Printable Energy-Absorption Formulation with Shear-Thinning Flow
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Solution Overview
Problem
Traditional impact-hardening polymers used in printing and extruding processes are prone to nozzle clogging due to shear thickening behavior and high viscosity, which disrupts the printing/extruding process, and there is a need for flexible, lightweight protective materials that can be printed or extruded effectively without clogging.
Innovation Solution
A formulation of a thixotropic ink with shear-thickening and shear-thinning properties, containing a polymer matrix, curing agent, sacrificial agent, dilatant material, and hydroxyl-functionalized fillers, which forms dynamic hydrogen bonds that break under shear stress, allowing for printing/extruding while providing impact-dampening properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional impact-hardening polymer formulation is used, then excellent impact protection and strain-rate sensitivity are achieved, but nozzle clogging occurs during printing/extruding due to shear thickening behavior and high viscosity
Solution Approach 1:
The patent modifies the rheological parameters of the polymer formulation by adding specific additives (deflocculants, dispersants, or solvents) to change the viscosity-shear rate relationship. This allows the material to maintain shear-thickening impact protection while reducing viscosity at low shear rates for printable/extrudable flow, and at high shear rates for impact hardening.
Solution Approach 2:
The patent creates a composite formulation combining the impact-hardening polymer with auxiliary components (deflocculants, dispersants, solvents) that modify the rheological behavior. This composite system enables decoupling of the printing/extruding process requirements from the impact protection requirements, allowing both functions to coexist without mutual interference.
2Strength
If high concentration of dilatant material is used to provide impact protection, then excellent shock-hardening performance is achieved, but clogging of mesh/nozzle occurs due to dramatically increased viscosity under shear force
Solution Approach 1:
The patent introduces intermediary substances (deflocculants, dispersants, or solvents) that mediate between the dilatant material particles and the continuous phase. These intermediaries prevent excessive particle aggregation under shear stress, reducing viscosity spikes that cause clogging while preserving the shock-hardening capability of the dilatant material.
Solution Approach 2:
The patent adjusts the rheological parameters of the formulation by incorporating additives that modify the shear-thickening response. This allows the system to maintain high viscosity only at extremely high shear rates (impact conditions) while keeping viscosity manageable at the shear rates encountered during printing and extruding operations.
3Loss of energy
If polymer chains are entangled to increase viscosity for impact protection, then excellent energy absorption is achieved, but ink flow is prevented and clogging occurs
Solution Approach 1:
The patent creates a dynamic rheological system where polymer chain entanglement is controlled and reversible. At low shear rates (printing/extruding), chains remain relatively disentangled allowing flow; at high shear rates (impact), chains entangle to absorb energy. This dynamic behavior is achieved through careful formulation with additives that modulate chain interactions.
Solution Approach 2:
The patent modifies the viscosity-shear rate curve by adding additives that suppress excessive chain entanglement at moderate shear rates while preserving entanglement at high shear rates. This creates a more gradual viscosity increase that prevents clogging during processing while maintaining energy absorption capability during impact.
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 formulation enables efficient printing/extruding with reduced viscosity under shear stress, forming a cured film/fiber with enhanced impact resistance and oscillation sensitivity, suitable for compression garments and textiles.
Implementation Method 1
hydroxyl-functionalized fillers, the hydroxyl-functionalized fillers are present in an amount sufficient to cause enough formation of dynamic hydrogen bonds between polymer chains and the fillers
Implementation Method 2
The ink can be directly printed onto a substrate... The formulation enables efficient printing/extruding with reduced viscosity under shear stress
Implementation Method 3
A dilatancy-promoting composition, containing a dilatant material... exhibiting shear thinning property during the printing/extruding process... providing impact-dampening properties
Implementation Method 4
A base composition, containing a polymer matrix, a curing agent, and a sacrificial agent... forming a cured film/fiber
Data Source
AI summary
The present invention discloses a printable and extrudable energy absorption materials formulation comprising: (a) a base composition, containing a polymer matrix, a curing agent, and a sacrificial agent; (b) a dilatancy-promoting composition, containing a dilatant material; and (c) a shear-thinning promoting composition, containing hydroxyl functionalized fillers. The present invention also discloses a method for forming the same.