The development of high-performance flame-retardant polymers with simultaneously increased integrated performance, especially thermal resistance, dimensional stability and dielectric properties, is a challenge. Progress in this field depends greatly on the development of high-performance flame retardants. In the work reported here, a unique ladder-like multi-functional polysiloxane (PN-PSQ), with a large number of amine groups and a phosphaphenanthrene structure, was synthesized through the controlled hydrolysis of self-made phosphorus-containing triethoxysilane and γ-aminopropyl triethoxysilane. A series of PN-PSQ/bismaleimide (BMI) resins was then prepared and their structure and integrated properties investigated. The results show that a small addition of PN-PSQ effectively gives BMI resins an improved curing process, outstanding flame retardant properties, remarkably improved thermal and dimensional stability as well as a decreased dielectric constant and dielectric loss, completely overcoming the critical disadvantages of currently available flame retardants for thermally resistant polymers. For example, for the PN-PSQ5/BMI resin with 5 wt% PN-PSQ, its limited oxygen index and average heat release rate are about, respectively, 1.6 times and 58% of that of BMI resin alone. Compared with BMI resin alone, the glass transition temperature of the PN-PSQ5/BMI resin is increased by about 10 °C. The coefficient of thermal expansion of the former in a glassy or rubbery state and the dielectric constant and loss at 1 MHz decrease by about 10–20%. These attractive performances are attributed to the special structure of PN-PSQ/BMI resins induced by the unique nature of PN-PSQ. This investigation provides a new approach to synthesizing multi-functional polysiloxane and related high-performance resins.
开发高性能阻燃聚合物,并同时增强其综合性能,特别是热阻、尺寸稳定性和介电性能,是一项挑战。该领域的进展在很大程度上依赖于高性能阻燃剂的发展。在此报告的工作中,合成了一种独特的梯状多功能聚
硅氧烷(
PN-PSQ),具有大量
氨基和
磷苯并
芘结构,通过对自制的含
磷三乙氧基
硅烷和γ-
氨丙基三乙氧基
硅烷进行控制
水解制得。然后准备了一系列
PN-PSQ/双马来
酰亚胺(BMI)
树脂,并对其结构和综合性能进行了研究。结果表明,少量添加
PN-PSQ能有效改善BMI
树脂的固化过程,显著提高其阻燃性能、热稳定性和尺寸稳定性,并降低介电常数和介电损耗,完全克服了当前可用的热稳定聚合物阻燃剂的关键缺点。例如,
PN-PSQ5/BMI
树脂中
PN-PSQ的含量为5wt%,其限制氧指数和平均热释放速率分别约为BMI
树脂的1.6倍和58%。与单独的BMI
树脂相比,
PN-PSQ5/BMI
树脂的
玻璃化转变温度提高了约10°C。前者在
玻璃态或橡胶态时的热膨胀系数及在1
MHz下的介电常数和损耗分别降低了约10-20%。这些吸引人的性能归功于
PN-PSQ独特特性所引发的
PN-PSQ/BMI
树脂的特殊结构。该研究为合成多功能聚
硅氧烷及相关高性能
树脂提供了一种新方法。