Megadalton Macromolecules Made-to-Order in Minutes: A Highly Active Nanosphere Catalyst for Preparing High-Molecular Weight Polymers

Abstract

A rhodium(I)-based polymer, [Rh2(cyclooctatetraene)-Cl2]n, was used as a heterogeneous catalyst to prepare stereoregular poly(phenylacetylene) under ambient conditions and within short periods of time. Ultrahigh-molecular weight polymers were obtained when silica and an amine were added to the reaction mixture. The additives promoted catalytic activity as the silica functioned as a support, while the amine induced the depolymerization of the polymer catalyst into its monomeric components. Kinetic analyses in conjunction with molecular weight measurements revealed that the polymerization reaction proceeded in a chain-growth fashion. The poly(phenylacetylene)s were analyzed using a series of tensile tests and found to be mechanically robust (sigma = 20.1 MPa and E = 2.0 GPa). Features intrinsic to the catalyst facilitated the realization of a novel "injection polymerization" method in which passing monomer through catalyst-loaded cartridges rapidly and conveniently afforded high-molecular weight polymer fibers.