Porous and microporous parts prepared by additive manufacturing as disclosed herein are useful in medical and non-medical applications. The parts are prepared from a composition containing both a solvent soluble component and a solvent insoluble component. After a part is printed by an additive manufacturing process it is exposed to solvent to extract solvent soluble component away from the printed part, resulting in a part having surface cavities.

Devices for radiative cooling and optical waveguiding are provided, wherein the devices comprise a fabric including one or more fibers extending for a length in a longitudinal direction and a plurality of void structures positioned within each of the one or more fibers and extended over the length of each of the one or more fibers. Each of the plurality of void structures is configured to scatter at least a portion of an electromagnetic radiation received thereon to thereby radiatively cool the object.

Devices for radiative cooling and optical waveguiding are provided, wherein the devices comprise a fabric including one or more fibers extending for a length in a longitudinal direction and a plurality of void structures positioned within each of the one or more fibers and extended over the length of each of the one or more fibers. Each of the plurality of void structures is configured to scatter at least a portion of an electromagnetic radiation received thereon to thereby radiatively cool the object.

Porous and microporous parts prepared by additive manufacturing as disclosed herein are useful in medical and non-medical applications. The parts are prepared from a composition containing both a solvent soluble component and a solvent insoluble component. After a part is printed by an additive manufacturing process it is exposed to solvent to extract solvent soluble component away from the printed part, resulting in a part having surface cavities.

A rubber composition includes a rubber matrix and carbon fibers dispersed within the rubber matrix. The carbon fibers define a plurality of pores distributed throughout the carbon fibers and a surface chemistry including doped nitrogen and doped oxygen. The rubber composition also may include a plurality of additives selected from a crosslinking agent, at least one activator, and at least one accelerator, among others.

A method of extruding filament comprises the steps of cutting a bulk source material into pieces having size S.sub.1, performing a first extrusion pass comprising the steps of melting the pieces in an extruding device at a temperature T.sub.1 and extruding a first filament at an extrusion speed V.sub.1, and performing at least one additional extrusion pass k comprising the steps of cutting the first filament into pieces having size S.sub.k, melting the pieces in an extruding device at temperature T.sub.k, and extruding a final filament at an extrusion speed V.sub.k. A system for extruding filament is also described.

A hollow fibre membrane having a coiled, a hemihelix, a helical or an undulated native form, in which the membrane can be stretched by up to 4-times its original length with no plastic deformation, and wherein the native form of the membrane is produced by the asymmetric flow of liquid polymer through an opening of a die or nozzle.

A hollow fibre membrane having a coiled, a hemihelix, a helical or an undulated native form, in which the membrane can be stretched by up to 4-times its original length with no plastic deformation, and wherein the native form of the membrane is produced by the asymmetric flow of liquid polymer through an opening of a die or nozzle.

A solid fiber is described, where the solid fiber is characterized by (a) a modification degree Do/Di, in a cross section of the solid fiber of 1.20 to 8.50 where the inscribed circle diameter is denoted by Di and the circumscribed circle diameter is denoted by Do; and (b) a porous specific surface area of not less than 30 m.sup.2/g.

A solid fiber is described, where the solid fiber is characterized by (a) a modification degree Do/Di, in a cross section of the solid fiber of 1.20 to 8.50 where the inscribed circle diameter is denoted by Di and the circumscribed circle diameter is denoted by Do; and (b) a porous specific surface area of not less than 30 m.sup.2/g.