Described herein are methods of lowering the endotoxin content from a polyanionic polymer conjugate. In particular, methods of reducing the endotoxin content from a polyanionic polymer conjugate that can be useful for a variety of drug delivery applications are described herein.

A process and an apparatus for production of a low-shrinkage aliphatic polyamide fibre, in which polyamide is extruded through a spinneret to form filaments, then cooled and combined to form at least one yarn. The at least one yarn is subjected to drawing between the spinneret and a pair of inlet rolls, then in a further multi-stage drawing step is subjected to 4-fold to 6-fold drawing by pairs of draw rolls. The pairs of draw rolls successively heat the yarn and at least the last pair of draw rolls has a temperature of 5° C. to 20° C. below the melting point of the yarn. The yarn is relaxed by from 6% to 10% in a subsequent at least three-stage relaxation zone and is kept in a temperature range of 5° C. to 15° C. below the melting point of the yarn, and is subsequently wound up on a reel device. The invention further relates to a yarn composed of a low-shrinkage aliphatic polyamide fibre.

A process and an apparatus for production of a low-shrinkage aliphatic polyamide fibre, in which polyamide is extruded through a spinneret to form filaments, then cooled and combined to form at least one yarn. The at least one yarn is subjected to drawing between the spinneret and a pair of inlet rolls, then in a further multi-stage drawing step is subjected to 4-fold to 6-fold drawing by pairs of draw rolls. The pairs of draw rolls successively heat the yarn and at least the last pair of draw rolls has a temperature of 5° C. to 20° C. below the melting point of the yarn. The yarn is relaxed by from 6% to 10% in a subsequent at least three-stage relaxation zone and is kept in a temperature range of 5° C. to 15° C. below the melting point of the yarn, and is subsequently wound up on a reel device. The invention further relates to a yarn composed of a low-shrinkage aliphatic polyamide fibre.

The invention relates to a method for synthesizing a polyamide, in which method an aqueous solution is sprayed onto the polyamide before and/or during a solid-state post-condensation process. The aqueous solution comprises at least a first compound, selected from the group comprising phosphoric acid, fully neutralized salts of phosphoric acid, partially neutralized salts of phosphoric acid, and mixtures thereof, and a second compound, selected from the group comprising an acid, an anhydride, a lactone, ammonia, an amine, and mixtures thereof, with the stipulation that the second compound is not phosphoric acid and is not phosphoric acid anhydride. The spraying occurs at a temperature that lies below the boiling point of water. A polyamide that can be produced by means of the method according to the invention can be used in particular to produce films, monofilaments, fibers, threads, or textile sheet materials.

The invention relates to a method for synthesizing a polyamide, in which method an aqueous solution is sprayed onto the polyamide before and/or during a solid-state post-condensation process. The aqueous solution comprises at least a first compound, selected from the group comprising phosphoric acid, fully neutralized salts of phosphoric acid, partially neutralized salts of phosphoric acid, and mixtures thereof, and a second compound, selected from the group comprising an acid, an anhydride, a lactone, ammonia, an amine, and mixtures thereof, with the stipulation that the second compound is not phosphoric acid and is not phosphoric acid anhydride. The spraying occurs at a temperature that lies below the boiling point of water. A polyamide that can be produced by means of the method according to the invention can be used in particular to produce films, monofilaments, fibers, threads, or textile sheet materials.

This invention relates to a high molecular weight nylon powder composition for 3D printing, its preparation method and use. The composition comprises: 100 parts by weight of high-viscosity nylon powder, 1-5 parts by weight of a flow agent, and 0.1-1 parts by weight of an antioxidant; the high-viscosity nylon powder is one or more selected from nylon 6, nylon 66, nylon 11, nylon 12, nylon 612 and nylon 610; or the powder composition is obtained via polymerization reaction of the raw materials comprising the following components, based on the weight parts of lactam monomers or amide monomers: 100 parts by weight of lactam monomers or amide monomers, 0.005-1 parts by weight of a catalyst, and 0.1-1 parts by weight of an antioxidant. The high molecular weight nylon powder composition prepared in the present invention has a particle diameter in the range of 20-100 micrometers, good powder spreading performance, and is suitable for the 3D printing process, and the product of the high molecular weight nylon powder composition has good mechanical properties, good dimensional stability and low manufacturing cost.

A base polyamide composition comprising a nylon mixture having caprolactam units from 1 wppb to 50 wppm catalyst composition; and greater than 0.75 wt % residual caprolactam, wherein the base polyamide composition has a delta end group level ranging from 30 μeq/gram to 90 μeq/gram.

A base polyamide composition comprising a nylon mixture having caprolactam units from 1 wppb to 50 wppm catalyst composition; and greater than 0.75 wt % residual caprolactam, wherein the base polyamide composition has a delta end group level ranging from 30 μeq/gram to 90 μeq/gram.

The use of ultrasound or acoustics applied at a level below that which causes cavitation to control the energy balance between particles and the liquid phase in a metastable liquid.

A subject-matter of the present invention are new complexes comprising cyclic alkylene carbonates and polyamides, processes for their preparation and uses. Additionally, a subject-matter of the invention is the use of alkylene carbonates for recycling, solubilization, purification, and/or powdering of polyamide-based materials.