Metallocene-Based Branch−Block Thermoplastic Elastomers

摘要: Long chain branched (LCB) polyethylene block copolymers having thermoplastic elastomer character were made using mixed metallocene catalysts. Conceptually, the synthesis can be divided into two steps. Step 1 involves generation of vinyl-terminated, crystallizable macromonomers, and step 2 incorporation these macromonomers an amorphous or plastomeric copolymer backbone. In practice, steps may conducted sequentially simultaneously. The polymer properties depend on catalyst pair process conditions selected, which determine populations reactive macromonomer probability incorporating them One such useful is mixture Cp2ZrCl2 (C5Me4SiMe2NC12H23)TiCl2, activated with MAO. presence a ethylene/butene feed catalyst, by virtue its low comonomer capability, will produce primarily crystalline macromonomers. titanium other hand, has high...