Turk J Chem 26 (2002) , 925 – 937. c  T ¨ UB ˙ ITAK Poly(methacrylic) Acid and γ -methacryloxypropyltrimethoxy Silane/Clay Nanocomposites Prepared by In-Situ Polymerization Ahmet G ¨ ULTEK, Turgay SEC ¸K ˙ IN ∗ ˙ Inonu University, Chemistry Dept. 44069 Malatya-TURKEY e-mail: tseckin@inonu.edu.tr Yunus ¨ ONAL ˙ Inonu University, Chemical Eng. Dept., 44069 Malatya-TURKEY M. Galip ˙ IC ¸ DUYGU ˙ Inonu University, Chemistry Dept. 44069 Malatya-TURKEY Received 20.03.2002 Poly(methacrylic acid) and poly(acrylic acid) nanocomposites were prepared by in-situ polymerization of γ-methacryloxypropyltrimethoxysilane (A174)/clay nanocomposites in which the macromonomer was generated by grafting A-174 onto activated clay samples via hydroxyl groups or via intercalation. In- situ polymerization was carried out in the presence of an initiator. It was found that the structural affinity between the methacrylic or acrylic acid monomers and the amount of clay played an important role in the hybrid structure. The nanocomposites were quantified by both X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), thermo-gravimetric analysis (TGA), and differential thermal analysis (DTA). Key Words: Nanocomposites, clay, kaolinite, in-situ polymerization, macromonomer Introduction In-situ polymerization and melt intercalation are the most common ways of preparing polymer/clay nanocom- posites 1−2 . This methodology involves monomer intercalation followed by polymerization. A great deal of research has been carried out in this field over the past decade 3−5 . With the addition of a very small amount of nanofiller into the polymer matrix, substantial increases in many physical properties including tensile modulus and strength, flexural modulus, thermal stability, flame retardance, and other barrier resistances were increased 5−15 . Intercalated PMMA and PS nanocomposites, exfoliated nylon-6, poly(ε-caprolactone), and epoxy have been synthesized either in emulsion or via ring opening polymerization 15−20 . ∗ Corresponding Author 925