Modification on glass fiber surface and their improved properties of fiber-reinforced composites via enhanced interfacial properties.

For fiber reinforced composite laminates, properties of laminates can be significantly affected by interfacial properties. In this work, a kind of phthalonitrile containing aromatic ether nitrile linkage (PEN-BAPh) was applied to modify glass fibers (GFs). Cured PEN-BAPh on GFs surface were investigated by Fourier transform infrared spectroscopy (FT-IR) and Ultraviolet–visible spectroscopy (UV–Vis). Scanning electron microscope (SEM) and thermogravimetry (TGA) testing were also applied to confirm the modification. Then, modified fiber-reinforced phthalonitrile-based resin composite laminates were fabricated. As the results indicated that all of the composite laminates showed improved flexural strength, flexural modulus and glass transition temperature (T g = 296.8–299.6 °C). Improved interfacial adhesion was also studied via interlaminar shear strength (ILSS), impact strength test and monitoring the fracture surfaces. Stable dielectric constants, relative low dielectric loss and outstanding thermal stability (T 5% > 350 °C) were obtained for designed composite laminates. Image 1 • Phthalonitrile containing aromatic ether nitrile linkage (PEN-BAPh) was applied to modify glass fiber (GF) surface. • Copolymerization and molecular entanglement between PEN-BAPh and BA-ph/CE contributed to the interfacial adhesion. • Improved interfacial properties contributed to the increase of mechanical properties and T g (increased 16 °C). • Composites with improved interfacial properties were confirmed by flexural properties, DMA, SEM, ILSS and impact strength. • Decreasing of interfacial polarization and polar nitrile groups on GF surface leaded to improved dielectric properties. [ABSTRACT FROM AUTHOR]