PET-based Nanocomposites Made by Reactive and Remodified Clays

Anovel modification method is used for the synthesis of reactive organoclays. Acommercial organoclay (Cloisite® 30B) was therefore remodified with two kindsof acid chloride based monomers. Chlorinated diacid monomers of differentchemical structures, terephthaloyl chloride (TPC) and adipoyl chloride (APC), wereused as remodifying agents. The remodification process was confirmed by Fouriertransform infrared (FTIR) spectroscopy. A series of poly(ethylene terephthalate)(PET)-based nanocomposites were formed by compounding the remodified clays andalso the commercial organoclay with the polymer using a twin-screw extruder. Themorphology of the nanocomposites was examined by transmission electronmicroscopy (TEM) and X-ray diffraction (XRD) techniques and their thermal stability bythermogravimetry analysis (TGA). The XRD and TEM investigations confirmed that thereactive remodified clays were much more efficiently dispersed in PET matrixcompared to conventional commercial clay. The PET/virgin commercial clay nanocompositesshowed a partially intercalated structure, however the PET/remodifiedclays showed exfoliated structure. Both remodification processes through aromatic andaliphatic moieties proved to be useful in aiding the exfoliation process, but thenanocomposites made from the remodified clays with APC monomer showed moreimprovement in thermal stability as compared to the samples made from TPC. This wasattributed to the slightly better dispersion of APC-based clays in PET matrix. This studydemonstrated the success of the reactive remodification process in more efficientdispersion of the clays in PET matrix changing the morphology from a partiallyintercalated to a more complete exfoliated structure and leading to an improvedthermal stability.