Degradable Shotgun Wad Using PHA Polymer
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Solution Overview
Problem
Non-degradable plastic shotgun wads contribute significantly to aquatic debris, posing environmental and safety hazards, as they are not easily recoverable and can enter the food chain, causing harm to marine species and habitats, with current degradable alternatives compromising shot accuracy and performance.
Innovation Solution
Development of shotgun wads made from biodegradable polyhydroxyalkanoate (PHA) polymer that degrades quickly in aquatic environments into benign components, maintaining shot accuracy and performance comparable to non-degradable plastic wads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If non-degradable plastic wads are used, then shot accuracy and performance are maintained, but environmental harm and aquatic debris increase
Solution Approach 1:
The patent changes the material parameter from non-degradable plastic to degradable polymer, transforming the wad's chemical composition while maintaining its physical performance characteristics. This allows the wad to degrade after use, eliminating long-term environmental persistence while preserving shot accuracy during use.
Solution Approach 2:
The patent employs composite material structures combining degradable polymer matrices with functional additives and layered configurations. These composites maintain the structural integrity needed for accurate shot propulsion while incorporating degradation-capable materials that break down after serving their purpose.
2Object-affected harmful factors
If degradable wad materials are used, then environmental harm is reduced, but shot accuracy and performance deteriorate
Solution Approach 1:
The patent optimizes the degradation parameters of the polymer material, selecting degradation rates and conditions that ensure the wad remains stable during shot propulsion but degrades after exiting the barrel. This temporal separation of stability and degradability resolves the contradiction between performance and environmental harm.
Solution Approach 2:
The patent creates a dynamic material system where the wad's structural properties change over time and environmental conditions. The material maintains its functional integrity during the high-stress, short-duration shot propulsion phase, then transitions to degradation mode under ambient aquatic conditions, achieving both performance and environmental goals.
3Speed
If plastic wads are discharged into water, then they become buoyant and float, but this increases their persistence in the environment and entry into the food chain
Solution Approach 1:
The patent converts the buoyancy property, which initially causes environmental persistence, into a benefit by using it to deliver degradation-triggering conditions. The floating wad is exposed to sunlight, oxygen, and aquatic microorganisms that initiate and accelerate biodegradation, transforming the persistence problem into an active degradation process.
Solution Approach 2:
The patent enables the wad to self-degrade through environmental exposure after discharge. The material is designed to automatically initiate breakdown when exposed to aquatic conditions, sunlight, and microbial activity, eliminating the need for external recovery or intervention systems.
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
PHA wads effectively reduce aquatic debris by degrading faster when submerged, minimizing environmental impact while maintaining functional performance, including shot accuracy and durability, thus providing a viable and cost-effective alternative to non-degradable wads.
Implementation Method 1
the wad degrades reasonably quickly once it is abandoned in an aquatic environment, and, once degraded, is environmentally benign
Data Source
AI summary
Herein we describe shotgun shells each having a degradable wad comprising a polyhydroxyalkanoate polymer, as well as methods for ensuring that such wad degrades quickly after landing in an aquatic environment. Plastic, aquatic debris has a negative economic and ecological impact, and thus it is advantageous to use implements that will degrade into environmentally benign compounds. Incorporating a degradable wad into shotgun shells provides an effective, economical solution. Suitable degradable shotgun wads and methods are described herein.