Effect of Injection Parameters and Addition of Nanoscale Materials on the Shrinkage of Polypropylene Copolymer

Abstract

The effect of variation of injection conditions and addition of nano-calcium carbonate (CaCO₃), nano-silicon dioxide (SiO₂) and full-vulcanized nano-powdered styrene butadiene rubber (PSBR) on the shrinkage of injection-molded polypropylene-ethylene copolymer (90/10, co-PP) were investigated. The results showed that the shrinkage was different for different locations along the flow path. The shrinkage in the length direction of the injection-molded sample varied with the adjustment of the processing parameters, while the shrinkage in the width and thickness direction was almost unchanged. The addition of nano-CaCO₃ and PSBR decreased the shrinkage of co-PP, while the shrinkage of co-PP/ SiO₂ composite was almost unchanged.

Keywords:

• injection molding
• nanoparticle
• polypropylene copolymer (co-PP)
• shrinkage

Acknowledgements

The authors gratefully acknowledge the financial support of National Natural Science Foundation of China (Grant No. 20734005, 10590351), the Program for New Century Excellent Talents in University, and the Special Funds for Major Basic Research (Grant No: 2005CB623808).