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US 2023/0227702 A1Published application
Methods for enhancing the bonding strength of thermoset adhesives and sealants via disulfide dynamic chemistry
AssigneeNorthwestern University
InventorsLingqiao Li, Xi Chen, John M. Torkelson
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Abstract
Curable compositions for dynamic epoxy-based thermoset adhesives and/or sealants are provided. Methods of applying the compositions to form strong, low-stress, cured adhesive polymer films are also provided. The cured polymer films use crosslinkers that include disulfide and carbon-nitrogen bonds, wherein the disulfide bonds impart dynamic chemistry to the polymer network structure in order to the achieve adaptable thermoset adhesives and sealants.
Claims18
A method of bonding a first substrate to a second substrate, the method comprising:
- applying a composition to a surface of the first substrate, the composition comprising epoxy-functional molecules having at least two epoxy groups and crosslinkers comprising at least two reactive amine groups and a disulfide bond, wherein the composition is free of organic solvents;
- curing the applied composition at a first temperature that induces epoxy groups of the epoxy-functional molecules to react with amine groups of the crosslinkers to form a crosslinked polymer film;
- before, during, or after the curing of the applied composition, applying the second substrate over the composition, such that the composition is between the first substrate and the second substrate;
- and
- annealing the crosslinked polymer film at a second temperature that is higher than the first temperature and that induces the cleavage and reformation of the disulfide bonds, wherein the annealing of the crosslinked polymer film takes place while the crosslinked polymer film is between the first substrate and the second substrate and forms an adhesive bond between the first substrate and the second substrate.
2 more elements
Dependencies are inferred from the claim text.