10 research outputs found
Tunable Blocking Agents for Temperature-Controlled Triazolinedione-Based Cross-Linking Reactions
The
remarkable reactivity of triazolinediones (TADs) toward olefin-type
substrates marks them as highly attractive click reagents, in particular
for polymer modification and cross-linking. Critically, their ultrafast
reaction rates result in handling issues and a rather limited shelf
life whereas a particular concern for polymer material applications
is homogeneous network formation. Herein, we introduce 2-phenylindoles
as highly promising blocking agents for TADs, giving bench-stable
reagents at ambient temperature from which the initial TADs can be
released upon heating. A set of 11 indoles with varying substitution
patterns was synthesized, leading to a precise control for the temperature
of deblocking within a broad range of 35–100 °C. The established
indole–TAD platform was next applied to bivalent TAD reagents
to enable on-demand TAD-based cross-linking reactions of a diene-containing
polyurethane (<i>M</i><sub>n</sub> = 12.5 kDa). Fine-tuning
of the curing temperatures, down to 50 °C, was evidenced via rheological
measurements