Ionone Stabilisers for Nitrocellulose Propellants
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Solution Overview
Problem
Conventional stabilizers for nitrocellulose-based propellants are prone to producing carcinogenic and mutagenic by-products, which poses safety concerns and reduces the long-term stability of these compositions, necessitating the development of stabilizers that can inhibit nitrocellulose degradation without generating harmful compounds.
Innovation Solution
A non-aromatic ionone-type compound with specific formulas, capable of reacting with alkoxy radicals and NOx species, is used as a stabilizer in nitrocellulose-based propellant compositions, preventing the formation of harmful N-NO groups and enhancing long-term stability by forming stable alcohol compounds that trap further radicals, combined with aromatic compounds for synergistic effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If conventional stabilisers (aromatic amines or aromatic urea derivatives) are used to stabilise nitrocellulose-based propellants, then the long-term stability is improved, but carcinogenic and mutagenic by-products are formed
Solution Approach 1:
The invention changes the chemical structure parameter of the stabiliser from aromatic (conventional) to non-aromatic (ionone-type). This structural parameter change allows the stabiliser to effectively scavenge radicals and stabilise nitrocellulose without forming carcinogenic N-NO groups, thus resolving the contradiction between long-term stability and harmful by-product formation
Solution Approach 2:
The invention uses a composite stabilising system combining ionone-type compounds with other stabilisers (such as phenolic compounds or amine compounds). This composite approach enhances the stabilising effect while maintaining low formation of harmful by-products, achieving both long-term stability and safety
2Object-generated harmful factors
If hindered amines are used to reduce N-NO group formation, then carcinogenic by-product formation is reduced, but nitrocellulose stabilisation is insufficient
Solution Approach 1:
The invention changes the chemical structure from hindered amine to ionone-type compound. The ionone structure contains a conjugated double bond system and carbonyl group that can effectively trap radicals through resonance stabilisation, providing both adequate nitrocellulose stabilisation and reduced N-NO group formation
Solution Approach 2:
The ionone-type compound acts as an intermediary substance that intercepts radicals generated during nitrocellulose degradation. By forming stable radical adducts through its unique molecular structure, it prevents further degradation reactions and N-NO group formation, mediating between the propellant components and degradation products
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 stabilizer composition achieves long-term stability, meeting STANAG 4582 requirements by maintaining low heat flow over extended periods, ensuring safety and environmental friendliness by avoiding carcinogenic and mutagenic by-product formation.
Implementation Method 1
stabilisers are added to the energetic mixture in order to scavenge these radical species and slow down the degradation pattern
Implementation Method 2
by hydrogen abstraction of the labile proton of the stabiliser, by reaction with a radical group, thus forming a stable alcohol compound and a first by-product able to trap further alkoxy/ NOx species
Implementation Method 3
The phenols are able to trap the alkoxy radicals generated during the degradation of nitrocellulose and thus form new, relatively stable alkoxy radicals, by delocalisation of an electron at the foot of electron-rich, hindered groups
Implementation Method 4
Nitrocellulose, as most nitrate esters, is prone to self-ignition as a result of thermal degradation due to the weakness of its O-N bond
Implementation Method 5
The decomposition of nitrocellulose usually starts with a bond scission or hydrolysis, generating alkoxy radicals and nitrogen oxide (NOx) species
Data Source
Figure 1~2(a)
Figure 2(b)
Figure 3a
AI summary
The present invention concerns a nitrocellulose-based propellant composition comprising: (a) a nitrate ester-based propellant comprising nitrocellulose; and (b) a stabiliser comprising a non-aromatic compound (12) consisting of a general ionone formula (12-1), (12-11), (12-111) or (12-IV): Wherein R1 represents a ketone, hydroxyl, carboxyl, aldehyde or an unsaturated alkyl group, preferably -C(O)CH3 (corresponding to alpha, beta, gamma and pseudo ionone).