A Comprehensive Review on Controlled Synthesis of Long‐Chain Branched Polyolefins: Part 1, Single Catalyst Systems

Polyolefins (POs) are the largest polymer product in the world. The innovation in converting commodity olefin monomers to highly value added high‐performance POs has been and will continue to be a major theme in both academic research and industry practice. The excellent properties of POs can be achieved through precise engineering of their chain architectures, which largely involves control of the chain branching structures. Long‐chain branching is one of the most important parameters in the aspect of various chain branching structures. A huge amount of literatures have been reported to achieve better control of long‐chain branched structures over the last two decades. Recently, good effort has been made in reviewing all the major literatures and summarizing the catalytic systems and synthetic strategies for the controlled synthesis of long‐chain branched POs. This paper represents the first of the series, that is, controlled synthesis of long‐chain branched POs via single catalyst systems. Long‐chain branching (LCB) represents one of the key chain microstructural parameters and has significant influence on polymer melt strength and shear thinning performance. Polyolefins having controlled LCB structure can be prepared using one‐pot in‐situ polymerization with single metallocene or late transition metal catalysts. The catalyst systems and the influences of various polymerization parameters on LCB structure are summarized and discussed in this review paper.