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Evolution of cellular morphologies and crystalline structures in high-expansion isotactic polypropylene/cellulose nanofiber nanocomposite foams

Herein, the development of cell morphology and crystalline microstructure of injection-molded isotactic polypropylene/cellulose nanofiber (PP/CNF) composite foams with 2–10-fold expansion ratios was investigated through scanning electron microscopy (SEM), wide-angle X-ray diffraction (WAXD), and sma...

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Detalles Bibliográficos
Autores principales: Wang, Long, Hikima, Yuta, Ohshima, Masahiro, Sekiguchi, Takafumi, Yano, Hiroyuki
Formato: Online Artículo Texto
Lenguaje:English
Publicado: The Royal Society of Chemistry 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9079998/
https://www.ncbi.nlm.nih.gov/pubmed/35539453
http://dx.doi.org/10.1039/c8ra01833b
Descripción
Sumario:Herein, the development of cell morphology and crystalline microstructure of injection-molded isotactic polypropylene/cellulose nanofiber (PP/CNF) composite foams with 2–10-fold expansion ratios was investigated through scanning electron microscopy (SEM), wide-angle X-ray diffraction (WAXD), and small-angle X-ray scattering (SAXS). Compared with isotactic polypropylene (iPP) foams, the added CNF improved the cell morphology and resulted in a great reduction in cell size. Additionally, the PP lamella orientation and crystal type were notably altered during the core-back FIM process. As the expansion ratio increased, the original isotropic lamellae in the iPP foams were transformed into an oriented lamellar structure and then further transformed into a typical shish-kebab structure, while hybrid shish-kebab structures were simultaneously generated in the high-expansion PP/CNF nanocomposite foams. Accordingly, the highest content of β-crystals was observed in the low-expansion iPP foams. In contrast, the β-crystal content in PP/CNF composites decreased monotonously as the expansion ratio increased, which resulted from the combined effects of CNF's nucleating ability for α-crystals and the more dominant extensional flow effect assisted by the added CNF.