A novel process for the manufacture of auxetic foams and for their re-conversion to conventional form

Abstract

Auxetic materials expand laterally when stretched and get thinner when uniaxially compressed,[1] i.e., they have a negative Poisson’s ratio (conventional materials, like rubber, steel, glass etc., which contract laterally when stretched, have a positive Poisson’s ratio). Apart from such counter-intuitive behavior, auxetic materials have several additional beneficial properties including, amongst others, an improved indenta- tion resistance,[2–5] making them suitable to use in protective equipment, an enhanced ability to form doubly curved surfaces,[1–4] a property which is particularly desired in materials used to construct dome-shaped structures/surfaces, and enhanced acoustic properties,[6–8] making them suitable for sound-proofing applications.