Preparation and characterization of poly(2-hydroxyethyl methacrylate)/Na-montmorillonite intercalated nanocomposites

A series of intercalated nanocomposites were prepared via in situ polymerization of 2-hydroxyethyl methacrylate (HEMA) between the interlayer spacing of hydrous Na-montmorillonite (Na-MMT) using benzoyl peroxide (Bz(2)O(2)) as a radical initiator. X-ray diffraction patterns showed the absence of any intercalation up to 61.7 mass % of HEMA, but anhydrous Na-MMT formed by the hydrophilic effect of HEMA. The interlayer spacing (d(001)) values of hydrous and anhydrous Na-MMT were calculated as 1.19 and 1.03 nm, respectively. At higher monomer contents, the increase in the value of d(001) from 1.19 to 2.01 nm indicated intercalation of polymer in the interlayer spacing of Na-MMT. Besides, transmission electron microscopy results supported the formation of the intercalated nanocomposites. Thermogravimetric analysis showed that the thermal stability of the nanocomposites increased considerably by intercalation of pure poly-HEMA. Specific surface area and specific nanopore volume of the nanocomposites decreased with the increasing of the monomer content taken by the preparations. The decrease is due to the nonporous nature of the polymer matrix.