posted on 2018-12-17, 00:00authored byTaylor Wright, Tanja Tomkovic, Savvas G. Hatzikiriakos, Michael O. Wolf
A composite polymer based on vinylogous
urethane vitrimer bonding
with both photodimerizable and thermally exchangeable functionalities
is described. Polymers containing various ratios of photodimerizable
diaminoanthracene monomers and thermally exchangeable diaminoalkyl
monomers linked by a common bisacetoacetate group are studied. It
is demonstrated that alkyl amines undergo the necessary thermal exchange
reactions for vinylogous urethane vitrimers, while aromatic amines
do not. UV-induced dimerization of the anthracene units results in
changes to the rheological properties and the glass transition temperature
due to polymer cross-linking. Rapid and near-complete scratch healing
upon heating is demonstrated, with a tunable onset temperature for
healing controlled by UV irradiation. The viability of a composite
vitrimeric system, wherein vitrimeric monomers are combined with non-vitrimeric,
stimuli-responsive monomers to generate random copolymers with new
properties, is demonstrated.