Preparation of Polybutene-Based Thermoplastic Elastomers Through the Copolymerization of 1-Butene with Higher Α-Olefins

A series of 1-butene-based random copolymers were synthesized through the direct copolymerization of 1-butene with higher alpha-olefins, namely 1-octene (C8), 1-dodecene (C12), 1-hexadecene (C16), and 1-eicosene (C20). Four catalysts, namely rac-Et(Ind)(2)ZrCl2 (Cat.1), rac-Me2Si(1-Ind)(2)ZrCl2 (Cat.2), Me2C(Cp)(9-Flu)ZrCl2 (Cat.3), and dimethyl(pyridyl-amido)hafnium (Cat.4), were adopted to promote the copolymerization upon activation with iBu(3)Al/Ph3CB(C6F5)(4). The post-metallocene catalyst, Cat.4, displayed superior catalytic activity (>10(7) gpolymer molHf(-1) h(-1)) and alpha-olefin incorporation ability, yielding copolymers with ultra-high molecular weight (M-w > 10(3) kDa) and isotactic selectivity (mmmm up to 90%). The copolymerizations in this study enable the synthesis of a series of rigid and tough polybutene-based thermoplastic elastomers under mild conditions, with the copolymers exhibiting impressive tensile strengths ranging from 18 to 31 MPa, elongation at breaks between 480% and 650%, and elastic recoveries ranging from 44.7% to 60.7%.