CN-116514438-B - Water-based epoxy resin microcapsule assembly for repeated self-repairing of concrete cracks and preparation method thereof

Abstract

The invention relates to a water-based epoxy resin microcapsule assembly for repeated self-repairing of concrete cracks and a preparation method thereof, the microcapsule assembly is prepared by coating aqueous epoxy resin with polyethylene terephthalate with a higher melting point to form small-particle-size microcapsules, and then coating aqueous epoxy resin with polyoxymethylene with a lower melting point and the small-particle-size microcapsules. When the concrete generates micro-cracks for the first time, the expanded cracks encounter the microcapsule assembly, the outer layer capsule wall of the microcapsule assembly is broken under the action of the tip stress of the cracks, the internal aqueous epoxy resin flows out and diffuses into the concrete cracks, and the cracks are repaired by reacting with the curing agent doped in the concrete. Meanwhile, the small-particle-size microcapsules can flow out along with the water-based epoxy resin and are dispersed in the concrete, and when cracks appear in the concrete again, the small-particle-size microcapsules at the cracks are broken so as to repair the cracks, so that the concrete cracks are repaired for a plurality of times, and the durability of the concrete is greatly improved.

Inventors

• DU WEI
• LIU BO
• ZUO DANYING
• WANG LUOXIN
• LI JINHUI
• WU MINGLI
• DU FEI

Assignees

• 武汉纺织大学

Dates

Publication Date

20260505

Application Date

20230322

Claims (6)

1. 1. The aqueous epoxy resin microcapsule assembly for repeated self-repairing of concrete cracks is characterized in that firstly, polyethylene terephthalate with a higher melting point is used for coating aqueous epoxy resin to form small-particle-size microcapsules, and then polyoxymethylene with a lower melting point is used for coating the aqueous epoxy resin and the small-particle-size microcapsules to prepare the aqueous epoxy resin microcapsule assembly for repeated self-repairing of concrete cracks; Wherein the raw materials comprise 30-50 parts by weight of polyformaldehyde, 30-50 parts by weight of polyethylene terephthalate and 40-140 parts by weight of aqueous epoxy resin; The aqueous epoxy resin is aqueous polyimide modified epoxy resin.
2. 2. The preparation method of the water-based epoxy resin microcapsule assembly for repeated self-repairing of concrete cracks is characterized by comprising the following steps of: Step 1, heating 30-50 parts by weight of polyethylene terephthalate to 280-300 ℃, stirring for 30min at a rotating speed of 300-400rpm, adding 20-70 parts by weight of aqueous epoxy resin, and continuously stirring for 30min to obtain a polyethylene terephthalate/aqueous epoxy resin mixture; step 2, stopping heating, increasing the stirring speed to 1200-1300rpm, and adding perfluoro tributylamine into the mixture obtained in the previous step to obtain a suspension of the polyethylene terephthalate coated waterborne epoxy resin microcapsule; Step 3, dispersing the suspension by ultrasonic waves for more than 20min, and drying the microcapsule obtained after filtration and separation to obtain the polyethylene terephthalate coated waterborne epoxy resin microcapsule; Step 4, heating 30-50 parts by weight of polyoxymethylene to 200-220 ℃, stirring for more than 30 minutes at a rotating speed of 300-400rpm, adding 20-70 parts by weight of aqueous epoxy resin and the polyethylene terephthalate coated aqueous epoxy resin microcapsule obtained in the step 3, and continuously stirring for more than 60 minutes; stopping heating, increasing the stirring speed to 1200-1300rpm, and adding perfluoro tributylamine into the mixture obtained in the previous step to obtain a suspension containing microcapsule assemblies; And 6, carrying out ultrasonic dispersion treatment on the suspension containing the microcapsule assembly in the step 5 for more than 20min, and drying the microcapsule assembly obtained after filtration and separation to obtain the aqueous epoxy resin microcapsule assembly for repeated self-repairing of concrete cracks.
3. 3. The method for preparing an aqueous epoxy resin microcapsule assembly for multiple self-repairing concrete cracks according to claim 2, wherein the melting point of the polyethylene terephthalate is 240-260 ℃.
4. 4. The method for preparing an aqueous epoxy resin microcapsule assembly for multiple self-repairing concrete cracks according to claim 2, wherein the melting point of the polyoxymethylene is 160-180 ℃.
5. 5. The method for preparing an aqueous epoxy resin microcapsule assembly for multiple self-repairing concrete cracks according to claim 2, wherein the aqueous epoxy resin is an aqueous polyimide modified epoxy resin.
6. 6. The method for preparing an aqueous epoxy resin microcapsule assembly for multiple self-repairing concrete cracks according to claim 2, wherein the temperature of the drying treatment in the step 3 and the step 6 is 40-60 ℃.

Description

Water-based epoxy resin microcapsule assembly for repeated self-repairing of concrete cracks and preparation method thereof Technical Field The invention relates to the technical field of concrete, in particular to a water-based epoxy resin microcapsule assembly for repeated self-repairing of concrete cracks and a preparation method thereof. Background Concrete has become the most important building material because of its low cost, convenient construction and good durability. However, the defects of high brittleness, low tensile strength and the like cause cracking to be unavoidable in service, thereby affecting the strength and the safety of the building structure. In addition, the crack can accelerate penetration of corrosive substances in the external environment, so that chemical corrosion of concrete and corrosion of reinforcing steel bars are increased, and service life of the concrete is reduced. In special structures such as underground infrastructure, hydropower stations and nuclear power plants, concrete is increasingly used, and requirements on durability are also increasingly high. In order to improve durability of concrete, concrete having a crack self-repairing function is becoming more and more important. The self-repairing concrete is characterized in that local damage or micro cracks are timely repaired when the local damage or the micro cracks are generated in the using process of the concrete through a self-response mechanism in the concrete, so that hidden danger in the concrete is eliminated, and the service life of the concrete is prolonged. The test of the patent CN112811845A takes dimethyl thiotoluene diamine as a core material and glyceryl tristearate as a wall material, the preparation method is simple, the microcapsule is spherical, the dispersibility is good, the compressive strength restoration rate reaches 31% when the pre-compaction degree is 80% after the cement-based self-restoration material prepared by compounding the microcapsule with epoxy resin and ordinary Portland cement is cured for 28d, and the self-restoration effect is obvious. However, the microcapsule has limited repairing times in concrete, and when the repairing part is cracked again, the microcapsule and the repairing agent at the part are consumed, so that the crack cannot be repaired repeatedly, and the practical application of the microcapsule in life is restricted. Disclosure of Invention Aiming at the problems, the invention provides a water-based epoxy resin microcapsule assembly for repeated self-repairing of concrete cracks and a preparation method thereof. The technical scheme for solving the technical problems is as follows: A water-based epoxy resin microcapsule assembly for repeated self-repairing of concrete cracks is prepared from water-based epoxy resin coated by polyethylene terephthalate with higher melting point to form small-particle-size microcapsules, and then prepared from water-based epoxy resin coated by polyoxymethylene with lower melting point and the small-particle-size microcapsules. Further, the raw materials comprise 30-50 parts by weight of polyoxymethylene, 30-50 parts by weight of polyethylene terephthalate and 40-140 parts by weight of aqueous epoxy resin. The preparation method of the water-based epoxy resin microcapsule assembly for repeated self-repairing of concrete cracks comprises the following steps: Step1, heating 30-50 parts by weight of polyethylene terephthalate to 280-300 ℃, stirring for 30 min at a speed of 300-400rpm, adding 20-70 parts by weight of aqueous epoxy resin, and continuously stirring for 30 min to obtain a polyethylene terephthalate/aqueous epoxy resin mixture; step 2, stopping heating, increasing the stirring speed to 1200-1300rpm, and adding perfluoro tributylamine into the mixture obtained in the previous step to obtain a suspension of the polyethylene terephthalate coated waterborne epoxy resin microcapsule; Step 3, dispersing the suspension by ultrasonic waves for more than 20min, and drying the microcapsule obtained after filtration and separation to obtain the polyethylene terephthalate coated waterborne epoxy resin microcapsule; Step 4, heating 30-50 parts by weight of polyoxymethylene to 200-220 ℃, stirring at a speed of 300-400rpm for more than 30 min, adding 20-70 parts by weight of aqueous epoxy resin and the polyethylene terephthalate coated aqueous epoxy resin microcapsule obtained in the step 3, and continuously stirring for more than 60min; stopping heating, increasing the stirring speed to 1200-1300rpm, and adding perfluoro tributylamine into the mixture obtained in the previous step to obtain a suspension containing microcapsule assemblies; And 6, carrying out ultrasonic dispersion treatment on the suspension containing the microcapsule assembly in the step 5 for more than 20 min, and drying the microcapsule assembly obtained after filtration and separation to obtain the aqueous epoxy resin microcapsule assembly for repeated self-r