AbstractSome physico‐mechanical properties of mixtures of polyethylene and polyacrylonitrile have been studied. The samples were obtained by two methods: 1 by radical polymerization of acrylonitrile on polyethylene, 2 by roll‐mixing of polyethylene with the compositions obtained by the first method. By light microscopy was established that these polymer‐polymer mixtures are heterophase systems. Their properties depend on the method of production rather than on their component compos