Mechanical property enhancement of polypropylene and polyester/cotton composites using a plasma focus device

Abstract

An application of a UNU/ICTP Plasma Focus device for enhancing mechanical properties of a composite material is presented. Polypropylene (PP) nonwoven was surface-modified using a small 3 kJ plasma focus device operated with nitrogen or oxygen gases at a pressure of 1.5 mbar and 4 plasma shots. Water contact angle analysis revealed an increase in hydrophilicity of the surface of plasma-modified PP nonwoven due to the formation of hydrophilic groups on fabric suface confirmed by ATR-FTIR spectroscopy. The lamination of PP and polyester/cotton (PET/C) nonwovens at weight ratio of 80:20 was carried out by compression molding at 190 C for 12 minutes to obtain PP-PET/C composite material. It was found that impact strength of all surface-modified composites greatly increased when compared to those of unmodified composite and PP plastic while their tensile and flexural properties were comparable. It was also found that the type of gas and the treatment position of PP nonwoven in the chamber affected the mechanical properties of the composites. Overall results indicated that the composite prepared from PP nonwoven surface-modified by oxygen plasma had the best mechanical properties, when PP nonwoven was placed directly on top of the focusing position.