Abstract: A composite material includes a layer of fibres conjoined to a matrix, wherein one of the matrix and fibres has a first component which exhibits auxetic behaviour for loading along a first direction, and the other of the matrix and fibres has a second component which exhibits non-auxetic behaviour for loading along the first direction.

Abstract: A multi-layer adhesive interface, comprising at least one film layer and at least one adhesive layer, each adhesive layer being adhered to at least one film layer, the film layers being impermeable to the adhesive of the adhesive layers, wherein at least one of the adhesive or film layers has a negative Poisson's ratio. The Poisson's ratio of the layers may vary through the interface and may vary from positive at one surface to negative at the other surface.

Abstract: A composite material comprises a layer of fibres conjoined to a matrix, where one of the matrix and fibres comprises a first component which exhibits auxetic behaviour for loading along a first direction, and the other of the matrix and fibres comprises a second component which exhibits non-auxetic behaviour for loading along the first direction.

Abstract: A composite material comprises a layer of fibres conjoined to a matrix, where one of the matrix and fibres comprises a first component which exhibits auxetic behaviour for loading along a first direction, and the other of the matrix and fibres comprises a second component which exhibits non-auxetic behaviour for loading along the first direction.

Abstract: A process for the preparation of thermoplastic auxetic foams comprising the steps of: a) taking conventional thermoplastic foam; b) subjecting said foam to at least one process cycle wherein the foam is biaxially compressed and heated; c) optionally subjecting the foam to at least one process cycle wherein the biaxial compression is removed and the foam mechanically agitated prior to reapplying biaxial compression and heating; d) cooling said foam to a temperature below the softening temperature of said foam; and e) removing said compression and heat.