Tham khảo nhé bạn! 1. A composition comprising,

a) at least one oligomer, cooligomer, polymer or copolymer, containing a stable free nitroxyl radical ##STR51##

and

b) a reducing agent;

which olipomer, cooligomer, polymer or copolymer is obtained by radical polymerization or by grafting, which polymerization has been carried out in the presence of a stable free nitroxyl radical ##STR52##

and a source of free radicals capable of initiating the polymerization, or in the presence of a nitroxyl ether ##STR53##

wherein X represents a group having at least one carbon atom and is such that the free radical derived from X is capable of initiating polymerization and the remaining radical is a stable free nitroxyl radical, and

which grafting has been carried out in the presence of a nitroxyl radical or a nitroxyl ether; and

which reducing agent is

a cyclic ethylenically unsaturated compound having an allylic hydrogen atom,

a phosphorus compound selected from the group consisting of H3 PO2 (phosphinic acid), H4 P2 O4 (hypodiphosphonic acid), H3 PO3 /H4 P2 O5 (phosphonic-/diphosphonic acid), H4 P2 O6 (hypodiphosphoric acid) and the ammonium, alkali metal or alkali earth metal salts thereof, or

a sulfur compound selected from the group consisting of H2 S2 O2 /H2 S2 O3 (sulfoxylic-/thiosulfuric acid), H2 S2 O4 (dithionic acid), H2 SO3 /H2 S2 O5 (sulfurous-/disulfurous acid), R--S--OH (sulfenic acid), R--S=O--OH (sulfinic acid) and the ammonium, alkali metal or alkali earth metal salts thereof, or

a mixture thereof; and

with the proviso that the composition is essentially free of a polymerizable monomer.