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Cristallinity Evaluation of Oriented Nanocomposites Based on Polypropylene and Silica by Time Domain NMR
Author(s) -
Alves Lorena G.,
Ferreira Luana M.,
Melo Amanda R. A.,
Junior Jorge P. Chimanowsky,
Tavares Maria I.B.
Publication year - 2020
Publication title -
macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 1022-1360
DOI - 10.1002/masy.202000069
Subject(s) - materials science , differential scanning calorimetry , polypropylene , nanocomposite , tacticity , polymer , chemical engineering , diffraction , composite material , polymer chemistry , polymerization , thermodynamics , physics , optics , engineering
Abstract Hybrid films made of isotactic polypropylene (PP) and silica (SiO 2 ) are produced in a single‐screw extruder, followed by uniaxial orientation induced by winding at different speeds. Aiming their application in packaging, the influence of uniaxial orientation on properties of films containing pure (A200) and modified (R972, modified with dimethylchlorosilane) silicas is studied. The microstructural changes of the PP are evaluated by x‐ray diffraction (XRD) and by differential scanning calorimetry (DSC) and these data are correlated to nuclear magnetic resonance in the time domain (NMR‐TD). The orientation given to the films is monitored by intensity alterations of the XRD peaks, which are influenced by the nanoparticle concentration and the affinity between PP/silica. Through the DSC analysis, the nucleating effect of silica A200 at a concentration of 1 wt% is evidenced. Finally, the NMR‐TD corroborated the previous results, showing an increase in the stiffness of the more oriented nanocomposites due to the alignment of polymer chains.