Effects of corona discharge and UV treatment on the properties of jute-fibre epoxy composites

In this paper, tossa jute fibres were corona discharge and ultraviolet (UV) treated to improve the mechanical properties of natural-fibre/epoxy composites. Corona-treated fibres exhibited significantly higher polar components of the free surface energy with increasing treatment energy output. Owing to the difficulties in effective treatment of three-dimensional objects with corona discharge, the increase of polarity of treated yarns is relatively small, in comparison to the results achieved with single fibres. Furthermore a decrease in the yam tenacity was observed with increasing corona energy level. The UV treatment of the single fibres and yarns led to significantly higher gains in polarity in comparison with those observed in relation to corona-treated materials. Increasing treatment time at a constant bulb-sample distance or alternatively decreasing the distance significantly increased the polarity and decreased yam tenacity. To improve the overall mechanical properties of jute/epoxy composites, an appropriate balance needs to be achieved between increased polarity of fibre surface and the decrease of fibre strength subsequent to excessive surface oxidation by corona discharge or UV radiation. At the optimum treatment conditions an increase in the composite flexural strength of about 30% was achieved. (C) 2000 Elsevier Science Ltd. All rights reserved.