Abstract: A thermoplastic filament or preform comprising a thermoplastic liquid crystal polymer (TLCP) is described. It can be incorporated into threads with one or more thermoplastics, where this filament can be used in 3D printing to produce parts that are stiffer and stronger than conventional 3D printed polymers. In one particularly advantageous embodiment, the TLCP is a multi-fiber core that is surrounded by a continuous solid polymer sheath. Also described are unique processing methods for manufacturing these TLCP-containing filaments.

Abstract: We disclose dual filament-based flexible material extrusion which is suitable of additive manufacturing for of at least two thermoplastic elastomers. To enhance printability of a thermoplastic elastomer (TPE), a series of core-shell filaments comprising a TPE shell and a rigid core are fabricated, such as ABS with the ABS volume fraction varying from 11% to 78%, in one particular embodiment. The presence of an ABS core imparts rigidity to the filament to inhibit buckling and allow for successful high-fidelity 3D printing. Rheological characterizations of TPE and ABS using capillary and parallel-plate viscometry point to the optimized extrusion parameters suitable for filament coextrusion, printability, and wettability between the print interfaces. Printed specimens with less than 20% ABS preserve the hardness, providing flexibility and a soft touch to the printed structures. Lower ABS content exhibits higher flexibility and impact resistance, while higher ABS imparts higher stiffness and tensile strength.

Abstract: Two-dimensional (2D) polymers and methods for their formation are described herein. To create oriented 2D polymer films, monomers are combined with processing additives within a solvent, creating a solution that can be cast and dried to remove the solvent and form a solid film. The methods can enable transformation of the monomers into oriented films. Film quality can be controlled via multiple processing parameters, including monomer and additive concentrations, shear and elongational flow rates during casting, evaporation rates, and post-process rinsing, buffering, stretching, and thermal treatments. By combining stiff carbon-containing cyclic polymer nodal units with more compliant linear polymer bridge units in an ordered, 2D repeating molecular structure it is possible to tailor the mechanical properties of 2D polymers and their assemblies to provide high stiffness, strength, and toughness.

Abstract: A family of new and novel molecules for mechanically superior two-dimensional (2D) polymers is described herein. By combining stiff carbon-containing cyclic polymer nodal units with more compliant linear polymer bridge units in an ordered, 2D repeating molecular structure it is possible to tailor the mechanical properties of 2D polymers and their assemblies to provide high stiffness, strength, and toughness. Furthermore, the inherent dimensionality of 2D polymers and their ability to be stacked into ordered and chemically interactive ensembles gives them inherent benefits in a variety of barrier and structural applications over current stiff and strong linear polymer technologies.

Abstract: A family of new and novel molecules for mechanically superior two-dimensional (2D) polymers is described herein. By combining stiff carbon-containing cyclic polymer nodal units with more compliant linear polymer bridge units in an ordered, 2D repeating molecular structure it is possible to tailor the mechanical properties of 2D polymers and their assemblies to provide high stiffness, strength, and toughness. Furthermore, the inherent dimensionality of 2D polymers and their ability to be stacked into ordered and chemically interactive ensembles gives them inherent benefits in a variety of barrier and structural applications over current stiff and strong linear polymer technologies.

Abstract: A polymer body includes a first thermoplastic polymer, and a second thermoplastic polymer. The first thermoplastic polymer and the second thermoplastic polymer form a continuous solid structure. The first thermoplastic polymer forms an external supporting structure that at least partially envelops the second thermoplastic polymer. A first flow temperature of the first thermoplastic polymer is at least 10° C. higher than a second flow temperature of the second thermoplastic polymer. The first thermoplastic polymer may be removable by exposure to a selective solvent.

Abstract: A polymer body includes a first thermoplastic polymer, and a second thermoplastic polymer. The first thermoplastic polymer and the second thermoplastic polymer form a continuous solid structure. The first thermoplastic polymer forms an external supporting structure that at least partially envelops the second thermoplastic polymer. A first flow temperature of the first thermoplastic polymer is at least 10° C. higher than a second flow temperature of the second thermoplastic polymer. The first thermoplastic polymer may be removable by exposure to a selective solvent.

Abstract: A thermoplastic filament comprising multiple polymers of differing flow temperatures in a geometric arrangement is described. A method for producing such a filament is also described. Because of the difference in flow temperatures, there exists a temperature range at which one polymer is mechanically stable while the other is flowable. This property is extremely useful for creating thermoplastic monofilament feedstock for three-dimensionally printed parts, wherein the mechanically stable polymer enables geometric stability while the flowable polymer can fill gaps and provide strong bonding and homogenization between deposited material lines and layers. These multimaterial filaments can be produced via thermal drawing from a thermoplastic preform, which itself can be three-dimensionally printed. Furthermore, the preform can be printed with precisely controlled and complex geometries, enabling the creation of a filament or fiber with a wide range of applications.

Abstract: Impact energy absorbing devices, in some embodiments, may be configured as a helmet having suspension elements employing “rate activated tethers” (RATs), a speed-sensitive flexible strapping material. The RATs are configured to suspend a helmet shell on the head of a wearer, so that impact to the helmet causes extension of the RATs. The RATs provide for: (1) steady force over long strokes, and (2) a stroke force that increases with increasing impact velocity. Standard impact testing of a helmeted headform shows that the RAT suspension decreases head accelerations by 50% relative to a standard suspension system. This decrease in head acceleration is expected to lead to a reduced likelihood of brain and head injury. Because the RATs absorb energy during tensile extension, they offer increases in energy absorption efficiency. These RAT suspensions can potentially replace or complement existing helmet pad and suspension systems in military, sports, and industrial safety-wear.

Abstract: A thermoplastic filament comprising multiple polymers of differing flow temperatures in a regular geometric arrangement, and a method for producing such a filament, are described. Because of the difference in flow temperatures, there exists a temperature range at which one polymer is mechanically stable while the other is flowable. This property is extremely useful for creating thermoplastic monofilament feedstock for three-dimensionally printed parts, wherein the mechanically stable polymer enables geometric stability while the flowable polymer can fill gaps and provide strong bonding and homogenization between deposited material lines and layers. These multimaterial filaments can be produced via thermal drawing from a thermoplastic preform, which itself can be three-dimensionally printed. Furthermore, the preform can be printed with precisely controlled and complex geometries, enabling the creation of monofilament and fiber with unique decorative or functional properties.

Abstract: Two-dimensional (2D) polymers and methods for their formation are described herein. To create oriented 2D polymer films, monomers are combined with processing additives within a solvent, creating a solution that can be cast and dried to remove the solvent and form a solid film. The methods can enable transformation of the monomers into oriented films. Film quality can be controlled via multiple processing parameters, including monomer and additive concentrations, shear and elongational flow rates during casting, evaporation rates, and post-process rinsing, buffering, stretching, and thermal treatments. By combining stiff carbon-containing cyclic polymer nodal units with more compliant linear polymer bridge units in an ordered, 2D repeating molecular structure it is possible to tailor the mechanical properties of 2D polymers and their assemblies to provide high stiffness, strength, and toughness.

Abstract: A thermoplastic filament comprising multiple polymers of differing flow temperatures in a geometric arrangement and an interior channel containing a structural or functional thread therein is described. A method for producing such a filament is also described. Because of the difference in flow temperatures, there exists a temperature range at which one polymer is mechanically stable while the other is flowable. This property is extremely useful for creating thermoplastic monofilament feedstock for three-dimensionally printed parts, wherein the mechanically stable polymer enables geometric stability while the flowable polymer can fill gaps and provide strong bonding and homogenization between deposited material lines and layers. These multimaterial filaments can be produced via thermal drawing from a thermoplastic preform, which itself can be three-dimensionally printed.

Abstract: A thermoplastic filament comprising multiple polymers of differing flow temperatures in a regular geometric arrangement, and a method for producing such a filament, are described. Because of the difference in flow temperatures, there exists a temperature range at which one polymer is mechanically stable while the other is flowable. This property is extremely useful for creating thermoplastic monofilament feedstock for three-dimensionally printed parts, wherein the mechanically stable polymer enables geometric stability while the flowable polymer can fill gaps and provide strong bonding and homogenization between deposited material lines and layers. These multimaterial filaments can be produced via thermal drawing from a thermoplastic preform, which itself can be three-dimensionally printed. Furthermore, the preform can be printed with precisely controlled and complex geometries, enabling the creation of monofilament and fiber with unique decorative or functional properties.

Abstract: A thermoplastic filament comprising multiple polymers of differing flow temperatures in a geometric arrangement and an interior channel containing a structural or functional thread therein is described. A method for producing such a filament is also described. Because of the difference in flow temperatures, there exists a temperature range at which one polymer is mechanically stable while the other is flowable. This property is extremely useful for creating thermoplastic monofilament feedstock for three-dimensionally printed parts, wherein the mechanically stable polymer enables geometric stability while the flowable polymer can fill gaps and provide strong bonding and homogenization between deposited material lines and layers. These multimaterial filaments can be produced via thermal drawing from a thermoplastic preform, which itself can be three-dimensionally printed.

Abstract: Rate-dependent, elastically-deformable devices according to various embodiments can be stretched and recovered at low elongation rates. Yet they become stiff and resistive to stretching at high elongation rates. These device can be utilized in orthotics, braces, and circulation-enhancing compression garments for the prevention of injury, promotion of personal health, and/or enhancement in human performance. The rate-responsive properties of the devices are critical performance enablers, as they allow the devices to provide a unique balance of comfort and performance that cannot be achieved with conventional, passive straps, braces, and compression garments.

Abstract: A polymer body includes a first thermoplastic polymer, and a second thermoplastic polymer. The first thermoplastic polymer and the second thermoplastic polymer form a continuous solid structure. The first thermoplastic polymer forms an external supporting structure that at least partially envelops the second thermoplastic polymer. A first flow temperature of the first thermoplastic polymer is at least 10° C. higher than a second flow temperature of the second thermoplastic polymer. The first thermoplastic polymer may be removable by exposure to a selective solvent.

Abstract: A family of new and novel molecules for mechanically superior two-dimensional (2D) polymers is described herein. By combining stiff carbon-containing cyclic polymer nodal units with more compliant linear polymer bridge units in an ordered, 2D repeating molecular structure it is possible to tailor the mechanical properties of 2D polymers and their assemblies to provide high stiffness, strength, and toughness. Furthermore, the inherent dimensionality of 2D polymers and their ability to be stacked into ordered and chemically interactive ensembles gives them inherent benefits in a variety of barrier and structural applications over current stiff and strong linear polymer technologies.

Abstract: A family of new and novel molecules for mechanically superior two-dimensional (2D) polymers is described herein. By combining stiff carbon-containing cyclic polymer nodal units with more compliant linear polymer bridge units in an ordered, 2D repeating molecular structure it is possible to tailor the mechanical properties of 2D polymers and their assemblies to provide high stiffness, strength, and toughness. Furthermore, the inherent dimensionality of 2D polymers and their ability to be stacked into ordered and chemically interactive ensembles gives them inherent benefits in a variety of barrier and structural applications over current stiff and strong linear polymer technologies.

Abstract: Impact energy absorbing devices, in some embodiments, may be configured as a helmet having suspension elements employing “rate activated tethers” (RATs), a speed-sensitive flexible strapping material. The RATs are configured to suspend a helmet shell on the head of a wearer, so that impact to the helmet causes extension of the RATs. The RATs provide for: (1) steady force over long strokes, and (2) a stroke force that increases with increasing impact velocity. Standard impact testing of a helmeted headform shows that the RAT suspension decreases head accelerations by 50% relative to a standard suspension system. This decrease in head acceleration is expected to lead to a reduced likelihood of brain and head injury. Because the RATs absorb energy during tensile extension, they offer increases in energy absorption efficiency. These RAT suspensions can potentially replace or complement existing helmet pad and suspension systems in military, sports, and industrial safety-wear.

Abstract: Rate-dependent, elastically-deformable devices according to various embodiments can be stretched and recovered at low elongation rates. Yet they become stiff and resistive to stretching at high elongation rates. These device can be utilized in orthotics, braces, and circulation-enhancing compression garments for the prevention of injury, promotion of personal health, and/or enhancement in human performance. The rate-responsive properties of the devices are critical performance enablers, as they allow the devices to provide a unique balance of comfort and performance that cannot be achieved with conventional, passive straps, braces, and compression garments.