Possibility of disentanglement process of condensation polymer by transesterification proof by growth rate of spherulite

In order to proof of the possibility of disentanglement process of condensation polymers via transesterificartion, we measured the growth rate of spherulite (G) of PLLA as a function of melt annealing time (Δt) before isothermal crystallization. We prepared three PLLA samples by means of reaction induced crystallization of oligomers during polymerization. For the sample with unclear crystal habit, we found that G was almost constant at Δt<30 min, and then monotonially decreased with increasing Δt. From GPC measurements, we confirmed that molecular weight did not change and molecular weight distribution became broad. This implies that condensation polymers within the melt disentangle via transesterification.