Lignin Carbon Fiber via Esterification and Mixing
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Solution Overview
Problem
The limited utilization of lignin in industrial materials due to its complex chemical structure, poor viscoelasticity, and incompatibility with non-polar media hinders its effective conversion into carbon fibers, limiting its market potential.
Innovation Solution
Esterification of lignin with acids or acid derivatives to reduce its glass transition temperature, followed by mixing with carbon residues and spinning into fibers, which enhances compatibility and processability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If lignin is used directly as a precursor for carbon fiber production, then the process is simple and cost-effective, but the poor viscoelasticity and incompatibility with non-polar media prevent successful fiber formation
Solution Approach 1:
The patent applies parameter changes by modifying the chemical structure of lignin through esterification with fatty acid derivatives. This chemical modification changes the physical and chemical parameters of lignin, including reducing polarity and improving viscoelasticity, thereby enabling compatibility with non-polar carbon residues and successful fiber formation while maintaining the simplicity of using lignin as a precursor
Solution Approach 2:
The patent creates a composite material system by combining modified lignin with carbon residues (pitch, coal tar, or petroleum-based materials). This composite approach leverages the renewable properties of lignin while incorporating the processability and compatibility of carbon residues, resulting in a fiber precursor mixture that overcomes the limitations of pure lignin
2Adaptability or versatility
If lignin is chemically modified to improve its properties, then compatibility and processability improve, but the manufacturing complexity increases
Solution Approach 1:
The esterification process with fatty acid derivatives represents a controlled parameter change approach. By selecting specific acid derivatives and reaction conditions, the modification achieves the desired improvement in compatibility and viscoelasticity through a relatively straightforward chemical process that adds functionality without excessive complexity
3Ease of manufacture
If unmodified lignin is processed, then the cost is low and the process is simple, but the poor melt flow and viscoelasticity prevent fiber spinning
Solution Approach 1:
The patent employs parameter changes through esterification to improve melt flow and viscoelasticity. The chemical modification alters the molecular interactions in lignin, reducing the strength of intermolecular forces and improving flow characteristics during processing, thereby enabling successful fiber spinning while maintaining cost-effectiveness
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 method allows for the production of carbon fibers with improved viscoelasticity and compatibility with carbon residues, enabling successful spinning and stabilization, thereby expanding lignin's application in carbon fiber production.
Implementation Method 1
esterification of the lignin with an acid or acid derivative compound
Implementation Method 2
spinning the fiber precursor mixture into a fiber
Data Source
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Figure 5~6B
AI summary
A method of making a carbon fiber comprising esterification of a lignin precursor with an acid, acid anhydride, or acyl halide, thereby forming a reduced Tg lignin. Mixing the reduced Tg lignin with a carbon residue selected from the group of coal based raw material, petroleum based raw material and combinations thereof, thereby forming a fiber precursor mixture; and spinning the fiber precursor mixture into a fiber.