Nano Graphene Platelet-Modified Curing Agents for Epoxy Resins
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Solution Overview
Problem
Existing methods for producing nanocomposites with high concentrations of carbon nanotubes face challenges due to high costs and difficult processing, while achieving uniform dispersion of nano graphene platelets (NGPs) in epoxy resins is poor, leading to lower-than-expected mechanical, thermal, and electrical properties in composites.
Innovation Solution
A modified curing agent comprising NGPs, a chemical functional group capable of reacting with the epoxy resin, and reactive molecules acting as a primary cross-linking agent, which improves NGP dispersion and interfacial bonding, allowing for the production of NGP-modified curing agents that can be mixed with epoxy resin or other thermosetting resins to enhance composite properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If carbon nanotubes (CNTs) are used as nanoscale fillers in polymer composites, then unique nanotechnology properties are achieved, but fabrication and purification costs become prohibitively expensive for high-volume applications
Solution Approach 1:
The patent replaces expensive carbon nanotubes with cheaper nano graphene platelets (NGPs) as the nanoscale filler material. NGPs can be produced more cost-effectively through mechanical exfoliation methods, making them suitable for high-volume polymer composite applications while maintaining the desired nanotechnology properties
Solution Approach 2:
The patent changes the physical form and production method of the nanoscale filler from carbon nanotubes to nano graphene platelets. This parameter change includes using mechanical exfoliation techniques that are more cost-effective for large-scale production while achieving comparable or superior dispersion and interfacial bonding properties
2Reliability
If high concentrations of carbon nanotubes are used in polymer composites, then enhanced properties are achieved, but processing becomes difficult due to high melt viscosity
Solution Approach 1:
The patent substitutes carbon nanotubes with nano graphene platelets that exhibit lower melt viscosity at high concentrations. This allows the composite to be processed more easily through conventional manufacturing methods while still achieving enhanced mechanical, thermal, and electrical properties
Solution Approach 2:
The patent changes the nanoscale filler geometry from one-dimensional carbon nanotubes to two-dimensional nano graphene platelets. This geometric parameter change results in lower melt viscosity and improved processability while maintaining or enhancing the desired composite properties
3Productivity
If nano graphene platelets are dispersed in epoxy resin using conventional methods, then composite materials are produced, but uniform dispersion is poor leading to lower-than-expected properties
Solution Approach 1:
The patent uses a curing agent as an intermediary medium to disperse nano graphene platelets before incorporating them into the epoxy resin. The curing agent facilitates uniform distribution of NGPs through chemical interaction, and subsequent curing locks in this uniform dispersion, achieving superior mechanical, thermal, and electrical properties
Solution Approach 2:
The patent performs preliminary dispersion of nano graphene platelets in the curing agent before mixing with the epoxy resin. This preliminary action ensures uniform distribution of NGPs is achieved in advance, preventing aggregation and enabling better final composite properties
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 approach results in significantly improved physical properties of nanocomposites, including enhanced electrical and thermal conductivity, with a lower percolation threshold and better dispersion of NGPs, making the process cost-effective and scalable.
Implementation Method 1
dispersion of NGPs in a thermosetting resin matrix
Implementation Method 2
a chemical functional group having multiple ends, with a first end being bonded to the nano graphene platelet and at least a second end that is capable of reacting with the epoxy resin
Implementation Method 3
Single-sheet NGPs possess twice the specific surface areas compared with single-walled CNTs... single-layer graphene (also referred to as single-sheet NGP) was found to exhibit the highest intrinsic strength and highest thermal conductivity of all existing materials
Implementation Method 4
single-layer graphene was found to exhibit the highest intrinsic strength and highest thermal conductivity of all existing materials
Data Source
AI summary
The present invention provides a modified curing agent for a thermosetting resin, such as epoxy resin. As one example, the epoxy curing agent comprises: (a) multiple nano graphene platelets; (b) a chemical functional group having multiple ends with a first end being bonded to a nano graphene platelet and at least a second end reactive with the epoxy resin; and (c) reactive molecules acting as a primary cross-linking agent for the epoxy resin; wherein the nano graphene platelet content is no less than 0.01% by weight based on the total weight of the modified curing agent. A modified curing agent containing reactive molecule-functionalized NGPs enable excellent dispersion of NGP in a resin matrix and the resulting nanocomposites exhibit much better properties than those of corresponding nanocomposites prepared by directly mixing dried NGPs with the thermosetting resins.