Lobanova Marina Sergeevna, Babkin Alexandr Vladimirovich, Kepman Alexey Valeryevich, Avdeev Victor Vasil'evich, Morozov Oleg Sergeevich, Bulgakov Boris Anatol'evich
Department of Chemistry, M. V. Lomonosov Moscow State University, 119991 Moscow, Russia.
Polymers (Basel). 2024 Aug 7;16(16):2239. doi: 10.3390/polym16162239.
Phthalonitrile thermosets are known for their excellent mechanical, physico-chemical, and fire-retardant properties, making them attractive for aerospace and mechanical engineering applications. When producing and applying phthalonitrile-based structural parts, it is essential to consider aspects such as processability and the long-term stability of the material's properties at high temperatures. In our previous studies, we demonstrated that resins containing phosphate-bridged bisphthalonitrile monomers are easily processable due to their low melting temperature and wide processing window. In this study, we investigated the impact of bis(3-(3,4-dicyanophenoxy)phenyl)phenyl phosphate (PPhPN) monomer content on physico-chemical and mechanical properties, thermal stability, and thermal oxidative stability. This research highlights the importance of conducting long-term thermal oxidative aging studies in addition to thermogravimetric analysis to properly assess the stability of thermosets. The findings indicate that adding less than 15% of PPhPN results in the formation of a crystalline phase, which impairs the resin's processability. Conversely, a high PPhPN content reduces the material's thermal oxidative stability. Therefore, based on mechanical and physico-chemical tests after thermal oxidative aging, it can be concluded that a 10-15% concentration of the phosphate-containing monomer enables easy processability of the phthalonitrile resin and provides excellent long-term thermal oxidative stability at temperatures up to 300 °C, while maintaining a flexural strength exceeding 120 MPa and an elasticity modulus of 4.3 GPa.
邻苯二甲腈热固性材料以其优异的机械、物理化学和阻燃性能而闻名，这使其在航空航天和机械工程应用中颇具吸引力。在生产和应用基于邻苯二甲腈的结构部件时，必须考虑诸如加工性能以及材料在高温下性能的长期稳定性等方面。在我们之前的研究中，我们证明了含有磷酸桥联双邻苯二甲腈单体的树脂由于其低熔点温度和较宽的加工窗口而易于加工。在本研究中，我们研究了双（3 - （3,4 - 二氰基苯氧基）苯基）苯基磷酸酯（PPhPN）单体含量对物理化学和机械性能、热稳定性以及热氧化稳定性的影响。这项研究强调了除热重分析外进行长期热氧化老化研究对于正确评估热固性材料稳定性的重要性。研究结果表明，添加少于15%的PPhPN会导致结晶相的形成，这会损害树脂的加工性能。相反，高PPhPN含量会降低材料的热氧化稳定性。因此，基于热氧化老化后的机械和物理化学测试，可以得出结论，10 - 15%浓度的含磷单体能够使邻苯二甲腈树脂易于加工，并在高达300°C的温度下提供优异的长期热氧化稳定性，同时保持弯曲强度超过120 MPa和弹性模量为4.3 GPa。
