Lignin-Polyamide Blend for Melt Extrusion

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Solution Overview

Problem

Lignin-based thermoplastics exhibit high viscosity and brittleness, making them unsuitable for melt extrusion and additive manufacturing due to their inability to withstand high feeding rates and elevated temperatures without degrading or buckling.

Innovation Solution

A lignin-containing solid polymer blend material is developed by combining lignin with a polyamide having a melting point below the decomposition temperature of lignin, resulting in a homogeneous blend with reduced melt viscosity and resistance to buckling, allowing for higher lignin loadings and improved printability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If lignin-based thermoplastics are used for melt extrusion, then renewable feedstock utilization is improved, but melt viscosity is excessively high and melt stability is poor

Engineering Contradiction:

Improverenewable feedstock utilizationVSAvoidmelt viscosity

Core Design Contradiction:

Adaptability or versatilityVSTemperature

Solution Approach 1:

The patent creates a composite material system combining lignin with polyethylene glycol (PEG) and a polyamide matrix. This composite approach allows the lignin to be incorporated into a polymer blend that maintains processability. The PEG acts as a compatibilizer and processing aid, enabling the lignin-polyamide blend to achieve acceptable melt viscosity for extrusion while preserving the high renewable content advantage.

Inventive Principle:

Principle #40Composite materials

2Adaptability or versatility

If lignin-based thermoplastics are used for melt extrusion, then renewable feedstock utilization is improved, but brittleness at room temperature increases

Engineering Contradiction:

Improverenewable feedstock utilizationVSAvoidbrittleness

Core Design Contradiction:

Adaptability or versatilityVSStrength

Solution Approach 1:

The patent develops a composite material system combining lignin with polyethylene glycol (PEG) and a polyamide matrix. This composite approach allows the lignin to be incorporated into a polymer blend that maintains processability. The PEG acts as a compatibilizer and processing aid, enabling the lignin-polyamide blend to achieve acceptable melt viscosity for extrusion while preserving the high renewable content advantage.

Inventive Principle:

Principle #40Composite materials

3Temperature

If elevated temperature is used to reduce viscosity, then melt flowability is improved, but lignin crosslinking and degradation occur

Engineering Contradiction:

Improvemelt flowabilityVSAvoidlignin stability

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The patent modifies the processing parameters by incorporating PEG, which enables effective blending and extrusion at reduced temperatures (below 200°C). This parameter change prevents thermal degradation and crosslinking of lignin while achieving sufficient melt flowability through the synergistic effect of PEG as a processing aid and the polyamide matrix providing appropriate rheological properties.

Inventive Principle:

Principle #35Parameter changes

4Productivity

If high feeding rate is used for additive manufacturing, then productivity is improved, but filament buckling occurs due to insufficient room temperature stiffness

Engineering Contradiction:

Improvefeeding rateVSAvoidfilament stiffness

Core Design Contradiction:

ProductivityVSStrength

Solution Approach 1:

Inventive Principle:

Principle #40Composite materials

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 polymer blend material achieves reduced melt viscosities, enhanced mechanical properties, and improved resistance to buckling during extrusion, enabling the use of lignin in various objects produced through melt extrusion methods like fused deposition modeling.

Implementation Method 1

a polyamide having a melting point of no more than 240° C. and which is below the decomposition temperature of the lignin

Methodology Applied

Scientific EffectMelting: Melting

Implementation Method 2

the polymer blend exhibits a melt viscosity of no more than 2000 Pa·s at a shear rate of 100-1000 s−1

Methodology Applied

Scientific EffectShear thinning: Shear Thinning

Data Source

PatentUS11248121B2Lignin-based polymers with enhanced melt extrusion ability

Publication Date: 2022.02.15 UT BATTELLE LLC

AI summary

A solid polymer blend material comprising: (i) lignin; and (ii) a polyamide having a melting point of no more than 240° C. and which is below the decomposition temperature of the lignin; wherein said lignin is homogeneously dispersed in said polyamide. Methods for producing the blend material are also described. Methods for producing objects made of the blend material by melt extrusion are also described, comprising: (a) melt blending components (i) and (ii) to form a polymer blend in which components (i) and (ii) are homogeneously blended, wherein the polymer blend exhibits a melt viscosity of no more than 2000 Pa·s at a shear rate of 100-1000 s−1 and when heated to a temperature of no more than 240° C.; and; (b) forming an object made of said polymer blend material.