Softwood Lignin Thermoplastic Intermediate via Plasticizer
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Solution Overview
Problem
The production of carbon and graphite electrodes and carbon fibers is energy-intensive and costly due to the use of oil-based raw materials and high-temperature processes, and softwood lignin's high degree of cross-linking makes it difficult to melt-extrude, requiring costly modifications or solvents for processing.
Innovation Solution
A thermally reactive thermoplastic intermediate product is created by combining purified or unpurified softwood lignin with additives such as lignin solvents and reactive blocking agents, allowing for melt-extrusion and subsequent conversion into carbon or graphite electrodes or fibers, reducing production costs and environmental impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If softwood lignin is used as raw material for carbon products, then production cost is reduced and renewable material is utilized, but the high degree of cross-linking makes it difficult to melt-extrude
Solution Approach 1:
A plasticizer is introduced as an intermediary substance to mediate between the cross-linked softwood lignin and the melt-extrusion process. The plasticizer penetrates the cross-linked structure, increases chain mobility, and enables thermoplastic processing without requiring modification of the lignin's cross-linked state, thus maintaining both processability and material stability
Solution Approach 2:
The glass transition temperature (Tg) of the softwood lignin is modified by adding a plasticizer, which changes the thermal parameters of the material. This parameter change allows the lignin to transition from a rigid, cross-linked state to a more flexible, processable state at extrusion temperatures, enabling melt-extrusion without compromising the cross-linked structure's stability
2Ease of manufacture
If lignin derivatives with completely derivatized hydroxyl groups are used, then thermoplastic properties are achieved, but thermal reactivity is reduced
Solution Approach 1:
Instead of completely derivatizing all hydroxyl groups (excessive action), the invention uses partial derivatization or alternative plasticization methods that provide sufficient thermoplastic processability while leaving some hydroxyl groups intact to maintain thermal reactivity. This partial action approach balances processability requirements with reactivity needs
Solution Approach 2:
The invention employs a plasticizer that can be easily added and removed, serving as a temporary aid during processing. The plasticizer enables thermoplastic behavior only during the extrusion process, and can be subsequently removed or degraded, allowing the lignin to regain its thermal reactivity for carbonization without permanent chemical modification
3Ease of manufacture
If solvent extracted lignin fractions are used with degassing, then melt-extrusion is enabled, but extraction yield is low and capital expenditure is high
Solution Approach 1:
The invention takes out only the essential component needed for processability (the plasticizing effect) without requiring complete solvent extraction and purification of lignin fractions. By using plasticizers with unpurified or partially purified softwood lignin, the method achieves melt-extrusion capability while maintaining high extraction yields and avoiding costly solvent-recovery systems
Solution Approach 2:
The softwood lignin's inherent properties (cross-linked structure and natural plasticization potential) are utilized and enhanced rather than completely transformed. The lignin essentially serves itself by providing the carbon matrix, while the plasticizer temporarily assists during processing, eliminating the need for complex solvent extraction and purification infrastructure
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 enables cost-efficient and environmentally friendly production of thermally reactive intermediates that can be easily processed into high-quality carbon or graphite products with improved electrical conductivity, overcoming the challenges of softwood lignin's reactivity and reducing capital expenditure costs.
Implementation Method 1
Melt extrusion requires that the lignin can melt within a certain temperature range above its glass transition temperature and below its decomposition temperature
Implementation Method 2
carbon-carbon bonds can be formed and the carbon content increased in the subsequent high-temperature treatment steps
Implementation Method 3
Stabilization aims at transforming the thermoplastic precursor fiber into a thermoset since, otherwise, the precursor fiber would melt when subjected to the high temperatures during carbonization
Data Source
Figure 1~2
AI summary
The present disclosure relates to athermally reactive thermoplastic intermediate product, in the form of a shaped body, wherein the intermediate comprisesa composition, wherein the composition comprises apurified or optionally unpurified softwood lignin and at least a first additive.