Cold nitrogen plasma treated glass fiber warp knitted structural composites: mechanical properties and response surface analysis

Abstract

This study reveals the characterization and mechanical properties of glass fiber warp knit structural fabric/vinyl ester resin composites treated by cold nitrogen glow discharge plasma. The effects of nitrogen plasma treating parameters (including power, flow rate, and time) on tensile and bending properties of glass fiber warp knit structural composites were investigated. It was shown that nitrogen plasma treatment enhanced the tensile and bending property of the glass fiber warp knit structural composites. SEM, FTIR and AFM characterized etching existing on the surface, C-N and N-H groups were introduced, and varying degrees of roughness. The response surface analysis represented that the nitrogen plasma treated glass fiber warp knit structural composites obtained optimized bending properties with the power ranging from 130 W to 160 W, the flow rate ranging from 8sccm to 9sccm, and the time ranging from 100s to 110s.

Shear Strength Range of GF/Polyester Composites Controlled by Plasma Nanotechnology

“…The mean free path of plasma species increases with decreasing pressure [ 26 ] and only in the case of low-pressure plasma the plasma species can penetrate the bundle or fabrics, but their activity is affected by the shielding effect of surrounding fibers. Plasma species cannot penetrate effectively into compact fabrics [ 6 , 7 , 8 , 10 , 15 ], and therefore, plasma treatment and plasma coating are effective only to a certain depth below the outer surface of the fabrics. The deposition time (68–1020 s) was calculated [ 22 ] based on knowledge of the number of filaments in the bundle (1600), the shielding factor (0.9), and the deposition rate (13–171 nm min −1 ) for a given power and oxygen fraction to cover even the central filament in a bundle with a nanocoating of at least 20 nm thickness.…”

“…Plasma processing can be used for both fibers and nanofibers [ 4 ]. Many studies using nonthermal plasma, characterized by low kinetic energy of neutral and ionic species (≈300 K), are devoted to carbon fibers [ 5 , 6 ], glass [ 7 , 8 ], aramid [ 9 ], polyethylene [ 10 ] or natural fibers [ 11 , 12 , 13 ]. In the case of a thermoplastic matrix, the fibers are plasma treated in argon, oxygen, nitrogen, ammonia or in their mixtures, and in the air in order to ablate or etch the smooth surface of the fibers and thereby increase the roughness of the surface, or to oxidize (air, oxygen plasma) the surface of the fiber to improve its wettability, both of which lead to improved interfacial adhesion [ 14 ].…”