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 rein-forcements,and fluorin...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 rein-forcements,and fluorine/adamantane PBO precursor(pre FABPBO)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 perfor-mance,mechanical properties,and intrinsic thermal conductivity.The dielectric constant and dielectric loss of PBO fibers/FABPBO/LCFE-BADCy composites are highly temperature(25–200℃)and frequency(10^(4)–10^(7) Hz and 8.2–12.4 GHz)stable with the value of 2.49 and 0.003 under 10^(6) Hz at 25℃,and the corresponding wave transmission efficiency is 95.0%,higher than that of 92.5%for PBO fibers/BADCy com-posites.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 ul-timate oxygen index of PBO fibers/FABPBO/LCFE-BADCy composites are respectively 5.3×10^(15)Ωcm,29.75 kV/mm,217.2℃,245.7℃,V-1 grade,and 33.6%,expected to be performed as a new generation of“lightweight/loading/wave-transparent”electromagnetic window materials in advanced military weapons and civil communication base station.展开更多
A block copolymer of PDMS-b-PGMA is synthesized by polymerizing glycidyl methacrylate(GMA)via reversible addition-fragmentation chain transfer(RAFT)polymerization applying a polydimethylsiloxane(PDMS)based macro-RAFT ...A block copolymer of PDMS-b-PGMA is synthesized by polymerizing glycidyl methacrylate(GMA)via reversible addition-fragmentation chain transfer(RAFT)polymerization applying a polydimethylsiloxane(PDMS)based macro-RAFT agent,which is then performed to functionalize the quartz fibers(QFs@PDMS-b-PGMA)via a simple coating process.Finally,the QFs@PDMS-b-PGMA/bisphenol A dicyanate ester(BADCy)wave-transparent laminated composites are fabricated by high-temperature molding.Nuclear magnetic resonance(NMR)spectroscopy,Fourier transform infrared(FT-IR)spectroscopy and size ex-clusion chromatography(SEC)demonstrate the successful preparation of PDMS-b-PGMA with expected structure.When the molar mass and coating amount of PDMS-b-PGMA are respectively 8100 g/mol and 2.0 wt.%,QFs@PDMS-b-PGMA/BADCy wave-transparent laminated composites present optimal mechan-ical properties and wave-transparent performance.The interlaminar shear strength(ILSS)and flexural strength are 53.6 and 552.0 MPa,respectively.Meanwhile,the dielectric constant and dielectric loss val-ues are 2.61 and 0.0028 at 1 MHz(wave transmittance of 93.8%),showing good stability at different frequencies(102-106 Hz and 8.4-12.4 GHz)and temperatures(25-250℃).展开更多
基金The authors are grateful for the support and funding from National Scientific Research Project(Basis Strengthening Plan)State Key Laboratory of Solidification Processing in NWPU(No.SKLSP202103).
文摘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 rein-forcements,and fluorine/adamantane PBO precursor(pre FABPBO)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 perfor-mance,mechanical properties,and intrinsic thermal conductivity.The dielectric constant and dielectric loss of PBO fibers/FABPBO/LCFE-BADCy composites are highly temperature(25–200℃)and frequency(10^(4)–10^(7) Hz and 8.2–12.4 GHz)stable with the value of 2.49 and 0.003 under 10^(6) Hz at 25℃,and the corresponding wave transmission efficiency is 95.0%,higher than that of 92.5%for PBO fibers/BADCy com-posites.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 ul-timate oxygen index of PBO fibers/FABPBO/LCFE-BADCy composites are respectively 5.3×10^(15)Ωcm,29.75 kV/mm,217.2℃,245.7℃,V-1 grade,and 33.6%,expected to be performed as a new generation of“lightweight/loading/wave-transparent”electromagnetic window materials in advanced military weapons and civil communication base station.
文摘A block copolymer of PDMS-b-PGMA is synthesized by polymerizing glycidyl methacrylate(GMA)via reversible addition-fragmentation chain transfer(RAFT)polymerization applying a polydimethylsiloxane(PDMS)based macro-RAFT agent,which is then performed to functionalize the quartz fibers(QFs@PDMS-b-PGMA)via a simple coating process.Finally,the QFs@PDMS-b-PGMA/bisphenol A dicyanate ester(BADCy)wave-transparent laminated composites are fabricated by high-temperature molding.Nuclear magnetic resonance(NMR)spectroscopy,Fourier transform infrared(FT-IR)spectroscopy and size ex-clusion chromatography(SEC)demonstrate the successful preparation of PDMS-b-PGMA with expected structure.When the molar mass and coating amount of PDMS-b-PGMA are respectively 8100 g/mol and 2.0 wt.%,QFs@PDMS-b-PGMA/BADCy wave-transparent laminated composites present optimal mechan-ical properties and wave-transparent performance.The interlaminar shear strength(ILSS)and flexural strength are 53.6 and 552.0 MPa,respectively.Meanwhile,the dielectric constant and dielectric loss val-ues are 2.61 and 0.0028 at 1 MHz(wave transmittance of 93.8%),showing good stability at different frequencies(102-106 Hz and 8.4-12.4 GHz)and temperatures(25-250℃).