A protective article is described. The protective article comprises auxetic structures including: (i) a first auxetic structure having a first auxetic plane exhibiting auxetic behaviour and a first auxetic structure axis, the first auxetic structure axis being substantially perpendicular to the first auxetic plane; and (ii) a second auxetic structure having a second auxetic plane exhibiting auxetic behaviour and a second auxetic structure axis, the second auxetic structure axis being substantially perpendicular to the second auxetic plane. The second auxetic structure axis is arranged in a non-parallel relationship to the first auxetic structure axis. An auxetic structure for use in a protective article and a method for forming the auxetic structure are also described.

A method for manufacturing a high performance thermoplastic matrix composite ballistic helmet includes forming/shaping highly consolidated helmet preforms free of wrinkles and with no cuts or seams from a flat stack of 0/90 uni-directional prepreg layers, both with and without carbon epoxy skins or layers, using a pressure forming process. The wrinkle free and no cuts pre-formed helmet shell is pre-heated and placed between match-metal dies in a compression molding press to be molded under constant pressure during heating at high temperature and cooling down to below 160 F. in less than 45 minutes.

Described herein are helmets comprising at least one surface reinforcing component. In some embodiments the surface reinforcing component comprises at least one anchoring feature embedded in a structural feature of the helmet, such as a force absorbing element. In other embodiments, the surface reinforcing component comprises fasteners configured to mate with a respective fastener on a shell of the helmet.

Disclosed are s full-form flat-knitted helmet shell preform, the preparation method, and the helmet shell, which belong to the field of helmet material technology. Two different knitting directions of the helmet shell preforms are prepared by means of longitudinal knitting and transverse knitting combined with partial knitting respectively; Meanwhile, reinforced yarn is added during the knitting process of the preforms to obtain the transversely and longitudinally knitted helmet shell preforms with reinforced yarn. The fabric structure of the preforms disclosed in this invention is a flat-knitted three-dimensional fabric with reinforced yarns, which solves the problem of low tensile strength and high elongation of flat-knitted fabrics, and solves the poor impact resistance caused by poor bonding strength between layers of helmet shells to some extent. Moreover, the method of preparing helmet shells from preforms improves production efficiency, reduces material waste, and solves the problem of poor dimensional stability.

A method of making a foamed article comprises (a) milling a block or sheet of thermoplastic polymer to form a precursor; (b) crosslinking the thermoplastic polymer; (c) heating the precursor to a first temperature to soften the thermoplastic polymer; (d) infusing the thermoplastic polymer with at least one inert gas at a first pressure that is sufficient to cause the at least one inert gas to permeate into the softened thermoplastic polymer; and (e) while the thermoplastic polymer is softened, reducing the pressure to a second pressure below the first pressure to at least partially foam the precursor into a foamed article, wherein the foamed article is substantially the same shape as the precursor.

A composite element for the realization of protection devices of parts of the human body includes a matrix, a reinforcing element, at least partially embedded in the matrix, wherein the reinforcing element has at least one opening shaped so as to define an undercut between the matrix and the reinforcing element, such undercut being suitable for determining a mechanical constraint between the matrix and the reinforcement element.

A helmet manufacturing method involves: producing a shell and a protector, the shell having two opposing cheek-protecting portions, the protector having a jaw-protecting portion and a neck-protecting portion connected to the jaw-protecting portion; putting the shell and the protector in a die such that bottom edges of the cheek-protecting portions of the shell connect to a top edge of the neck-protecting portion of the protector; introducing a foam material into the die, apply heat and pressure to the foam material such that the foam material expands and binds to an inner side of the shell and an inner side of the protector; and taking a helmet finished product out of the die. Therefore, both the jaw-protecting portion of the integrally-formed protector and the helmet finished product are reinforced.

A method of applying a polymeric film to an article when forming an assembly according to the invention comprises: providing a polymeric film sized to cover at least a portion of at least one exterior surface of the article; providing at least one gaseous agent to form a coating on at least one surface of the polymeric film and/or at least one exterior surface of the article to be contacted when forming an assembly; contacting at least a portion of the polymeric film and at least a portion of the at least one exterior surface of the article; and form-fitting the polymeric film with the portion of the at least one exterior surface of the article.

A method of making a foamed article comprises (a) milling a block or sheet of thermoplastic polymer to form a precursor; (b) crosslinking the thermoplastic polymer; (c) heating the precursor to a first temperature to soften the thermoplastic polymer; (d) infusing the thermoplastic polymer with at least one inert gas at a first pressure that is sufficient to cause the at least one inert gas to permeate into the softened thermoplastic polymer; and (e) while the thermoplastic polymer is softened, reducing the pressure to a second pressure below the first pressure to at least partially foam the precursor into a foamed article, wherein the foamed article is substantially the same shape as the precursor.

A method of producing high modulus and strength polymer materials includes compressive rolling a semicrystalline polymer material in at least two different axial directions of the material; and axially orienting at least a portion of the compressive rolled material to a draw ratio less than the ultimate elongation or the elongation % at break of the material.