1 research outputs found
Copolymerization of Ethylene and 1,4–Pentadiene: Structure Characterization and Reaction Mechanism
Copolymerization of ethylene and 1,4-pentadiene was conducted
by
using a homogeneous catalyst to understand the insertion mode of 1,4-pentadiene.
The polymer microstructure of the synthesized material was subjected
to structural characterization using quantitative NMR spectroscopy,
diffusometry, two-dimensional correlation spectroscopy, and selectively
refocused insensitive nuclei enhanced by polarization transfer (Sel-RINEPT).
The multimodal NMR characterization allows effective differentiation
of chain ends and backbone signals, filters irrelevant spectral information,
and provides site-specific information to achieve unambiguous structural
elucidation. The experimental results reveal that pentadiene has been
primarily converted to cis- and trans-dialkyl-substituted cyclohexane moieties along the polymer backbone
over the course of polymerization. The analysis also confirms that
unreacted pendant allyl groups from pentadiene remain at a concentration
that is significantly lower than the cyclic structures. In comparison
to the literature results, some discrepancies in structural assignment
have been identified and the results will be discussed. Detailed molecular
structure elucidation provides critical insights into advancing the
understanding of the reaction mechanism