Entanglement is one of the most fragile, and promising, properties of a quantum state: several quantum information protocols rely on it; nevertheless, entanglement between physical systems is rapidly destroyed because of the unavoidable interaction with the surrounding environment. In this talk, the dynamics of two maximally entangled qubits interacting with indipendent environments composed of spin chains is shown to have quite different regimes, ranging from entanglement preservation to ESD (entanglement sudden death) depending on the environmental properties.