Is this Sealy Essentials foam mattress memory foam?

No, it is a poly-foam bed, not memory foam. A 3-inch SealySupport HD comfort layer sits over a dense high-density foam core, all CertiPUR-US certified. Poly foam conforms gently and recovers faster than memory foam, so you settle in without the deep, slow-sinking quicksand feel. At a medium-firm 8 inches, it rests you near the surface rather than enveloping you. If you specifically want a deep memory-foam hug, this is not that bed, by design.