Enhancing the Interfacial Strength of Carbon Fiber/Poly(ether ether ketone) Hybrid Composites by Plasma Treatments

Abstract

As a promising alternative to traditional prepreg, carbon fiber/poly(ether ether ketone) (CF/PEEK) hybrid composites have attracted wide public interest for their flexibility and conformability. However, modification methods focused on the hybrid premix have not been previously studied. In the present work, the interfacial strength of the hybrid composite was improved by treating the carbon and PEEK fibers together in a radiofrequency (RF) plasma containing one of the following gases to achieve surface activation: air, Ar, or Ar–air. After plasma treatment, the increased roughness of CF and the grafted chemical groups of CFs and PEEK fibers were propitious to the mechanical interlocking and interfacial strength. Significant interfacial shear strength (IFSS) enhancement was achieved after Ar 1 min, air 1 min plasma treatment. This study offers an alternative method for improving the interfacial properties of CF/PEEK composites by focusing on the boundary layer and modifying and controlling the fiber–matrix interface.

Advance in Using Plasma Technology for Modification or Fabrication of Carbon‐Based Materials and Their Applications in Environmental, Material, and Energy Fields

“…Lu et al. [ 121 ] used a different plasma treatment than Brès et al. to improve the interfacial strength of carbon fiber/PEEK composites in a RF plasma by alternating 1 min of Ar atmosphere followed by 1 min of air atmosphere.…”

Influence of argon plasma treatment on carbon fibre reinforced high performance thermoplastic composite

“…The tensile stress concentrations in PAEK/CF composite lead to initial crack propagation in matrix material. 27 The fibre–matrix failure is observed as well making it an adhesive mode of failure.…”

Plasma and Polymers: Recent Progress and Trends

“…Lu et al demonstrated the enhancement of the interfacial strength of carbon fiber/poly(ether ether ketone) hybrid composites by plasma treatment [ 30 ]. Fiber-reinforced thermoplastic composites such as hybrid composites based on carbon fibers and poly(ether ether ketone) (CF/PEEK) are considered as viable options to replace conventional prepreg systems for applications across automotive, aerospace, and other industries.…”

“…The energy for ionization is delivered into the chamber using a variety of means, with a radio frequency source of 13.56 MHz inductively coupled to the reactor being a common option ( Figure 1 b). In the example presented in Figure 1 c, the reactor operated at the power of 18 W and pressure of about 1 Torr, with gas supply to the reactor chamber at the rate of about 8 standard cubic centimeters per minute, producing excited plasma free radicals that are sufficiently energetic to cleave bonds present in organic molecules [ 30 ]. Radicals (i.e., molecular fragments, atoms, and ions) that are generated at the result of these bond breaks can engage in subsequent reactions with molecules in the gas and on the surfaces of the solid, producing volatile species.…”