Block copolymer functionalized quartz fibers/cyanate ester wave-transparent laminated composites

Abstract

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 exclusion 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 mechanical 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 values are 2.61 and 0.0028 at 1 MHz (wave transmittance of 93.8%), showing good stability at different frequencies (10 2 -10 6 Hz and 8.4-12.4 GHz) and temperatures (25-250 °C).