Optical Study Of OH Radicals And Hydrophilicity Treatment Of Polypropylene In Atmospheric Pressure

1.In this study, the spatial distributions of the emission intensity of OH (A^Σ→X²Î , 0-0) and N₂⁺ (B²Î£_u⁺→X²Î£_g⁺, 0-0, 391.4 nm) are investigated in the atmospheric pressure pulsed streamer discharge of H₂O and N₂ mixture in a needle-plate reactor configuration. The effects of pulsed peak voltage, pulsed repetition rate, input power, and O₂ flow rate on the spatial distributions of the emission intensity of OH (A²Î£â†’X²Î , 0-0), N₂⁺ (B²Î£_u⁺→X^Σ+g⁺, 0-0, 391.4 nm), and the vibrational temperature of N₂ (C) in the lengthwise direction from needle to plate are attained. It is found that the emission intensities of OH (A²Î£â†’X²Î , 0-0) and N₂⁺ (B²Î£_u⁺→X²Î£_g⁺, 0-0, 391.4 nm) rise with increasing the pulsed peak voltage, the pulsed repetition rate and the input power, and decrease with increasing O₂ flow rate. In the direction from needle to plate, the emission intensity of OH (A²Î£â†’X²Î , 0-0) decreases firstly, and rises near the plate electrode, while the emission intensity of (N₂⁺(B²Î£_u⁺→X²Î£_g⁺, 0-0, 391.4 nm) is nearly constant along the needle to plate direction firstly, and rises sharply near the plate electrode. The vibrational temperature of N₂ (C) is almost independent of the pulsed peak voltage and the pulsed repetition rate, but rises with increasing the O₂ flow rate and keeps nearly constant in the lengthwise direction.2. The hydrophilicity of polypropylene (PP) has been investigated in atomsperic pressure glow discharge (He, N₂, N₂+CO₂ ) and dielectric barrier discharge (Air, N₂+He+CO₂) by using the character of water contact angle. The emission intensities of OH (A²Î£â†’X²Î , 0-0) and O⁺ have also been abtained. In air DBD, when the time of treatment is 180 s, the water contact angle of PP can be decreased from 144.7°to 115.5°. In N₂ APGD, when the time of treatment is 90 s, the water contact angle can be decreased from 144.7°to 89°. In N₂+CO₂+He DBD, when the time of treatment is 600 s, the water contact angle can be decreased from 144.7°to 124.15°. In N₂+CO₂ APGD, when the time of treatment is 180 s, the water contact angle can be decreased from 144.7°to 85.38°. In He APGD, when the time of treatment is 180 s, the water contact angle can be decreased from 144.7°to 121.6°. The emission intensity of OH (A²Î£â†’X²Î , 0-0) is stronger with PP than without it, which is seen from the spectra obtained in N₂ and N₂+CO₂ APGD, separately. The emission intensity of O⁺ (2s²2p²(³P)3p→2s²2p² (³P)3d ) and 0⁺ (2s²2p³â†’2s²2p²(³P)6s) have also been obtained in N₂ APGD.