Emulsion Aggregation for Conductive 3D Printing Filaments
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Solution Overview
Problem
Current additive manufacturing techniques, such as fused deposition modeling (FDM), face limitations in achieving high electrical conductivity due to the need for high melt temperatures and polymer degradation, which restrict the use of conductive materials like carbon nanotubes, and lack efficient methods to incorporate high loadings of graphitic materials into filaments.
Innovation Solution
The method employs emulsion aggregation to create composite particles with thermoplastic polymers and carbon particle materials, allowing for high carbon nanotube loadings and improved conductivity while maintaining processability for 3D printing, by forming stable emulsions, aggregating, and coalescing particles at temperatures below 250°C.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high loadings of conductive materials (e.g., carbon nanotubes) are used to achieve high electrical conductivity, then electrical conductivity is improved, but melt temperature increases to over 250°C or 300°C which causes polymer degradation and renders materials unsuitable for 3D printing
Solution Approach 1:
The patent changes the processing parameters by using emulsion aggregation instead of traditional melt mixing, allowing incorporation of high loadings of conductive materials (5-50 wt% carbon nanotubes) without requiring high melt temperatures. The emulsion process occurs at lower temperatures where the polymer remains stable, yet still achieves high electrical conductivity due to the high concentration of conductive fillers in the final composite.
2Reliability
If high loadings of conductive materials are used to achieve high electrical conductivity, then electrical conductivity is improved, but polymer degradation occurs at high temperatures
Solution Approach 1:
The patent changes the processing methodology from melt-based to emulsion-based aggregation, fundamentally altering the temperature regime. The emulsion aggregation process occurs at temperatures below the polymer degradation point, yet still achieves high conductive material loading (5-50 wt% CNTs). This parameter change eliminates polymer degradation while maintaining high electrical conductivity.
3Stability of the object's composition
If traditional melt processing is used to prepare composite filaments, then good mixing and dispersion are achieved, but minimum polymer viscosity requirements preclude the use of low viscosity or low glass transition temperature polymers
Solution Approach 1:
The patent replaces the mechanical mixing system (extruder-based melt processing) with a chemical/emulsion-based aggregation system. This substitution allows low viscosity and low Tg polymers to be used because the emulsion aggregation process does not rely on mechanical mixing of molten polymer. The conductive materials are incorporated during particle formation in the emulsion phase, not during melt extrusion, thus eliminating the viscosity constraint.
4Reliability
If emulsion aggregation is used to incorporate high loadings of conductive materials, then electrical conductivity is significantly increased, but the process differs from traditional FDM filament production methods
Solution Approach 1:
The patent performs preliminary action by incorporating the conductive materials during the emulsion aggregation and particle formation stages, before the final filament extrusion step. The composite particles are pre-formed with high CNT loading (5-50 wt%) through emulsion aggregation, then these pre-formed composite particles are simply extruded as filament. This preliminary incorporation of conductive materials simplifies the overall process compared to attempting to mix such high loadings during traditional melt extrusion.
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 enables the production of filaments with significantly increased electrical conductivity, doubling that of traditional melt-mixed composites, and allows for the use of low viscosity and low glass transition temperature polymers, enhancing the range of materials suitable for 3D printing applications.
Implementation Method 1
The latex thermoplastic polymer particles are aggregated in the presence of at least one carbon particle material to form aggregate particles comprising both the latex thermoplastic polymer particles and the carbon particle material
Implementation Method 2
The aggregate particles are heated to coalesce the latex polymer particles and form composite particles comprising the coalesced latex polymer and the carbon particle material
Data Source
AI summary
A method of making a composite feed material for fused deposition modeling (FDM) is disclosed. The method comprises providing composite particles made by a process of emulsion aggregation, the composite particles comprising at least one thermoplastic polymer and at least one carbon particle material. A composite feed material is formed for fused deposition modeling from the composite particles. The composite feed material is in a form selected from a filament and a paste.