Abstract


Auxetics are unique materials that exhibit negativePoissons ratio i.e. which expand laterally when extended axially. This is dueto the molecular reorientation at micro molecular level and structuraldeformations at macro scale. These auxetic textiles possess high indentationand fracture resistance, shear modulus and dynamic properties. Producing fiberswith auxetic properties involves the modification in polymer preparation stagefollowed by spinning process. Auxetic fabric structures are produced in majorby knitting and are achieved by suitably choosing the structure of fabric.These textiles have potential applications in defense and protective fields andin major other areas which require its properties.


Introduction


Auxetics are materials that have a negative Poisson's ratio.Elastic characteristics of Engineering materials follows the effect proposed bySimeon Poisson, stating the slightmovements between molecules and the stretching of molecular bonds within thematerial lattice to accommodate the stress. When the bonds elongate in thestress direction, they shorten in the other directions. This behaviormultiplied millions of times throughout the material lattice is what drives thephenomenon.


When a sample of material is stretched in one direction, ittends to contract (or rarely, expand) in the other two directions. Conversely,when a sample of material iscompressed in one direction, it tends to expand (or rarely, contract) in theother two directions. Poisson's ratio (ν) is a measure of this tendency.



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Theauthors are Third Year B.TechFashion Technology students from PSG College of Technology Coimbatore