Novel sub‐ceiling temperature rapid depolymerization‐repolymerization reactions of cyanoacrylate polymers

Dilute solutions of unimodal high‐molecular‐weight poly(butyl cyanoacrylate) (“parent” polymer) in tetrahydrofuran (THF) at 21°C underwent rapid depolymerization accompanied by simultaneous repolymerization of the unzipped monomer to yield lower‐molecular‐weight “daughter” polymer following addition of tetrabutylammonium hydroxide (TBAOH), a slow initiator of butyl cyanoacrylate (BCA) monomer. The rate‐determining step for the reaction was tentatively identified as abstraction of the terminal chain proton. Similarly, addition of TBAOH to a THF solution of BCA monomer resulted in initial formation of high‐molecular‐weight (MW) polymer that subsequently rapidly depolymerized with simultaneous formation of TBAOH initiated, low‐MW daughter polymer. The depolymerization‐repolymerization reaction is the relaxation process that occurs following perturbation of the monomer/high‐MW parent polymer equilibrium by low‐MW daughter polymer and proceeds at least 100°C below the ceiling temperature of the parent polymer.