Prevention of Plasticizer Leaching From the Inner Surface of Narrow Polyvinyl Chloride Tube by DC Glow Discharge Plasma

The prevention of plasticizer leaching from the inner surface of a narrow polyvinyl chloride (PVC) tube by dc glow discharge plasma generated inside the tube was investigated. The inner surface of PVC tubes with a 4-mm inner diameter was treated by Ar plasma. The amount of plasticizer leached from the inner surface of the PVC tubes was measured by using a novel extraction device. The effects of the treatment time, working pressure, and applied voltage on the leaching of the plasticizer were investigated. All the plasma-treated samples showed a strong reduction of the leaching of the plasticizer with respect to the untreated one. The amount of plasticizer leached from the inner surface was reduced by a factor of three after the 30-min treatment at 40 Pa and 700 V. It was found that the applied voltage had little effect on the leaching of the plasticizer and that the amount of leached plasticizer decreased with increasing treatment time and decreasing working pressure.