Untersuchungen zur Modifizierung von Folien und Nadelfilzen aus Polyethylenterephthalat mit Fluorcarbonplasmen

摘要

Needle felts from PET are commonly used for textile filters because of their low costs and good mechanic properties. The filter surface is provided with fluorocarbon compounds by a wet chemical process as best available technology for achieving a low surface energy and an easy dedustion. Although a high water and oil repellency grade is achievable by this standard procedure, needlefelts provided with fluorocarbons are not protected against alkaline degradation particular in wet and hot environment. In this work investigations on a plasma-based modification of PET foils and needlefelts will be presented. C2F6 and mixtures of C2F6 with C2H4 were used as process gases. Wetting properties were determined by contact angle measurements and drop penetration tests. The plasma induced chemical properties of treated surfaces were investigated by x-ray photoelectron spectroscopy. For determination of topografic modification scanning electron microscopy, white light interferometry and atomic force microscopy were used and the results were compared to those of untreated material. The change of residual gas composition against time was investigated by mass spetrometry. The barrier properties of modified needle felts were studied by treatment in aqueous methanolic caustic soda solution. Both treatments in C2F6- and C2F6/C2H4-Plasma respectively yielded highly hydrophobic surfaces. The degree of hydrophobicity and barrier properties depended on process parameters.