Polymer blends with improved impact resistance

A composition comprising

• i.) a polymer selected from the group consisting of polyphenylene ether and polystyrene,
• ii.) at least one other polymer containing amine or carboxylic acid end groups,
• iii.) an oligomer, polymer, cooligomer or copolymer prepared by free-radical polymerization of at least one ethylenically unsaturated monomer or oligomer in the presence of a glycidyl-functionalized nitroxyl initiator, and
• iv.) an elastomeric impact modifier,
• wherein the glycidyl-functionalized nitroxyl initiator is of the formula
• wherein
• R are independently hydrogen, halogen, NO2, cyano, —CONR5R6, —(R9)COOR4, —C(O)—R7, —OR8, —SR8, —NHR8, —N(R8)2, carbamoyl, di(C1-C18alkyl)carbamoyl, —C(═NR5)(NHR6)or R has the same definition as R1;
• R1 are independently unsubstituted C1-C18alkyl, C2-C18alkenyl, C2-C18alkynyl, C7-C9phenylalkyl, C3-C12cycloalkyl or C2-C12heterocycloalkyl;
• or C1-C18alkyl, C2-C18alkynyl, C2-C18alkynl, C7-C9phenylalkyl, C3-C12cycloalkyl or C2-C12heterocycloalkyl, which are substituted by NO2, halogen, amino, hydroxy, cyano, carboxy, C1-C4alkoxy, C1-C4alkylthio, C1-C4alkylamino or di(C1-C4alkyl)amino;
• or phenyl, naphthyl, which are unsubstituted or substituted by C1-C4alkyl, C1-C4alkoxy, C1-C4alkylthio, halogen, cyano, hydroxy, carboxy, C1-C4alkylamino or di(C1-C4alkyl)amino;
• R4 is hydrogen, C1-C18alkyl, phenyl, an alkali metal cation or a tetraalkylammonium cation;
• R5 and R6 are hydrogen, C1-C18alkyl, C2-C18alkyl which is substituted by at least one hydroxy group or, taken together, form a C2-C12alkylene bridge or a C2-C12-alkylene bridge interrupted by at least one O or/and NR8 atom;
• R7 is hydrogen, C1-C18alkyl or phenyl;
• R8 is hydrogen, C1-C18alkyl or C2-C18alkyl which is substituted by at least one hydroxy group;
• R9 is C1-C12alkylene or a direct bond;
• or all R1 form together the residue of a polycyclic cycloaliphatic ring system or a polycyclic heterocycloaliphatic ring system with at least one di- or trivalent nitrogen atom;
• R2 are independently of each other phenyl or C1-C6alkyl or two together with the linking carbon atom form a C5-C6cycloalkyl group;
• A is a divalent group which forms a carbocyclic or heterocyclic 5-, 6- or 7-membered ring which may be further substituted;
• and
• R3 is a radical of formula (II)
• wherein
• X is phenylene, naphthylene or biphenylene, which are unsubstituted or substituted by NO2, halogen, amino, hydroxy, cyano, carboxy, C1-C4alkoxy, C1-C4alkylthio, C1-C4alkylamino or di(C1-C4alkyl)amino;
• R12 are independently of each other H or CH3;
• D is a group
• and
• m is a number from 1 to 4.