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Hydroxyl-modified polypropylenes (PPOH) with side chains containing OH groups were synthesized by copolymerization of the propylene and undecenyloxytrimethylsilane monomers. The isothermal and non-isothermal crystallization behavior of the modified polypropylenes (PPOH) with side chains containing up to 6.8 mol% OH groups were compared with that of polypropylene (PP). The introduction of the OH-comonomer...
SiO 2 nanoparticles grafted to terminally hydroxylated polypropylene (PP-g-SiO 2 ) with different molecular weights were melt mixed with PP to prepare a series of PP/PP-g-SiO 2 nanocomposites. PP/PP-g-SiO 2 offered several advantages over pristine PP and PP/unmodified SiO 2 such as highly uniform dispersion up to 10 wt.-%, +200–400% faster crystallization and +30%...
Composites of polypropylene (PP) filled with multiwalled carbon nanotubes (CNTs) of various concentrations were prepared by a twin screw extruder using direct compounding (DC) method without and with ultrasonic treatment. In addition, a masterbatch of 20 wt% PP/CNT composites were prepared without and with ultrasonic treatment and diluted to the same concentrations as in the DC method without ultrasonic...
The influence of two different trisamide-based additives on the morphological and mechanical behavior of isotactic polypropylene (PP) is investigated. Morphological investigations by wide-angle X-ray scattering (WAXS) show that only 0.04 wt.-% of one of the additives is enough to induce 80% beta modification in the crystalline part of the polymer. The materials are investigated with quasistatic (tensile...
The influence of in situ thermal reduction of graphene oxides (GO) on the isotactic polypropylene (iPP) crystallization were systematically investigated by comparing the crystallization behavior of iPP with different annealing procedures at 200 °C. Polarizing optical microscopy and differential scanning calorimetry results show that, for iPP/GO composite after annealing, both the number of nucleation...
Propylene was polymerized with TiCl4/Di/MgCl2 catalyst and cocatalysts containing triethylaluminum (TEA) and triisobutylaluminum (TiBA) in the presence of Ph2Si(OMe)2 (external donor) and hydrogen. Chain structure of the formed polypropylene (PP) was characterized by temperature-rise elution fractionation (TREF) combined with DSC and 13C NMR analysis of the main fractions. Increasing the amount of...
Using a unique slit flow device and in situ synchrotron X-ray methods, the entire evolution of flow induced crystallization in isotactic polypropylene (iPP) was studied from the start-up of flow up to completion of crystallization. Two WAXD detectors, including the ultrafast Pilatus and the two-dimensional Frelon, were combined to achieve a sufficient time resolution for a fairly short period (during...
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