The present invention relates to polyamide (A) and polyolefin (B) blends containing nanofillers in which the polyamide forms the matrix. These blends can also be referred to as nullpolyamide (A), polyolefin (B) and nanofiller blends in which the polyamide forms the matrixnull. The invention also relates to compositions with barrier properties which are polyamide (A) and polyolefin (B) blends containing nanofillers in which the polyamide forms the matrix. The invention also relates to structures with barrier properties comprising at least one layer of these blends and optionally at least one layer of another material. The invention also relates to the use of these structures for producing a barrier effect. These structures are a barrier to numerous fluids, and in particular to oxygen, to styrene, to fumigation fluids, to pentane and to air conditioning fluids. These structures can be made into bottles, reservoirs, containers, pipes and vessels of all sorts. They can also be converted to films which are used to make packagings. These films are also useful in food packaging, in SMC technology, in fumigation and in expandable polystyrene packaging. These pipes are useful in air conditioning devices. The invention also relates to the use of these objects.