A scaffold of hollow fibers comprising a mixture of polylactic acid (PLA) and polybutylene succinate (PBS) and cellulose nanofibers (CNF), medical products made of these scaffolds and methods of using the scaffolds in regenerative medicine. A method for producing the scaffolds is also disclosed.

A method for producing ultrafine fibers of the present invention includes forming an electric field between an discharging nozzle from which a raw resin is discharged and a charging electrode which is disposed apart from the discharging nozzle, and supplying the raw resin which has been heated and melted into the electric field from the discharging nozzle to spin the raw resin. The raw resin is a resin mixture which contains a resin having a melting point and an additive, and satisfies a relation (I) below:
A/B≥1.0×10.sup.2  (I)
wherein A represents the absolute value (Ω) of electrical impedance of the raw resin at 50° C., and B represents the absolute value (Ω) of electrical impedance of the raw resin at a temperature 50° C. higher than a melting point of the raw resin.

A method for producing ultrafine fibers of the present invention includes forming an electric field between an discharging nozzle from which a raw resin is discharged and a charging electrode which is disposed apart from the discharging nozzle, and supplying the raw resin which has been heated and melted into the electric field from the discharging nozzle to spin the raw resin. The raw resin is a resin mixture which contains a resin having a melting point and an additive, and satisfies a relation (I) below:
A/B≥1.0×10.sup.2  (I)
wherein A represents the absolute value (Ω) of electrical impedance of the raw resin at 50° C., and B represents the absolute value (Ω) of electrical impedance of the raw resin at a temperature 50° C. higher than a melting point of the raw resin.

A method for producing a polyurethane elastic fiber according to the present invention contains the steps of: [1] producing a polyurethane urea polymer (A) having a number average molecular weight ranging from 12,000 to 50,000, and represented by general formula (1); [2] preparing a spinning dope by adding the polyurethane urea polymer (A) to a polyurethane urea polymer (B); and [3] spinning a polyurethane elastic fiber using the spinning dope. ##STR00001##
In the formula, R.sup.1 and R.sup.2 are an alkyl group or a hydroxyalkyl group, R.sup.3 is an alkylene group, a polyethyleneoxy group or a polypropyleneoxy group, R.sup.4 is a diisocyanate residue, X is a urethane bond or a urea bond, R.sup.5 and R.sup.6 are a diisocyanate residue, P is a diol residue, Q is a diamine residue, UT is a urethane bond, UA is a urea bond, each of k, l, m and n is 0 or a positive number.

A method for manufacturing an artificial turf fiber includes creating a polymer mixture that includes, 60-99% by weight of an LLDPE polymer and 1-15% by weight of an LDPE polymer. The method further includes extruding the polymer mixture into a monofilament; quenching the monofilament; reheating the monofilament; and stretching the reheated monofilament to form the monofilament into the artificial turf fiber.

A method for manufacturing an artificial turf fiber includes creating a polymer mixture that includes, 60-99% by weight of an LLDPE polymer and 1-15% by weight of an LDPE polymer. The method further includes extruding the polymer mixture into a monofilament; quenching the monofilament; reheating the monofilament; and stretching the reheated monofilament to form the monofilament into the artificial turf fiber.

A composition for forming a fiber includes at least one polyamide and caprolactam. The at least one polyamide has a number average molecular weight between 38,000 Da and 100,000 Da. The polyamide is at least partially dissolved in the caprolactam. The caprolactam comprises between 20 wt. % and 90 wt. % of the composition.

A composition for forming a fiber includes at least one polyamide and caprolactam. The at least one polyamide has a number average molecular weight between 38,000 Da and 100,000 Da. The polyamide is at least partially dissolved in the caprolactam. The caprolactam comprises between 20 wt. % and 90 wt. % of the composition.

The present disclosure relates to a process for producing carbon fibers utilizing a salt of an organic cation containing C═N imine group, and carbon fibers produced by such process.

A method for tuning characteristics of a polyamide nanofiber nonwoven comprising the step of targeting a specific average nanofiber diameter and/or a specific relative viscosity for the polyamide nanofiber nonwoven. The specific average nanofiber diameter is within a range from 100 nm to 1000 nm and/or the specific relative viscosity is within a range from 5 to 75, e.g., from 15 to 50. The process further comprises the steps of extruding a polyamide composition having a moisture content with a pressurized gas through a fiber forming channel having a channel temperature to form the polyamide nanofiber nonwoven having the target average nanofiber diameter and/or relative viscosity and controlling the moisture content, the pressure of pressurized gas, and/or the channel temperature based on the specific average nanofiber diameter and/or the specific relative viscosity.