Semi-interpenetrating polymer networks (semi-IPNs) based polyurethane (PU), polyvinyl alcohol (PVA) and functionalized single–walled carbon nanotubes (f-SWCNTs), films were prepared using sequential polymerization technique. Carboxyl functionalized SWCNTs in semi-IPNs matrixes were confirmed by Raman spectroscopy and  hydrogen bond interactions were studied using attenuated total reflectance fourier transform infrared spectroscopy. The soft segments of the PU with nanotubes interact much stronger than hard segments, this was observed by Differential Scanning Calorimeter. The activation energy and thermal degradation temperatures were calculated from thermogravimetric analysis. The tensile strength and Young’s modulus was increases with increase f-SWCNTs loadings. The AFM micrographs clearly shows f-SWCNTs were located in semi-IPNs matrix. Further, SWCNTs are attached in PU and spherical structures were dispersed in polymer matrix. The surface activation energy of the composites were increases up to 29 kJ/mole with increasing SWCNTs content on PU networks.