Dynamic polymers containing one acylhydrazone linkage and dynamic behavior thereof

Dynamic polystyrene (d-PS) and poly(n-butyl acrylate) (d-PBA) with an acylhydrazone linkage at each chain center were synthesized by atom transfer radical polymerization (ATRP) of corresponding monomers using a bis-bromoisobutyrate initiator bearing one acylhydrazone bond. Kinetic studies demonstrated that the polymerization followed a first-order mechanism. When treated with trifluoroacetic acid or heated at 120 °C in solution, the polymer chains of d-PS and d-PBA were found to be cleaved partially into blocks of half original length, i.e. PS/2 and PBA/2, implying that a dynamic equilibrium of forming and breaking acylhydrazone bond was established.