Nonisothermal Crystallization Kinetics of Polypropylene Composites Reinforced With Down Feather Fiber

Nonisothermal crystallization kinetics of pure polypropylene and polypropylene/down feather fiber composites were investigated using a differential scanning calorimeter at five different cooling rates. The experimental data on crystallinity versus temperature were analyzed by Avrami, Ozawa, and Liu models, respectively. The results indicated that the presence of down feather fiber served as nucleating agent and increased the onset and peak temperatures of crystallization of polypropylene/down feather fiber composites. Interestingly, polypropylene/down feather fiber composites showed a slower primary crystallization and a faster secondary crystallization than pure PP, meaning that down feather fiber retired the crystallizaiton process of PP matrix. The nucleation activity and activation energies were also calculated and agreed well with these results. Wide-Angle X-ray diffraction patterns indicated that down feather fiber induced the formation of b-monoclinic crystals in polypropylene matrix. These phenomena were definitely different from the nonisothermal crystallization kinetics of polypropylene composite based on inorganic particles and organic cellulose fibers. (C) 2015 Society of Plastics Engineers