Polyisoprene Bearing Dual Functionalized Mini-blocky Chain-ends Prepared from Neodymium-mediated Coordinative Chain Transfer Polymerizations

Through neodymium-mediated coordinative chain transfer copolymerizaiton(CCTcoP),polyisoprenes bearing dual hydroxylated mini-blocky chain-ends were prepared via a three-step strategy.Kinetic studies revealed that,the polymerization demonstrated typical features of CCTcoP across the whole polymerization process,i.e.,quasi-living polymerization characteristic,tunable molecular weights,narrow molecular weight distributions,and atom economies.Comparing to previously reported CCTP homopolymerization systems,the presence of oxygen-containing IpOAl polar comonomer slowed down chain transfer rates obviously,rendering slightly higher molecular weights of the resultant PIps and smaller Np(number of polymer chains per Nd atom)values.Moreover,to mimic the structure of natural rubber,the hydroxyl end groups can be facilely modified into phosphonate,amide,and UPy,whose structures were further confirmed by NMR spectra.Incorporation these functionalities could greatly improve the hydrophilic properties of the polymers,as revealed from the significantly reduced static water contact angles.

Lanthanide complexes mediated coordinative chain transfer polymerization of conjugated dienes

Tremendous advances has been witnessed in the past few years in the lanthanide complexes mediated coordinative chain transfer polymerization(CCTP) of conjugated dienes. CCTP features catalyst economy, well-controlling over both microstructure and architecture of the resulting polymers, and accessibility for novel(co)polymers. This review highlights the recent progresses made in the field of CCTP of dienes. After a brief introduction, the body of this review is divided into three parts:(1) principle of CCTP;(2) coordinative chain transfer homopolymerization of dienes;(3) coordinative chain transfer copolymerization of dienes.At the end, we present some challenges remaining in this area and our personal opinion regarding where this field should continue to develop. CCTP represents a novel strategy to prepare polydiene synthetic rubbers with controlled high molecular weight and narrow molecular weight distribution, which has reached the practical industrial application level, demonstrating a great potential in industrialization.