Modified Lignin Ethers for Direct Ink Writing
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Solution Overview
Problem
Existing compositions for direct ink writing (DIW) in additive manufacturing face challenges in achieving suitable viscoelastic properties, particularly due to the limited solubility of lignin in common solvents, which restricts the use of lignin as a major component in DIW inks.
Innovation Solution
A composition comprising a functional ether of lignin, a functional ether of cellulose, and a solvent comprising an aliphatic alcohol and optionally water, where the functional ether of lignin constitutes at least 25 wt. % of the combined weights of lignin and cellulose ethers, enhancing solubility and viscoelastic properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lignin is used as a major component in DIW inks, then ecological sustainability and mechanical properties are improved, but solubility in common solvents deteriorates
Solution Approach 1:
The patent applies parameter changes by modifying the chemical structure of lignin through etherification reactions, converting native lignin into functionalized derivatives with altered solubility parameters. This allows lignin to be dissolved in common solvents while retaining its ecological benefits and mechanical reinforcement properties in the final composite material
Solution Approach 2:
The patent uses etherification agents as intermediaries to bridge the incompatibility between lignin and common solvents. The etherification process introduces functional groups that act as mediators, enabling lignin to interact favorably with solvent molecules while maintaining the integrity of the lignin polymer structure
2Strength
If lignin content in DIW inks is increased, then mechanical properties of printed parts are improved, but viscosity control and printability deteriorate
Solution Approach 1:
The patent changes the rheological parameters of the ink by introducing etherified lignin derivatives that modify the viscosity-shear rate relationship. The functionalized lignin provides better shear thinning behavior, allowing the ink to flow easily during extrusion while maintaining shape fidelity after deposition, thus improving printability without sacrificing mechanical strength
Solution Approach 2:
The patent creates a composite ink system combining etherified lignin with other biopolymers and solvents in optimized ratios. This composite approach allows the lignin to contribute mechanical strength while the other components provide viscosity control and flow characteristics necessary for successful DIW printing
3Quantity of substance
If native lignin is used in DIW compositions, then availability and cost-effectiveness are improved, but solubility and processability deteriorate
Solution Approach 1:
The patent applies preliminary action by performing etherification modification on native lignin before incorporating it into the DIW ink formulation. This pre-treatment step prepares the lignin for better dissolution and processing in subsequent steps, enabling the use of abundant, low-cost native lignin while overcoming its inherent processability limitations
Solution Approach 2:
The patent changes the chemical parameters of native lignin through etherification, introducing functional groups that enhance solubility and processability. This parameter modification allows the abundant, inexpensive native lignin to be effectively processed into high-performance 3D printed parts
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 composition enables higher lignin content inks with improved printability, stability, and shape fidelity, allowing for the creation of complex 3D models with enhanced mechanical properties and ecological sustainability.
Implementation Method 1
a composition suitable for direct ink writing, comprising a) a functional ether of lignin, b) a functional ether of cellulose, and c) a solvent comprising an aliphatic alcohol and optionally water
Implementation Method 2
Strong shear thinning properties and low zero rate shear compliance are important prerequisites for polymeric inks in DIW
Implementation Method 3
The main challenge in DIW is to achieve suitable viscoelastic properties so that the ink can easily flow through the nozzle during printing and form free standing structures after extrusion
Data Source
AI summary
The present invention relates to compositions comprising modified lignin and modified cellulose which are suitable for use in additive manufacturing (e.g. 3D printing), in particular for direct ink writing (DIW). In particular, the invention relates to a composition suitable for direct ink writing, comprising a) a functional ether of lignin, b) a functional ether of cellulose, and c) a solvent comprising an aliphatic alcohol and optionally water. The content of the functional ether of lignin in the composition is at least 25 wt. % based on the combined weights of functional ether of lignin and functional ether of cellulose.