We show ~10x polariton-enhanced infrared reflectivity of epitaxial graphene on 4H-SiC, in SiCs restrahlen band (8-10um). By fitting measurements to theory, we extract the thickness, N, in monolayers (ML), momentum scattering time, Fermi level position of graphene and estimate carrier mobility. By showing that 1/root(ns), the carrier concentration/ML, we argue that scattering is dominated by short-range interactions at the SiC/graphene interface. Polariton formation finds application in near-field optical devices such as superlenses.