Study On The Form Of APGD In Air And The Surface Treatment Of Polymers By DBD

Because its simpleness for operation and convenience for applications, discharges at atmospheric pressure are always the focus of scientific researches. Usually, atmospheric pressure discharges have the forms of corona, spark, arc and streamer. Corona discharge can be controlled easily, however its discharge intensity is low. The controllability of others is bad and the discharges are not uniform spatially, the energy density is high and the discharge plasma temperature is high too, so the application has been restricted greatly. So it is a very significative research work to produce and control an atmospheric pressure glow discharge (APGD). The research can not only extend the physical insightion about gas discharge but can also extend the application field of APGD.The main works of the paper is to investigate APGD in air by enhanced corona discharge with a fast airflow blowing the discharge space, to learn the mechanism of controlling the APGD, the transition of the discharge modes and the effect of the fast airflow on the stabilization of the APGD. With water as an electrode and DC discharge in ambient air, glow discharge which with conical and hollow profile had been produced. The effect of discharge parameters on the discharge stabilization had been studied and the vibrational and rotational temperature of N₂ were calculated by the measurements of the emission spectra. By nanosecond pulse high voltage, a kind of glow-like discharge in air had been formed when insulating dielectric had been added at the discharge space at lognitudinal direction. Modified by dielectric barrier discharge (DBD), the surface energy and surface adhesive strength of the surface of polyethylene (PET) had been increased. To modify linen surface to change the morphology and surface chemical structure by DBD in air, the grafting degree of acrylic acid onto the linen surface had been increased.The study results are as follows: Realized stable APGD in air by enhanced negative corona discharge with an airflow blowing the discharge space, and discussed the effect of the gas flow velocity and the discharge gap on the discharge stabilization and the transition of the corona-to-glow and glow-to-spark discharges and the stabilization mechanism of the APGD. Investigated and analyzed the mechanism for the forming of the conical and hollow discharge mode and the changes of the vibrational and rotational temperature of N₂ with the discharge parameters. Investigated the effect of the dielectric on the form of the diffused high voltage nanosecond pulse glow discharge with large volume in air and discussed the physical mechanism. The surface energy of the PET treated by DBD is increased greatly and the reasons attribute to the changes of the surface morphology and the chemical structure of the treated PET surface. The surface morphology and the chemical structure of the DBD treated linen have been greatly changed. Based on the changes, the grafting degree of acrylic acid onto the linen surface has been increased about 30%.