Abstract: For the preparation of powders formed of copolyesteramides by anionic polymerization, at least one lactam and at least one lactone are copolymerized in solution in a solvent in the presence of a catalyst and of an activator, the solvent being a solvent of the lactam and the powders being insoluble in the solvent. Preferably at least two lactams and at least one lactone are copolymerized, and the copolymerization is preferably carried out in the presence of a finely divided organic or inorganic filler. The copolymerization is preferably carried out in the presence of an N,N′-alkylenebisamide, such as ethylenebisstearamide (EBS) disclosed in EP 192 515, or generally amides of formula R1-NH—CO—R2, in which R1 can be replaced by an R3-CO—NH— or R3-O— radical and in which R1, R2 and R3 denote an aryl, alkyl or cycloalkyl radical.

Abstract: For the preparation of powders formed of copolyesteramides by anionic polymerization, at least one lactam and at least one lactone are copolymerized in solution in a solvent in the presence of a catalyst and of an activator, the solvent being a solvent of the lactam and the powders being insoluble in the solvent. Preferably at least two lactams and at least one lactone are copolymerized, and the copolymerization is preferably carried out in the presence of a finely divided organic or inorganic filler. The copolymerization is preferably carried out in the presence of an N,N′-alkylenebisamide, such as ethylenebisstearamide (EBS) disclosed in EP 192 515, or generally amides of formula R1—NH—CO—R2, in which R1 can be replaced by an R3—CO—NH— or R3—O— radical and in which R1, R2 and R3 denote an aryl, alkyl or cycloalkyl radical.

Abstract: A polyamide powder consisting essentially of elementary porous particles having a "gypsum rose" structure and a process for preparing a polyamide powder comprising polymerizing by anionic polymerization lactam in a solvent medium in the presence of a catalyst, an activator, and at least one amide; one of which is N,N'-alkylene bisamide; said polymerization being initiated with said lactam and said amide used in an amount such that the solvent is in the supersaturated state at the polymerization initiation temperature.

Abstract: A polyamide powder consisting essentially of elementary porous particles having a "gypsum rose" structure and a process for preparing a polyamide powder comprising polymerizing by anionic polymerization lactam in a solvent medium in the presence of a catalyst, an activator, and at least one amide; one of which is N,N'-alkylene bisamide; said polymerization being initiated with said lactam and said amide used in an amount such that the solvent is in the supersaturated state at the polymerization initiation temperature.

Abstract: A process for the manufacture of a polyamide powder comprising polymerizing in solution a reaction mixture comprising a monomer lactam or lactams capable of generating said polyamide in the presence of an N,N'-alkylene bisamide.