Aromatic interactions in aryl-capped polylactides: A thermorheological investigation

A series of aryl-capped poly(lactide)s (PLAs) were synthesized by living ring-opening polymerization with a chain transfer agent (also referred to as immortal polymerization, iROP) using a previously reported dinuclear indium catalyst, [(NNO)InCl]2(μ-Cl)(μ-OEt) (A). For understanding the extent and strength of association caused by the arylated chain ends, end-functionalized PLAs were analysed using thermal, rheological, and mechanical techniques. We show that the end-group has a greater effect on the properties of low molecular weight PLAs due to the larger number density of the aryl end groups; significant interactions can be induced under oscillatory shear conditions in the low frequency flow regime (terminal zone). The effects of associations on the extensional properties are also discussed.