Department of Chemical Engineering, Kyoto University , Kyoto 615-8510, Japan.
New Business Development Division, SEIKO PMC Corp. , Chiba 267-0056, Japan.
ACS Appl Mater Interfaces. 2017 Mar 22;9(11):9250-9254. doi: 10.1021/acsami.7b01329. Epub 2017 Mar 13.
Herein, an ultrahigh 18-fold expansion of isotactic polypropylene (iPP)/cellulose nanofiber (CNF) nanocomposite foams was achieved for the first time using a core-back foam injection molding technique. It was found that CNFs were well dispersed and aligned along the cell wall in the core-back direction. Interestingly, the formations of a hybrid shish-kebab of CNFs and classic shish-kebab of PP were simultaneously achieved in the PP/CNF composites. Finally, we proposed that the combination of local strong melt strength, probably resulting from the strong alignment of CNFs and subsequent formation of hybrid shish-kebab structures, and weak melt strength in the unreinforced PP melt might be the driving force for remarkably enhancing the PP foamability.
本文首次采用中心-背面注模发泡技术，实现了超高 18 倍的等规聚丙烯（iPP）/纤维素纳米纤维（CNF）纳米复合材料发泡。结果发现，CNF 在中心-背面方向上很好地分散和排列在泡孔壁上。有趣的是，在 PP/CNF 复合材料中同时形成了 CNF 杂化的 shish-kebab 和经典的 PP shish-kebab。最后，我们提出，局部强熔体强度的结合，可能是由于 CNF 的强烈取向和随后形成的杂化 shish-kebab 结构，以及未增强的 PP 熔体中的弱熔体强度，可能是显著提高 PP 发泡能力的驱动力。
