Note: When clicking on a Digital Object Identifier (DOI) number, you will be taken to an external site maintained by the publisher.
Some full text articles may not yet be available without a charge during the embargo (administrative interval).
What is a DOI Number?
Some links on this page may take you to non-federal websites. Their policies may differ from this site.
-
null (Ed.)
-
more » « less
Abstract A highly versatile new strategy for manipulating the molecular weight profiles, including breadth, asymmetry (skewness) and modal nature (mono‐, bi‐, and multimodal), of a variety of different polyolefins is reported. It 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 , with time, different populations of chains within a bi‐ or multimodal polyolefin product can be selectively tagged with different end‐groups. By changing the nature of the main‐group metal of the CTA, programmed manipulation of the relative magnitudes of the dispersities of the different maxima that make up the final MWD profile can be achieved. This strategy can be 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. -
more » « less
Abstract A highly versatile new strategy for manipulating the molecular weight profiles, including breadth, asymmetry (skewness) and modal nature (mono‐, bi‐, and multimodal), of a variety of different polyolefins is reported. It 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 , with time, different populations of chains within a bi‐ or multimodal polyolefin product can be selectively tagged with different end‐groups. By changing the nature of the main‐group metal of the CTA, programmed manipulation of the relative magnitudes of the dispersities of the different maxima that make up the final MWD profile can be achieved. This strategy can be 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.
