Self-repairing polyurethane, and preparation method and self-repairing method thereof

Abstract

The invention provides self-repairing polyurethane, and a preparation method and a self-repairing method thereof. The preparation method comprises the following steps: (1) subjecting diisocyanate andpolyether glycol to a prepolymerization reaction so as to obtain a prepolymer mixed liquid; (2) subjecting 4-methylumbelliferone to cross-linking under the irradiation of ultraviolet light to obtain adimer of 4-methylumbelliferone; (3) adding the dimer obtained in the step (2) to the prepolymer mixed liquid obtained in the step (1), carrying out polymerization, and then performing post-treatmentto remove a solvent and unreacted reactants so as to obtain the self-repairing polyurethane. The polyurethane material obtained by using the preparation method provided by the invention has a molecular weight of 53,000 or more, narrow molecular weight distribution (which is in a range of 1.1 to 1.48), good mechanical properties (with tensile strength being 17 to 28 MPa and elongation at break being 590 to 920%), and high self-repairing efficiency (55% or more).

Description

technical field [0001] The invention belongs to the technical field of self-repairing materials, and relates to a self-repairing polyurethane, a preparation method thereof and a self-repairing method. Background technique [0002] Due to its excellent mechanical properties, light weight, easy processing, and low price, polymer materials are widely used in various fields such as medical equipment, aerospace, transportation, and mechanical construction. However, during the processing and use of polymer materials, cracks and damages are prone to occur on the surface and inside of the material, resulting in poor performance and reduced service life. If the self-repair mechanism can be introduced into the design of polymer materials, when the matrix material is damaged, it can perform damage self-repair, so that the material can restore its original performance, thereby greatly extending the service life of the polymer material and maintaining its excellent performance. [0003]...

AI Technical Summary

Problems solved by technology

CN105440692A discloses a microcapsule type self-healing polysiloxane elastomer and a preparation method thereof. In terms of mass percentage, each raw material is composed of α, ω-dihydroxy polydimethylsiloxane 45-68%, and the reinforcement Agent 4.5-27%, silane compound 4.5-21%, organotin catalyst 1.4-7%, microcapsule 6-27%, among them, the microcapsule uses polymethyl methacrylate as the wall material, and α, ω-dihydroxy The mixture of polydimethylsiloxane and silane compound is used as the core material, and the self-healing function is realized by microcapsules. The disadvantage is that the number of repairs is limited. When the healing agent is exhausted, the material cannot undergo the self-healing process

CN107903636A discloses a PDMS-based fast self-healing elastic film without external stimulation and a preparation method thereof, wherein the elastic film includes 1-5 parts by weight of hydroxyl or amino-terminated polydimethylsiloxane, 4-5 parts by weight of polydimethylsiloxane containing Carboxyl or ester-based acrylic polymers, 1-2 parts by weight of polymers containing hydroxyl or amino groups, the self-repairing elastic film is a polymer material based on hydrogen bonds, which can repair damaged parts at room temperature, but the mechanical properties of the film are relatively low. Poor, the resilience is poor and the use conditions are limited, which cannot meet the application requirements

Covalent bond self-repair includes D-A reaction, disulfide exchange reaction, etc. The strength of the material is relatively high, but the self-repair process requires light, heat, electricity and other stimuli. Some stimuli are difficult to achieve, such as lasers, etc. Some stimuli Will destroy the structure of the material, such as thermal stimulation may change the performance of the material

CN102153856A discloses a photoreversible self-repairing polyurethane film and its preparation method and repairing method. The preparation method includes first reacting phenolic hydroxycoumarin derivatives with alkyl bromohydrin compounds to generate alcoholic hydroxycoumarin derivatives, and then Alcohol hydroxycoumarin derivatives react with polyisocyanate and then react with polyether polyol or polyester polyol, and after film formation, ultraviolet light is irradiated and cross-linked to obtain a polyurethane film; its preparation method is more complicated, and a catalyst is added during the preparation process to make the reaction It is difficult to control and easy to gel, and the polyurethane obtained by its preparation method has a small molecular weight and a wide molecular weight distribution. For polyurethane materials with the same structural monomers, the polyurethane material with a small molecular weight and a wide molecular weight distribution has poor mechanical properties and poor resilience. lower

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