The structural and physico-chemical characteristics of thermoplastic polymers filled with multiwall carbon nanotubes (CNTs) such as polyethylene (PE), polyamide 6 (PA 6) and layered fiberglass with PA 6 are investigated. The influence of their concentrations and homogeneity degree of nanotubes distribution is studied. The properties of new composites are compared with the well investigated polytetrafluoroethylene (PTFE)-CNTs and polypropylene (PP)-CNTs systems. It is shown that an addition of CNTs into thermoplastic polymeric materials leads to the significant changes in structural characteristics, growth of strength, electrical, thermal properties. It is coursed by the formation of CNTs continuous network in the original matrix, the crystallinity degree of the matrix depending on the concentration of CNTs. In turn, the crystallinity degree of the matrix is increased by homogeneity arising of the composite as a result of the strong interaction of the matrix with nanofiller. The changes of not only bulk but also the surface properties of the composites are observed, which explains the best biocompatibility of the nanocomposites observed in natural conditions experiments (in vivo).