The Effects of Conventional Stabilizers and Phenol Compounds Used as Antioxidants on the Stabilization of Nitrocellulose

Propellants containing nitrocellulose (NC) continuously decompose. The decomposition products released in the process increase the rate of the decomposition and a self‐accelerating behavior is obtained. To prevent the autocatalysis, stabilizers are added to NC/NG‐based propellants. The action of the stabilizers is to trap the nitrous decomposition products and form stable compounds, which prevent or delay further decomposition. The most common stabilizers are aniline derivatives, which can form potentially toxic and/or carcinogenic nitrosamine derivatives during prolonged storage in propellants. This work is the joint effort between the Swedish Defence Research Agency (FOI) and Eurenco Bofors (EuB) to find new stabilizers without any amine moiety to avoid nitrosamine formation, which has resulted in a new class of stabilizers with plasticizing properties. The paper describes the concept of this class of plasticizing stabilizers, the synthesis of these compounds and characterization of their performance as stabilizers. The most promising stabilizer was found to be bis(2,6‐dimethoxyphenyl)triethyleneglycol (Stab‐5). Kilogram scale production of this substance at FOI allowed evaluation of its stabilizing effect in real propellants and its effect on the burning rate in a double‐base rocket motor at EuB. Accelerated ageing of a double‐base propellant stabilized with Stab‐5 was applied in order to identify the compounds that were obtained in the reaction between the stabilizer and the decomposition products.

Section: Introductionsupporting

confidence: 79%

“…Recently,v ariouss ubstitutedp henols were suggested as new stabilizers and exhibited promising but less stabilizing effect than the conventional stabilizers [14][15][16][17][18]. The investigated phenols werei nm ost cases sterically hindered with largea lkyl substituents present on the aromatic ring.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Characterization of Novel Stabilizers for Nitrocellulose‐Based Propellants

Krumlinde

Tunestål³

et al. 2016

“…The latter two compounds are very similar in structure to 2,4‐ditertbutylphenol and butylated hydroxytoluene (BHT), which are commercially used as antiaging agents for natural and synthetic rubber, food preservatives, plastic antioxidants, fuel stabilizers, and ultraviolet absorbents 15, 16. The purpose of these phenolic antioxidants is to act as free radical scavengers to inhibit or slow the oxidative process through a recognized polymer autoxidation mechanism 17. These phenol antioxidant compounds have been shown to react with ROO .…”

Section: Resultsmentioning

confidence: 99%

Characterization of Three Types of Semtex (H, 1A, and 10)

Moore

Schantz

MacCrehan

2010

Solid phase microextraction and solvent extraction were used with GC/MS to determine the vapor and compositional profile of three samples of Semtex (1A, H, and 10). Semtex is reported to contain PETN and/or RDX, along with plasticizers, binding materials, and fuel oil components. In an effort to differentiate and compare these three variations of Semtex, this report summarizes the headspace and solvent extraction results for each material. Components that can be used to differentiate varieties of Semtex were identified and all three Semtex profiles were distinguished.

“…Not only a reduction in the performances of the propellant will be observed, but self-ignition may ensue by accelerated decomposition caused by autocatalysis and/or by self-heating, posing important safety issues. This exothermic process has already caused numerous incidents in the propellant industry [3].…”

Section: Introductionmentioning

confidence: 99%

“…Many new stabilisers for propellant powders have been examined [6,7], such as hindered amines, e. g. triphenylamine (TPA) [8] and malonanilide derivatives [9], hindered phenols [3,[10][11][12], organic sulphur and phosphor organic compounds [13], and an activated aromatic ether (STAB-5) [14][15][16]. TPA is a tertiary amine and therefore does not have [ 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 any NÀH bonds, so that no carcinogenic N-nitrosamines can be formed [17].…”

Section: Introductionmentioning

confidence: 99%

Making Progress Towards «Green» Propellants

Dejeaifve¹,

Fantin²,

Monseur³

et al. 2018

Stabilisers are used in propellants to prevent the various effects such as oxidation, chain scission, energy loss and uncontrolled heat generation that are caused by homolytic and heterolytic cleavage of the weakest Nitrogen‐Oxygen bond of the nitrate ester functional group. Conventional stabilisers for nitrocellulose‐based propellants belong to a‐aromatic amines (e. g., diphenylamine, 4‐nitro‐N‐methylaniline…) or b‐aromatic urea derivatives (e. g., Akardite, centralite…) and are/or produce highly toxic and/or potentially carcinogenic species at some point during a propellant's lifetime. There is an obvious need for alternative stabilisers presenting a low toxicity profile and providing efficiencies similar to, or better than conventional stabilisers. This paper presents novel, environmentally friendly, efficient and readily‐available stabilisers for use in nitrocellulose‐based compositions. With REACh legislation (1907/2006), industry in Europe has made progress in using less toxic compounds, that are often more environmentally‐friendly. The aim of this work is to go beyond REACh and to anticipate the inclusion of other molecules that produce non‐ or less toxic daughter products and that can fulfil their role in the propellant's formulation.