Superhydrophilic functionalized graphene/fiberglass/epoxy laminates with high mechanical, impact and thermal performance and treated by plasma

This research aims to develop superhydrophilic fiberglass/epoxy nanocomposite (FGEC) laminates with high mechanical, thermal, and impact properties. In order to achieve this goal, functionalized graphene (FGA) was used as a nanofiller material to improve the mechanical, impact, and thermal behaviors of FGEC, while the plasma treatment helped to form the oxidized polar functional groups (C90 groups and C-O groups) on the fabricated FGEC laminates, thus modifying their hydrophilic behavior. The experiments were started with production of FGEC laminates by mixing FGA (0.05-0.4 wt%) with epoxy resin in presence of Acetone (to obtain better dispersion), followed by preparation of FGEC laminates using vacuum-assisted resin transfer and curing processes. Afterwards, the surfaces of the fabricated FGEC laminates were treated by air plasma at 13Pa and 30W for different treatment times in the range 5-30 min. Mechanical and impact properties of the untreated and treated laminates were investigated according to ASTM-D7025 and ISO 6603-2 standards, respectively. Also, thermal behavior of the laminates was investigated using a thermogravimetric analysis, while a high resolution camera was used to record and calculate a contact angle of the untreated and treated laminates. SEM and Optical Microscope was used to observe dispersion of FGA, microstructure, impact mechanism, and surface morphology of the fabricated FGEC matrix. Meanwhile, XPS was used to evaluate changes in the surface structures of the untreated and treated samples. The results showed that 0.35 wt% of FGA and 15-min exposure to plasma treatment were enough to improve tensile strength and impact energy of the laminates by 18% and 70%, respectively, and to decrease the water contact angle from 67 degrees to 14 degrees.