Synthesis And Properties Of Block Copolymers Composed Of Norbornene/Higher Alpha-Olefin Gradient Segments Using Ansa-Fluorenylamidodimethyltitanium-[Ph3c][B(C6f5)(4)] Catalyst System

A series of di- and triblock copolymers composed of gradient norbornene (NB)/higher alpha-olefin (1-octene (O) or 1-dodecene (Do)) segments (NB/alpha-olefin-gradient segments) were synthesized with (t-BuNSiMe(2)Flu)TiMe2 (1) - [Ph3C][B(C6F5)(4)] using 2,6-bis(1,1-dimethylethyl)-4-methylphenol (BHT)-treated tri-n-octylaluminium (Oct(3)Al) as a scavenger. The copolymers were molded to form transparent films using a melt-pressing procedure. The strain at break behaviors of the block copolymer films were significantly improved by controlling the block length, NB mol fraction, and/or the type of alpha-olefin, without a corresponding loss of strength compared to the corresponding gradient copolymer films. This improvement in the mechanical properties of NB/alpha-olefin copolymers is expected to broaden their potential applications in optical and medical fields.