Effects of ionic substitution on physical properties, and crystallization rates of, poly(oxyethylene-b-butylene adipate) ionomers

Poly(oxyethylene-b-butylene adipate) ionomers (POBAis) were synthesized and the relationship between the nature of the ionic subsistent and the non-isothermal crystallization behavior and physical properties of the ionomer was evaluated. Non-isothermal crystallization analyses confirmed that additional ionic groups on POBA prevented chain diffusion and slowed the crystallization process. Mechanical analyses demonstrated that ionomers with an additional 2.5 mol% of ionic substituents exhibited enhanced mechanical strength, as a result of strong physical cross-linkages between polymer chains. This effect was reversed with an excess of ionic groups, due to preferential intramolecular ion pair associations. It was thus concluded that optimization of the ionic group content could be used to tailor the physical properties and crystallization rates of poly(oxyethylene-b-butylene adipate) ionomers.