The Influence of Processing Parameters on the Supermolecular Structure of Isotactic Polypropylene in PP/LDPE Blends
Research and development
Author:
- Borysiak Sławomir
Poznan University of Technology
 Full text | Abstract: In order to analyse the effect of the addition of low-density polyethylene (LD-PE) on the polymorphic transformation in isotactic polypropylene (iPP), structure studies of iPP/LDPE blends have been carried out. In this work, iPP/LD-PE blends (100/0, 90/10, 80/20 and 70/30 w/w) were prepared by injection moulding under various injection speeds. The supermolecular structure of the blends by means of wide-angle X-ray scattering (WAXS) was analysed. The results have shown that polymorphs of polypropylene developed due to melt-shearing in the mould strongly depend on the injection speed as well as the content of LD-PE in the blends. The polypropylene (without the PE component) was characterized by the highest amount of the hexagonal form. The addition of polyethylene to iPP importantly depressed the formation of â-iPP. Moreover, an increase in the amount of polyethylene caused a significant decrease in the content of the hexagonal phase of polypropylene. The polymorphs of the polypropylene matrix strongly depend on the technological parameters of the processing. At a higher speed of injection, the amount of the hexagonal form of polypropylene slightly increases. |
Tags: isotactic polypropylene, polymorphs, blends, processing.