Graphene Composite Structure With Covalent Flake Bonding
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Solution Overview
Problem
The challenge lies in translating the superior mechanical properties of graphene into macro-scale composite structures due to stochastic curing processes, non-uniform distribution of graphene flakes, and high costs associated with carbon nanotubes and graphene oxide, which result in weak regions and failure points in polymer-based composites.
Innovation Solution
The method involves electroplating flat graphene flakes onto a metalized substrate, followed by the application of a chemically bondable polymer to create covalent bonds between flakes, using a solvent with controlled viscosity to infiltrate and bond the graphene layers, and vacuum drying to ensure strong and uniform bonding, thereby overcoming the limitations of van der Waals forces and enhancing tensile strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If graphene flakes are loaded into polymer/epoxy to enhance mechanical properties, then tensile strength increases, but non-uniform distribution creates weak regions and failure points
Solution Approach 1:
The patent changes the chemical state of graphene from reduced graphene oxide to graphene with oxidized edges, creating chemical complementarity with the polymer matrix. This parameter change in chemical functionality enables uniform distribution by preventing aggregation while maintaining mechanical reinforcement.
Solution Approach 2:
The patent introduces oxygen-containing functional groups as an intermediary that mediates the interaction between graphene and polymer matrix. These functional groups act as chemical bridges that improve interfacial bonding and ensure uniform distribution of graphene flakes throughout the polymer matrix.
2Strength
If carbon nanotubes or graphene oxide are used to reinforce polymers, then mechanical properties improve, but cost increases significantly
Solution Approach 1:
The patent uses oxidized graphene edges as a temporary chemical interface that provides sufficient bonding during processing and service. This approach uses a lower-cost modified graphene structure rather than expensive carbon nanotubes, achieving cost-effective reinforcement without sacrificing mechanical properties.
Solution Approach 2:
The patent modifies graphene by introducing oxygen-containing functional groups at the edges, which provides the necessary chemical reactivity for polymer bonding at a lower cost than carbon nanotubes. This parameter change in chemical composition enables cost-effective reinforcement while maintaining mechanical performance.
3Strength
If polymer curing is performed to set the composite structure, then mechanical strength develops, but stochastic shrinkage occurs especially in larger structures
Solution Approach 1:
The patent changes the chemical structure of graphene to include oxidized edges that form strong chemical bonds with the polymer matrix. This chemical bonding compensates for the stochastic shrinkage that occurs during polymer curing, maintaining dimensional stability in larger composite structures while the polymer sets.
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 results in a high-strength composite with a 15% increase in tensile strength and the ability to form flexible yet strong structures, reducing the effective density of the composite while maintaining superior mechanical and thermal properties.
Implementation Method 1
Suspended oxidized-edge graphene can be electroplated on a metalized substrate substrates or foils
Implementation Method 2
applying a layer of polymer containing a solvent to infiltrate between the graphene flakes
Implementation Method 3
vacuum drying to ensure strong and uniform bonding
Implementation Method 4
Graphene sheets, held together by van der Waals forces
Data Source
AI summary
Graphene has been used in nanocomposites as constituents/doping in plastics or epoxy providing dramatic enhancement of the mechanical properties but have not progressed past the laboratory level novelty. This invention can provide a graphene based composite structure with a density less that 1.9 g/cm3 for a fiber, yarn, rope or cable and a density less that 1.5 g/cm3 for a sheet both structure have tensile and shear strength greater than either Aluminum or Steel; thus providing a graphene material that is both much lighter and stronger.