Microstructure of 2,3 erythro di-isotactic polynorbornene from atomistic simulation

RIS Model of the Helix‐Kink Conformation of Erythro Diisotactic Polynobornene

“…[4] However, the origin of the kink was not deduced from these simulations, because the torsional angle sequence in the kinks was longer than the simulated sequence in these earlier simulations. These short sequences in the previous simulations also prevented the formulation of the accurate rotational isomeric states (RIS) model developed herein.…”

“…This aforementioned helix-kink morphology present in erythro diisotactic PNB induces a level of structural order in PNB that is intermediate between a crystal and a truly amorphous glass. [4,13] We suspect that the PNB helical conformation is similar to substituted polyacetylenes and this is presumably due to the alternating double bonds these polymer share. [4] This intermediate order manifests…”

“…[4,13] We suspect that the PNB helical conformation is similar to substituted polyacetylenes and this is presumably due to the alternating double bonds these polymer share. [4] This intermediate order manifests…”

“…[1] Recent advances in polymerization catalyst technology allow norbornene monomer to undergo a metal-catalyzed vinyl addition polymerization that retains the bicycloheptane group in the polymer backbone. [1][2][3][4] This retention of the bicycloheptane group, in contrast to the ring-opening metathesis polymerization (ROMP) mechanism for norbornene which retains only a single cyclopentyl ring in the polymer backbone, is shown in Figure 1. [5,6] As seen in Figure 1, there are a variety of stereochemical configurations that can result from this polymerization, depending on the exact nature of the catalyst used and resulting monomer enchainment mechanism.…”

“…[4,13,14] The splitting of the first peak in the amorphous halo into two peaks in the WAXD pattern for PNB is indicative of the formation of intermediate range order due to strong intramolecular interactions. [4] This extended chain behavior that mimics the conformation of a rigid-rod appears to be unique to the erythro diisotactic isomer of PNB. Simulation of PNB without this alternating bridge-head carbon showed a much less extended conformation that was similar to a random coil conformation.…”