Lightweight and
High Mechanical Properties of In Situ
Poly(ethylene terephthalate) Reinforced Polypropylene Composite Foams
by Chemical Foam Injection Molding
posted on 2023-12-13, 09:29authored byJing Jiang, Lian Yang, Caiyi Jia, Yongjun Cao, Yuhui Qiao, Jianhua Hou, Qian Li, Xianhu Liu
The issue of saving energy and reducing environmental
pollution
has attracted enormous interest in developing lightweight plastic
materials. As a cost-effective technology for manufacturing porous
plastic products, chemical foam injection molding (CFIM) has become
one of the most widely used processes in industry fields, especially
for automotive. However, it is still challenging to fabricate high-performance
plastic cellular products for structural application. Herein, a facile,
efficient, and easy-to-scale-up strategy was reported to produce lightweight
and strong foamed polypropylene (PP) composites by combining in situ
polyethylene terephthalate (PET) fibrillation (INF) and CFIM technologies.
First, the INF composite was prepared using a co-rotating twin-screw
compounding and melt spinning. SEM micrographs showed nanoscale reticular
PET fibrils with φ231 nm were achieved and distributed uniformly
in the PP matrix due to the particle-induced PET domain elaboration.
Rheological analysis and DSC combined with online optical microscopy
observation revealed that PET fibrils pronouncedly improved viscoelasticity
and crystallization rate, respectively. Compared with PP foam, the
INF foam showed a uniform and refined cell structure with 69 μm
cell size and 7.3 × 105 cells/cm3, respectively.
Moreover, more than 12% of the average weight loss rate was achieved
for the INF foamed sample. Due to the refined cellular morphology,
as well as the synergistic effect of PET fibrils in the skin layer
and Talc particles distributed in the cell wall, the yield strength
and impact strength of INF foam were 38 and 112% higher than that
of PP foam. Thus, the results gathered in this study demonstrated
a promising future in offering lightweight porous components with
improved mechanical strength.