Effect of nanoclay on the extent of transesterification in PET/PEN nanocomposite

The extent of transesterification reaction has been explored in PET/PEN blends in presence of three nano-fillers Cloisite® 30B nanoclay, a silane re-modified and a copper re-modified nanoclays. Wide angle X-ray diffraction (WAXD) has been performed to qualify the extent of nanofiler dispersion in PET/PEN blend. The occurrence of transesterification reaction and its extent have been determined by proton nuclear magnetic resonance (1H NMR). It is found that the extent of transesterification decreases by incorporating the nano-fillers to the blend. Among the investigated nano-fillers the Cloisite® 30B nanoclay and the silane re-modified nanoclay showed the highest influence on depression of transesterification level. The FTIR results revealed that the incorporation of nanoclays in PET/PEN blend decreases the reactive carboxyl end groups of PET and PEN as a result of reaction with the surface hydroxyl groups of nano-fillers, and hence, the reduction of reactive groups leads to the depression of transesterification level in PET/PEN blend. In re-modified nanoclay the depression of extent of transesterification is less than Cloisite® 30B. This is due to less reduction of surface reactive groups that are located at nanoclay layers and more spatial hindrance of regenerated groups.

Keywords:

transesterification , PET/PEN , nanoclay , nanocomposite