A novel material for producing auxetic foams is disclosed. The material comprises a multiphase, multicomponent polymer foam with a filler polymer having a carefully selected glass transition temperature. Novel methods for producing auxetic foams from the material are also disclosed that consistently, reliably and quickly produce auxetic polyurethane foam at about room temperature (25° C.). This technology overcomes challenging issues in the large-scale production of auxetic PU foams, such as unfavorable heat-transmission problem and harmful organic solvents.

A novel material for producing auxetic foams is disclosed. The material comprises a multiphase, multicomponent polymer foam with a filler polymer having a carefully selected glass transition temperature. Novel methods for producing auxetic foams from the material are also disclosed that consistently, reliably and quickly produce auxetic polyurethane foam at about room temperature (25° C.). This technology overcomes challenging issues in the large-scale production of auxetic PU foams, such as unfavorable heat-transmission problem and harmful organic solvents.

A material that includes at least one layer made of an auxetic structure and articles of footwear having soles comprising the materials. When the material is under tension, it expands in both the direction under tension and in the directional orthogonal to the direction under tension. The articles of footwear have soles that have at least one layer made of a material that has a pattern of apertures to provide the auxetic structure. The apertures are surrounded by sole portions that can rotate or pivot to change the size of the apertures.

In methods and apparatuses for producing auxetic foam from conventional foam, conventional foam is compressed into a mold before thermal, chemical or thermo-chemical treatment processes are performed. A segmented mold is accommodated in a compressing apparatus. After compressing the foam between the mold segments, the mold is fastened shut and removed from the compressing apparatus. The forces applied to any given volume of foam and the amounts by which the foam is compressed while being processed are controlled to impart desired mechanical properties to the produced foam. Poisson's ratio and density of discrete portions of finished foam shapes are reliably predicted and controlled to achieve uniform and non-uniform mechanical properties within a single continuous quantity of foam.

A sole structure includes a sole component, which has an inner surface and an outer surface opposite the inner surface. The sole component has a length and a thickness. The sole component includes a sole material, and the sole material has a density. At least one of the thickness or the density varies along the length of the sole component. The sole component defines a plurality of holes extending from at least one of the inner surface and the outer surface and arranged to form an auxetic structure. The auxetic structure is configured such that, when the sole component is tensioned in a first direction, the sole component expands in both the first direction and in a second direction orthogonal to the first direction. A property of the auxetic structure varies as a function of the density or the thickness of the sole component.

An article made from an auxetic material, the auxetic material having a plurality of unit structures joined together, is provided. The unit structure includes a first strut element, and a second strut element joined to the first strut element. Each of the first strut element and the second strut element have a predetermined thickness and width, wherein the first strut element being connected to the second strut element at a predetermined re-entrant angle (Θ). Further, the first strut element includes a top first strut element, and a bottom first strut element, and the second strut element includes a set of top second strut elements and a set of bottom second strut elements and wherein the strut element of the set of top second strut elements being connected to respective strut member of the set of bottom second strut elements.

Provided is a method of manufacturing a stretchable substrate according to various embodiments of the present disclosure in order to implement the above-described objects. The method may include forming an auxetic including a plurality of unit structures and forming one or more microstructures.

Described herein is a process for preparing a foam (FA) with a Poisson's ratio in the range of from −0.5 to 0.3, the method including the steps of providing a foam (F1) with a flow resistance in the range of from 3000 to 8000 Pas/m, determined according to DIN EN 29053, and subjecting the foam (F1) to thermoforming including triaxial compression, wherein the foam (F1) is not reticulated prior to step (ii). Also described herein is the foam obtained or obtainable according to the process and the use of the foam as, for example, an energy absorbing device, preferably in protective gear, furniture, cushions, in cleaning devices with improved rinse-out behavior, in shoe soles, or as sealing, insulating or anchorage providing material for example used in earphones, ear plugs or dowels, or as acoustic material.

A method of sub-ambient pressure processing of blow-molded polymer foams and skin-over-foam sandwich panel configurations for lightweight components having improved structural properties. The method can create either skinned or un-skinned foams that offer smooth interior and exterior surfaces, zero or controlled surface porosity, skins of pre-defined thickness, and foam cells that are expanded and oriented normal to the material plane, effectively spherical or polyhedral in nature, and offering improved bending and compressive strength.

Multi-body interpenetrating lattices comprise two or more lattices that interlace or interpenetrate through the same volume without any direct physical connection to each other, wherein energy transfer is controlled by surface interactions. As a result, multifunctional or composite-like responses can be achieved by additive manufacturing of the interpenetrating lattices, even with only a single print material, with programmable interface-dominated properties. As a result, the interpenetrating lattices can have unique mechanical properties, including improved toughness, multi-stable/negative stiffness, and electromechanical coupling.