mz8b00370_si_001.pdf (2.04 MB)
Brønsted-Acid-Catalyzed Exchange in Polyester Dynamic Covalent Networks
journal contribution
posted on 2018-06-22, 17:24 authored by Jeffrey
L. Self, Neil D. Dolinski, Manuel S. Zayas, Javier Read de Alaniz, Christopher M. BatesThe effect of catalyst
strength on polyester–alcohol dynamic
covalent exchange was systematically studied using Brønsted acids
and a low-Tg poly(4-methylcaprolactone)
vitrimer formulation. Relaxation times, activation energies, and Arrhenius
prefactors are correlated with pKa. Strong
protic acids induce facile network relaxation at 25 °C on the
order of 104–105 s, significantly faster
than Lewis acid alternatives that function only above 100 °C.
Activation energies span 49–67 kJ/mol and increase as pKa decreases. The opposite trend is observed
with the Arrhenius prefactor. We anticipate that the quantitative
understanding of Brønsted acid effects disclosed herein will
be of utility in future studies that exploit acid-catalyzed dynamic
covalent bond exchange.