CNT Graphene Hybrid Composite Conductive Network
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Solution Overview
Problem
Isotropic polymer composites reinforced with conductive fillers, such as GNP/CNT hybrids, exhibit inconsistent electrical conductivity due to filler type and synthesis techniques, with reported conductivity levels significantly lower than 1 S/m, necessitating improved understanding and composition to achieve enhanced electrical performance.
Innovation Solution
The use of carbon nanotubes with an average length greater than 10 µm and graphene nanoplatelets in the range of 0.005 wt.% to 0.06 wt.% within a polymer matrix, optimized through a controlled shear mixing and degassing process, forms a synergistic conductive hybrid filler network, significantly increasing electrical conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional conductive fillers (CNTs, CB, GNPs) are used in polymer composites, then electrical conductivity is improved, but the composites remain prone to lightning strike damage and electromagnetic interference
Solution Approach 1:
The patent employs a hybrid composite system combining carbon nanotubes (CNTs) and graphene nanoplatelets (GNPs) within a polymer matrix. This composite approach creates a synergistic conductive network that achieves superior electrical conductivity (exceeding 1 S/m) while providing enhanced protection against lightning strike damage and electromagnetic interference, overcoming the limitations of single-filler systems
2Reliability
If carbon nanotubes are incorporated into uncured polymer matrix, then electrical conductivity is improved, but viscosity significantly increases even at low weight fractions
Solution Approach 1:
The patent optimizes the weight fraction parameter of CNTs to remain below 1 wt%, a critical threshold that maintains acceptable viscosity for processing while still achieving the desired conductive network formation. This parameter control enables both good processability and enhanced electrical conductivity in the final composite
3Stability of the object's composition
If shear-intensive mechanical mixing is used to disperse carbon nanotubes, then homogeneity is improved, but processing complexity increases due to shear mixing and degassing requirements
Solution Approach 1:
The patent incorporates CNTs and GNPs into the polymer matrix before curing, allowing the conductive fillers to be pre-dispersed and pre-positioned within the matrix. This preliminary action ensures homogeneous distribution is achieved during the mixing and curing process, eliminating the need for separate degassing steps and simplifying the overall manufacturing procedure
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
This approach achieves electrical conductivity values greater than 5 S/m, the highest for an isotropic polymer composite system with low filler loading, while maintaining processability and ease of fabrication, enabling applications like EMI shielding and lightning strike protection.
Implementation Method 1
Similar to CNTs, GNPs have the tendency to agglomerate owing to van der Waals attractive forces and inter-planar π-π stacking
Implementation Method 2
Similar to CNTs, GNPs have the tendency to agglomerate owing to van der Waals attractive forces and inter-planar π-π stacking
Implementation Method 3
shear-intensive mechanical mixing processes have been widely used to effectively disperse CNTs as well as other fillers of different geometric shapes
Data Source
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Figure 3(a)~3(b)
Figure 4
AI summary
An electrically conductive composite material comprising carbon nanotubes and graphene nanoplatelets within a polymer matrix, wherein the carbon nanotubes have an average length greater than 10 pm; and wherein the graphene nanoplatelets form in the range of 0.005 wt.% to 0.06 wt. % of the composite material. Also provided is a mixture having such a composition, an article comprising such a composite material, and a composite production method.