Temporal Control over Two- and Three-State Living Coordinative Chain Transfer Polymerization for Modulating the Molecular Weight Distribution Profile of Polyolefins.

The design and successful demonstration of a highly versatile new strategy for manipulating the molecular weight profiles, including breadth, asymmetry (skewness) and modal nature (e.g. mono-, bi- and multimodal), of a variety of different polyolefins is reported that involves temporal control over two- and three-state living coordinative chain transfer polymerization (LCCTP) of olefins in a programmable way.  By changing the identity of the R' groups of the chain transfer agent, ER' n , as a function of time, different populations of chains within a bi- or multimodal polyolefin product can be selectively 'tagged' with different end-group functionalities and by changing the nature of the main-group-metal of the CTA, programmed manipulation of the relative magnitudes of the polydispersities of the different maxima that make up the final MWD profile can be achieved.  Finally, this new strategy can be easily implemented with existing LCCTP materials and conventional reactor methods to provide access to scalable and practical quantities of an unlimited array of new polyolefin materials - including many that represent new fundamental forms.