Polyimide Film Composition for Graphite Sheet Thermal Conductivity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing polyimide films for graphite sheets do not provide sufficient thermal conductivity and are costly to manufacture.
Innovation Solution
A polyimide film for graphite sheets is prepared using a precursor composition comprising a polyamic acid derived from a specific ratio of 4,4′-methylenedianiline and 4,4′-oxydianiline diamine monomers, along with sublimable inorganic fillers, to enhance thermal conductivity and reduce production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional polyimide films are used for graphite sheet fabrication, then mechanical and thermal dimensional stability is maintained, but thermal conductivity is insufficient
Solution Approach 1:
The patent changes the chemical composition parameters of the diamine monomer by specifying a molar ratio between 4,4'-methylenedianiline (30-70 mol%) and 4,4'-oxydianiline (30-70 mol%). This compositional parameter change in the polyimide film directly improves thermal conductivity while maintaining mechanical stability, resolving the contradiction between thermal performance and structural reliability.
2Temperature
If high-performance polyimide films with improved thermal conductivity are developed, then thermal management performance increases, but fabrication cost increases
Solution Approach 1:
The patent optimizes the molar ratio parameters of the diamine monomers to achieve a balance between performance and cost. By specifying 4,4'-methylenedianiline at 30-70 mol% (a more cost-effective component) and 4,4'-oxydianiline at 30-70 mol%, the formulation achieves improved thermal conductivity while controlling raw material costs, thereby resolving the cost-performance contradiction.
3Temperature
If the diamine monomer composition is optimized for thermal conductivity, then thermal diffusion coefficient increases to 795 mm2/s or more, but the complexity of monomer selection and ratio control increases
Solution Approach 1:
The patent establishes specific parameter ranges for the diamine monomer composition (4,4'-methylenedianiline: 30-70 mol%, 4,4'-oxydianiline: 30-70 mol%) to achieve the target thermal diffusion coefficient of 795 mm2/s or more. These defined parameter ranges provide a clear formulation guideline that achieves high thermal performance while controlling the complexity of composition design through standardized specifications.
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 resulting graphite sheet exhibits improved thermal conductivity and can be produced at a lower cost, with a coefficient of thermal diffusion of 795 mm2/s or more and a density of 1.8 g/cm3 to 3.0 g/cm3.
Implementation Method 1
a polyimide film for graphite sheets is prepared by imidizing a precursor composition including: a polyamic acid prepared by reacting a dianhydride monomer with a diamine monomer
Implementation Method 2
the precursor composition may further include sublimable inorganic fillers, the sublimable inorganic fillers including at least one selected from the group of calcium carbonate and dicalcium phosphate
Data Source
AI summary
Disclosed herein are a polyimide film for graphite sheets and a graphite sheet manufactured using the same. The polyimide film is fabricated by imidizing a precursor composition including: a polyamic acid prepared by reacting a dianhydride monomer with a diamine monomer; and an organic solvent, wherein the diamine monomer includes about 30 mol % to about 70 mol % of 4,4′-methylenedianiline and about 30 mol % to about 70 mol % of 4,4′-oxydianiline based on the total number of moles of the diamine monomer, 4,4′-methylenedianiline and 4,4′-oxydianiline being present in total in an amount of about 85 mol % or more based on the total number of moles of the diamine monomer.