Fateme Minavand - Polymer Engineering Department, Amirkabir Universitycof technology / Tehran, Iran.
Mehdi Rafizade - Polymer Engineering Department, Amirkabir Universitycof technology / Tehran, Iran.
Faramarz Afshar Taromi - Polymer Engineering Department, Amirkabir Universitycof technology / Tehran, Iran.

The temperature of the preparation of PET is about 280 , and in this temperature most of the organo-modifiers have been decomposed. This is a major problem in preparingPET/MMT nanocomposites. Modification of Na-MMT with organo modifiers, is an effective way to improve the compatibility between polymer matrix and clay filler , but organo-modifier don’t have good thermal stability due to the high temperature that it has to withstand during the process ofPET. We prepare a new treatment for Na-MMT which could improve its thermal stability during the in situ polymerization.We modified Na-MMT with BHET (Bis hydroxylethyl terephthalate, the monomer of PET) and our new clay – modification don’t degrade up the 400 And can stand out during the polycondonsation stage in synthesize of PET. BHET that has been used , recovered from the glycolysis of off-grade PET.