Metal Ligand Prepolymers for Aerospace Sealant Adhesion

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Solution Overview

Problem

Current aerospace sealants fail to provide enhanced adhesion to lightweight metal surfaces such as aluminum and titanium alloys over a wide temperature range and exhibit limited fuel resistance, necessitating the development of sulfur-containing prepolymers with improved mechanical, chemical, and environmental performance.

Innovation Solution

The development of thiol-terminated metal ligand-containing polythioethers, incorporating metal ligands like bis(sulfonyl)alkanol and acetylacetonate groups into the backbone of polythioether prepolymers, which react with metal chelating agents to form coordination complexes that enhance adhesion to metal surfaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If conventional sealant formulations are used, then the sealant can be applied to metal surfaces, but the adhesion to lightweight metal surfaces such as aluminum and titanium alloys is insufficient

Engineering Contradiction:
Improveadhesion to metal surfacesVSAvoidperformance over temperature range and fuel resistance
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent modifies the chemical composition parameters of the sealant by incorporating metal ligands (such as carboxylic acids, phenols, and their derivatives) into the polymer structure. These ligands form coordination complexes with metal surfaces, fundamentally changing the adhesion mechanism from physical bonding to chemical coordination bonding, thereby enhancing adhesion strength to lightweight metals while maintaining environmental resistance

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite sealant system combining organic polymer matrices with metal ligand complexes. The sealant comprises a polymer component and a metal ligand component that work synergistically - the polymer provides structural integrity and flexibility, while the metal ligands provide enhanced adhesion to aluminum and titanium surfaces through coordination chemistry, achieving both strong adhesion and environmental reliability

Inventive Principle:
Principle #40Composite materials

2Strength

If sealants are designed for strong adhesion to metal surfaces, then bonding strength improves, but resistance to fuel and environmental degradation deteriorates

Engineering Contradiction:
Improveadhesion to metal surfacesVSAvoidfuel resistance and environmental stability
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The metal ligands act as intermediary molecules between the organic polymer sealant and the metal surface. These ligands form stable coordination complexes with metal surfaces while maintaining compatibility with the polymer matrix, serving as a bridge that provides both strong adhesion and chemical stability against fuel and environmental degradation

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent selects specific metal ligands with appropriate chemical parameters - carboxylic acids, phenols, and their derivatives - that have optimal balance between metal-binding affinity and environmental stability. The ligand structure parameters (functional groups, molecular weight, hydrophobicity) are optimized to simultaneously achieve strong adhesion and resistance to fuel solvents and environmental conditions

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

These metal ligand-containing prepolymers demonstrate improved adhesion and mechanical properties, meeting the demanding requirements for aerospace applications by forming stable coordination complexes with metal surfaces, thereby enhancing the performance of aerospace sealants.

Implementation Method 1

react with metal chelating agents to form coordination complexes that enhance adhesion to metal surfaces

Methodology Applied
Scientific EffectCoordination complex formation: Chemical Bonding

Data Source

PatentUS9382462B2Metal ligand-containing prepolymers, methods of synthesis, and compositions thereof
Publication Date: 2016.07.05 PRC DESOTO INTERNATIONAL INC

AI summary

Metal ligand-containing prepolymers, compositions containing metal ligand-containing prepolymers, methods of synthesizing metal ligand-containing prepolymers and the use of metal ligand-containing prepolymers in aerospace sealant applications are disclosed. The metal ligand-containing prepolymers have metal ligands incorporated into the backbone of the prepolymer. Cured sealant compositions comprising the metal ligand-containing prepolymers exhibit enhanced properties suitable for aerospace sealant applications.