This proposal intends to study the effects of MWNTs and alkilated-MWNTs (A-MWNTs) on the dinamycs of PVC/MWNTs nanocomposites. The presence of MWNTs dispersed in the PVC matrix sligthly displaces the glass transition temperature (2-5 ºC) and improves the Young's modulus as well as the termal conductivity of the nanocomposites. QENS could provide us with information on the origin of these changes and to give a deeper microscopic view into the striking dynamics of MWNTs-based PVC nanocomposites. Only a few studies on the dynamics of PVC and plasticized PVC have been reported. However, the dynamics of PVC nanocomposites reinforced with MWNTs remains unexplored. Considering the tangible applications of MWNTs it would be very interesting to study its effect on the dynamics of MWNTs-based polymer nanocomposites and QENS emerges as the best tool for doing.