Properties regulation of poly(butylene succinate) ionomers through their ionic group distribution

- Ionic group distribution of PBSI could be controlled through chain extension reaction.
- The morphology of PBSI was determined by its ionic group distribution.
- The physical properties of PBSI depend strongly on its ionic group distribution.

Dihydroxyl terminated poly(butylene succinate) ionomer precursors (Pre-PBSIs) with different ionic group contents were prepared to chain-extend with dihydroxyl terminated poly(butylene succinate) to synthesize high molecular weight poly(butylene succinate) ionomers (PBSIs) with controlled ionic group distributions. The chemical structures and molecular weights of the precursors and PBSIs were characterized by nuclear magnetic resonance spectroscopy and gel permeation chromatography. The effect of ionic group distribution on the morphology, thermal behavior, isothermal crystallization kinetics, rheological behavior, and mechanical properties of PBSIs were investigated by transmission electron microscopy (TEM), differential scanning calorimeter (DSC), polarizing optical microscopy (POM), wide angle X-ray diffraction (WAXD), rotational rheometer, and tensile testing. With the increase of ionic group content in incorporated Pre-PBSI, phase separation between PBSI and PBS segments occurred as observed by TEM, the crystallization was improved as investigated by DSC and WAXD, while the complex viscosity and tensile strength decreased as studied by rotational rheometer and tensile testing. All the results indicated that the properties of PBSI can be regulated by the ionic group distribution.