A model for plasma modification of polypropylene using atmospheric pressure discharges

• Published in: Journal of physics. D, Applied physics Applied physics, 2003-03, Vol.36 (6), p.666-685
• Main Authors: Dorai, Rajesh, Kushner, Mark J
• Format: Article
• Language: English
• Subjects: Electric discharges; Exact sciences and technology; Glow; corona; Physics; Physics of gases, plasmas and electric discharges; Physics of plasmas and electric discharges; Plasma applications
• ISSN: 0022-3727; 1361-6463
• DOI: 10.1088/0022-3727/36/6/309

Atmospheric pressure plasmas are commonly used to improve the wetting and adhesion properties of polymers. In spite of their use, the mechanisms for achieving these properties are unclear. In this regard, we report on a computational investigation of the gas phase and surface kinetics during humid-air corona treatment of polypropylene (PP) and the resulting modification of its surface properties while varying energy deposition, relative humidity (RH), web speed, and gas temperature. Using results from a global plasma chemistry model validated against experiments, we found that increasing energy deposition increased the densities of alcohol, carbonyl, acid, and peroxy radicals on thePP surface. In doing so, significant amounts of gas phase O3 and NxOy are produced. Increasing the RH increased the production of peroxy and acid groups, while decreasing those of alcohol and carbonyl groups. Production of O3 decreased while that of HNO3 increased. Increasing the temperature decreased the concentrations of alcohol, carbonyl, and acid groups onPP while those of the peroxy radicals increased. For a given energy deposition, higher web speeds resulted in decreased concentrations of alcohols, peroxy radicals, carbonyl, and acid groups on PP.