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首页> 外文会议>Seminar on New Trends in Research of Energetic Materials >Recent achievements in kinetic modelling of stabilizer consumption and molar mass degradation in NC-based propellants
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Recent achievements in kinetic modelling of stabilizer consumption and molar mass degradation in NC-based propellants

机译：基于NC的推进剂稳定剂消耗和摩尔质量降解动力学模型的最新研究进展

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With nitrocellulose stabilizers must be used to prevent it against the autocatalytic decomposition. However, the slow intrinsic decomposition cannot be prevented and therefore a slow degradation happens always, which leads to stabilizer consumption and the scission-ing of the NC chains. The last effect means molar mass degradation of NC. Both phenomena are irresolvable coupled. In splitting-off the •NO_2 radical from the nitrate ester groups RCO-NO_2 the remaining radical function written as RC-O • stabilizes itself by molecular rearrangement of the. anhyroglucopyranose ring and by splitting-off stable small molecular species. This means molar mass degradation happens by destruction of chain units and not be mere bond scissioning between chain units. This is in accordance with the well observed phenomena of mass loss with NC. To model the stabilizer consumption correctly, the production of NOx by NC has to be regarded as well as the bimolecular reaction between NOx and the stabilizer. The preceding production of NOx from NC is explicitly included, because the concentration of it is not constant with time. The elaboration of this relatively simple reaction scheme ends up in an equation for the bimolecular stabilizer reaction. The model contains both reaction rate constants of the two reactions of the scheme, which is a general and necessary condition for correct modelling of stabilizer consumption. Molar mass decrease of NC caused by random chain scission is describable with models based on the averaged characterizing parameters of the molar mass distribution (MMD) functions. The correct distribution function in terms of reaction kinetics is the one which counts the numbers (or mols) of polymers in the molar mass fraction M+dM. This one is named polymer number related MMD, in short hn and the first moment (center of gravity or arithmetic mean or expectation value) of it is the number averaged mean molar mass Mn. Based on this quantity Mn models of random chain scission and random chain scission with chain recombination are discussed.
机译：对于硝酸纤维素，必须使用稳定剂以防止其自催化分解。但是，不能防止缓慢的内在分解，因此总是发生缓慢的分解，这导致稳定剂的消耗和NC链的断裂。最后一个作用意味着NC的摩尔质量下降。两种现象是无法解决的耦合。在从硝酸酯基团RCO-NO_2分离出•NO_2自由基时，剩余的自由基功能（写为RC-O•）通过使其分子重排而稳定下来。并通过吡喃葡萄糖吡喃糖环分离出稳定的小分子物质。这意味着摩尔质量的降解是通过链单元的破坏而发生的，而不仅仅是链单元之间的键断裂。这与使用NC观察到的质量损失现象一致。为了正确地模拟稳定剂的消耗，必须考虑NC产生的NOx以及NOx和稳定剂之间的双分子反应。明确包括了以前由NC生产的NOx，因为它的浓度不是随时间变化的。对这种相对简单的反应方案的详细说明以双分子稳定剂反应的方程式告终。该模型包含该方案的两个反应的两个反应速率常数，这是稳定剂消耗正确建模的一般和必要条件。用基于摩尔质量分布（MMD）函数的平均特征参数的模型描述由随机断链引起的NC摩尔质量下降。就反应动力学而言，正确的分布函数是一种计算摩尔质量分数M + dM中聚合物的数量（或摩尔）的函数。简称为聚合物数相关的MMD，简称hn，其一阶矩（重心或算术平均值或期望值）为数均平均摩尔质量Mn。基于这一数量，讨论了随机断链和随机断链与链重组的Mn模型。

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