Central Slit Tearing Behaviour of Thermoplastic Polyurethane-Coated High-Strength Fabrics

This research study reports the central slit tearing behaviour of three different varieties of industrial-grade high-strength fabrics, namely (a) Kevlar, (b) Nylon 6, 6, and (c) Polyester, all of these with a special thermoplastic polyurethane (TPU) coating. Tear resistance was evaluated and the tear behaviour was analyzed based on the critical load required for tear initiation and the energy required for tear propagation, by changing slit length and slit orientation. The study revealed that the coated Kevlar fabric has the highest specific tear energy among all the fabric materials, but the Polyester fabric displayed highest tear load and tear energy. This research work also showed that there are three major factors that determine the tear performance of envelope material, namely the yarn tenacity, yarn count, and yarn weaving density/yarn spacing, so the index based on the three factors was proposed for explaining the tearing behaviour. The materials for coating were selected for assessing the performance for inflatable application, so the degree of anisotropy was calculated for the tearing parameters; load, energy, and specific energy for all the coated fabrics. The breaking strengths of three varieties of basic and coated fabrics were evaluated for assessment of the influence of TPU coating.