HTPB Solid Rocket Propellant Binder with High Molecular Weight Diol
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Solution Overview
Problem
Existing solid rocket propellants face challenges in achieving optimal burn rate suppression and binder properties without using dimeryl diisocyanate, which is often undesirable due to its limitations.
Innovation Solution
A solid rocket propellant formulation incorporating a hydroxyl-terminated polybutadiene (HTPB) binder system with a high molecular weight dimer diol (greater than 30 to less than 50 carbon atoms) and a diisocyanate, excluding dimeryl diisocyanate, along with a perchlorate oxidizer and fuel, such as aluminum, to achieve desired burn rate and thrust characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If dimeryl diisocyanate is used as curing agent, then binder properties are improved, but harmful factors increase due to its limitations
Solution Approach 1:
The patent extracts and removes dimeryl diisocyanate from the binder system, replacing it with alternative curing agents such as hexamethylene diisocyanate or isophorone diisocyanate. This extraction eliminates the harmful factors associated with dimeryl diisocyanate while maintaining the essential binder properties through the use of alternative isocyanates that provide comparable or improved performance without the detrimental effects.
2Object-affected harmful factors
If burn rate suppression is enhanced, then safety is improved, but thrust characteristics may be affected
Solution Approach 1:
The patent changes the molecular weight parameter of the polybutadiene binder to greater than 300,000 g/mol, which fundamentally alters the burn rate characteristics. This parameter change suppresses the burn rate to improve safety while the specific combination with alternative isocyanate curing agents and oxidizer/fuel formulations maintains or optimizes thrust characteristics, resolving the contradiction between burn rate suppression and thrust performance.
3Object-affected harmful factors
If molecular weight of binder is increased, then burn rate suppression is improved, but manufacturing complexity increases
Solution Approach 1:
The patent merges the high molecular weight polybutadiene binder (greater than 300,000 g/mol) with alternative isocyanate curing agents in a unified binder system formulation. This combination approach achieves burn rate suppression through the high molecular weight binder while the synergistic interaction with alternative isocyanates simplifies the overall manufacturing process by eliminating the need for separate processing steps, thus resolving the contradiction between burn rate control and manufacturing complexity.
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 formulation effectively suppresses burn rate and enhances binder properties, similar to those achieved with dimeryl diisocyanate, while avoiding its use, thereby improving the performance and safety of solid rocket motors.
Implementation Method 1
a hydroxyl-terminated polybutadiene (HTPB) binder system with a high molecular weight dimer diol (greater than 30 to less than 50 carbon atoms) and a diisocyanate
Implementation Method 2
Ignition of the solid propellant generates high pressure gas, which is expelled through a nozzle to generate thrust
Data Source
Figure 1~2
AI summary
A solid rocket propellant includes a hydroxyl-terminated polybudadiene (HTPB) binder system having a high molecular weight diol that is greater than thirty carbon atoms (> C30) and less than fifty carbon atoms (< C50) and excluding dimeryl diisocyanate (DDI).