Unfolding of Isotactic Polypropylene under Uniaxial Stretching

作者：Kang Jia; Yuan Shichen; Hong You lee; Chen Wei; Kamimura Akihiro; Otsubo Akihiro; Miyoshi Toshikazu

来源：ACS Macro Letters, 2016, 5(1): 70-73.

DOI：10.1021/acsmacrolett.5b00727

Despite numerous investigations on polymer 16 processing, understanding the deformation mechanisms of semicrystalline polymer under uniaxial stretching is still challenging. In this work, C-13-C-13 Double Quantum (DQ) NMR was applied to trace the structural evolution of C-13-labeled isotactic polypropylene (iPP) chains inside the crystallites stretched to an engineering strain (e) of 21 at 100 degrees C. DQ NMR based on spatial proximity of C-13 labeled nuclei proved conformational changes from the folded chains to the locally extended chains induced by stretching. By combining experimental findings with literature results on molecular dynamics, it was concluded that transportation of the crystalline chains plays a critical role to achieve large deformability of iPP.

• 出版日期2016-1