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近年来,长期作为光稳定剂的受阻胺在性能改善过程中发现其中的N-取代烷氧基受阻胺具有优异的阻燃性能。本文对N-取代烷氧基受阻胺类阻燃剂(NORs)的结构、性能、合成、阻燃机理及其在聚烯烃中的应用进行了系统的评述。NORs主要是以22,,6,6-四甲基哌啶衍生物在催化剂作用下与烷基自由基经过数步反应制得,其在聚烯烃中的阻燃功效主要是通过燃烧分解产生的高效可循环再生的自由基捕捉剂干扰和抑制燃烧过程中产生的自由基,并使之转化为相对稳定的醇、酮等化合物来实现的。此外,通过凝聚相的自由基反应,NORs还可提升含溴或磷系等传统阻燃剂的阻燃效率。研究表明,NORs应用于聚烯烃薄制品如纤维和薄膜等体现出优异的阻燃效率,且低浓高效,添加0.5%左右即能达到满意的阻燃性能。同时,其良好的阻燃协效作用可显著减少传统阻燃剂的用量。此外,NORs本身作为一种受阻胺稳定剂,能为聚烯烃材料提供优良的光稳定性和长效的热稳定性。
In recent years, long-term as a light stabilizer hindered amine in the process of improving performance which found that N-substituted alkoxy hindered amine has excellent flame retardant properties. In this paper, the structure, properties, synthesis, flame retardant mechanism and applications of N-substituted alkoxy hindered amine flame retardants (NORs) in polyolefins were systematically reviewed. NORs mainly by 22,6,6-tetramethylpiperidine derivatives in the catalyst and alkyl radicals after several steps in the reaction, the flame retardant effect in polyolefins is mainly produced by combustion decomposition Highly efficient and recyclable radical scavenger interferes with and restrain the free radicals generated in the combustion process and make them into relatively stable alcohols, ketones and other compounds to achieve. In addition, NORs can also enhance the flame retardancy of traditional flame retardants such as bromine or phosphorous through free radical reactions of the condensed phase. Studies have shown that NORs used in polyolefin thin products such as fibers and films show excellent flame retardant efficiency, and low concentration and high efficiency, add about 0.5% to achieve satisfactory flame retardant properties. At the same time, its good flame retardant synergistic effect can significantly reduce the amount of traditional flame retardants. In addition, NORs, as a hindered amine stabilizer per se, provide excellent photostability and long-term thermal stability for polyolefin materials.