Zheng Liu, Xiaoli Fan, Junliang Zhang, Lixin Chen, Yusheng Tang*, Jie Kong and Junwei Gu*. PBO fibers/ fluorine-containing liquid crystal compound modified cyanate ester wave-transparent laminated composites with excellent mechanical and flame retardance properties. Journal of Materials Science & Technology, 2023, 152: 16-29. 2021IF=10.319.（1区材料科学Top期刊，中国科技期刊卓越行动计划-重点类期刊项目，2021中国最具国际影响力学术期刊）

https://doi.org/10.1016/j.jmst.2023.01.007

Abstract

Bisphenol A dicyanate ester resins modified by fluorine-containing liquid crystal compound (LCFE) are applied as polymer matrix (LCFE-BADCy), poly(p-phenylene-2,6-benzobisoxazole) (PBO) fibers as reinforcements, and fluorine/adamantane PBO precursor (preFABPBO) as interfacial compatibilizer to prepare the corresponding PBO fibers/FABPBO/LCFE-BADCy wave-transparent laminated composites. LCFE could improve the order degree of BADCy cured network, in favor of enhancing the wave-transparent performance, mechanical properties, and intrinsic thermal conductivity. The dielectric constant and dielectric loss of PBO fibers/FABPBO/LCFE-BADCy composites are highly temperature (25~200^oC) and frequency (104~107 Hz and 8.2~12.4 GHz) stable with the value of 2.49 and 0.003 under 106 Hz at 25oC, and the corresponding wave transmission efficiency is 95.0%, higher than that of 92.5% for PBO fibers/BADCy composites. The interlamellar shear strength and flexural strength are respectively 50.7 MPa and 682.5 MPa, 38.1% and 16.2% higher than those of PBO fibers/BADCy composites. Besides, the volume resistivity, breakdown voltage, heat resistance index, glass transition temperature, flame retardant grade, and ultimate oxygen index of PBO fibers/FABPBO/LCFE-BADCy composites are respectively 5.3×1015 Ω·cm, 29.75 kV/mm, 217.2oC, 245.7oC, V-1 grade, and 33.6%, expected to be performed as a new generation of “light weight/loading/wave-transparent” electromagnetic window materials in advanced military weapons and civil communication base station.

以含氟液晶环氧化合物（LCFE）改性的双酚A氰酸酯（LCFE-BADCy）树脂为基体、聚对苯撑苯并二噁唑（PBO）纤维为增强体、含氟金刚烷PBO前驱体（preFABPBO）为界面相容剂，经高温模压制备PBO纤维/FABPBO/LCFE-BADCy层压透波复合材料。LCFE的引入提升了BADCy树脂固化网络的有序性，同步提升了LCFE-BADCy树脂的透波性能、力学性能和本体导热性能。PBO纤维/FABPBO/LCFE-BADCy层压透波复合材料的介电常数和介电损耗角正切值分别为2.49和0.003（106 Hz，25oC），相应的理论透波率为95.0%，高于PBO纤维/BADCy（92.5%），在较宽温度（25~200^oC）和频率范围内（104~107 Hz和8.2~12.4 GHz）均具有优异稳定性；且在高频段下具有较低的插入相位移，能够保证电磁信号的高效和高保真传输；其层间剪切强度（ILSS）和弯曲强度分别为50.7 MPa和682.5 MPa，较PBO纤维/BADCy的36.7 MPa和587.4 MPa分别提升了38.1%和16.2%。PBO纤维/FABPBO/LCFE-BADCy层压透波复合材料的体积电阻率、击穿电压、耐热指数、玻璃化转变温度、阻燃等级和极限氧指数分别为5.3×1015 Ω·cm、29.75 kV/mm、217.2oC、245.7oC、V-1级和33.6%。本文制备的层压复合材料兼具优异的透波性能、力学性能、绝缘性能、耐热性能、耐环境老化性能和阻燃性能，有望作为新一代“轻量/承载/透波”一体化电磁窗口材料在新型军用武器装备和民用通信基站获得更广泛的应用。

论文亮点

1. LCFE的共聚引入提升了BADCy树脂固化网络的有序性，同步提升了LCFE-BADCy树脂的透波性能、力学性能和本体导热性能。

2. PBO纤维/FABPBO/LCFE-BADCy层压透波复合材料的理论透波率达95.0%，明显优于PBO纤维/BADCy的92.5%，且具有优异温度和频率稳定性。

3. PBO纤维/FABPBO/LCFE-BADCy层压透波复合材料的ILSS和弯曲强度较PBO纤维/BADCy的ILSS（36.7 MPa）和弯曲强度（587.4 MPa）分别提升了38.1%和16.2%。

4. PBO纤维/FABPBO/LCFE-BADCy层压透波复合材料的体积电阻率、击穿电压、耐热指数、玻璃化转变温度、阻燃等级和极限氧指数分别为5.3×10¹⁵ Ω·cm、29.75 kV/mm、217.2^oC、245.7^oC、V-1级和33.6%。