Comparison of the Influence of Two Types of Plasma Treatment of Short Carbon Fibers on Mechanical Properties of Epoxy Composites Filled with These Treated Fibers

• Published in: Materials Vol. 15; no. 18; p. 6290
• Main Authors: Novotná, Jana, Kormunda, Martin, Perner, Jakub, Tomková, Blanka
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 09.09.2022; MDPI
• Subjects: Analysis; Carbon fiber reinforced plastics; Carbon fibers; Composite materials; Contact angle; Covalent bonds; Electron microscopy; Epoxy matrix composites; Epoxy resins; fiber-reinforced epoxy composites (FRE); Fluidized bed reactors; Impact analysis; Impact strength; Low concentrations; Mechanical properties; Microwave communications; Modulus of elasticity; Photoelectrons; Plasma physics; plasma treatment; Radio frequency; Radio frequency plasma; recycled carbon fiber (RCF); Scanning electron microscopy; Spectrum analysis; Surface treatment; Wettability; X-ray spectroscopy; Czech Republic; Germany; United Kingdom > UK
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma15186290

The interfacial interface between fibers and matrix plays a key role for epoxy matrix composites and short recycled randomly arranged fibers. This study used short recycled carbon fiber (RCF) as a filler. Plasma treatment was used for carbon fiber surface treatment. This treatment was performed using radio (RF) and microwave (MW) frequencies at the same pressure and atmosphere. Appropriate chemical modification of the fiber surfaces helps to improve the wettability of the carbon fibers and, at the same time, allows the necessary covalent bonds to form between fibers and the epoxy matrix. The effect of the plasma treatment was analyzed and confirmed by X-ray photoelectron spectroscopy, Raman microscopy, scanning electron microscopy, transmission electron microscopy and wettability measurements. Composite samples filled with recycled carbon fibers with low concentrations (1 wt%, 2.5 wt% and 5 wt%) and high concentrations (20 wt% and 30 wt%) were made from selected treated fibers. The mechanical properties (impact toughness, 3PB) were analyzed on these samples. It was found that the modulus of elasticity and bending stress increase with the increasing content of recycled carbon fibers. A more significant change in impact strength occurred in samples with low concentration.