Properties Of Dielectric Barrier Discharge Research Articles

The effect of polysaccharide type on dielectric barrier discharge (DBD) plasma glycosylation of sodium caseinate-part I: Physicochemical, structural and thermal properties

This study aimed to investigate the impact of polysaccharide type on the physicochemical, structural, and thermal properties of dielectric barrier discharge (DBD) plasma glycosylated sodium caseinate (SC). The polysaccharides Quince seed gum (QSG), carboxymethyl cellulose (CMC), and maltodextrin (MD) were mixed with SC and treated with DBD plasma at 18 kV for 10 min. The grafting degree, electrophoresis pattern, FTIR, XRD, carbonyl, sulfhydryl, and di-tyrosine content, FE-SEM, color, and thermal properties of SC and its polysaccharide mixtures before and after plasma treatment were analyzed. Results showed that the SC-QSG conjugate had the highest glycation degree and color change after plasma treatment. The SC-CMC and SC-QSG conjugates exhibited disappearance of distinct SC bands in electrophoresis pattern compared to SC. Also, significant changes in functional group and crystallinity were occurred in SC-CMC conjugate. Plasma treatment caused oxidation of SC, but the presence of polysaccharides offered protection against oxidation. The microstructure of SC was altered by mixing with polysaccharides and exposure to plasma. Also, the mixtures indicated higher thermal stability after plasma treatment. Results confirmed that the generation of protein-polysaccharide conjugates through DBD plasma technique was depended on with SC-MD conjugate unable to form through this method.

Conjugation of soy protein isolate with carboxymethyl cellulose through dielectric barrier discharge (DBD) plasma

The present study aimed to evaluate the physicochemical properties of dielectric barrier discharge (DBD) plasma grafted carboxymethyl cellulose (CMC) and soy protein isolate (SPI). Therefore, the mixture of SPI and CMC was treated at 16, 18 and 20 kV for 5, 10 and 15 min with DBD plasma. The results of FTIR, XRD, FESEM and SDS-PAGE confirmed the SPI-CMC conjugate formation after plasma treatment, and a glycation degree of about 21 % was obtained after 15 min treatment at 18 kV. Significantly higher levels of emulsifying activity and stability, as well as solubility, were obtained for the conjugates, as compared with the SPI-CMC mixture. Also, the smaller droplet sizes were observed in emulsions obtained from conjugate produced at 18 kV for 5 min, which had the most stability after 14 days of storage at 4 °C. Eventually, it was detected that DBD plasma could graft SPI and CMC in a short time.

Change of fundamental properties of dielectric barrier discharge due to the alumina-based barrier layer composition

Dielectric barrier discharges (DBDs) are widely used in various branches of industry. One of the main characteristics of the DBD is the material of the dielectric barrier–in present days, alumina ceramic is the most frequently used material. Basic plasma parameters are affected by the chemical composition of these dielectric barriers, and also by their surface properties. These surface properties are even more dominant in a coplanar arrangement of the DBD (CDBD). Due to this fact, we studied the effect of adding several types of oxides into a pure alumina ceramic (Al2O3). The aim was to determine the impact of the chemical composition of the dielectric barrier and to see complex changes in respect to the surface morphology of the CDBD barrier layer. In the presented study, we focused mainly on determining ignition voltage and quenching voltage. With the help of atomic force microscopy (AFM) images, the results of these measurements were put into correlation with the surface structure of the DBD barrier.

Influence of Oxygen Content on Argon/Oxygen Dielectric Barrier Discharge Plasma Treatment of Polyethylene Terephthalate Film

In this paper, the dielectric barrier discharge (DBD) is generated in argon/oxygen gas mixtures with various of oxygen content and is employed to treat Polyethylene terephthalate (PET) surface. The effects of oxygen content in the argon/oxygen feeding gas on the properties of DBD and surface properties of PET films are investigated by means of electrical measurements, optical diagnostics, and the surface characteristics analysis. It is shown that after all DBD plasma treatments, the water contact angles on the surface decrease and oxygen containing polar groups on the surface increase. The improvement of hydrophobicity on PET surface is found to be significantly influenced by the addition oxygen content. Adding a small content of oxygen to feeding gas can result in a more efficient treatment, while the discharge induces less effective treatments at relative large oxygen content. There exists an optimum oxygen content for the hydrophilicity improvement on the PET surface, and the lowest contact angle and the highest incorporation of oxygen-containing groups are obtained after argon/oxygen DBD treatment with 0.3% addition of oxygen, which is in agree with the optimum oxygen content for atomic oxygen generation in the discharge regime. The results can be explained by the influences of oxygen addition on the generation and quenching mechanisms of corresponding atomic oxygen radicals in the DBD plasma, which suggests that the efficiency of DBD plasma surface modification can be increased and controlled by a way of adding an appropriate ratio of oxygen into the carrier gas.

Dyeing properties of the atmospheric pressure plasma-treated polypropylene fabric subjected to butane tetra carboxylic acid

In this paper, dyeing properties of dielectric barrier discharge (DBD)-treated polypropylene (PP) fabrics padded with butanetetracarboxylic acid (BTCA) were evaluated. We have used a DBD, working in an atmospheric pressure air. More polar functional groups were presented on the substrate surface after DBD pretreatment. After DBD treatment, BTCA was applied to PP fabrics by pad–dry–cure system. Both treated and untreated fabrics were dyed using acidic and basic dyestuffs. The surface morphology was investigated by scanning electron microscopy images. Treated samples were also characterized by means of Fourier transform infrared spectroscopy. The wettability of the samples was evaluated by water drop test according to AATCC 79-2000 standard. Color intensities of the dyed fabrics with both acidic and basic dyestuffs were measured using a UV–vis–NIR reflective spectrophotometer, over the range of 400–700 nm. The results showed that, by treating the fabric, the relative color strength (K/S values) of the dyed fabrics has been increased. From the results of tensile strength test, both weft and warp directions, no significant difference was obtained within the accuracies of the measurement. Also, the fastnesses properties of samples were measured.

Atmospheric Dielectric Barrier Discharge Treatments of Polyethylene, Polypropylene, Polystyrene and Poly(ethylene terephthalate) for Enhanced Adhesion

A critical review of published studies investigating the dielectric barrier discharge (DBD) treatment of four polymers widely employed in the packaging sector, namely: polyethylene (PE), polypropylene (PP), poly(ethylene terephthalate) (PET) and polystyrene (PS) is presented. The DBD treatment process operates at atmospheric pressure in air, and thereby offers a low cost method of enhancing the surface properties of polymers. The method is suitable for high volume in-line applications such as packaging. It has been reported that treatment doses as low as 0.01 J/cm2 result in significant increases in surface energy and wettability, leading to enhanced adhesive bonding and printing performance. Two critical issues limit the improvements obtained via the DBD processing of polymers. Firstly, DBD processing can produce a poorly adhered surface layer of low molecular weight material, which can then interfere with bonding and printing processes. Secondly, the properties of DBD treated polymers tend to revert towards that of the untreated state during storage.

Properties of the dielectric barrier discharge in mixtures of methane with helium

The influence of the chemical composition of the feeding gas mixtures CH4-He on the physical properties of dielectric barrier discharge was investigated experimentally as well as theoretically. Certain changes in the shape of charge-voltage characteristics (Lissajous figures) were observed when the content of He was varied within the range 0–90%. An increase of the He concentration was found to cause monotonous but not linear decrease of the ignition voltage as well as of the burning voltage of the discharge. Measurements of the burning voltage were used to estimate the characteristic energy of electrons in the mixtures under consideration. These estimates were compared with experimentally determined values of the energy consumption for the synthesis of C2H2, C2H4 and C2H6, respectively. It was demonstrated that the observed dependencies of the energy consumption upon He content can be explained taking into consideration the influence of the chemical composition of feeding gas mixture upon the characteristic energy of electrons in the dielectric barrier discharge.