Polymer-Bonded Explosive Defoaming for Void Reduction
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Solution Overview
Problem
Conventional cast explosive compositions often retain air bubbles during the casting process, leading to reduced performance, stability, and increased sensitivity to friction, impact, and heat, which can result in inadvertent initiation.
Innovation Solution
A polymer-bonded explosive composition comprising 75-95 wt% RDX, 5-25 wt% polyurethane binder, and 0.05-2 wt% silicone-free defoaming agent, which reduces voids and enhances stability by using a combination of surface-active polymers to eliminate air bubbles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional casting techniques are used to shape explosive compositions, then design flexibility is improved, but air bubbles and voids are introduced that reduce performance and stability
Solution Approach 1:
A defoaming agent is added to the explosive composition before casting to prevent void formation during the pouring process. The defoaming agent is mixed with the binder and explosive particles in advance, so that when the composition is poured into the mold, bubbles are eliminated and a void-free structure is achieved while maintaining casting flexibility.
2Ease of manufacture
If pouring technique is used to place composition into mould, then ease of manufacture is improved, but voids are introduced that reduce explosive content per unit volume
Solution Approach 1:
A defoaming agent acts as an intermediary substance added to the explosive composition. This agent reduces surface tension and eliminates bubbles during pouring, allowing the simple pouring method to be used while achieving void-free packing and maximum explosive density in the final product.
3Ease of manufacture
If voids are present in composition, then casting process is simpler, but shock sensitivity increases making composition less stable
Solution Approach 1:
The defoaming agent is incorporated into the explosive composition before casting to prevent void formation during the simple pouring process. This preliminary action eliminates bubbles that would otherwise create shock-sensitive defects, allowing casting simplicity to be maintained while achieving shock-stable, void-free explosive charges.
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 composition achieves improved stability and reduced sensitivity to environmental stimuli, with increased density indicating reduced voids, and is suitable for high-force applications like artillery shells and missiles, while also facilitating complex shape production and safer handling.
Implementation Method 1
0.05 - 2 wt% of a silicone free defoaming agent, wherein the defoaming agent is a combination of polymers
Data Source
AI summary
The invention relates to a cast explosive composition comprising a polymer-bonded explosive and a defoaming agent, and to a process for reducing the number and/or total volume of voids in a cast explosive composition comprising the steps of: combining a polymer-bonded explosive and a defoaming agent; and casting the explosive composition. The defoaming agent may be used for reducing the number and/or total volume of voids in a cast explosive composition and the cast explosive composition may be used in an explosive product.