Conductive Composition with Expanded Graphite and Carbon Nanotubes
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Solution Overview
Problem
Existing electrically conductive compositions face challenges in achieving high flexibility and electrical conductivity when mixed with polymer materials, often resulting in rigidity or insufficient conductivity, particularly when using carbon additives like acetylene black or carbon nanotubes with rubbers such as NBR, and existing conductive resins lack sufficient conductivity.
Innovation Solution
An electrically conductive composition comprising expanded graphite, carbon nanotubes, and a polymer compound, where the expanded graphite is between 30-70 parts by weight and carbon nanotubes are 0.5-10 parts by weight, with an average particle diameter of 20-300 µm, and the polymer compound is either rubber or thermoplastic elastomer, enhancing both flexibility and conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large amount of carbon additive is mixed with polymer material to achieve high electrical conductivity, then electrical conductivity is improved, but flexibility is impaired and the mixture becomes rigid
Solution Approach 1:
The patent uses a composite carbon additive system combining expanded graphite (providing flexibility and basic conductivity) with carbon nanotubes (providing high conductivity at low concentrations). This composite approach allows achieving high electrical conductivity while maintaining flexibility, as the two carbon materials have complementary properties that resolve the contradiction between conductivity and flexibility.
Solution Approach 2:
The patent optimizes the concentration ratio of different carbon additives (expanded graphite 30-70 parts, carbon nanotubes 0.5-10 parts per 100 parts polymer) to achieve the desired balance between conductivity and flexibility. By carefully controlling these parameters, the invention resolves the contradiction by finding the optimal composition point where both requirements are satisfied.
2Reliability
If a large amount of carbon additive is mixed with polymer material to achieve high electrical conductivity, then electrical conductivity is improved, but moldability is impaired
Solution Approach 1:
The composite carbon additive system resolves the moldability contradiction by using expanded graphite as a bulk filler that maintains processability, while carbon nanotubes provide the necessary conductivity enhancement at low concentrations that do not interfere with molding operations.
Solution Approach 2:
The patent maintains moldability by controlling the total carbon additive content and optimizing the distribution between expanded graphite and carbon nanotubes, ensuring the mixture remains workable during molding while achieving target conductivity levels.
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 composition achieves high flexibility and electrical conductivity, surpassing the limitations of previous materials by maintaining moldability and strength, with specific formulations achieving electrical conductivities of up to 102.1 S/cm while maintaining flexibility and preventing material bleaching.
Implementation Method 1
an electrically conductive composition, including: an expanded graphite; carbon nanotubes; and a polymer compound
Data Source
AI summary
An electrically conductive composition of the present invention contains an expanded graphite, carbon nanotubes, and a polymer compound. An amount of the expanded graphite to be contained is not less than 30 parts by weight and not more than 70 parts by weight with respect to 100 parts by weight of a total amount of the expanded graphite and the polymer compound. An amount of the carbon nanotubes to be contained is not less than 0.5 part by weight and not more than 10 parts by weight with respect to 100 parts by weight of the total amount of the expanded graphite and the polymer compound.