.alpha.-monoolefinic graft copolymers

A polymer alloy comprising a polyamide, a polyolefin incompatible with the polyamide and a compatibilizing amount of a graft copolymer having the formula A.sub.a M.sub.b X.sub.c P.sub.d in which:

• A.sub.a M.sub.b is the (co)polymer backbone;
• X.sub.c P.sub.d denotes the polymers grafted on the (co)polymer backbone;
• A is a recurring unit of an .alpha.-monoolefin containing from 2 to 8 carbon atoms;
• M is selected from among:
• (i) recurring units of an .alpha.-monoolefin containing from 2 to 8 carbon atoms;
• or
• (ii) recurring units of a plurality of .alpha.-monoolefins as defined above;
• X is a recurring unit of a monomer which can be grafted by a free-radical mechanism onto an .alpha.-monoolefin homo- or copolymer and containing a functional group which is reactive with an amino-substituted recurring unit;
• P is derived from a polyamide oligomer of the formula:
• ##STR7## in which f is a number ranging from 3 to 11;
• g is a number ranging from 5 to 80;
• R.sup.5 is hydrogen or a linear or branched chain alkyl radical containing up to 20 carbon atoms;
• and R.sup.6 is a linear or branched chain alkyl or alkenyl group containing up to 20 carbon atoms, a saturated or unsaturated cycloaliphatic radical, an aromatic radical, or combination thereof;
• a is a number ranging from 0 to 5,000;
• b is a number from 0 to 45,000 and the sum a+b ranges from 350 to 45,000;
• c is a number such that the ratio by weight of the monomer X grafted on the (co)polymer backbone to the copolymer grafted with X ranges from 500 ppm to 10%;
• and
• d is a number other than zero or less than or equal to C.