Polyester-based nanocomposites prepared by the entropically-driven ring-opening polymerisation of macrocyclic oligomers

In order to investigate the great potential of macrocyclic oligomers (MCOs) for producing polymer-clay nanocomposites with well-dispersed nanoplatelets and consequently improved final properties, we initiated a study aimed at obtaining polymer/clay nanocomposites based on homo- and co-polyesters of PET, PTT and PBT. The MCOs were prepared by cyclo-depolymerization (CDP) of the corresponding polyester carried out in refluxing o-dichlorobenzene. Different montmorillonites were mixed with the MCOs in the presence of an ED-ROP (entropically-driven ring-opening polymerization ) catalyst, such as dibutyltin oxide. The ensuing mixture was melt blended with one of the above mentioned polyesters in a Brabender internal mixer. The influence of processing conditions, such as temperature, time and rotors speed on the morphology of the resultant nanocomposites was investigated. Reagents and products were thoroughly characterized by using various techniques such as NMR, GPC and MALDI-ToF for macrocyclics, DSC, TGA, WAXD and TEM for modified clays and nanocomposites.