High molecular weight polypropylene nanospheres: Synthesis and characterization |
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| Authors: | Pradip Paik Kamal K. Kar |
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| Affiliation: | 1. Advanced Nano Engineering Materials Laboratory, Materials Science Programme, Indian Institute of Technology, Kanpur 208016, India;2. Advanced Nano Engineering Materials Laboratory, Department of Mechanical Engineering, Indian Institute of Technology, Kanpur 208016, India |
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| Abstract: | The high molecular weight (MW) polypropylene with average particle size of 60 nm was synthesized by controlled growth mechanism using Ziegler–Natta catalyst. The atomic force microscopy (AFM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) studies showed that PP nanoparticles were spherical in shape. Structure and crystallinity were concomitantly studied through Fourier transform infrared spectroscopy and X‐ray diffraction, respectively. It shows nanospherical PP particles with more crystallinity (～ 75%) compared with macrosized PP (～ 59%). In addition, differential scanning calorimetry studies revealed the finite particle size effect on Tg and the scale dependence Tg followed a first order exponential trend. As particle size goes down to nano‐ scale from macrosize, continuous elevation of Tg's were observed from ?25 to ?11°C. This phenomenon was directed to configuration entropy of single spherical nanoparticles of PP. The mechanical properties and surface roughness were also evaluated through AFM. At last, the properties of nanosized PP were compared with micron and macrosized particles. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007 |
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| Keywords: | polypropylene nanosphere high molecular weight mechanical properties morphology |
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