Papers by Keyword: Plasma Modification

Abstract: The paper presents the results of a study of the effect of radio-frequency (RF) plasma modification on the adhesion of ultra-high molecular weight polyethylene (UHMWPE) and polypropylene (PP) fibers to epoxy-diane (ED), epoxy-urethane (EU) and polyester (PES) binder. To assess the adhesive properties, the wet-pull-out method was used, which makes it possible to determine the normalized value of the destructive load of the microcomposite by the force of pulling out the fiber from the polymer matrix.

Abstract: A method to modify polymer surface properties responsible for wettability and surface free energy has been proposed. Plasma-based chemical modification of polymer surfaces with gas discharges allows adjusting their functional properties. The main changes in polymer wettability occur within short-term exposure of polymer surfaces to pulsed plasma at atmospheric pressure (1-60 sec). The contact angle values for the modified polymers depend on the gaseous medium and the conditions of the plasma processing. Changing the power, the pulse repetition rate and plasma exposure time allow controlling the free surface energy, making the surface either hydrophobic or hydrophilic.

Abstract: Polymer matrices add carbon nanotubes have significantly improved mechanical and electrical properties at very low carbon nanotube loading. That mechanical and electrical properties of aligned composites are better than those of random ones has been demonstrated in past studies. The non-conductive barriers of surface contaminants and weakly bound polymer layers will deform on the surface of composite resulted from the effects of micro gravity and oxidization. Addition of the adaptive plasma modification makes improvement in the surface properties of the composites is necessary. In this study, we actively align and network multiwall carbon nanotubes (MWCNTs) in a polymer matrix, then adopt O₂/CF₄ radio frequency (RF) plasma to modify the surface of polymeric composite. MWCNTs were aligned using an AC electric field to elicit dipolar interactions among the nanotubes in a viscous matrix following immobilization by curing under continuous application of an anisotropic electric field, and the barriers of surface contaminants and weakly bound polymer layers can be reduced to the smallest degree or eliminated by RF plasma modification. Consequently, the MWCNTs polymeric composite amplify the flexural modulus, wear resistance, and electrical conductivity in the reality.

Abstract: A coating was made by electrostatic spraying of epoxy resin / TiO₂ particles for the purpose of suppressing audible noise caused by corona discharge on high-voltage transmission lines. Wetting property of the coating was improved by oxygen plasma treatment. It was found that the coating became more wettable as the increase of TiO₂ content during electrostatic spraying process. With respect to the coating for suppression of audible noise from transmission lines, the optimal mass ratio of TiO₂ particles (diameter:5-10μm ) to epoxy resin was 30%, and the contact angle was 73°on the epoxy / TiO₂ coating surface which could be reduced to less than 5°after oxygen plasma treatment for 20s.

Abstract: In this paper, the surface of non-woven polypropylene secondary battery separator was modified by Hollow Cathode Remote Plasma. The effects of treating parameters on separator’s properties were studied. The IR and SEM were used to analyze the chemical composition and the surface morphology. Using electrical chemical property measurement, the electrical chemical property was measured and analyzed. The results show that the hydrophilic group was imported on the surface of polypropylene after Hollow Cathode Remote Plasma modification, so that the wettability of the non-woven polypropylene secondary battery separator and the property of secondary battery were greatly improved.

Abstract: The PANI-CNTs composite material was synthesized through emulsion polymerization, and then the composite had been modified by the oxygen plasma to get the electrode material for super-capacitor. The influences of the modification time on the electrode material surface property and the electrochemical performance were investigated. And based on the analysis of the scanning electron microscope(SEM) and fourier transform-infrared spectroscopy (FT-IR), the results revealed that the particle size of the composite material become smaller, more micro pores were etched by the oxygen plasma and some active functional groups were introduced. The electrochemical tests demonstrated that the PANI/CNTs composite material modified by the oxygen material after 10 min has perfect capacitive properties, the specific capacitance is 287.8 Fg-1, and the ESR is 0.320 Ω.

Abstract: The interaction of cells with polymers is important for their potential applications in medicine and various areas of biotechnology. Their physico-chemical surface properties strongly influence the cell morphology, adhesion and growth. Physical and chemical properties of pristine and modified polyethylene (PE) films were studied. PE was modified by Ar plasma (0–400 s, 2.0 W) and than grafted with amino acid (glycine). Structural and morphological changes of polymer were studied by goniometry and Rutherford back-scattering (RBS). The interaction of these samples with vascular smooth muscle cell (VSMC) from the rat aorta was studied. Number and morphology of the adhered and proliferated cell on the pristine and modified PE was studied in vitro method. It was found that wetting angle of the modified films decreased with exposure time. Experiments in vitro indicated that the adhesion and proliferation of VSMC is increasing function of degradation time and glycine grafting.