Simple Strategy for Dual Control of Crystallization and Thermal Property on Polyesters by Dispersing Metal Salts Via Multiple Coordination Bonds

Abstract

AbstractIn this study, metallo‐supramolecular polyesters with multiple coordination bonds along the chains are prepared, to demonstrate a simple strategy to control both the thermal property and crystallizability. Firstly, polyesters with multiple pyridine‐ligands are synthesized through melt polycondensation and subsequent Michael addition reaction. By adding a metal salt (ZnCl2), the fraction of metal‐coordinated pyridine‐ligands is systematically increased with increasing the Zn2+/pyridine‐ligands mole ratio according to Fourier transform infrared spectroscopy (FT‐IR) measurements, which is found to play a role in tuning the glass transition temperature. The metal‐ligand coordination simultaneously causes the disappearance of crystallization/melting peaks in differential scanning calorimetry (DSC) thermograms, and scattering measurements also indicate the disappearance of crystalline domains. A transparent film is thus obtained after blending small amounts of ZnCl2 (≪10 wt%), although the neat crystalline sample is highly opaque. This non‐crystallization phenomenon is induced by inhibition of the chain arrangement due to the existence of metal salts dispersed via coordination with pyridine‐ligands. By changing the fraction of pyridine‐ligands in the chain, it is found that the wider temperature range Tg tuning can be achieved for samples with higher ligand fractions.