Premium
Polypropylene Made with In‐Situ Supported Me 2 Si(Ind) 2 ZrCl 2 and Me 2 Si(2‐Me‐Ind) 2 ZrCl 2 Catalysts: Properties Comparison
Author(s) -
Franceschini Fernando C.,
da R. Tavares Tatiana T.,
dos Santos João H. Z.,
Soares João B. P.
Publication year - 2004
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.200400020
Subject(s) - polypropylene , polymerization , polymer chemistry , molar mass , polymer , differential scanning calorimetry , catalysis , materials science , ziegler–natta catalyst , chemistry , gel permeation chromatography , post metallocene catalyst , metallocene , composite material , organic chemistry , physics , thermodynamics
Abstract Summary: Propylene homopolymerizations were carried out using Me 2 Si(Ind) 2 ZrCl 2 and Me 2 Si(2‐Me‐Ind) 2 ZrCl 2 , MAO‐modified silica, and common alkylaluminum cocatalysts. Supported catalysts were prepared by the in‐situ immobilization technique. The effect of the type and concentration of alkylaluminum on propylene polymerization was evaluated using TEA (triethylaluminum), IPRA (isoprenylaluminum), and TIBA (triisobutylaluminum) as cocatalysts. The polymers were analyzed by gel permeation chromatography (GPC), differential scanning calorimetry (DSC), and scanning electronic microscopy (SEM). The effect of the type and concentration of alkylaluminum on the melting temperature and the molar mass of the polypropylene was the same for both catalysts. The polymers made with in‐situ supported catalyst had lower melting points and, in almost all polymerization conditions, higher molar masses than those produced by homogeneous polymerization. Polypropylene samples made with Me 2 Si(2‐Me‐Ind) 2 ZrCl 2 had higher melting temperatures and molar masses than those made with Me 2 Si(Ind) 2 ZrCl 2 . SEM micrographs showed that the polymers obtained with in‐situ supported systems had a well‐defined morphology, confirming that the polymerization indeed took place onto the silica support.SEM micrographs of polypropylene particles obtained with Me 2 Si(2‐Me‐Ind) 2 ZrCl 2 in the presence of IPRA.