Synthesis and characterization of norbornene-ethylene-styrene terpolymers with a substituted ansa-fluorenylamidodimethyltitanium-based catalyst

This article reports a synthetic method for a norbornene-ethylene-styrene (N-E-S) terpolymer, which has not been well investigated so far, via incorporation of styrene (S) into vinyl-type norbornene-ethylene (N-E) copolymers catalyzed by a substituted ansa-fluorenylamidodimethyltitanium [Me2Si(3,6-tBu(2)Flu)(tBuN)/TiMe2 catalyst (I) activated with a [Ph(3)Q][B(C6F5)(4)]/Al(iBu)(3) cocatalyst at room temperature in toluene. The resulting terpolymerization product contained the targeted N-E-S terpolymer and the contaminated homopolymers, which were then able to be completely removed by solvent fractionation techniques. While homopolystyrene was easily extracted by fractionation with methylethylketone as a soluble part, homopolyethylene and a trace amount of homopolynorbornene could be perfectly separated by fractionation with chloroform as insoluble parts. The detail characterizations of a chloroform-soluble polymer with gel permeation chromatography, nuclear magnetic resonance, and differential scanning calorimetry analyses proved that it contained a true N-E-S terpolymer with long N-E sequences incorporated with isolated or short styrene sequences. The homogeneity of the morphology together with a single glass transition temperature that proportionally decreased with the increase of the styrene contents indicated that the N-E-S terpolymer obtained in this work is a random polymer with an amorphous structure. (c) 2007 Wiley Periodicals, Inc.