A blend of polymeric materials comprising (A) of from about 1 to about 99.99 weight percent based on the combined weights of Components A, B and C of at least one substantially random interpolymer; and wherein said interpolymer; (1) contains of from about 0.5 to about 65 mole percent of polymer units derived from; (a) at least one vinyl or vinylidene aromatic monomer, or (b) at least one hindered aliphatic or cycloaliphatic vinyl or vinylidene monomer, or (c) a combination of at least one vinyl or vinylidene aromatic monomer and at least one hindered aliphatic or cycloaliphatic vinyl or vinylidene monomer; (2) contains of from about 35 to about 99.5 mole percent of polymer units derived from at least one aliphatic .alpha.-olefin having from 2 to 20 carbon atoms; (3) has a molecular weight (Mn) greater than about 1,000; (4) has a melt index (I.sub.2) of from about 0.01 to about 1,000; (5) has a molecular weight distribution (M.sub.w /M.sub.n) of from about 1.5 to about 20; and (B) of from about 99 to about 0.01 weight percent based on the combined weights of Components A, B, and C of one or more conductive additives and/or one or more additives with high magnetic permeability ; and (C) of from 0 to about 98.99 weight percent based on the combined weights of Components A, B, and C of one or more polymers other than A.