Atmospheric pressure plasma jet treatment of wheat straw for improved compatibility in epoxy composites

Abstract

The aim of this study was to investigate the effects of an atmospheric-pressure gas plasma jet treatment on the interior and exterior surface characteristics of wheat straw and on the mechanical properties of epoxy composites reinforced with wheat straw. Dry air was used as the process gas in the plasma system. A distance between the nozzle and the substrate surface (DNSS) of 35 mm was determined as the most effective parameter enabling remarkable decreases in the g p S (surface energy) values of both the interior and exterior surfaces of virgin wheat straw. Increased intensities of the peaks related to carbon-rich species and 11% to 43% decreases in the oxygen/carbon ratios on the surfaces confirmed the more hydrophobic nature of the plasma-treated wheat straw. A further increase in the DNSS decreased the effectiveness of the plasma treatment, while a decrease in the DNSS caused an inverse effect on the g p S value, probably due to the etching effect of the plasma action, which was supported by the atomic force microscopy analysis. The overall results indicated that the increased hydrophobicity and valley-like occurrences without sharp pits created by the plasma action improved the compatibility of the wheat straw with the epoxy matrix, which contributed to superior mechanical properties of the composites.

Simple approach for the plasma treatment of polymeric membranes and investigation of the aging effect

“…4,12,13 These changes include breaking covalent bonds, adsorption of new functional groups on the surface, polymer crosslinking and polymerization. 12,14,15 Regarding the use of NTP in polymeric membranes, the plasma's ability to modify the physical and chemical properties of the membrane surface without affecting the characteristics of the base material is advantageous in several cases, since this type of treatment does not change the volume polymer and has little effect on its crystallinity. The changes frequently reported in the literature are related to the size and distribution of pores, roughness and morphology.…”

“…Once the plasma, an ionized gas consisting of excited atomic, molecular, ionic and free‐radical species, interacts with the polymer surface, it transfers the energy through elastic and inelastic collisions that induce significant changes on the surface 4,12,13 . These changes include breaking covalent bonds, adsorption of new functional groups on the surface, polymer crosslinking and polymerization 12,14,15 …”

Fabrication of Water‐Soluble Polythiophene/Poly (sulfonic acid diphenyl aniline)/Polyethylene Oxide Electrospun Nanofibers and Their Antioxidant Activities

“…spectroscopy, XRD, X-Ray Photoelectron Spectrometer (XPS) and dynamic light scaterring (DLS). [13] In particular, it was observed that PTh/ PSDA composites were successfully obtained by XPS spectra of N 1s and S 2p core levels. In the light of these results, it is focused on the analysis of PTh/PSDA/PEO electrospun nanofibers in this study.…”

“…The characterization of PTh/PSDA composites was performed in our previous study with FT‐IR, UV‐Vis. spectroscopy, XRD, X‐Ray Photoelectron Spectrometer (XPS) and dynamic light scaterring (DLS) [13] . In particular, it was observed that PTh/PSDA composites were successfully obtained by XPS spectra of N 1s and S 2p core levels.…”

Functionalized Multi-Walled Carbon Nanotubes and Micro Cellulose Reinforced Poly (Vinyl Alcohol) Hybrid Composite Films: Characterization and Reprocessing Performance

“…The contact angle measurements were performed at 5 random locations on the composite film surfaces at room temperature (23 ± 2 ºC) and were expressed as the mean of these measurements and the standard deviation. The mean contact angle values were used to calculate the components of surface free energy (SFE) according to the Owens-Wendt method (1969) described by Huner, Gulec, Damar Huner [14] in detail.…”