The present disclosure relates to the field of polymer chemistry and more particularly to poly(sarcosine) polymers and uses thereof. The disclosure is also directed to compositions comprising a protein and a poly(sarcosine) polymer and uses thereof.

The invention concerns a method for producing polyamide from an amino ester of formula NH.sub.2—(CH.sub.2).sub.n—COOR, in which R represents an alkyl group and n represents an integer ranging from 5 to 14, comprising: a first reaction step in the presence of water, at a first temperature; followed by a second reaction step at a second temperature higher than the first temperature.

The invention concerns a method for producing polyamide from an amino ester of formula NH.sub.2—(CH.sub.2).sub.n—COOR, in which R represents an alkyl group and n represents an integer ranging from 5 to 14, comprising: a first reaction step in the presence of water, at a first temperature; followed by a second reaction step at a second temperature higher than the first temperature.

Described herein is a polymeric stabilizing agent selected from poly-lysine derivatives obtained by process including heating an aqueous lysine solution to boiling, increasing a temperature of the aqueous lysine solution to a reaction temperature in the range of about 105° C. to about 180° C., and keeping the reaction temperature in the range of about 105° C. to about 180° C. until a melt viscosity of the reaction mixture is in the range of about 350 mPa*s to about 6,500 mPa*s, and (ii) an amine number in the range of about 100 mg KOH/g to about 500 mg KOH/g is achieved. The process also includes adding alkyl-carboxylic acid or alkenyl-carboxylic acid in amounts of 2.5 mol % to 10 mol %, and increasing or keeping the reaction temperature in the range of about 105° C. to about 180° C. until number of free alkyl-carboxylic acid or alkenyl-carboxylic acid is ≤9% by weight.

Described herein is a polymeric stabilizing agent selected from poly-lysine derivatives obtained by process including heating an aqueous lysine solution to boiling, increasing a temperature of the aqueous lysine solution to a reaction temperature in the range of about 105° C. to about 180° C., and keeping the reaction temperature in the range of about 105° C. to about 180° C. until a melt viscosity of the reaction mixture is in the range of about 350 mPa*s to about 6,500 mPa*s, and (ii) an amine number in the range of about 100 mg KOH/g to about 500 mg KOH/g is achieved. The process also includes adding alkyl-carboxylic acid or alkenyl-carboxylic acid in amounts of 2.5 mol % to 10 mol %, and increasing or keeping the reaction temperature in the range of about 105° C. to about 180° C. until number of free alkyl-carboxylic acid or alkenyl-carboxylic acid is ≤9% by weight.

Described herein is a poly-lysine derivative obtained by a process including heating an aqueous lysine solution to boiling, increasing a temperature of the aqueous lysine solution to a reaction temperature in the range of about 105° C. to about 180° C., and keeping the reaction temperature in the range of about 105° C. to about 180° C. until (i) a melt viscosity of the reaction mixture is in the range of about 350 mPa*s to about 6,500 mPa*s, and (ii) an amine number in the range of about 100 mg KOH/g to about 500 mg KOH/g is achieved. The process also includes adding alkyl-carboxylic acid or alkenyl-carboxylic acid in amounts of 2.5 mol % to 10 mol %, and increasing or keeping the reaction temperature in the range of about 105° C. to about 180° C. until number of free alkyl-carboxylic acid or alkenyl-carboxylic acid is ≤9% by weight.

Described herein is a poly-lysine derivative obtained by a process including heating an aqueous lysine solution to boiling, increasing a temperature of the aqueous lysine solution to a reaction temperature in the range of about 105° C. to about 180° C., and keeping the reaction temperature in the range of about 105° C. to about 180° C. until (i) a melt viscosity of the reaction mixture is in the range of about 350 mPa*s to about 6,500 mPa*s, and (ii) an amine number in the range of about 100 mg KOH/g to about 500 mg KOH/g is achieved. The process also includes adding alkyl-carboxylic acid or alkenyl-carboxylic acid in amounts of 2.5 mol % to 10 mol %, and increasing or keeping the reaction temperature in the range of about 105° C. to about 180° C. until number of free alkyl-carboxylic acid or alkenyl-carboxylic acid is ≤9% by weight.

Process for producing polyamide powders by precipitation The present invention relates to a process for producing polyamide powders and to the polyamide powders obtainable by this process. The present invention additionally relates to the use of the polyamide powder as sintering powder in selective laser sintering.

Process for producing polyamide powders by precipitation The present invention relates to a process for producing polyamide powders and to the polyamide powders obtainable by this process. The present invention additionally relates to the use of the polyamide powder as sintering powder in selective laser sintering.

A method for producing a polycondensate powder dispersion, characterised in that it includes at least one step of polycondensation: i) of at least one diester and at least one diamine, and/or ii) at least one amino ester, while stirring, in a solvent that can solubilise both the diamine and the diester and/or the amino ester but not the polyamide that forms during the polycondensation, at a temperature between 30° C. and the boiling temperature of the solvent, in order to produce a powder precipitate dispersed in the solvent.