Preparation and Characterization of Exfoliated Poly(ethyleneterephthalate)/Montmorillonite Nanocomposites Using Modified MMTs with Variable Content of Antimony Acetate

Poly(ethylene terephthalate) (PET)/montmorillonite (MMT) nanocomposite was prepared by the direct polymerization with MMTs modified with variable content of antimony acetate (Sb(OAc)3), which was also used as catalyst polymerization. The modified MMTs (AS-Sb-MMT) were prepared by intercalating both Sb(OAc)3 and amphoteric surfactant (AS) into MMT layers. Nine kinds of Sb-MMTs [MMT treated with Sb(OAc)3] with different Sb content were obtained, but only six kinds of PET/MMT nanocomposites could be prepared. ICPAES was used to characterize Sb content of modified MMT, XRD was used to characterize interlayer spacing, IR spectroscopy was used to characterize composition change of Sb catalyst in modified MMT and TEM was used to investigate micromorphology of PET/MMT nanocomposites. Several results are obtained, i.e., (a) Sb content of Sb-MMT is affected by both drying temperature and washing-drying sequence, (b) compared with Na-MMT (unmodified MMT), the change in the interlayer spacing of Sb-MMT is attributed to the solvent ethylene glycol (EG) rather than the intercalated or absorbed Sb(OAc)3, (c) based on this, a model is developed to describe the swelling of Na-MMT and modified MMT by EG and the effect of drying temperature on the interlayer spacing, (d) exfoliation state of MMT in PET matrix of nanocomposites is controlled not only by Sb content and interlayer spacing, but also by the composition of Sb catalyst in modified MMT.