We present an extension of the SLIPLINK technology introduced by A. Likhtman to polymer nanocomposites in order to model explicitly free and grafted chains. Entanglements are explicitly modeled by slip-springs (SS) and follow the constraint release algorithm of destruction/recreation when reaching the chain end. Following the birth/death process, one can compute the age of slip-springs and the entire population age pyramid. We varied nanoparticle volume fraction, grafting density, and polymer/particle interactions to determine structural and dynamic properties of the nanocomposite materials. Scaling laws for slip-springs average age versus chain length have been obtained. While the dynamics of slip-springs between free chains in the nanocomposite is almost identical to that of a pure polymer melt, a characteristic exponent close to 3.7 has emerged governing the average age of slip-springs between grafted chains. The number of inter-particle graft-graft entanglements and their increased average lifetimes have a strong impact on the viscoelastic response of the material and the nanoparticle cluster formation. The emergence of polymer network elasticity will be discussed for high grafting density and high-volume fraction.