Thermal properties of poly (methyl methacrylate)/organomodified montmorillonite nanocomposites obtained by in situ photopolymerization

Abstract

The organoclay/poly(methyl methacrylate) (PMMA) nanocomposites were prepared by in situ photopolymerization method using two solvents, ethanol and acetonitrile. The influences of organoclay loading, solvent nature and length of attached surfactant (C8 or C16) on thermal and mechanical properties were studied by thermogravimetric analysis and dynamic mechanical analysis. Alkylammonium surfactants with C8 and C16 chain lengths were evaluated as clay modifiers. All the nanocomposites prepared in acetonitrile exhibited improvement in their thermal stability, mainly due to the interaction between the clay and the polymer which is maximized by the exfoliated clay structure. In the case of PMMA and nanocomposites synthesized in ethanol, the thermal stability of polymer and nanocomposites remained practically the same once the clay structure is predominantly of the intercalated type. In comparison with pure PMMA, glass transition temperature and storage modulus of polymer are notably increased by the presence of clay. It was found that the chain length of surfactant attached to the SWy-1 clay affects the Tg values. Glass transition temperatures of nanocomposites SWy-1-C16/PMMA were significantly higher than the values obtained for nanocomposites SWy-1-C8/ PMMA. This can be attributed to the modifying agent C16, which has a greater hydrophobic chain length. The organic tail can provide a better dispersion of the MMA monomer in the organoclay, resulting in a nanocomposite with predominant exfoliated structure. Another significant factor to be considered was the effect of solvent used in the nanocomposite preparation. Considering nanocomposites with the same chain length (C8 or C16), Tg values obtained for nanocomposites prepared with ethanol is higher than those observed for those prepared in acetonitrile. This was attributed to the influence of the average molecular weight; once the nanocomposites prepared in ethanol exhibited higher polymeric chains.

Enhancements of clay exfoliation in polymer nanocomposites using a chemical blowing agent

“…Overall, the thermal degradation temperature of the PCNs is influenced by the presence of the surfactant, the nature of the polymer matrix and the interactions between the polymer and the clay . For the nanocomposites investigated in this work, the results show that the thermal stabilization effect from the strong bonding between the polymer and the clay dominates, which suppresses the catalytic effect of the surfactant.…”

Al-Pillared-Montmorillonite (AlPMt)/Poly(Methyl Methacrylate)(PMMA) Nanocomposites: The Effects of Solvent Types and Synthesis Methods

“…However, its poor thermal stability has limited its application in these areas. To improve the heat resistance, preparation of nanocomposite is an effective way [2][3][4].…”

Electrospun Poly(methyl Methacrylate)/Polyaniline Blend Nanofibres with Enhanced Toxic Gas Sensing at Room Temperature

“…The high intensity peak in the DTG of pure PMMA may be attributed to the corresponding higher weight loss in the third degradation step. 26 The degradation of the PMMA-PANI also takes place in three steps. Increased thermal stability of PMMA-PANI blend can be attributed to the shift in the third degradation step of PMMA-PANI towards higher temperature.…”