Renewable furan based amine curing agents for epoxy thermoset
Inventors
Palmese, Giuseppe R. • Yadav, Santosh K. • Vergara, John • LaScala, John J.
Assignees
Drexel Unversity • United States Department of the Army
Publication Number
US-11629220-B2
Publication Date
2023-04-18
Expiration Date
2038-08-21
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Abstract
The present invention relates novel furan based amine cross-linkers with improved thermomechanical and water barrier properties. The novelty of this invention is the use of aromatic, and hydrophobic aliphatic aldehydes to bridge two furfuryl amines, which yields a diamine or tetra amines with a significantly enhanced hydrophobic character. These diamine cross-linkers exhibit enhanced water barrier properties and thermomechanical properties when cured with both commercial and synthetic epoxies.
Core Innovation
The invention relates to novel furan based amine cross-linkers with improved thermomechanical and water barrier properties. The novelty lies in using aromatic and hydrophobic aliphatic aldehydes to bridge two furfuryl amines, producing diamines or tetra amines with significantly enhanced hydrophobic character. These diamine cross-linkers exhibit improved water barrier properties and thermomechanical properties when cured with both commercial and synthetic epoxies.
The background identifies a problem with existing furan based epoxy curing agents: thermosets made with furanyl amine curing agents have poor properties, particularly poor glass transition temperature and poor water barrier properties. Aromatic amine hardeners used so far are non-renewable and toxic, and renewable furanyl derivatives reported in literature produce materials with inferior properties. Thus, there is a need for furan based epoxy curing agents that significantly improve thermomechanical and water barrier properties.
The invention solves this problem by synthesizing various furan based di- and tetra-amines via acidic condensation of aldehydes with furfuryl amine. Epoxy thermosets made with these novel amines cured with diglycidyl ether of bisphenol A (DGEBA) exhibit superior thermomechanical and water barrier properties, thereby providing renewable, hydrophobic amine curing agents with enhanced performance over commonly-used curing agents.
Claims Coverage
The patent contains one independent claim focused on a specified group of compounds, detailing furan-based diamine and tetraamine structures with defined substituents. The inventive features concern novel chemical compositions with specific bridging aldehydes and substituted furan amine structures.
Specified furan-based amine compounds
The claim covers compounds selected from a defined group including 4-{bis[5-(aminomethyl)furan-2-yl]methyl}-2-methoxyphenol, 4-{bis[5-(aminomethyl)furan-2-yl]methyl}-2,6-dimethoxyphenol, and other diamines and a tetraamine with specific bridging groups enhancing hydrophobic and thermomechanical properties.
The claims focus on novel furan-containing amine compounds with defined aromatic and aliphatic aldehyde bridges, conferring enhanced water barrier and thermomechanical properties to epoxy thermosets formed therefrom, representing an inventive chemical composition and curing agent group.
Stated Advantages
The invention provides hydrophobic resins with superior thermomechanical properties resulting from aromatic and aliphatic substituents incorporated in the furan amine bridge.
The renewable furan based amine monomers exhibit higher thermomechanical performance and lower water uptake compared to commonly-used curing agents.
The amine curing agents are less mutagenic and toxic than phenolic amines.
Documented Applications
Use as amine curing agents for epoxy thermosets combining with epoxy-containing compounds such as diglycidyl ether of bisphenol A to produce thermosetting resins with superior performance.
Preparation of polymers, including epoxy-amine thermosets, polyurea thermoplastics and thermosets, polyamide thermoplastics, and polyurethane polymers.
Use in thermoplastic and thermoset Michael addition products through reaction with methacrylate and/or acrylate groups and the furan-containing amines.
Use as pH indicators by contacting the compound or polymer with compositions and evaluating their ultraviolet visible spectrum changes.
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