Search

CN-122010459-A - Phase change-repair microcapsule with core-shell composite structure and preparation method and application thereof

CN122010459ACN 122010459 ACN122010459 ACN 122010459ACN-122010459-A

Abstract

The invention relates to the technical field of intelligent concrete functional materials, in particular to a phase change-repair microcapsule with a core-shell composite structure, and a preparation method and application thereof. The invention provides a core-shell composite structure phase change-repair microcapsule which sequentially comprises an inner core, an inner shell layer and an outer shell layer from inside to outside. The inner core comprises a normal-temperature phase-change material capable of absorbing early hydration heat of concrete, the inner shell layer is a high-molecular coating layer and is wrapped on the outer side of the inner core, stability of the inner core can be guaranteed, and the outer shell layer comprises a composite functional layer formed by a high-temperature phase-change material, a self-repairing agent and an alkali-resistant shell material, so that later-stage high-temperature response and crack self-repairing can be realized. The invention breaks through the limitation of the traditional single-function microcapsule through the integration of the functional materials and the multistage response structure, is especially suitable for complex scenes such as concrete in low-temperature environment service, and can obviously improve the crack resistance and durability of the concrete.

Inventors

  • LUO TAO
  • PAN XIAOFENG
  • ZHANG TIANQI
  • LI YUJIE

Assignees

  • 西京学院

Dates

Publication Date
20260512
Application Date
20260203

Claims (10)

  1. 1. The phase change-repair microcapsule with the core-shell composite structure is characterized by sequentially comprising an inner core, an inner shell layer and an outer shell layer from inside to outside; The inner core comprises a normal-temperature phase change material; the phase transition temperature of the normal-temperature phase-change material is 12-40 ℃; the inner shell layer comprises a polymer coating layer; the shell layer comprises a composite functional layer, wherein the composite functional layer comprises a high-temperature phase change material, a self-repairing agent and an alkali-resistant shell material; The phase transition temperature of the high-temperature phase-change material is 45-80 ℃.
  2. 2. The core-shell composite structure phase-change-repair microcapsule according to claim 1, wherein the latent heat of the normal-temperature phase-change material is 120-200 j/g; The normal temperature phase change material comprises one or more of paraffin, decane, tetradecanol and diethylene glycol monoethyl ether stearate.
  3. 3. The core-shell composite structure phase-change-repair microcapsule according to claim 1, wherein the polymer material of the inner shell layer comprises one or more of urea formaldehyde resin, polyurethane and polymethyl methacrylate.
  4. 4. The core-shell composite structure phase-change-repair microcapsule according to claim 1, wherein the latent heat of the high-temperature phase-change material is 80-150 j/g; The high-temperature phase change material comprises one or more of high-melting-point paraffin, stearic acid, butyl stearate and palmitic acid; The phase transition temperature of the high-melting-point paraffin wax is 52-70 ℃.
  5. 5. The core-shell composite structure phase-change-repair microcapsule according to claim 1 or 4, wherein the self-repair agent comprises one or more of bacillus pasteurizer spores, urease spores, carbonic anhydrase, urea, sulfate reducing bacteria spores, and calcium phosphate crystallization agent.
  6. 6. The core-shell composite structure phase-change-repair microcapsule according to claim 1 or 4, wherein the mass ratio of the high-temperature phase-change material to the self-repair agent is 3-5:1; the mass of the self-repairing agent accounts for 5-15% of the total mass of the shell layer.
  7. 7. The core-shell composite structure phase-change-repair microcapsule according to claim 1, wherein the alkali-resistant shell material comprises one or more of silica sol, epoxy-modified silica sol, epoxy resin and cement-based composite material; the epoxy resin is bisphenol A type epoxy resin; The bisphenol A type epoxy resin comprises one or more of bisphenol A type epoxy resin E-44, bisphenol A type epoxy resin E-51 and modified epoxy resin.
  8. 8. The core-shell composite structure phase-change-repair microcapsule according to claim 7, wherein the preparation method of the modified epoxy resin comprises the following steps: mixing bisphenol A epoxy resin, acetic acid buffer solution and deionized water to obtain microcapsule dispersion liquid; Mixing an aminosilane coupling agent and ethanol to obtain a modifier, and dripping the modifier into microcapsule dispersion liquid to carry out hydrolysis and grafting reaction.
  9. 9. The method for preparing the phase-change-repair microcapsule with the core-shell composite structure according to any one of claims 1 to 8, which is characterized by comprising the following steps: (1) Mixing a normal-temperature phase-change material, an emulsifying agent and water for emulsification to obtain emulsion, and mixing the emulsion and an initiator for a first polymerization reaction to obtain a core microcapsule; Or mixing a normal temperature phase change material and an organic solvent to obtain an oil phase, mixing an emulsifier and water to obtain a water phase, mixing the oil phase and the water phase to emulsify to obtain a water-in-oil emulsion, and mixing the water-in-oil emulsion and an interface initiator to perform an interface polymerization reaction to obtain the inner core microcapsule; (2) Mixing the core microcapsule with a polymer prepolymer, a catalyst and water to perform a second polymerization reaction to obtain a core-inner shell microcapsule; (3) And mixing the core-shell microcapsule with the melted high-temperature phase change material, the self-repairing agent and the alkali-resistant shell material precursor to perform surface in-situ polymerization reaction to obtain the phase change-repairing microcapsule with the core-shell composite structure.
  10. 10. The use of the phase-change-repair microcapsule with a core-shell composite structure according to any one of claims 1 to 8 or the phase-change-repair microcapsule with a core-shell composite structure obtained by the preparation method according to claim 9 in concrete products.

Description

Phase change-repair microcapsule with core-shell composite structure and preparation method and application thereof Technical Field The invention relates to the technical field of intelligent concrete functional materials, in particular to a phase change-repair microcapsule with a core-shell composite structure, and a preparation method and application thereof. Background Concrete is used as a common engineering material, and has very wide application, such as dams, buildings, bridges, roads and the like. Overall, the environment faced by concrete materials is quite complex, with temperature affecting the properties of the concrete significantly. For example, in cold areas, concrete is subject to degradation such as freeze thawing under an excessively large day and night temperature difference, and the strength of the concrete is reduced, cracks are generated, and even functions are completely lost. Later, researchers found that self-repairing concrete was an effective method of solving the deterioration of concrete, in which microcapsule-filled concrete has attracted a great deal of attention. The microcapsule self-repairing is to pre-set the microcapsule with the repairing agent inside in the concrete, release the repairing material after the microcapsule breaks when the concrete is destroyed by the external action, and fill and repair the crack to realize the self-healing of the concrete. However, the existing microcapsule only has a temperature control function or a self-repairing function, cannot completely adapt to the complex requirement of concrete in a low-temperature environment, and has poor stability in a low-temperature alkaline environment, and the temperature control and repairing timeliness are not matched. Disclosure of Invention In view of the above, the invention provides a phase change-repair microcapsule with a core-shell composite structure, a preparation method and application thereof, and the phase change-repair microcapsule with the core-shell composite structure has good stability, suitability and functional effectiveness in a low-temperature environment, and fills the technical blank of intelligent concrete functional materials in service in the low-temperature environment. The invention provides a phase change-repair microcapsule with a core-shell composite structure, which sequentially comprises an inner core, an inner shell layer and an outer shell layer from inside to outside, wherein the inner core comprises a normal-temperature phase change material, the phase change temperature of the normal-temperature phase change material is 12-40 ℃, the inner shell layer comprises a polymer coating layer, the outer shell layer comprises a composite functional layer, the composite functional layer comprises a high-temperature phase change material, a self-repairing agent and an alkali-resistant shell material, and the phase change temperature of the high-temperature phase change material is 45-80 ℃. Preferably, the latent heat of the normal-temperature phase-change material is 120-200J/g, and the normal-temperature phase-change material comprises one or more of paraffin, decane, tetradecanol and diethylene glycol monoethyl ether stearate. Preferably, the polymer material of the inner shell layer comprises one or more of urea formaldehyde resin, polyurethane and polymethyl methacrylate. Preferably, the latent heat of the high-temperature phase-change material is 80-150J/g, the high-temperature phase-change material comprises one or more of high-melting-point paraffin, stearic acid, butyl stearate and palmitic acid, and the phase-change temperature of the high-melting-point paraffin is 52-70 ℃. Preferably, the self-repairing agent comprises one or more of bacillus barbituric spores, urease spores, carbonic anhydrase, urea, sulfate reducing bacteria spores and calcium phosphate crystallization agent. Preferably, the mass ratio of the high-temperature phase change material to the self-repairing agent is 3-5:1, and the mass of the self-repairing agent accounts for 5-15% of the total mass of the shell layer. Preferably, the alkali-resistant shell material comprises one or more of silica sol, epoxy modified silica sol, epoxy resin and cement-based composite material, wherein the epoxy resin is bisphenol A epoxy resin, and the bisphenol A epoxy resin comprises one or more of bisphenol A epoxy resin E-44, bisphenol A epoxy resin E-51 and modified epoxy resin. Preferably, the preparation method of the modified epoxy resin comprises the following steps of mixing bisphenol A epoxy resin, acetic acid buffer solution and deionized water to obtain microcapsule dispersion liquid, mixing an aminosilane coupling agent and ethanol to obtain a modifier, and dropwise adding the modifier into the microcapsule dispersion liquid to carry out hydrolysis and grafting reaction. The invention also provides a preparation method of the core-shell composite structure phase-change-repair microcapsule, which comprises t