Synthesis and characterization of norbornene–ethylene–styrene terpolymers with a substituted <i>ansa</i>‐fluorenylamidodimethyltitanium‐based catalyst

Abstract

Abstract 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 [Me 2 Si(3,6‐ t Bu 2 Flu)( t BuN)]TiMe 2 catalyst ( I ) activated with a [Ph 3 C][B(C 6 F 5 ) 4 ]/Al( i Bu) 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. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 2765–2773, 2007