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Zheng Liu, Xiaoli Fan, Junliang Zhang*, Zhiyong Yang, Yusheng Tang, Jianwei Li, Jie Kong and Junwei Gu*. Improving the comprehensive properties of PBO fibres/cyanate ester composites using a hyperbranched fluorine and epoxy containing PBO precursor. Composites Part A: Applied Science and Manufacturing, 2021, 150: 106596. 2020IF=7.664.（1區材料科學Top期刊）

（https://doi.org/10.1016/j.compositesa.2021.106596）

Abstract

Hyperbranched fluorine and epoxy containing PBO precursor (epoxy-preFHBPBO) was synthesized and utilized as interface compatibilizer to synchronously improve the mechanical and dielectric properties of poly(p-phenylene-2, 6-benzobisoxazole) (PBO) fibres reinforced bisphenol A dicyanate ester (BADCy) resins (PBO fibres/FHBPBO-co-BADCy) laminated composites. ¹H NMR, ¹³C NMR, and FTIR analyses confirmed the successful preparation of epoxy-preFHBPBO. The introduction of hyperbranched structure and fluorine groups significantly improved the mechanical properties and wave-transparent performance. Compared with PBO fibres/BADCy, the flexural strength and interlaminar shear strength of PBO fibres/FHBPBO-co-BADCy composites with 7 wt.% epoxy-preFHBPBO were respectively enhanced to 634.9 and 46.9 MPa, increased by 8.1% and 27.8%. The corresponding dielectric constant and dielectric loss were 2.65 and 0.003, respectively, lower than those of PBO fibres/BADCy (3.06 and 0.006) composites. Meanwhile, the corresponding volume resistivity and breakdown strength were 4.93×10¹⁵ Ω?cm and 25.38 kV/mm, higher than PBO fibres/BADCy resins composites (2.2×10¹⁵ Ω?cm and 17.69 kV/mm).

以縮聚和端基修飾制備得到的環氧端基含氟超支化PBO前驅體（epoxy-preFHBPBO）為界面相容劑，經高溫模壓制備PBO纖維/FHBPBO-co-BADCy層壓透波復合材料。FTIR、¹H NMR和¹³C NMR證明成功制備出具有預期分子結構的epoxy-preFHBPBO。超支化拓撲結構和含氟基團的引入能夠顯著改善BADCy樹脂的力學性能和介電性能。當epoxy-preFHBPBO的用量為7 wt%時，PBO纖維/FHBPBO-co-BADCy層壓透波復合材料的彎曲強度和層間剪切強度分別從PBO纖維/BADCy的587.4 MPa和36.7 MPa提升至634.9 MPa和46.9 MPa，分別提升了8.1%和27.8%；1 MHz下PBO纖維/FHBPBO-co-BADCy的介電常數和介電損耗角正切值分別為2.65和0.003，低于PBO纖維/BADCy層壓透波復合材料的ε和tanδ（3.06和0.006）。PBO纖維/FHBPBO-co-BADCy層壓透波復合材料的體積電阻率和擊穿電壓值分別為4.93×10¹⁵ Ω?cm和25.38 kV/mm，高于PBO纖維/BADCy層壓透波復合材料（2.2×10¹⁵ Ω?cm and 17.69 kV/mm）。

論文創新點

1. 環氧端基含氟超支化PBO前驅體（epoxy-preFHBPBO）的引入能夠顯著改善BADCy樹脂的力學性能、介電性能及與PBO纖維之間的界面相容性。
2. PBO纖維/FHBPBO-co-BADCy層壓透波復合材料的彎曲強度和ILSS分別從PBO纖維/BADCy的587.4 MPa和36.7 MPa提升至634.9 MPa和46.9 MPa。1 MHz下的ε和tanδ分別為2.65和0.003，均低于PBO纖維/BADCy的ε和tanδ（3.06和0.006）。
3. 基于傳輸/反射法建立的仿真透波模型表明PBO纖維/FHBPBO-co-BADCy層壓復合材料在不同厚度（1~5 mm）下均具有優異的透波性能。