Abstract:
Naturally, Na
+
Montmorillonite (MMT) has hydrophilic properties due to the
presence of inorganic cations on their surface. Thus, the surface modification
becomes indispensable to enhance its interfacial interaction with the organic phase.
Current commercial organo modified MMT products have stable temperature
limitation of about 200
o
C. In order to improve its thermal stability, this study
proposed surface modification of MMT by using alkylphosphonium as surfactant
due to the participation of its low energy d-orbitals in the processes of making and
breaking bonds, which inhibits decomposition from easily occurring. Two types of
alkylphosphonium surfactants; tributyl(methyl) phosphonium (TBMP) and tetraoctyl
phosphonium (TOP) were used in this study as surface modifier of MMT via ion
exchange reaction. The OMMT’s formed characterized by TGA, XRD, FTIR,
elemental analysis (CHNS) and ASAP analysis. The successful insertion of TBMP
and TOP ions into the interlayer of MMT increased the interlayer distance and
altered the nature of Na
+
-MMT from hydrophilic to organophilic MMT (OMMT) as
well as exhibited substantially higher thermal stability in organic region in TGA
thermogram compared to the commercial alkylammonium MMT. OMMT’s were
then underwent melt intercalation technique as nanofiller in poly(methyl
methacrylate) (PMMA).
