The comparative behaviour under the oxidative degradation occurred during accelerating conditions of ageing (γ-irradiation and artificial weathering) is analysed for three polyamide-6-based formulations destined to special services like outdoor and nuclear fields. Pristine PA-6 and its blends with two ethylene elastomers (ethylene–propylene copolymer and ethylene–acrylic ester terpolymer) grafted with maleic anhydride were tested under accelerated degradation (radiation processing and weathering) by chemiluminescence and swelling. The elastomers are minor components with three loading degrees (5, 10 and 20%). The influence of elastomer fractions on the promotion of oxidation is revealed by the comparison with neat PA-6, which is a most stable of the three involved polymers. The results demonstrate that the minor components are the sources of radicals that are reactive spots. The competition between degradation and partial cross-linking is analysed. The calculated activation energies of oxidation allow the prediction of stability for long-term operation. The mechanistic aspects connected to the availability of blending components to oxidation are discussed for the explanation of ageing propagation under various factors acting during ageing promotion service.

中文翻译：

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户外和核应用的 PA-6/乙烯弹性体混合物的稳定性分析

针对用于户外和核领域等特殊服务的三种基于聚酰胺 6 的配方，分析了在加速老化条件（γ 辐射和人工风化）期间发生的氧化降解的比较行为。在通过化学发光和溶胀加速降解（辐射加工和风化）下测试原始 PA-6 及其与两种乙烯弹性体（乙烯-丙烯共聚物和乙烯-丙烯酸酯三元共聚物）的共混物接枝马来酸酐。弹性体是具有三个加载度（5%、10% 和 20%）的次要组分。通过与纯 PA-6 的比较揭示了弹性体分数对氧化促进的影响，纯 PA-6 是三种相关聚合物中最稳定的。结果表明，微量成分是反应点自由基的来源。分析了降解和部分交联之间的竞争。计算出的氧化活化能可以预测长期运行的稳定性。为了解释老化促进服务期间作用的各种因素下的老化传播，讨论了与混合成分可用于氧化有关的机械方面。