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Quiescent and shear-induced non-isothermal crystallization of isotactic polypropylene-based nanocomposites
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Resumo(s)
The paper reports a study of the effect of the addition of clay nanoparticles
on melt rheology, phase structure, and non-isothermal crystallization process
of isotactic polypropylene/hydrogenated oligocyclopentadiene (iPP/HOCP) system
in quiescent conditions by DSC and under shear applied at different temperatures by SAXS. For both crystallization conditions, the addition of clay and/or HOCP shifts
always the crystallization onset to lower values with respect to iPP. These results
can be attributed to the diluent effect of HOCP that causes a decrease in the rate of
nucleation and grow of the crystals, to the presence of segregated non-crystallizable
phases/particles which hinder the transport of macromolecules chains toward the
growing nuclei, and to the formation of beta iPP crystals and in the case of shearinduced crystallization to the presence of HPS which seems to reduce, mainly at low Ts, the amount of oriented polymer crystals, which are nuclei for the crystallization. At a given composition, the crystallization temperatures related at the crystallization under shear are always higher that those obtained by quiescent crystallization supporting the idea that the presence of extended chains in these samples act as nucleating agents favoring the crystallization process of iPP.
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Contexto Educativo
Citação
Silvestre, C., Pezzuto, M., Duraccio, D. et al. Quiescent and shear-induced non-isothermal crystallization of isotactic polypropylene-based nanocomposites. Polym. Bull. 74, 145–165 (2017). https://doi.org/10.1007/s00289-016-1704-5
Editora
Springer Science and Business Media LLC
Licença CC
Sem licença CC