A Novel Interlaced-helical Wrapping Yarn with Negative Poisson's Ratio

The two-component complex yarn with helical wrapping structure has been reported with auxetic behavior and unique performance, however, the residual torque could lead to the slippage of the wrap component from the core in the natural state and poor stability and applicability. Therefore, this paper aims to introduce a novel interlaced-helical wrapping yarn with negative Poisson's ratio, stable structure, practicability and continuous preparation. The differences in geometry and auxetic behavior between helical structure and interlaced-helical structure were presented and analyzed. Both the structure stability and auxetic effect of the interlaced-helical complex yarn have advantages over the helical wrap yarn with same materials and initial wrap angle. It can be shown that the interlaced-helical wrap yarns with lower initial wrap angle and bigger tensile modulus of the stiff yarns will produce better auxetic effect. Besides, the deformation mechanism and the manufacturing process were described in detail. Several kinds of yarns have been fabricated to discuss the effect of initial wrap angle and tensile modulus on the Poisson's ratio of the structure. The maximum value of Poisson's ratio for the yarns manufactured was -2.8. It is also expected that auxetic yarns with novel braided structure can prompt the applications of auxetic textiles.