Polymer emulsion microcapsule for cement concrete crack self-repairing and preparation method thereof

A technology of polymer emulsion and cement concrete, applied in the field of concrete, can solve the problems of high strength of capsule wall, difficult reaction between liquid repairing agent and curing agent, and difficulty in realizing self-repair of concrete cracks, so as to achieve the effect of prolonging service life.

Active Publication Date: 2018-06-22
WUHAN UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, most of the capsule walls of existing self-repairing microcapsules are thermosetting resin materials (such as urea-formaldehyde resin, phenolic resin, sodium alginate, etc.), and the capsule wall has high strength and is difficult to break under the stress of the crack tip. The agent is a liquid low molecular weight substance (such as methyl methacrylate, epoxy resin prepolymer, etc.), which needs to react with the curing agent to form a solid product to block the crack and play a role in self-repair. In concrete, the liquid repair agent and It is very difficult for the curing agent to react
These factors make it difficult for existing microcapsules to achieve the purpose of concrete crack self-healing

Method used

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  • Polymer emulsion microcapsule for cement concrete crack self-repairing and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] A kind of acrylic acid emulsion microcapsule is prepared by the following method:

[0027] (1) Weigh 35 parts of paraffin wax (melting point is 50~52 ℃), 5 parts of C9 petroleum resin, 60 parts of acrylic acid emulsion (solid content 46%) according to the required parts by weight of each raw material;

[0028] (2) Mix 35 parts of paraffin and 20 parts of perfluorotributylamine, heat to 65°C, and stir at 300-400rpm for 30 minutes to melt and disperse the paraffin in the perfluorotributylamine solution;

[0029] (3) Add 5 parts of petroleum resin into a three-necked flask with a heating mantle, heat to 130-140°C, stir at a speed of 300-400rpm for 15 minutes, then add the above paraffin / perfluorotributylamine mixture into the three-necked flask to control The temperature is 85°C, and the stirring is continued for 15 minutes;

[0030] (4) Add 60 parts of acrylic emulsion into a three-necked flask, control the temperature at 70°C, and stir at 300-400rpm for 10min;

[0031]...

Embodiment 2

[0038] An ethylene-vinyl acetate copolymer emulsion microcapsule, the parts by weight of each raw material are: 42 parts of paraffin wax (fusing point is 54~56 ℃), 8 parts of C9 petroleum resin, 50 parts of ethylene-vinyl acetate copolymer emulsion (solid content 45%); the preparation method is the same as in Example 1.

[0039] The average particle size and wall thickness of the microcapsules prepared in this example were tested, and the coating ratio and capsule core / capsule wall mass ratio were tested and calculated. The results are listed in Table 2. The results in Table 2 show that the ethylene-vinyl acetate copolymer emulsion microcapsules prepared in this example have a small average particle size, a thin wall thickness, a high coating rate and a high capsule core / capsule wall mass ratio.

[0040] The microcapsules that table 2 embodiment 2 prepares

[0041] Average particle size (μm)

Embodiment 3

[0043] A polyurethane emulsion microcapsule, the parts by weight of each raw material are: 42 parts of paraffin wax (fusing point is 54~56 ℃), 8 parts of C5 petroleum resin, 50 parts of polyurethane emulsion (solid content 45%); Preparation method is the same as embodiment 1 .

[0044] The average particle size and wall thickness of the microcapsules prepared in this example were tested, and the coating ratio and capsule core / capsule wall mass ratio were tested and calculated. The results are listed in Table 3. The results in Table 3 show that the average particle size of the polyurethane emulsion microcapsules prepared in this example is small, the wall thickness is thin, the coating rate and the capsule core / capsule wall mass ratio are high.

[0045] The microcapsules that table 3 embodiment 3 prepares

[0046] Average particle size (μm)

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Abstract

The invention belongs to the technical field of concrete, and particularly relates to a polymer emulsion microcapsule for cement concrete crack self-repairing and a preparation method thereof. The microcapsule is prepared from, by weight, 35-50 parts of paraffin, 5-10 parts of petroleum resin and 40-60 parts of polymer emulsion. The polymer emulsion microcapsule takes the polymer emulsion as a core material and the paraffin and the petroleum resin as a capsule wall. The paraffin and the petroleum resin belong to brittle thermoplastic materials, when a micro-crack produces in the concrete due to temperature stress or exogenic action, the expanded crack encounters the microcapsule, under the action of extension force of a crack tip, a mixed capsule wall of the paraffin and the petroleum resin is easy to rupture, the polymer emulsion flows out and enters into the concrete crack, after water is evaporated, the polymer emulsion microcapsule forms into to a film, so that the crack is repaired in time; the polymer emulsion microcapsule is adopted to endow the self-repairing ability on concrete cracks, and thereby the service life of the concrete is prolonged.

Description

technical field [0001] The invention belongs to the technical field of concrete, and in particular relates to a cement concrete crack self-repairing polymer emulsion microcapsule and a preparation method thereof. Background technique [0002] Cement concrete has the advantages of low cost, convenient molding, and good durability, and is widely used in the construction field. However, cement concrete also has the disadvantages of early shrinkage, high brittleness, and low tensile strength. During use, it is prone to internal damage due to external stress, which will inevitably produce microcracks, and then develop into larger cracks. Cracks cause damage to the concrete structure and seriously affect its durability. [0003] Microencapsulation technology has been used to repair microcracks and cracks in concrete. When concrete is mixed with microcapsules containing a liquid repairing agent, when microcracks occur in the concrete, the microcapsules are broken by the stress at...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B20/10C04B24/26C04B24/28
CPCC04B20/1044C04B20/1033C04B24/2641C04B24/2623C04B24/282
Inventor 余剑英张莹李颖杜玮査亚刚薛理辉谢君
Owner WUHAN UNIV OF TECH
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