Theoretical study on thermal curing mechanism of arylethynyl-containing resins
Theoretical study on thermal curing mechanism of arylethynyl-containing resins
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含芳基乙炔基树脂热固化机理的理论研究
DOI：
10.1039/c9cp06892a
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发表时间：
2020
影响因子：
3.3
通讯作者：
Du Lei
中科院分区：
文献类型：
--
作者：
Chen Zuowei;Wang Liquan;Lin Jiaping;Du Lei
芳基乙炔基反应性基团在高温聚合物中有着广泛的应用，因此了解其固化机理对于学术研究和工程应用具有重要意义。然而，迄今为止，对含芳基乙炔基树脂的实际固化机理还没有达成共识。本文以苯乙炔和二苯乙炔为模型化合物，采用密度泛函理论研究了含芳基乙炔基树脂的热固化机理。发现反应的速率控制步骤是芳基乙炔二聚成双自由基中间体。两个芳基乙炔之间的Straus型中间体和协同Diels-Alder环加成反应的可能性可以被排除。环丁二烯和环丙二烯是双自由基分子内偶联产生的关键中间体。多烯的形成优选通过单价基引发而不是双价基生长。整个反应路径可以很好地解释萘二聚体，苯三聚体和多烯链的形成。最后，将计算结果与已有的实验结果进行了比较，并与实验结果一致。
Arylethynyl reactive groups have been widely used in high-temperature polymers, and therefore, understanding their curing mechanism is of great importance for academic research and engineering applications. However, no consensus has been achieved on the actual curing mechanism of arylethynyl-containing resins so far. Herein, we present a density functional theory study on the thermal curing mechanism of arylethynyl-containing resins using phenylacetylene and diphenylacetylene as model compounds. It was discovered that the rate-determining step is the dimerization of arylacetylenes into diradical intermediates. The possibilities of the Straus-type intermediates and concerted Diels–Alder cycloaddition between two arylacetylenes can be ruled out. Cyclobutadiene and cyclic allene are the critical intermediates generated by the intramolecular coupling of diradicals. The formation of polyene is preferred by monoradical initiation rather than diradical growth. The overall reaction pathways can well account for the formation of naphthalenic dimers, benzenic trimers, and polyenic chains. The computational results of reactivity for the dimerization of arylacetylenes were finally compared with the existing experimental findings, and an agreement is shown.