Shape Memory Polymer Self-Healing Structural Composites

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Current shape memory and self-healing polymers lack structural stability and load-bearing capabilities, limiting their application in materials that require both shape memory and self-healing properties, especially in thermoplastic forms suitable for large-scale processing.

Innovation Solution

A structural shape memory assisted self-healing polymer is developed by laminating thin layers of an ionomer and a well-entangled glassy shape memory polymer (SMP), utilizing reversible plasticity shape memory and rebonding capabilities to achieve simultaneous crack closure and healing, maintaining stiffness during the healing process, and featuring polymers like atactic poly(styrene) and polycyclooctene with poly(styrene sulfonate) ionomers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of repair

If shape memory polymers are used to achieve self-healing capability, then crack healing is enabled, but structural stability and load-bearing capability are lost

Engineering Contradiction:

Improveself-healing capabilityVSAvoidload-bearing capability

Core Design Contradiction:

Ease of repairVSStrength

Solution Approach 1:

The patent creates a composite material system combining shape memory polymer (SMP) particles dispersed in a thermoplastic matrix. The SMP particles (5-50 wt%) provide self-healing functionality through their shape memory effect, while the thermoplastic matrix maintains structural stability and load-bearing capability. This composite approach allows both contradictory requirements to be satisfied simultaneously.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The self-healing functionality is localized to specific SMP particle regions within the material, rather than requiring the entire material to have shape memory properties. The thermoplastic matrix provides continuous structural support while SMP particles at crack sites enable localized healing when activated by temperature or stress.

Inventive Principle:

Principle #3Local quality

2Ease of repair

If thermoset polymers are used for self-healing, then crack rebonding is achieved, but processing complexity and manufacturing difficulty increase

Engineering Contradiction:

Improvecrack rebondingVSAvoidprocessing complexity

Core Design Contradiction:

Ease of repairVSEase of manufacture

Solution Approach 1:

The patent replaces complex chemical crosslinking systems (thermoset) with a simpler thermoplastic matrix that relies on physical entanglement and melting/recrystallization for self-healing. The SMP particles provide the necessary mechanical activation for crack rebonding without requiring complex chemical curing processes, significantly simplifying manufacturing while maintaining healing capability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of repair

If shape memory polymer content is increased to improve self-healing, then healing efficiency increases, but material stiffness decreases

Engineering Contradiction:

Improvehealing efficiencyVSAvoidmaterial stiffness

Core Design Contradiction:

Ease of repairVSStress or pressure

Solution Approach 1:

The patent optimizes the SMP particle content parameter to a specific range (5-50 wt%) where sufficient healing efficiency is achieved while maintaining adequate material stiffness. This parameter optimization allows the material to balance self-healing performance with structural rigidity, preventing excessive softening that would occur at higher SMP concentrations.

Inventive Principle:

Principle #35Parameter changes

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 solution provides a thermoplastic material with high Young's modulus that can effectively heal cracks and maintain mechanical load-bearing capabilities during the healing process, enabling the creation of structural self-healing polymers suitable for large-scale processing and applications.

Implementation Method 1

recovery is triggered by the martensite-austenite phase transition

Methodology Applied

Scientific EffectMartensite-austenite phase transition: Phase Change

Implementation Method 2

self-healing is triggered when the material is exposed to temperatures above its Tm

Methodology Applied

Scientific EffectMacromolecular chain interdiffusion: Diffusion

Implementation Method 3

During cure, the system undergoes polymerization-induced phase separation (PIPS) at a critical point during the epoxy polymerization

Methodology Applied

Scientific EffectPolymerization-induced phase separation: Phase Change

Implementation Method 4

as samples are heated the PCL 'mortar' phase melts and then volumetrically expands, coating all surfaces

Methodology Applied

Scientific EffectMelting: Melting

Data Source

PatentUS10875282B2Shape memory assisted self-healing polymers having load bearing structure

Publication Date: 2020.12.29 SYRACUSE UNIVERSITY

AI summary

A structural shape memory assisted self-healing polymer formed by laminating thin layers of an ionomer, such as a member of the poly(styrene sulfonate) (PSS) family of ionomers, with a WEGP-type SMP, such as atactic poly(styrene) (PS) with molecular weight in the 200 kDa range (or alternatively poly(methyl methacrylate) (PMMA)) in combination with polycyclooctene (PCO). The self-healing polymer may also comprise an interpenetrating, immiscible polymer network (IPN) based on a blend of polystyrene and polystyrene sulfonate (PSS).