Study on the effect of prepolymerization parameters on catalyst performance in propylene slurry polymerization using heterogeneous Ziegler natta catalyst

the effect of time, temperature and prepolymerization methode on melt flow index and bulk density of polypropylene particles and catalyst activity were studied. Slurry polymerization of propylene was carried out using a commercially available 4th Ziegler natta catalyst, Tri-ethyl aluminum as co catalyst and cyclohexil methyl dimethoxy silane as an external electron donor. Prepolymerization was carried out in two modes: isothermal (IPP) and nonisothermal (NIPP). The increasing of prepolymerization temperature causes to increase catalyst activity and bulk density. It also increases primarily melt flow index and then decreases it. In NIPP the catalyst activity and bulk density increase with initial reaction temperature but MFI of product dose not show a specificsensitivity. SEM photographs show that polymer products are relatively large and have a spherical morphology.

کلیدواژه ها:

prepolymerization ، Ziegler- natta ، polypropylene ، MFI