Inducing out‐of‐plane auxetic behavior in needle‐punched nonwovens

Abstract

We describe here a heat-compression protocol used on needlepunched commercial nonwoven fabrics which induces an out-of-plane auxetic response in these treated fabrics. The as-received samples, however, are not auxetic and show a decrease in thickness when stretched uniaxially. Using micro-CT imaging it was found that the vertical fiber bundles/columns, produced in the needle punching step of fabric manufacture, are tilted and buckled as a result of the heat-compression treatment. It is suggested that it is likely the reorientation of these columns during subsequent uniaxial strain that drives thickness increase (auxetic response).Variation of instantaneous Poisson's ratio with axial strain for as-received and treated nonwovens.

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“…Auxetic non-woven fabrics: Verma P et al [64] reported that it is possible to induce out-of-plane auxetic behavior in needlepunched nonwovens. They obtained needle-punched nonwoven fabrics from Ten Cate Protective Fabrics (Senoia, Georgia, USA).…”

“…Diagram showing the processing treatment of as-received samples in a Carver1 hot press to produce compressed" and "heat compressed" samples [64]. needle-punched nonwoven specimens tested along the machine direction.…”

“…needle-punched nonwoven specimens tested along the machine direction. Error bars represent the standard deviation in Poisson's ratio at each data point as calculated over five specimens of each type [64].…”

Auxetic Textile Materials - A review

“…Auxetic non-woven fabrics: Verma P et al 64 reported that it is possible to induce out-of-plane auxetic behavior in needle-punched nonwovens. They obtained needle-punched nonwoven fabrics from Ten Cate Protective Fabrics (Senoia, Georgia, USA).…”

Auxetics and other systems of “negative” characteristics

“…Induced out‐of‐plane auxetic behavior in needle‐punched commercial nonwoven fabrics is studied by Prateek Verma, Meisha L. Shofner, Angela Lin, Karla B. Wagner, and Anselm C. Griffin in their very interesting experimental paper . They describe a heat‐compression protocol used in the treated fabrics.…”