Structure and Deformation Behavior of Polyphenylene Sulfide-Based Laminates Reinforced with Carbon Fiber Tapes Activated by Cold Atmospheric Plasma

Abstract

Low-temperature plasma treatment with atmospheric discharge with runaway electrons (DRE) was shown to be an efficient way to activate carbon fiber’s (CF) surface and subsequently increase its interlayer shear strength (ILSS) values. It was demonstrated that an acceptable ILSS level was achieved after a DRE plasma treatment duration of 15 min. The treatment of CFs resulted in their surface roughness being increased and their functional groups grafting. The XPS data showed a change in the chemical composition and the formation of reactive oxygen-containing groups. SEM examinations of the PPS/CF laminates clearly demonstrated a difference in adhesive interaction at the PPS/CF interface. After the DRE plasma treatment, CFs were better wetted with the polymer, and the samples cohesively fractured predominantly through the matrix, but not along the PPS/CF interface, as was observed for the sample reinforced with the untreated CFs. The computer simulation results showed that raising the adhesive strength enhanced the ILSS values, but reduced resistance to transverse cracking under the loading pin. In general, higher flexural strength of the PPS/CF laminates was achieved with a greater interlayer adhesion level, which was consistent with the obtained experimental data.

Surface Modification of Polymers by Plasma Treatment for Appropriate Adhesion of Coatings

“…The improved adhesion was explained by the chemical interaction between the adhesive and oxygen-containing functional groups on the polymer surface. The large concentration of oxygen and no nitrogen on the polymer surface after the plasma treatment indicates that the effluent ambient air caused quenching of the nitrogen molecular metastables, similar to the experimental setup used by Kosmachev et al [20], who also found a minimal concentration of Jung et al [22] treated a carbon fiber-reinforced thermoplastic polymer with atmospheric pressure plasma sustained in nitrogen by a dielectric barrier discharge operating at the frequency of 13.56 MHz and voltage of 13.5 kV. The treatment time was 2 min.…”

“…The same team also probed the adhesion between PEEK polymers and carbon fiber tapes. In the paper [21], the authors studied the mechanical properties of laminates using Kosmachev et al [20] studied the influence of plasma treatment on the interlayer sheer strength of laminates consisting of carbon fiber tapes and interlayers of polyphenylene sulfide (PPS), which served as a thermoplastic binder. The surface of the carbon fiber tapes was treated with pulsed discharges sustained in the air.…”

“…In the paper [21], the authors studied the mechanical properties of laminates using 0.25 mm thick PEEK foils as thermoplastic binders. The discharge parameters were the same as in [20], and so were the selected treatment times. SEM micrographs showed the localized etching of carbon fibers after prolonged plasma treatments.…”

“…The appearance of the fragments was not reported in the articles analyzed in Section 3 of this paper, so it is impossible to quantify their influence on the adhesion properties. The ratio between adhesion after and before the plasma treatment (adhesion increase) versus the treatment time [13,[19][20][21][22][23]27,30,33,34,39].…”

“…Figure 10. The ratio between adhesion after and before the plasma treatment (adhesion increase) versus the treatment time [13,[19][20][21][22][23]27,30,33,34,39]. Figure 10.…”