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Blends of Syndiotactic Polystyrene and Isotactic Polypropene Prepared Using a Ziegler‐Natta Catalyst Containing a Novel Donor
Author(s) -
Xu Demin,
Wang Jun,
Liu Zhongyang,
Ke Yucai,
Hu Youliang
Publication year - 2001
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 - 10.1002/1521-3935(20010601)202:9<1817::aid-macp1817>3.0.co;2-2
Subject(s) - tacticity , polystyrene , materials science , methylaluminoxane , polymer chemistry , styrene , natta , catalysis , ziegler–natta catalyst , polymerization , glass transition , copolymer , chemical engineering , polymer , composite material , metallocene , chemistry , organic chemistry , engineering
Blends of syndiotactic polystyrene (sPS) and isotactic polypropene (iPP) have been prepared using TiCl 4 /MgCl 2 / β ‐diketone activated with methylaluminoxane (MAO). The influences of the Al/Ti ratio and the polymerization temperature on the catalyst activity and the blend composition have been investigated. It is shown that the polymerization temperature is an important factor in determining catalyst activity and the blend composition. Through controlling the polymerization conditions, blends containing a wide composition range of styrene/propene molar fractions can be prepared. The supported catalyst shows a good activity of about 1.5×10 5 (g blend)·(mol Ti) –1 ·h –1 . 13 C NMR analysis allows the composition of the blends to be calculated. Dynamic mechanical analysis (DMA) reveals that the blends of sPS/iPP prepared this way are partially compatible; the two glass transition temperatures ( T g 's) of the components shift towards each other. The values of T g , as well as the peaks of sPS intensity, increase with an increasing molar fraction of styrene in the blend. When the sPS content is in the range of 59–80 wt.‐%, dual phase continuity occurs in the blends. The morphology found by microscopic observation is consistent with the DMA results.