Copolymerization of Propylene with Higher α-Olefins by a Pyridylamidohafnium Catalyst: An Effective Approach to Polypropylene-Based Elastomer

Abstract

In this contribution, we explored the copolymerization of propylene with higher α-olefins, including 1-octene (C8) 1-dodecene (C12), 1-hexadecene (C16) and 1-eicosene (C20), by using a dimethyl pyridylamidohafnium catalyst. A series of copolymers with varied comonomer incorporation, high molecular weight and narrow molecular weight distribution were obtained at mild conditions. The effects of the insertion of the comonomers on the microstructure, thermal and final mechanical properties were systemically studied by 13C NMR, wide-angle X-ray scattering, DSC and tensile test. Excellent mechanical performances were achieved by tuning the incorporation and chain length of the higher α-olefins. When the comonomer content reached above 12 mol.%, polypropylene-based elastomers were obtained with high ductility. A combination of excellent elastic recovery and flexibility was achieved for the P/C16 copolymers with about 20 mol.% monomer incorporation. The monomer incorporation and side chain length played a crucial role in determining the mechanical property of the outstanding polypropylene-based elastomers.

Atomistic Simulation of the Polymerization Reaction by a (Pyridylamido)hafnium(IV) Catalyst: Counteranion Influence on the Reaction Rate and the Living Character of the Catalytic System

“…In this study, therefore, we would like to conduct RM simulations of the 1-octene polymerization reaction catalyzed by the (pyridylamido)­Hf­(IV) complex, which is used for industrial-scale production of various polyolefins, − aiming for its future application to more complex chemical reaction like chain-shuttling polymerization catalyst system, , where ethylene/1-octene block copolymers are produced. We would like to focus on the most important properties that have been paid attention to, i.e., activities and the living characters of catalytic systems, which determine the molecular weight distribution (MWD) of the polymers. − It is reported that the 1-octene polymerization by the (pyridylamido)­Hf­(IV) catalyst proceeds about twice faster with B­(C 6 F 5 ) 4 – than with MeB­(C 6 F 5 ) 3 – , which means that the activity of the catalyst is higher with B­(C 6 F 5 ) 4 – than with MeB­(C 6 F 5 ) 3 – . Notably, not only the catalytic activity but also the living character of the catalytic system is dependent on the CAs.…”

Enhancement of Adhesion Characteristics of Low-Density Polyethylene Using Atmospheric Plasma Initiated-Grafting of Polyethylene Glycol

“…Polyolefins are manufactured by cracking the petrochemical sources such as crude oil and natural gas [5,6]. Polyethylene (PE) polymers including low-density polyethylene (LDPE) and high-density polyethylene (HDPE) are the most famous polyolefins commonly employed in the food packaging industry, since they are easily heat sealable, can be fabricated into rigid films, with a good barrier against moisture and water vapor [7,8]. In spite of such features, their poor surface properties, including adhesion, wettability, and cytocompatibility, impede their integration with other materials to form multi-layered laminates.…”

Theoretical Elucidation of the Effect of Counteranions on the Olefin Polymerization Activity of (Pyridylamido)Hf(IV) Catalyst by QM and REMD Studies: MeB(C6F5)3– versus B(C6F5)4–

“…This catalyst has recently been utilized in a new polymerization technology, chain shuttling polymerization (CSP), − where ethylene/1-octene multiblock copolymers can be obtained by introducing a chain transfer agent into a solution mixture of two catalyst species with different 1-octene incorporation abilities. Hence, a lot of mechanistic studies − and ligand modifications − of (pyridylamido)­Hf­(IV) catalyst have been conducted so far.…”