This invention involves a new and better solution to the problems associated with the premature softening of PLA filaments in the additive manufacturing of three dimensional articles. It is based upon the finding that poly(lactic acid) filaments with high crystallinity offer much better resistance to heat-induced softening. The crystalline poly(lactic acid) filament of this invention can accordingly be used in the additive manufacturing of three dimensional articles without encountering the problems associated with premature softening, such as poor quality and printer jamming The crystalline poly(lactic acid) filaments of this invention can also be used in additive manufacturing of three dimensional articles without compromising the quality of the ultimate product, reducing printing speed, increasing cost, or leading to increased printer complexity. This invention more specifically discloses a filament for use in three-dimensional printing which is comprised of crystalized poly(lactic acid), wherein said filament has a diameter which is within the range of 1.65 mm to 1.85 mm

The invention relates to a method and to a device for stabilizing precursor fibers for the production of carbon fibers. In the method, precursor fibers are first heated to a first temperature and held at the temperature for a predefined duration. Subsequently, the precursor fibers are heated to at least one second temperature, which is higher than the first temperature, and held at said temperature for a predefined duration. During each heating and between the heating steps, the precursor fibers are in a gas atmosphere having a negative pressure in the range between 12 mbar and 300 mbar and having an oxygen partial pressure of 2.5 to 63 mbar. The device has at least one evacuable, elongate vacuum chamber for feeding the precursor fibers through, at least two lock units and at least one heating unit. At least one lock unit is used for the sealed insertion of precursor fibers into the at least one vacuum chamber, while at least one other lock unit is used for the sealed removal of precursor fibers from the at least one vacuum chamber. The heating unit has at least two individually controllable heating elements, which are suitable for heating the at least one vacuum chamber to at least two different temperatures in heating zones which are adjacent in the longitudinal direction.

A multi-step process is disclosed for heat setting twisted, bulk continuous filament (BCF) yarn comprising the steps of developing crimp in the yarn under hot atmospheric air and heat setting the yarn by saturated steam treatment.

A stretching apparatus of fibre tows in a pressurized steam environment comprises a plurality of stretching chests (1) and associated supporting structures (3, 4, 6) arranged side by side, at the same level, on a holding frame. The stretching chests (1) are each formed by two opposed metallic half-chests (1b, 1t), delimiting a stretching chamber (2). The stretching chamber (2) has a generally rectangular section of a low height and opens outwards in correspondence of the two transversal edges of the stretching chest (1) through tow entry and exit openings. Inside the stretching chambers (2) the tows are treated with saturated or overheated steam at high temperature and pressure and simultaneously undergo a mechanical stretching operation.

The described incandescent tension annealing processes involve thermally annealing twisted or coiled carbon nanotube (CNT) yarns at high-temperatures (1000 C. to 3000 C.) while these yarns are under tensile loads. These processes can be used for increasing yarn modulus and strength and for stabilizing both twisted and coiled CNT yarns with respect to unwanted irreversible untwist, thereby avoiding the need to tether torsional and tensile artificial muscles, and increasing the mechanical loads that can be moved by these muscles.

The described incandescent tension annealing processes involve thermally annealing twisted or coiled carbon nanotube (CNT) yarns at high-temperatures (1000 C. to 3000 C.) while these yarns are under tensile loads. These processes can be used for increasing yarn modulus and strength and for stabilizing both twisted and coiled CNT yarns with respect to unwanted irreversible untwist, thereby avoiding the need to tether torsional and tensile artificial muscles, and increasing the mechanical loads that can be moved by these muscles.

A continuous process heat set tunnel for exerting a sealing force against a top sealing roll, a yarn-transporting conveyor and a bottom sealing roll. At least first and second top pneumatic lamella sealing cylinders are mounted on the sealing roll frame for exerting against the top lamella a sealing force against the roll surface of the top sealing roll, and at least first and second bottom pneumatic lamella sealing cylinders are mounted on the sealing roll frame for exerting against the bottom lamella a sealing force against the roll surface of the bottom sealing roll.

This invention involves a new and better solution to the problems associated with the premature softening of PLA filaments in the additive manufacturing of three dimensional articles. It is based upon the finding that poly(lactic acid) filaments with high crystallinity offer much better resistance to heat-induced softening. The crystalline poly(lactic acid) filament of this invention can accordingly be used in the additive manufacturing of three dimensional articles without encountering the problems associated with premature softening, such as poor quality and printer jamming. The crystalline poly(lactic acid) filaments of this invention can also be used in additive manufacturing of three dimensional articles without compromising the quality of the ultimate product, reducing printing speed, increasing cost, or leading to increased printer complexity. This invention more specifically discloses a filament for use in three-dimensional printing which is comprised of crystallized poly(lactic acid), wherein said filament has a diameter which is within the range of 1.65 mm to 1.85 mm.

Reinforcing filaments or fibers, such as aromatic polyamide (aramid) fibers, can be reliably measured and consistently mixed into asphalt cement concrete by soaking the fibers in a wetting agent, then severing them to a desired length, and mixing the segments with other ACC ingredients. The wetting agent holds the fibers together loosely, so they can be distributed more uniformly throughout the ACC without clumping. The wetting agent soaks into the ACC mixture and/or evaporates, leaving the reinforcing fibers behind.

Embodiments of the invention relate generally to electrospun fibers and, more particularly, to the controlled release of an active pharmaceutical ingredient (API) from electrospun fiber scaffolds (EFSs).