A Novel Manufacturing Process for the Extrusion of Helical Auxetic Yarns

失活材料是一种呈现负泊松比的材料：这是一种反直觉的物理性质，材料在拉伸时变得更厚。在助塑剂领域，一项令人兴奋的新发明是螺旋助塑纱。这是一种由两种传统纤维组成的纱线，一种螺旋缠绕着另一种。通过适当选择材料和几何形状，可以使纱线在拉伸时有效地变宽。这为高性能或“智能”纺织品打开了有趣的可能性全景。用途包括医疗保健或安全和国防部门的开孔织物，过滤，医疗保健的变色织物，安全束带或时尚，以及减灾-龙卷风，飓风或地震防护。生产少量的生长丝用于实验室试验是很容易的。这些试验已经并将继续提供令人兴奋的证据，证明对社会有益。为了利用这些机会，我们需要开发一种以工业规模、数量和质量生产纱线的方法，使商业企业能够运作并赚取利润。该研究项目正在开发新的挤出制造技术，以生产螺旋形减长丝，特别是开发一种新的纱线，这将真正释放该技术的商业潜力。

An auxetic material is one which exhibits a negative Poisson's ratio: this is a counter-intuitive physical property whereby the material becomes thicker when stretched.An exciting new invention in the field of auxetics is the helical auxetic yarn. This is a yarn composed of two conventional fibres, one helically wrapped around the other. By appropriate choice of materials and geometry this yarn can be made such that it effectively gets wider when stretched. This opens a panorama of interesting possibilities for high-performance or 'smart' textiles. Uses include pore-opening fabrics in healthcare or security and defence sectors, filtration, colour-change fabrics for healthcare, safety harnesses or fashion, and disaster mitigation - tornado, hurricane or earthquake protection.It is easy to make small quantities of auxetic yarn for laboratory trials. These trials have provided, and continue to provide, exciting evidence of benefits to society. To exploit these opportunities we need to develop a method of manufacturing the yarn in industrial scale quantities and at a quality with which commercial enterprises can work and earn profit.This research project is developing new extrusion manufacturing techniques to produce helical auxetic yarns and, in particular, developing a new version of the yarn which will truly unleash the commercial potential of the technology.