In this study, ploy(N-hydroxymethyl acrylamide)/polyethylene glycol (PNHMPA/PEG) interpenetrating polymer networks gel was prepared as a novel form-stable composite phase change materials (PCMs) successfully. And PP/IPN (PNHMPA/PEG, hereinafter referred to as IPN) phase change fibers were also prepared by melt spinning. The composite PCMs and PP/IPN phase change fibers were characterized using scanning electron microscope (SEM) and mechanical analysis. The SEM results show that the PNHMPA/PEG interpenetrating polymer networks has porous structure but has no phase separation among multicomponent. In addition, the form-stable composite PCMs distribute evenly in PP. The breaking strength of PP/IPN phase change fibers is slightly smaller than that of pure PP fiber. Thermal properties and thermal stabilities of the composite PCMs and fibers were determined by using differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). DSC results show that the melting temperature and the latent heat of the prepared composite PCMs are 54.79 degrees C and 82.08 J g1, respectively. The melting temperatures of PEG in composite PCMs and PP/IPN phase change fibers has a little fluctuation, and the relevant data indicate that the latent heat enthalpy of the composite PCMs and fibers are slightly smaller than the theoretical value. TGA indicated that the composite PCMs have good thermal stability. Furthermore, damping performance of phase change fibers has been improved due to IPN. (c) 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013