Method for preparing an enhanced auxetic composite material (EACM)
Apparatus and associated methods relate to an enhanced auxetic composite material (EACM) of a base thermoplastic elastomer (TPE) and/or a thermoset material combined with an auxetic material, the composite formed with a molding process, where the base material is injected or dripped into or injected, dripped or formed around the auxetic material, the composite material providing higher impact performance than the individual materials. In an illustrative example, combining various energy absorbing materials with auxetic materials may further enhance impact performance. In some examples, TPE material injected into auxetic structures may fill internal voids. In some examples, the auxetic material may be suspended within the TPE material and be encapsulated around the auxetic material form. Auxetic materials may take various forms, for example, sheets, 3-D structures, and particles, each providing unique benefits. Various embodiments included within various personal protection articles may advantageously provide long life and enhance impact resistance.
1 . A method for preparing an enhanced auxetic composite material (EACM) comprising the steps of:
providing a quantity of auxetic material, wherein the quantity of auxetic material comprises a continuous unitary sheet of auxetic material;
providing a quantity of thermoplastic elastomer (TPE) material in a molten phase, wherein the quantity of TPE material comprises thermoplastic rubber (TPR);
combining the quantity of auxetic material and the quantity of TPE material together in a mold having a predetermined shape; and
transitioning the quantity of TPE material from the molten phase to a solid phase to form the EACM.
2 . The method of claim 1 , wherein the predetermined shape of the mold is a rectangular prism.
3 . The method of claim 1 , wherein the predetermined shape of the mold is sized to the dimensions and shape of a knuckle section of a glove.
4 . The method of claim 1 , wherein the predetermined shape of the mold is sized to the dimensions and shape of a cushion section of a helmet.
5 . The method of claim 1 , wherein the quantity of auxetic material further comprises a porous surface, and wherein the quantity of TPE material in the molten phase ingresses into the porous surface when the quantity of auxetic material and the quantity of TPE material are combined, such that the quantity of TPE material permeates the quantity of auxetic material to saturate the quantity of auxetic material with the quantity of TPE material.
6 . The method of claim 1 , wherein the mold comprises a mold of a compression molding machine.
7 . The method of claim 1 , further comprising cutting the EACM.
8 . The method of claim 7 , wherein the EACM is die-cut.
9 . The method of claim 1 , wherein combining the quantity of auxetic material and the quantity of TPE material together in the mold includes injecting the TPE material into the continuous unitary sheet of auxetic material.
10 . The method of claim 1 , wherein combining the quantity of auxetic material and the quantity of TPE material together in the mold includes injecting the TPE material around the continuous unitary sheet of auxetic material.
11 . The method of claim 1 , wherein combining the quantity of auxetic material and the quantity of TPE material together in the mold includes injecting the TPE material into and around the continuous unitary sheet of auxetic material.
12 . The method of claim 1 , wherein the auxetic material comprises crystalline cellulose.
13 . The method of claim 1 , wherein the auxetic material comprises molecular-level polymers.
14 . The method of claim 1 , wherein the auxetic material comprises microporous polymer and/or fibers.
15 . The method of claim 1 , wherein the auxetic material comprises a liquid crystalline polymer.
16 . The method of claim 1 , wherein the auxetic material comprises auxetic foam.