Method of making a homogeneous mixture of polyolefin solids and carbon solids

A method of making a homogeneous mixture of polyolefin solids and carbon solids without melting the polyolefin solids during the making, the method comprising applying acoustic energy at a frequency of from 20 to 100 hertz (Hz) to a heterogeneous mixture comprising (A) polyolefin solids and (B) carbon solids for a period of time sufficient to substantially intermix the (A) polyolefin solids and the (B) carbon solids together while maintaining temperature of the heterogeneous mixture below the melting temperature of the (A) polyolefin solids, thereby making the homogeneous mixture without melting the (A) polyolefin solids;

• wherein the (A) polyolefin solids are from 95.0 to 99.9 weight percent (wt %) and the (B) carbon solids are from 0.1 to 5.0 wt %, respectively, of the combined weights of the constituents (A) and (B).