Abstract: The present invention is directed to a coaxial cable comprising (a) an inner conductor, (b) an outer conductor, and (c) a foamed insulation, surrounding the inner conductor. The foamed insulation is prepared from an insulation composition comprising a foamable polymer, a foaming agent, and a particulate, non-halogenated, nonheterocyclic polyolefinic nucleating agent. The invention is also related to methods and compositions for making the foamed insulation.

Abstract: An expandable composition comprising: (A) about 60 to about 98 percent by weight of a polyolefin or mixture of polyolefins wherein the polyolefin or mixture has an &eegr;0 of less than about 9.0 kilopascal.seconds (kPa.s), a Jr greater than about 50×10−5/pascals (Pa), and an Ea greater than about 6.7 kilocalories per mole (kcal/mol); and (B) about 2 to about 40 percent by weight of a polyolefin or mixture of polyolefins having an nRSI greater than about 4.5, and no greater than about 19; or (C) a polyolefin or mixture of polyolefins wherein the polymer or mixture has an &eegr;0 of less than about 9.0 kilopascal.seconds, a Jr greater than about 50×10−5/pascals, an Ea greater than about 6.7 kilocalories/mole, and an nRSI greater than about 9.