A composition of matter formed by melt-blending certain thermoplastic polymers and from about 1.0 to about 7.5 wt. % of a fluorocarbon additive, the additive having a lower by surface energy than that of the polymer; the blending resulting in a cooled admixture having a concentration of fluorocarbon additive through a cross-section of the solid composition lower in the interior thereof and higher at the surfaces thereof.