Novel dynamic elongational flow procedure for reinforcing strong, tough, thermally stable polypropylene/thermoplastic polyurethane blends.
Thermoplastic polyurethane (TPU)/polypropylene (PP) blends of different weight ratios were prepared with a self-made vane extruder (VE), which generates global dynamic elongational flow, and a traditional twin-screw extruder (TSE), which generates shear flow. High-resolution scanning electron microscopy and polarizing microscopy showed a structure feature of fiber morphology and a clear interlocking structure of spherulites of PP/TPU blends prepared with a VE. The wide-angle X-ray diffraction results showed that the TPU/PP blend based on dynamic elongational flow had evident crystalline structure of the β form as a function of PP (90 wt %), compared to that of the conventional shear flow processing techniques. A significant improvement of the mechanical properties was obtained; the samples prepared with a VE had superior mechanical properties compared to those of the samples prepared with a TSE. Interestingly, differential scanning calorimetry curves showed that dynamic elongational flow could successfully improve the crystallinity of the PP/TPU blends. Furthermore, dynamic thermomechanical and thermogravimetric analysis curves revealed the apparent partial miscibility and strong interaction of the PP/TPU blends influenced by dynamic elongational flow, compared to that of TSE-extruded. Further research will provide significant understanding of the spherulite interface and high-performance manipulation of PP/TPU blends under dynamic elongational flow, achieving superior PP/TPU blends.
National Engineering Research Center of Novel Equipment for Polymer Processing, Key Laboratory of Polymer Processing Engineering of the Ministry of Education, South China University of Technology , Guangzhou 510640, China.
Shikui
S
Jia
Jinping
J
Qu
Chengran
C
Wu
Weifeng
W
Liu
Rongyuan
R
Chen
Shufeng
S
Zhai
Zan
Z
Huang
Fuquan
F
Chen