Thermally Conductive Adhesive for Aerospace Heat Dissipation
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Solution Overview
Problem
Current thermally conductive adhesives used in aerospace applications, such as unmanned spacecraft, have limited thermal conductivity, typically up to 0.6 W/mK, which restricts heat dissipation and poses reliability risks due to overheating, and lack the necessary electrical insulation, flexibility, and low glass transition temperature required for vacuum environments.
Innovation Solution
A method of forming thermally conductive flexible bonds using boron nitride particles with organofunctional groups attached, mixed with a urethane modified epoxy, to create an adhesive with enhanced thermal conductivity, flexibility, and low glass transition temperature, ensuring effective heat dissipation and mechanical stability in aerospace applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If alumina particles are used as conductive filler in epoxy or polyurethane resin, then the adhesive achieves electrical insulation, but the thermal conductivity is limited to only up to 0.6 W/mK
Solution Approach 1:
The patent employs a composite material system combining boron nitride particles with organofunctional groups (such as amino, epoxy, or carboxyl groups) suspended in an epoxy or polyurethane resin matrix. This composite structure achieves both electrical insulation from the resin matrix and enhanced thermal conductivity (exceeding 0.6 W/mK) from the boron nitride filler, while the organofunctional groups improve interfacial bonding between filler and matrix to reduce thermal contact resistance.
Solution Approach 2:
The patent modifies the surface chemistry of boron nitride particles by attaching organofunctional groups, which changes the interfacial thermal resistance parameters. This surface treatment increases the thermal conductivity of the composite adhesive by improving the thermal coupling between filler particles and resin matrix, thereby resolving the contradiction between electrical insulation and thermal conductivity.
2Temperature
If higher thermal conductivity adhesives are used, then heat dissipation improves, but the adhesive may lack the flexibility and low glass transition temperature required for vacuum environments
Solution Approach 1:
The patent modifies the resin matrix parameters by using flexible epoxy or polyurethane resins with low glass transition temperatures suitable for vacuum environments. Simultaneously, the boron nitride filler concentration and surface treatment are optimized to achieve high thermal conductivity, thus resolving the contradiction between thermal performance and environmental adaptability.
Solution Approach 2:
The composite adhesive system combines the flexibility and low Tg characteristics of the polymer matrix with the high thermal conductivity of boron nitride filler. The organofunctional groups on the filler surface ensure good interfacial adhesion, maintaining both mechanical flexibility and thermal performance in vacuum conditions.
3Temperature
If more conductive filler is added to increase thermal conductivity, then heat transfer improves, but the adhesive loses flexibility and increases outgassing in vacuum
Solution Approach 1:
The patent optimizes the filler concentration parameter and performs surface treatment of boron nitride particles to achieve maximum thermal conductivity at moderate filler loadings. The organofunctional groups improve dispersion and reduce agglomeration, allowing effective thermal performance with lower filler content, thus preserving flexibility and reducing outgassing.
Solution Approach 2:
The patent uses boron nitride particles with surface treatments that provide durable interfacial bonding, reducing the need for excessive filler content. This approach maintains adhesive flexibility and minimizes outgassing while achieving the required thermal conductivity for space applications.
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 solution achieves thermal conductivity of at least 2 W/mK, flexibility to prevent damage from temperature changes, and low outgassing, enabling improved heat management and reliability of electronic components in aerospace environments.
Implementation Method 1
Thermally conductive adhesives are often used to enhance the heat transfer between electronic components and boards supporting these components. A high thermal conductivity of these adhesives is essential for fast heat dissipation from the component and thermal management of the overall board.
Implementation Method 2
The solution achieves thermal conductivity of at least 2 W/mK, flexibility to prevent damage from temperature changes
Implementation Method 3
boron nitride particles with organofunctional groups attached, mixed with a urethane modified epoxy
Data Source
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AI summary
Provided are methods of forming thermally conductive flexible bonds for use in electronic boards of unmanned spacecrafts and other types of aircraft. Also provided are methods of preparing adhesive materials to form these bonds including methods of preparing treated filler particles. In some aspects, an adhesive material includes filler particles having organofunctional groups, such as boron nitride particles treated in silane. These particles may be combined with a urethane modified epoxy to form the adhesive material. The weight ratio of the particles in the adhesive material may be about 40-60%. The adhesive material may be thermally cured using a temperature of less than 110°C to prevent damage to bonded electronic components. The cured adhesive may have a thermal conductivity of at least about 2 W/m K measured in vacuum and may have a glass transition temperature if less than -40°C.