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Unusual Fabrication of Lightweight Injection-Molded Polypropylene Foams by Using Air as the Novel Foaming Agent
- Wang, Long, Hikima, Yuta, Ohshima, Masahiro, Yusa, Atsushi, Yamamoto, Satoshi, Goto, Hideto
- Industrial & engineering chemistry process design and development 2018 v.57 no.10 pp. 3800-3804
- Fourier transform infrared spectroscopy, air, carbon dioxide, cell structures, chemical structure, foaming, melting, nitrogen, polypropylenes, process design
- We report a novel approach to prepare injection-molded foams using air as the foaming agent, which is realized through our newly developed foam injection molding technology. Microcellular polypropylene (PP) foams exhibiting cell size of ∼7 μm and cell density of 1.63 × 10⁹ cells/cm³ were successfully obtained employing air foaming. Fourier transform infrared spectroscopy and rheological results illustrated that the molecular structures and melt properties of PP were greatly altered in air foaming, resembling a reactive foaming process. Furthermore, compared with nitrogen and carbon dioxide foaming, air foaming gave us a more flexible PP foam with finer cellular structure.