Radiation-crosslinked polyolefin compositions

A radiation cross-linked article comprising a polymer composition, the polymer composition comprising: (a) above 50 weight percent of a member selected from the group polyethylene is high density polyethylene (HDPE), polyethylene medium density (MDPE) and polyethylene linear medium density (LMDPE), wherein the HDPE has a density of at least 0.941 g / cm 3 and wherein the MDPE and the LMDPE have a density of 0.926 to 0.940 g / cm 3; and (b) from about 5 weight percent to less than 50 percent by weight of a polypropylene having a crystalline melting point, wherein the polypropylene is a polypropylene homopolymer or a polypropylene copolymer containing at least about 80 percent by weight propylene monomer; wherein the article is crosslinked by exposure to radiation and possesses a sufficient degree of crosslinking such that when the article is heated to a temperature above the crystalline melting point of polypropylene, it is softened but does not become liquid.