Chemical Structure Drives Memory Effects in the Crystallization of Homopolymers

Abstract

Although the study of melt memory has attracted much interest, the effect of polymer chemical structure on its origin has not been fully elucidated. In this work, we study the melt memory effects by differential scanning calorimetry employing a self-nucleation protocol. We use homologous series of homopolymers containing different polar groups and a different number of methylene groups in their repeating units: polycarbonate, polyesters, polyethers, and polyamides. We show that melt memory in homopolymers is generally controlled by the strength of the intermolecular interactions. The incorporation of methylene groups reduces the melt memory effects by decreasing the strength of segmental chain interactions, which is reflected by the decrease in dipolar moments and solubility parameters. This work presents for the first time a unified view of the melt memory effects in different homopolymers.