Propellant Binder System Oxidation Resistance

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Solution Overview

Problem

Solid propellants for rocket motors face issues with aging due to spontaneous oxidation reactions that cause cross-linking and hardening of polybutadiene binders, leading to reduced storage life and functionality.

Innovation Solution

A propellant composition incorporating a polybutadiene component, a hydrocarbon diluent component of higher saturation, and an anti-oxidant, such as triphenyl phosphine or polytetrahydrofuran, to mitigate aging by reducing unsaturated sites and preventing oxygen reactions, thereby maintaining propellant stability and performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If polybutadiene binder is used in solid propellant, then propellant can be formed into desired shape and maintain flexibility, but spontaneous oxidation reactions cause cross-linking and hardening leading to reduced storage life

Engineering Contradiction:

Improvestorage lifeVSAvoidoxidation reactions

Core Design Contradiction:

Stability of the object's compositionVSObject-generated harmful factors

Solution Approach 1:

A saturated hydrocarbon diluent is introduced as an intermediary substance between the polybutadiene binder and oxygen. This diluent occupies space and reduces the concentration of unsaturated sites available for oxidation, thereby mediating the interaction between the binder and oxidizing agents to extend storage life.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the chemical composition parameters of the binder system by incorporating saturated hydrocarbons with specific molecular weights (250-3000 grams/mol) and saturation levels higher than polybutadiene. This parameter change reduces the overall unsaturation in the binder system, thereby reducing oxidation susceptibility and extending storage life.

Inventive Principle:

Principle #35Parameter changes

2Stability of the object's composition

If polybutadiene binder is used to maintain flexibility and formability, then propellant can be shaped and remain flexible, but cross-linking and hardening occur reducing operational stability

Engineering Contradiction:

Improveoperational stabilityVSAvoidhardening

Core Design Contradiction:

Stability of the object's compositionVSStrength

Solution Approach 1:

The patent modifies the physical and chemical parameters of the binder system by incorporating saturated hydrocarbons with controlled molecular weights and saturation levels. These parameter changes reduce cross-linking density while maintaining sufficient binder integrity, thereby preventing excessive hardening and preserving operational stability.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite binder system combining polybutadiene with saturated hydrocarbon diluents. This composite structure leverages the flexibility of polybutadiene while the saturated hydrocarbon component suppresses cross-linking and hardening, achieving both formability and operational stability.

Inventive Principle:

Principle #40Composite materials

3Duration of action of stationary object

If unsaturated polybutadiene is used for binder properties, then propellant can be formed and remains flexible, but oxygen reactions increase causing reduced storage life

Engineering Contradiction:

Improvestorage lifeVSAvoidoxygen reactions

Core Design Contradiction:

Duration of action of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The patent changes the chemical composition parameters by introducing saturated hydrocarbons with higher saturation levels than polybutadiene. This parameter change reduces the overall unsaturation concentration in the binder system, thereby reducing the rate of oxygen reactions and extending storage life.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The saturated hydrocarbon diluent creates a more chemically inert environment within the binder system by occupying space and reducing the concentration of reactive unsaturated sites. This inerting effect protects the polybutadiene from oxygen reactions, thereby extending storage life.

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

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 proposed solution effectively extends the storage life and operational stability of rocket motors by reducing aging reactions and maintaining the propellant's strain capacity and performance.

Implementation Method 1

spontaneous oxidation reactions that cause cross-linking and hardening of polybutadiene binders

Methodology Applied

Scientific EffectOxidation: Oxidation

Implementation Method 2

reducing unsaturated sites and preventing oxygen reactions

Methodology Applied

Scientific EffectDilution:

Data Source

PatentUS10266458B2Propellant with extended storage life

Publication Date: 2019.04.23 AEROJET ROCKETDYNE INC

AI summary

A propellant includes a binder system that has a polybutadiene component, a polytetrahydrofuran component, and an anti-oxidant component. In an example, the propellant includes a solid oxidizer, a solid fuel, and a binder system that holds the solid oxidizer and the solid fuel together. The binder system includes a polybutadiene component, a hydrocarbon diluent component of a higher level of saturation than the polybutadiene component, and an anti-oxidant component.