Auxetic Behavior of Needle-Punched Nonwoven Structure

<p>This study explores how needle-punched nonwoven polyester fabrics can show auxetic behavior, <br>meaning they expand sideways when stretched instead of contracting like regular materials. The fabrics <br>were made using fibers of two different thicknesses (6 denier and 15 denier) and three weight levels <br>(200, 400, and 600 grams per square meter). Poisson’s ratio, which measures this unique stretching <br>behavior, was tested at different levels of strain. The results in this study showed that the nonwoven <br>structuresmight be expanded in thickness when stretched, demonstrating auxetic properties. However, <br>nonwoven fabrics made with 15-denier fibers had showed little to no auxetic effect in thickness when <br>under tension. This research suggests that nonwoven fabrics with auxetic properties could be useful in <br>applications like cushioning, protective clothing, and filtration materials. </p>