ZnGA-MMT catalyzed the copolymerization of carbon dioxide with propylene oxide

Zinc glutarate (ZnGA) synthesized from zinc oxide and glutarate acid was dispersed on the surface of acid-treated montmorillonite (MMT) in quinoline to prepare ZnGA-MMT catalyst. The results of X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) measurements indicated that the ZnGA on the surface of acid-treated MMT had the same crystalline structure as pure ZnGA. Copolymerization between CO2 and propylene oxide (PO) was carried out under optimized reaction conditions using ZnGA-MMT catalyst, consequently giving poly(propylene carbonate) (PPC) with high molecular weight in a very high yield (115.2 g polymer per gram of ZnGA). The obtained PPCs were investigated using 13C NMR and FTIR spectra, showing a completely alternating structure. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) examinations showed the PPCs with a high transition temperature of 38 °C and a very high decomposition temperature (>250 °C) due to the presence of MMT residual in polymer.