Solid Imidazolium Microwave Absorber Without Resin Discoloration
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Solution Overview
Problem
Existing microwave absorbers for resin heating, such as carbon black, graphite particles, or carbon fibers, result in black discoloration of resin products, while ionic liquids, though effective, remain as liquids post-curing, affecting resin properties.
Innovation Solution
A microwave absorber comprising an imidazolium salt with specific structural parameters, represented by formula (1), which is solid at room temperature and effectively heats resins without causing discoloration or remaining as a liquid.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If carbon black, graphite particles, or carbon fibers are used as microwave absorbers, then microwave absorption capacity is improved, but the resin products exhibit black discoloration
Solution Approach 1:
The invention changes the chemical composition and molecular structure parameters of the microwave absorber from carbon-based materials to ionic liquid compounds. By selecting specific cations (imidazolium, pyridinium, pyrrolidinium, piperidinium) and anions (BF4-, PF6-, CF3SO3-, CF3COO-), the material achieves high microwave absorption through ionic polarization mechanisms while maintaining colorless or light-colored appearance, thus resolving the discoloration issue
Solution Approach 2:
The invention uses composite ionic liquid formulations combining specific cation-anion pairs to achieve optimal microwave absorption properties. The composite structure of ionic liquids provides both high microwave absorption capacity through ion dipole interactions and maintains aesthetic appearance by avoiding carbon-based black pigments
2Object-affected harmful factors
If ionic liquids are used as microwave absorbers, then black discoloration is prevented, but the absorbers remain as liquid after resin solidification, affecting resin properties
Solution Approach 1:
The invention modifies the physical state parameter of ionic liquids by selecting specific cation and anion combinations that result in higher melting points. By choosing ionic liquids with melting points above the resin processing temperature, the material transitions from liquid to solid state upon resin solidification, ensuring compositional stability and preventing adverse effects on resin properties
Solution Approach 2:
The invention applies local quality control by selecting ionic liquids with specific melting point characteristics suitable for different resin processing conditions. The cation and anion selection is optimized to match the processing temperature range of specific resins, ensuring the absorber remains solid under operating conditions while maintaining high microwave absorption capacity
3Productivity
If conventional microwave absorbers are used, then heating efficiency is improved, but the absorbers solidify or cure together with resin, causing black color to appear on surface
Solution Approach 1:
The invention changes the fundamental heating mechanism parameter from carbon-based resistive heating to ionic liquid dipolar relaxation heating. This parameter change enables efficient microwave absorption through ion rotation and dipole alignment in alternating electric fields, achieving high heating efficiency without the black discoloration associated with carbon-based materials
Solution Approach 2:
The invention substitutes the heating mechanism from carbon-based electrical conduction heating to ionic liquid dielectric heating. The ionic liquids utilize dipolar relaxation and ionic conduction mechanisms that are more efficient and do not produce black surface discoloration, replacing the traditional carbon-based approach
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The imidazolium salt absorber efficiently heats resins, maintaining solid form and preventing discoloration, enabling high-quality resin production without black residues.
Implementation Method 1
ionic liquids have been reported as novel, recyclable and environmentally friendly materials to replace dipolar aprotic solvents for organic synthesis. Ionic liquids are known to absorb microwave radiation extremely efficiently
Implementation Method 2
NPLs 1 and 2 describe that using microwave heating in the heat molding of carbon fiber reinforced plastic (CFRP) causes the carbon fibers in the CFRP to selectively absorb the microwaves, allowing rapid heating from the inside
Data Source
AI summary
The present invention provides a novel microwave absorber that does not exhibit black color and is solid at room temperature. A microwave absorber including an imidazolium salt represented by a formula (1) (in the formula, R1 represents a linear alkyl group having the number of carbon atoms equal to or less than the number of carbon atoms of the alkyl group of R2, R2 represents an alkyl group having 9 or more carbon atoms. R3 and R4 may be the same or different from each other and represent hydrogen or an alkyl group having 1 to 6 carbon atoms, and X represents a halogen element) is useful as a novel microwave absorber that does not exhibit black color and is solid at room temperature.