OZONE EFFECT ON THE PROPERTIES OF ARAMID FABRIC Yan Wang, Jakub Wiener, Jiri Militky, Rajesh Mishra, Guocheng Zhu Department of Textile Material Engineering, Technical University of Liberec, Liberec, Czech Republic, Studentská 1402/2, Tel: +420 774846310, E-mail: zgc100100@hotmail.com 1 Introduction Aramid fbers have found applications in protective products, which mostly are ballistic proof, freman clothes, and reinforcement for high-performance composites due to its high specifc modulus and strength with excellent thermal stability, high melting point, excellent fame resistance with low levels of smoke generation, chemical inertness, and comfort [1, 2]. However, the utilization of aramid fber as reinforcement has been limited by the poor fber–matrix interfacial adhesion due to the fber’s smooth surface and its inert chemical structure, which provides very low bonding strength with most of the commercially available resins used in composites [3-5]. In order to solve the above issue, a number of researches have been focusing on the improvement of fber’s surface properties by various surface treatment techniques, such as chemical treatment (using coupling agents and chemically grafting methods), plasma treatment, corona discharge, irradiation with gamma-rays, ozonation, etc. [6-10]. Among these techniques, ozonation has the advantage of uniformly introducing peroxides on the polymer surfaces even with complex shapes. The generated peroxides are capable of initiating radical graft polymerization of hydrophilic vinyl monomers onto the polymers, resulting in hydrophilic surfaces [11]. The ozonation process removes impurities from the surface and introduces oxygen-containing functional groups, which aid in adhesion to the matrix. Moreover, ozonation is an easy-to-handle and inexpensive method [12]. Most researchers [5, 8, 13] investigated the surface property by evaluating the surface chemical functional groups or roughness. However, the biggest advantage of aramid fber as a high-performance fber is its high strength. Therefore, it is also important to evaluate the strength of aramid fber before and after surface modifcation. In this study, aramid fbers were treated by ozone at different time durations, and its fabrics were evaluated in terms of surface morphology, wicking property, tensile property, and ball-bursting property. 2 Materials and Methods 2.1. Materials and preparation 2.1.1 Aramid fabrics and chemicals Commercial grade 5/3 warp-face satin aramid fabrics with an areal density of 340g/m 2 were used. These fabrics were made of 2000D untwisted single yarns in warp and weft, having 68×68 ends/10 cm, and 0.7 mm in thickness. Fabrics were cut into the same size and dipped in laboratory grade acetone for two hours, and then dried over 10 minutes in ventilator. 2.1.2 Apparatus and procedure of ozone treatment Ozone treatment of the aramid fabrics was carried out in gaseous phase. The apparatus and the procedure of ozone treatment are described in the following. The ozone treatment system is described diagrammatically in Figure 1. Ozone was generated from air. Before air entered the ozone generator where ozone generated, it went through an exsiccator. Then, the generated ozone was sent to the reactor Abstract: The limitation of aramid fber is its surface property, which results in its very poor interfacial adhesion to most of commercial resins. In order to improve the surface property of the aramid fber, ozone treatment was carried out in this work. The aramid fabrics were evaluated in terms of surface morphology, wicking effect, tensile property, and ball bursting test. The results showed that the surface morphology of aramid fabrics did not undergo an obvious change; the wicking effect increased slightly with an increase in ozone treatment time; the tenacity and elongation of aramid fbers and fabrics did not signifcant change after ozone treatment, but the tenacity and elongation of aramid yarns showed signifcant improvement after ozone treatment, and increased with the increase of ozone treatment time; the ball bursting load and penetration displacement had a slight increase as well after ozone treatment. Therefore, ozone treatment could be one method to improve the surface property of the aramid fber. Keywords: Ozone treatment; Aramid fabric; Wicking effect; Mechanical properties http://www.autexrj.com AUTEX Research Journal, Vol. 17, No 2, June 2017, DOI: 10.1515/aut-2016-0027 © AUTEX 164