, heat to 80-82°C, react for 50-60 minutes, add the remaining mixed material B and mixed material C dropwise, heat to 85-86°C, react for 150-160 minutes, cool to 40-45°C, cool, and filter to obtain an epoxidized acrylic emulsion.

[0017] More optimally, the length of the straw fibers is 1.5-2 cm.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. This invention adds polyurea aerogel to the mortar to replace some of the manufactured sand. Polyurea aerogel is a porous, lightweight material. Adding polyurea aerogel to the mortar not only ensures lightweight but also enhances the thermal insulation properties of the cement mortar.

[0020] 2. Modifying the polyurea aerogel with triethanolamine renders it hydrophilic, reducing the mortar's consistency, increasing its dry density, and improving its strength. Further modification is achieved by adding a copper chloride dihydrate solution. The copper ions in the copper chloride dihydrate react with triethanolamine to enhance the copper chloride's loading on the polyurea aerogel, thereby improving the mortar's mechanical properties and compressive strength.

[0021] 3. Combining straw fiber with modified polyurea aerogel can further reduce thermal conductivity and enhance the thermal insulation properties of cement mortar. The present invention also prepares an epoxidized acrylic emulsion. This epoxidized acrylic emulsion is first uniformly mixed with the straw fiber-loaded polyurea aerogel, and then added to the remaining cement mortar materials for blending. This improves the dispersion of the straw fiber-loaded polyurea aerogel in the cement mortar, thereby enhancing the mechanical and thermal insulation properties of the mortar. DETAILED DESCRIPTION

[0022] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0023] The sources and models of the materials involved in the present invention are not particularly limited, and illustratively include: silicate cement: product number: PO 52.5, which can be purchased from Qufu Zhonglian Cement Plant; polycarboxylate water reducer: model: SPC-100; water glass water: which can be purchased from Wuhan Jiyesheng Chemical Co., Ltd.; redispersible latex powder: with an average particle size of 80 μm, which can be purchased from Jusheng; styrene acrylic emulsion: model: Y17677, which can be purchased from Shanghai Yuanye Biotechnology Co., Ltd.; straw fiber is rice straw fiber, with an apparent density of 1.63 g·cm -3 , bulk density is 0.12g·cm·cm -3 ; Bisphenol A epoxy resin: Model: E-51; can be purchased from Baling Petrochemical.

[0024] Example 1: A method for preparing a lightweight thermal insulation cement mortar, comprising the following steps:

[0025] Step 1: Preparation of polyurea aerogel:

[0026] 14.7 g of hexamethylene diisocyanate-type polyisocyanate, 5.5 g of 4,4'-diaminodiphenylmethane, 30 g of 4,4'-diaminodiphenyl ether, and 500 mL of acetone were mixed and stirred evenly. 200 mL of acetone was added and the mixture was stirred for 12 minutes. The mixture was aged for 24 hours to obtain a gel material. The mixture was impregnated with tert-butanol at a volume ratio of tert-butanol to gel material of 4:1 and freeze-dried to obtain a polyurea aerogel.

[0027] Step 2: Preparation of modified polyurea aerogel:

[0028] 30 g of polyurea aerogel and 100 mL of anhydrous ethanol were ultrasonically dispersed for 13 min, 2 g of triethanolamine was added, and the mixture was stirred for 22 min. 7 mL of 20 mg / mL copper chloride dihydrate solution was added and the mixture was stirred for 22 min. The mixture was washed and dried to obtain a modified polyurea aerogel.

[0029] Step 3: Preparation of polyurea aerogel loaded with straw fibers:

[0030] Take 13g of straw fiber and 500mL of deionized water, ultrasonically disperse for 35min, add 0.5g of dopamine, stir for 30min, add 1.2g of tris (hydroxymethyl)aminomethane buffer, add hydrochloric acid to adjust the pH to 8.5, stir for 23h, add 10g of modified polyurea aerogel, stir for 23h, centrifuge, wash, and dry to obtain polyurea aerogel loaded with straw fiber;

[0031] Step 4: Preparation of epoxidized acrylic emulsion:

[0032] 1.6 g of sodium lauryl sulfate, 1 g of alkylphenol polyoxyethylene ether, 7 g of acrylamide, 105 g of butyl acrylate, 15 g of bisphenol A epoxy resin, 130 g of styrene, 70 g of methyl methacrylate, 55 g of hydroxyethyl methacrylate, 4 g of glycidyl methacrylate, 1 g of ethylene glycol dimethacrylate, 15 g of methacrylic acid, and 200 mL of deionized water were mixed uniformly to obtain a mixed material A; 0.7 g of sodium bicarbonate, 0.25 g of sodium lauryl sulfate, 0.16 g of alkylphenol polyoxyethylene ether, and 200 mL of deionized water were mixed uniformly to obtain a mixed material B; 3 g of potassium persulfate and 100 mL of deionized water were mixed uniformly to obtain a mixed material C;

[0033] Take mixed material B, add 50g of mixed material A, stir evenly, heat to 68°C, add 40g of mixed material C dropwise, heat to 81°C, react for 55min, add the remaining mixed materials B and C dropwise, heat to 85°C, react for 155min, cool to 42°C, cool, and filter to obtain an epoxidized acrylic emulsion;

[0034] Step 5: Preparation of lightweight thermal insulation cement mortar:

[0035] Mixing silicate cement, kaolin, fly ash and silica fume uniformly to obtain an inorganic gelling material;

[0036] The inorganic gelling material comprises the following components, by weight: 73 parts of Portland cement, 8 parts of kaolin, 5 parts of silica fume, and 3.5 parts of fly ash;

[0037] Take epoxidized acrylic emulsion and straw fiber-loaded polyurea aerogel, stir them evenly, add acrylic emulsion, machine-made sand, inorganic gelling material, slag, deionized water, redispersible latex powder, water reducer, and hydroxypropyl methyl cellulose ether, stir them evenly to obtain a lightweight thermal insulation cement mortar;

[0038] The lightweight thermal insulation cement mortar includes the following components, by weight: 32 parts of acrylic emulsion, 18 parts of epoxidized acrylic emulsion, 47 parts of straw fiber-loaded polyurea aerogel, 34 parts of inorganic gelling material, 32 parts of machine-made sand, 11 parts of slag, 16 parts of deionized water, 2.5 parts of redispersible latex powder, 2.5 parts of water reducer, and 0.8 parts of hydroxypropyl methylcellulose ether.

[0039] Example 2: A method for preparing a lightweight thermal insulation cement mortar, comprising the following steps:

[0040] Step 1: Preparation of polyurea aerogel:

[0041] 14.7 g of hexamethylene diisocyanate-type polyisocyanate, 5.5 g of 4,4'-diaminodiphenylmethane, 30 g of 4,4'-diaminodiphenyl ether, and 500 mL of acetone were mixed and stirred evenly. 200 mL of acetone was added and the mixture was stirred for 10 min. The mixture was aged for 22 h to obtain a gel material. The mixture was impregnated with tert-butanol at a volume ratio of tert-butanol to gel material of 4:1 and freeze-dried to obtain a polyurea aerogel.

[0042] Step 2: Preparation of modified polyurea aerogel:

[0043] 30 g of polyurea aerogel and 100 mL of anhydrous ethanol were ultrasonically dispersed for 10 min, 2 g of triethanolamine was added, and the mixture was stirred for 20 min. 7 mL of 20 mg / mL copper chloride dihydrate solution was added and the mixture was stirred for 20 min. The mixture was washed and dried to obtain a modified polyurea aerogel.

[0044] Step 3: Preparation of polyurea aerogel loaded with straw fibers:

[0045] 13 g of straw fiber and 500 mL of deionized water were ultrasonically dispersed for 30 min, 0.5 g of dopamine was added, and the mixture was stirred for 30 min. 1.2 g of tris(hydroxymethyl)aminomethane) buffer was added, and hydrochloric acid was added to adjust the pH to 8.5. The mixture was stirred for 22 h. 10 g of modified polyurea aerogel was added, and the mixture was stirred for 22 h. The mixture was centrifuged, washed, and dried to obtain polyurea aerogel loaded with straw fiber.

[0046] Step 4: Preparation of epoxidized acrylic emulsion:

[0047] 1.6 g of sodium lauryl sulfate, 1 g of alkylphenol polyoxyethylene ether, 7 g of acrylamide, 105 g of butyl acrylate, 15 g of bisphenol A epoxy resin, 130 g of styrene, 70 g of methyl methacrylate, 55 g of hydroxyethyl methacrylate, 4 g of glycidyl methacrylate, 1 g of ethylene glycol dimethacrylate, 15 g of methacrylic acid, and 200 mL of deionized water were mixed uniformly to obtain a mixed material A; 0.7 g of sodium bicarbonate, 0.25 g of sodium lauryl sulfate, 0.16 g of alkylphenol polyoxyethylene ether, and 200 mL of deionized water were mixed uniformly to obtain a mixed material B; 3 g of potassium persulfate and 100 mL of deionized water were mixed uniformly to obtain a mixed material C;

[0048] Take mixed material B, add 50g of mixed material A, stir evenly, heat to 65°C, add 40g of mixed material C dropwise, heat to 80°C, react for 50min, add the remaining mixed material B and mixed material C dropwise, heat to 85°C, react for 150min, cool to 40°C, cool, and filter to obtain an epoxidized acrylic emulsion;

[0049] Step 5: Preparation of lightweight thermal insulation cement mortar:

[0050] Mixing silicate cement, kaolin, fly ash and silica fume uniformly to obtain an inorganic gelling material;

[0051] The inorganic gelling material comprises the following components, by weight: 70 parts of Portland cement, 7 parts of kaolin, 3 parts of silica fume, and 3 parts of fly ash;

[0052] Take epoxidized acrylic emulsion and straw fiber-loaded polyurea aerogel, stir them evenly, add acrylic emulsion, machine-made sand, inorganic gelling material, slag, deionized water, redispersible latex powder, water reducer, and hydroxypropyl methyl cellulose ether, stir them evenly to obtain a lightweight thermal insulation cement mortar;

[0053] The lightweight thermal insulation cement mortar includes the following components, by weight: 30 parts of acrylic emulsion, 15 parts of epoxidized acrylic emulsion, 45 parts of straw fiber-loaded polyurea aerogel, 33 parts of inorganic gelling material, 30 parts of machine-made sand, 10 parts of slag, 15 parts of deionized water, 2 parts of redispersible latex powder, 2 parts of water reducer, and 0.7 parts of hydroxypropyl methylcellulose ether.

[0054] Example 3: A method for preparing a lightweight thermal insulation cement mortar, comprising the following steps:

[0055] Step 1: Preparation of polyurea aerogel:

[0056] 14.7 g of hexamethylene diisocyanate-type polyisocyanate, 5.5 g of 4,4'-diaminodiphenylmethane, 30 g of 4,4'-diaminodiphenyl ether, and 500 mL of acetone were mixed and stirred evenly. 200 mL of acetone was added and the mixture was stirred for 15 minutes. The mixture was aged for 26 hours to obtain a gel material. The mixture was impregnated with tert-butanol at a volume ratio of tert-butanol to gel material of 4:1 and freeze-dried to obtain a polyurea aerogel.

[0057] Step 2: Preparation of modified polyurea aerogel:

[0058] 30 g of polyurea aerogel and 100 mL of anhydrous ethanol were ultrasonically dispersed for 15 min, 2 g of triethanolamine was added, and the mixture was stirred for 25 min. 7 mL of 20 mg / mL copper chloride dihydrate solution was added and the mixture was stirred for 25 min. The mixture was washed and dried to obtain a modified polyurea aerogel.

[0059] Step 3: Preparation of polyurea aerogel loaded with straw fibers:

[0060] Take 13g of straw fiber and 500mL of deionized water, ultrasonically disperse for 40min, add 0.5g of dopamine, stir for 30min, add 1.2g of tris (hydroxymethyl)aminomethane buffer, add hydrochloric acid to adjust the pH to 8.5, stir for 24h, add 10g of modified polyurea aerogel, stir for 24h, centrifuge, wash, and dry to obtain polyurea aerogel loaded with straw fiber;

[0061] Step 4: Preparation of epoxidized acrylic emulsion:

[0062] 1.6 g of sodium lauryl sulfate, 1 g of alkylphenol polyoxyethylene ether, 7 g of acrylamide, 105 g of butyl acrylate, 15 g of bisphenol A epoxy resin, 130 g of styrene, 70 g of methyl methacrylate, 55 g of hydroxyethyl methacrylate, 4 g of glycidyl methacrylate, 1 g of ethylene glycol dimethacrylate, 15 g of methacrylic acid, and 200 mL of deionized water were mixed uniformly to obtain a mixed material A; 0.7 g of sodium bicarbonate, 0.25 g of sodium lauryl sulfate, 0.16 g of alkylphenol polyoxyethylene ether, and 200 mL of deionized water were mixed uniformly to obtain a mixed material B; 3 g of potassium persulfate and 100 mL of deionized water were mixed uniformly to obtain a mixed material C;

[0063] Take mixed material B, add 50g of mixed material A, stir evenly, heat to 70°C, add 40g of mixed material C dropwise, heat to 82°C, react for 60min, add the remaining mixed materials B and C dropwise, heat to 86°C, react for 160min, cool to 45°C, cool, and filter to obtain an epoxidized acrylic emulsion;

[0064] Step 5: Preparation of lightweight thermal insulation cement mortar:

[0065] Mixing silicate cement, kaolin, fly ash and silica fume uniformly to obtain an inorganic gelling material;

[0066] The inorganic gelling material comprises the following components, by weight: 76 parts of Portland cement, 9 parts of kaolin, 6 parts of silica fume, and 4 parts of fly ash;

[0067] Take epoxidized acrylic emulsion and straw fiber-loaded polyurea aerogel, stir them evenly, add acrylic emulsion, machine-made sand, inorganic gelling material, slag, deionized water, redispersible latex powder, water reducer, and hydroxypropyl methyl cellulose ether, stir them evenly to obtain a lightweight thermal insulation cement mortar;

[0068] The lightweight thermal insulation cement mortar includes the following components, by weight: 35 parts of acrylic emulsion, 20 parts of epoxidized acrylic emulsion, 50 parts of straw fiber-loaded polyurea aerogel, 35 parts of inorganic gelling material, 35 parts of machine-made sand, 12 parts of slag, 18 parts of deionized water, 3 parts of redispersible latex powder, 3 parts of water reducer, and 1 part of hydroxypropyl methylcellulose ether.

[0069] Comparative Example 1: The polyurea aerogel was not modified using triethanolamine, and the rest was the same as in Example 1:

[0070] Step 1: Preparation of polyurea aerogel:

[0071] 14.7 g of hexamethylene diisocyanate-type polyisocyanate, 5.5 g of 4,4'-diaminodiphenylmethane, 30 g of 4,4'-diaminodiphenyl ether, and 500 mL of acetone were mixed and stirred evenly. 200 mL of acetone was added and the mixture was stirred for 12 minutes. The mixture was aged for 24 hours to obtain a gel material. The mixture was impregnated with tert-butanol at a volume ratio of tert-butanol to gel material of 4:1 and freeze-dried to obtain a polyurea aerogel.

[0072] Step 2: Preparation of modified polyurea aerogel:

[0073] 30 g of polyurea aerogel and 100 mL of anhydrous ethanol were ultrasonically dispersed for 13 min, 7 mL of 20 mg / mL copper chloride dihydrate solution was added, stirred for 22 min, washed, and dried to obtain modified polyurea aerogel;

[0074] Step 3: Preparation of polyurea aerogel loaded with straw fibers:

[0075] Take 13g of straw fiber and 500mL of deionized water, ultrasonically disperse for 35min, add 0.5g of dopamine, stir for 30min, add 1.2g of tris (hydroxymethyl)aminomethane buffer, add hydrochloric acid to adjust the pH to 8.5, stir for 23h, add 10g of modified polyurea aerogel, stir for 23h, centrifuge, wash, and dry to obtain polyurea aerogel loaded with straw fiber;

[0076] Step 4: Preparation of epoxidized acrylic emulsion:

[0077] 1.6 g of sodium lauryl sulfate, 1 g of alkylphenol polyoxyethylene ether, 7 g of acrylamide, 105 g of butyl acrylate, 15 g of bisphenol A epoxy resin, 130 g of styrene, 70 g of methyl methacrylate, 55 g of hydroxyethyl methacrylate, 4 g of glycidyl methacrylate, 1 g of ethylene glycol dimethacrylate, 15 g of methacrylic acid, and 200 mL of deionized water were mixed uniformly to obtain a mixed material A; 0.7 g of sodium bicarbonate, 0.25 g of sodium lauryl sulfate, 0.16 g of alkylphenol polyoxyethylene ether, and 200 mL of deionized water were mixed uniformly to obtain a mixed material B; 3 g of potassium persulfate and 100 mL of deionized water were mixed uniformly to obtain a mixed material C;

[0078] Take mixed material B, add 50g of mixed material A, stir evenly, heat to 68°C, add 40g of mixed material C dropwise, heat to 81°C, react for 55min, add the remaining mixed materials B and C dropwise, heat to 85°C, react for 155min, cool to 42°C, cool, and filter to obtain an epoxidized acrylic emulsion;

[0079] Step 5: Preparation of lightweight thermal insulation cement mortar:

[0080] Mixing silicate cement, kaolin, fly ash and silica fume uniformly to obtain an inorganic gelling material;

[0081] The inorganic gelling material comprises the following components, by weight: 73 parts of Portland cement, 8 parts of kaolin, 5 parts of silica fume, and 3.5 parts of fly ash;

[0082] Take epoxidized acrylic emulsion and straw fiber-loaded polyurea aerogel, stir them evenly, add acrylic emulsion, machine-made sand, inorganic gelling material, slag, deionized water, redispersible latex powder, water reducer, and hydroxypropyl methyl cellulose ether, stir them evenly to obtain a lightweight thermal insulation cement mortar;

[0083] The lightweight thermal insulation cement mortar includes the following components, by weight: 32 parts of acrylic emulsion, 18 parts of epoxidized acrylic emulsion, 47 parts of straw fiber-loaded polyurea aerogel, 34 parts of inorganic gelling material, 32 parts of machine-made sand, 11 parts of slag, 16 parts of deionized water, 2.5 parts of redispersible latex powder, 2.5 parts of water reducer, and 0.8 parts of hydroxypropyl methylcellulose ether.

[0084] Comparative Example 2: No copper chloride dihydrate solution was added, and the rest was the same as in Example 1:

[0085] Step 1: Preparation of polyurea aerogel:

[0086] 14.7 g of hexamethylene diisocyanate-type polyisocyanate, 5.5 g of 4,4'-diaminodiphenylmethane, 30 g of 4,4'-diaminodiphenyl ether, and 500 mL of acetone were mixed and stirred evenly. 200 mL of acetone was added and the mixture was stirred for 12 minutes. The mixture was aged for 24 hours to obtain a gel material. The mixture was impregnated with tert-butanol at a volume ratio of tert-butanol to gel material of 4:1 and freeze-dried to obtain a polyurea aerogel.

[0087] Step 2: Preparation of modified polyurea aerogel:

[0088] 30 g of polyurea aerogel and 100 mL of anhydrous ethanol were ultrasonically dispersed for 13 min, 2 g of triethanolamine was added, and the mixture was stirred for 22 min, washed, and dried to obtain a modified polyurea aerogel.

[0089] Step 3: Preparation of polyurea aerogel loaded with straw fibers:

[0090] Take 13g of straw fiber and 500mL of deionized water, ultrasonically disperse for 35min, add 0.5g of dopamine, stir for 30min, add 1.2g of tris (hydroxymethyl)aminomethane buffer, add hydrochloric acid to adjust the pH to 8.5, stir for 23h, add 10g of modified polyurea aerogel, stir for 23h, centrifuge, wash, and dry to obtain polyurea aerogel loaded with straw fiber;

[0091] Step 4: Preparation of epoxidized acrylic emulsion:

[0092] 1.6 g of sodium lauryl sulfate, 1 g of alkylphenol polyoxyethylene ether, 7 g of acrylamide, 105 g of butyl acrylate, 15 g of bisphenol A epoxy resin, 130 g of styrene, 70 g of methyl methacrylate, 55 g of hydroxyethyl methacrylate, 4 g of glycidyl methacrylate, 1 g of ethylene glycol dimethacrylate, 15 g of methacrylic acid, and 200 mL of deionized water were mixed uniformly to obtain a mixed material A; 0.7 g of sodium bicarbonate, 0.25 g of sodium lauryl sulfate, 0.16 g of alkylphenol polyoxyethylene ether, and 200 mL of deionized water were mixed uniformly to obtain a mixed material B; 3 g of potassium persulfate and 100 mL of deionized water were mixed uniformly to obtain a mixed material C;

[0093] Take mixed material B, add 50g of mixed material A, stir evenly, heat to 68°C, add 40g of mixed material C dropwise, heat to 81°C, react for 55min, add the remaining mixed materials B and C dropwise, heat to 85°C, react for 155min, cool to 42°C, cool, and filter to obtain an epoxidized acrylic emulsion;

[0094] Step 5: Preparation of lightweight thermal insulation cement mortar:

[0095] Mixing silicate cement, kaolin, fly ash and silica fume uniformly to obtain an inorganic gelling material;

[0096] The inorganic gelling material comprises the following components, by weight: 73 parts of Portland cement, 8 parts of kaolin, 5 parts of silica fume, and 3.5 parts of fly ash;

[0097] Take epoxidized acrylic emulsion and straw fiber-loaded polyurea aerogel, stir them evenly, add acrylic emulsion, machine-made sand, inorganic gelling material, slag, deionized water, redispersible latex powder, water reducer, and hydroxypropyl methyl cellulose ether, stir them evenly to obtain a lightweight thermal insulation cement mortar;

[0098] The lightweight thermal insulation cement mortar includes the following components, by weight: 32 parts of acrylic emulsion, 18 parts of epoxidized acrylic emulsion, 47 parts of straw fiber-loaded polyurea aerogel, 34 parts of inorganic gelling material, 32 parts of machine-made sand, 11 parts of slag, 16 parts of deionized water, 2.5 parts of redispersible latex powder, 2.5 parts of water reducer, and 0.8 parts of hydroxypropyl methylcellulose ether.

[0099] Comparative Example 3: No epoxidized acrylic emulsion was added, and the rest was the same as in Example 1:

[0100] Step 1: Preparation of polyurea aerogel:

[0101] 14.7 g of hexamethylene diisocyanate-type polyisocyanate, 5.5 g of 4,4'-diaminodiphenylmethane, 30 g of 4,4'-diaminodiphenyl ether, and 500 mL of acetone were mixed and stirred evenly. 200 mL of acetone was added and the mixture was stirred for 12 minutes. The mixture was aged for 24 hours to obtain a gel material. The mixture was impregnated with tert-butanol at a volume ratio of tert-butanol to gel material of 4:1 and freeze-dried to obtain a polyurea aerogel.

[0102] Step 2: Preparation of modified polyurea aerogel:

[0103] 30 g of polyurea aerogel and 100 mL of anhydrous ethanol were ultrasonically dispersed for 13 min, 2 g of triethanolamine was added, and the mixture was stirred for 22 min. 7 mL of 20 mg / mL copper chloride dihydrate solution was added and the mixture was stirred for 22 min. The mixture was washed and dried to obtain a modified polyurea aerogel.

[0104] Step 3: Preparation of polyurea aerogel loaded with straw fibers:

[0105] Take 13g of straw fiber and 500mL of deionized water, ultrasonically disperse for 35min, add 0.5g of dopamine, stir for 30min, add 1.2g of tris (hydroxymethyl)aminomethane buffer, add hydrochloric acid to adjust the pH to 8.5, stir for 23h, add 10g of modified polyurea aerogel, stir for 23h, centrifuge, wash, and dry to obtain polyurea aerogel loaded with straw fiber;

[0106] Step 4: Preparation of lightweight thermal insulation cement mortar:

[0107] Mixing silicate cement, kaolin, fly ash and silica fume uniformly to obtain an inorganic gelling material;

[0108] The inorganic gelling material comprises the following components, by weight: 73 parts of Portland cement, 8 parts of kaolin, 5 parts of silica fume, and 3.5 parts of fly ash;

[0109] Take straw fiber-loaded polyurea aerogel, acrylic emulsion, machine-made sand, inorganic gelling material, slag, deionized water, redispersible latex powder, water reducing agent, and hydroxypropyl methyl cellulose ether, stir evenly to obtain a lightweight thermal insulation cement mortar;

[0110] The lightweight thermal insulation cement mortar includes the following components, by weight: 50 parts of acrylic emulsion, 47 parts of straw fiber-loaded polyurea aerogel, 34 parts of inorganic gelling material, 32 parts of machine-made sand, 11 parts of slag, 16 parts of deionized water, 2.5 parts of redispersible latex powder, 2.5 parts of water reducer, and 0.8 parts of hydroxypropyl methylcellulose ether.

[0111] experiment:

[0112] The lightweight thermal insulation cement mortars prepared in Examples 1 to 3 and Comparative Examples 1 to 3 were cured at a constant temperature and humidity of 23°C and 60% for 28 days to prepare 40 mm × 40 mm × 160 mm test pieces. The test pieces were then uniformly loaded at a rate of 2400 N / s ± 200 N / s to test the compressive strength. The thermal conductivity of the 300 mm × 300 mm × 30 mm test pieces was tested using a flat-plate thermal conductivity meter in accordance with GB / T 10294-2008. The results are shown in Table 1 below.

[0113] Table 1

[0114] Compressive strength / Mpa Thermal conductivity w / m·k Example 1 11.1 0.06 Example 2 11.3 0.07 Example 3 11.0 0.06 Comparative Example 1 9.8 0.07 Comparative Example 2 10.2 0.06 Comparative Example 3 10.3 0.10

[0115] Conclusion: From the comparison of the data in the table, it can be seen that in Comparative Example 1, triethanolamine is not used to modify the polyurea aerogel, and the hydrophilicity of the polyurea aerogel decreases, the dry density decreases, and the strength of the mortar also decreases. In Comparative Example 2, copper chloride dihydrate solution is not added. The copper ions in copper chloride dihydrate can undergo a chelating reaction with triethanolamine, the loading amount of copper chloride on the polyurea aerogel decreases, and the mechanical properties of the mortar decrease. In Comparative Example 3, no epoxidized acrylic emulsion is added. The polyurea aerogel loaded with straw fibers is unevenly dispersed in the cement mortar, and the mechanical properties and thermal insulation properties of the mortar are reduced. Examples 1-3 of the present invention use triethanolamine to modify the polyurea aerogel, so that the polyurea aerogel becomes a hydrophilic substance, reduces the consistency of the mortar, increases the dry density, and improves the strength of the mortar. Copper chloride dihydrate solution was added for further modification. The copper ions in copper chloride dihydrate can undergo a chelating reaction with triethanolamine, thereby increasing the loading of copper chloride on the polyurea aerogel, thereby improving the mechanical properties of the mortar and enhancing the compressive strength.

[0116] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations that come within the meaning and range of equivalents of the claims be embraced therein.

Claims

1. A method for preparing a lightweight thermal insulation cement mortar, characterized in that: The following steps are involved: Step 1: Take straw fiber and deionized water, ultrasonically disperse for 30-40 minutes, add dopamine, stir for 30-40 minutes, add tris (hydroxymethyl)aminomethane buffer, add hydrochloric acid, adjust the pH, stir for 22-24 hours, add modified polyurea aerogel, stir for 22-24 hours, centrifuge, wash, and dry to obtain polyurea aerogel loaded with straw fiber; Step 2: Mixing silicate cement, kaolin, fly ash and silica fume to obtain an inorganic gelling material; Step 3: Take epoxidized acrylic emulsion and straw fiber-loaded polyurea aerogel, stir evenly, add acrylic emulsion, machine-made sand, inorganic gelling material, slag, deionized water, redispersible latex powder, water reducer, and hydroxypropyl methyl cellulose ether, stir evenly to obtain lightweight thermal insulation cement mortar.

2. The method for preparing a lightweight thermal insulation cement mortar according to claim 1, characterized in that: The inorganic gelling material comprises the following components, by weight: 70-76 parts of Portland cement, 7-9 parts of kaolin, 3-6 parts of silica fume, and 3-4 parts of fly ash.

3. The method for preparing a lightweight thermal insulation cement mortar according to claim 1, characterized in that: The lightweight thermal insulation cement mortar includes the following components, by weight: 30-35 parts of acrylic emulsion, 15-20 parts of epoxidized acrylic emulsion, 45-50 parts of straw fiber-loaded polyurea aerogel, 33-35 parts of inorganic gelling material, 30-35 parts of machine-made sand, 10-12 parts of slag, 15-18 parts of deionized water, 2-3 parts of redispersible latex powder, 2-3 parts of water reducer, and 0.7-1 part of hydroxypropyl methylcellulose ether.

4. The method for preparing a lightweight thermal insulation cement mortar according to claim 1, characterized in that: The preparation method of the modified polyurea aerogel comprises: taking polyurea aerogel and anhydrous ethanol, ultrasonically dispersing for 10-15 minutes, adding triethanolamine, stirring for 20-25 minutes, adding copper chloride dihydrate solution, stirring for 20-25 minutes, washing, and drying to obtain the modified polyurea aerogel.

5. The method for preparing a lightweight thermal insulation cement mortar according to claim 4, characterized in that: The preparation method of the polyurea aerogel comprises: taking hexamethylene diisocyanate-type polyisocyanate, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, and acetone, stirring evenly, adding acetone, continuing stirring for 10-15 minutes, and aging for 22-26 hours to obtain a gel material; impregnating the aerogel with tert-butyl alcohol, and freeze-drying to obtain the polyurea aerogel.

6. The method for preparing a lightweight thermal insulation cement mortar according to claim 3, characterized in that: The preparation method of the epoxidized acrylic emulsion is: The following steps are involved: S1: Sodium lauryl sulfate, alkylphenol polyoxyethylene ether, acrylamide, butyl acrylate, bisphenol A epoxy resin, styrene, methyl methacrylate, hydroxyethyl methacrylate, glycidyl methacrylate, ethylene glycol dimethacrylate, methacrylic acid, and deionized water are mixed uniformly to obtain a mixture A; sodium bicarbonate, sodium lauryl sulfate, alkylphenol polyoxyethylene ether, and deionized water are mixed uniformly to obtain a mixture B; potassium persulfate and deionized water are mixed uniformly to obtain a mixture C; S2: Take mixed material B, add mixed material A, stir evenly, heat to 65-70°C, add mixed material C dropwise, heat to 80-82°C, react for 50-60 minutes, add the remaining mixed material B and mixed material C dropwise, heat to 85-86°C, react for 150-160 minutes, cool to 40-45°C, cool, and filter to obtain an epoxidized acrylic emulsion.

7. The method for preparing a lightweight thermal insulation cement mortar according to claim 1, characterized in that: The length of the straw fibers is 1.5-2 cm.

8. Lightweight thermal insulation cement mortar prepared according to the preparation method of lightweight thermal insulation cement mortar according to any one of claims 1 to 7.