Preparation and characterization of intercalated calcium-based montmorillonite nanocompounds with organophosphorus flame retardants

Abstract

Three organophosphorus flame retardants (9, 10-dihydro-9-oxa-10-phosphophenanthrene-10-oxa (DOPO), triphenyl phosphate (TPP) and pentaerythritol phosphate (PEPA)) were intercalated into the layer of calcium-based montmorillonite (CaMMT) by a simple, direct and solvent-free method, and three organophosphorus flame retardant montmorillonite nanocompounds (DOPO-CaMMT, TPP-CaMMT and PEPA-CaMMT) were prepared. X-ray diffraction (XRD) shows that the three phosphorus-containing small molecules are successfully intercalated into the layer of CaMMT. It was verified by transmission electron microscope (TEM) that the interlayer spacing of CaMMT in the three nanocompounds shows different degrees of increase. The change of thermal stability of the nanocompounds was characterized by thermogravimetric analysis (TGA). The formation mechanism of the three nanocompounds was studied. The results show that TPP and PEPA are intercalated into CaMMT in one step, while DOPO is intercalated into CaMMT in two steps with a larger interlayer spacing. The nanocompounds formed by the intercalation of three organophosphorus flame retardants into CaMMT layer are expected to achieve better dispersion of CaMMT in polymer and synergistic flame retardant effect of phosphorus and silicon.

Keywords

• calcium-based montmorillonite
• 9, 10-dihydro-9-oxa-10-phosphophenanthrene-10-oxa
• triph-enyl phosphate
• pentaerythritol phosphate
• nanocompound
• intercalation