Effect of natural and organically modified montmorillonite clays on the properties of polydimethylsiloxane rubber

The effects of natural (MT) and organically modified (O-MT) montmorillonite clays on the properties of polydimethylsiloxane (PDMS) rubber were evaluated. Rubber composites with different clay contents were prepared by a compounding procedure in an open two-roll mill, which was followed by a compression-molding step in which the PDMS matrix was peroxide crosslinked. The clay rubber composites were characterized by swelling measurements in toluene, thermogravimetric analyses, X-ray diffraction, scanning electron microscopy, and tensile tests. The introduction of MT restricted the solvent swelling and increased the crosslinking density of the rubber, which indicated the formation of a covalent filler–matrix interface. The enhanced interaction between MT and PDMS reduced the aggregation size of MT particles in the MT composites and promoted an increase in the separation of the clay layers. When the rubber was filled with O-MT, a higher solvent amount was incorporated in the material, and this trend increased with the clay content. Moreover, the low interaction between O-MT and the PDMS chains resulted in larger clay aggregates in the O-MT composites compared to those with MT. Despite the different interface natures, both clays enhanced thermal stability and acted as reinforcing fillers in relation to Young's modulus and tensile strength. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

[1]  Helmy,et al.  Surface Area Evaluation of Montmorillonite. , 1999, Journal of colloid and interface science.

[2]  M. Osman,et al.  Reinforcement of poly(dimethylsiloxane) networks by montmorillonite platelets , 2002 .

[3]  S. Guggenheim,et al.  Baseline studies of the clay minerals society source clays: Thermal analysis , 2001 .

[4]  M. Gonçalves,et al.  Biogenic silica short fibers as alternative reinforcing fillers of silicone rubbers , 2006 .

[5]  Massimo Lazzari,et al.  Polydimethylsiloxane thermal degradation Part 1. Kinetic aspects , 2001 .

[6]  E. Abdel‐Bary,et al.  Effect of waste rubber powder in SBR formulations on the swelling of different organic solvents , 1997 .

[7]  M. Gonçalves,et al.  Eucalyptus kraft pulp fibers as an alternative reinforcement of silicone composites. II. Thermal, morphological, and mechanical properties of the composites , 2003 .

[8]  Dogu,et al.  Effect of pH in an Aqueous Medium on the Surface Area, Pore Size Distribution, Density, and Porosity of Montmorillonite. , 1999, Journal of colloid and interface science.

[9]  W. Weber,et al.  Evaluation of shale and organoclays as sorbent additives for low-permeability soil containment barriers. , 2001, Environmental science & technology.

[10]  Wei Xie,et al.  Thermal Degradation Chemistry of Alkyl Quaternary Ammonium Montmorillonite , 2001 .

[11]  V. Perrichon,et al.  Synthesis and characterization of Al-pillared and cationic surfactant modified Al-pillared Algerian bentonite , 1997 .

[12]  V. Farmer.  The Layer Silicates , 1974 .

[13]  J. Halpin.  Stiffness and Expansion Estimates for Oriented Short Fiber Composites , 1969 .

[14]  M. Richardson,et al.  Preparation and characterization of poly(styrene-co-butadiene) and polybutadiene rubber/clay nanocomposites , 2005 .

[15]  Liliane Bokobza,et al.  Elastomeric composites. I. Silicone composites , 2004 .

[16]  R. Vaia,et al.  Lattice model of polymer melt intercalation in organically-modified layered silicates , 1997 .

[17]  H. Olphen.  An Introduction to Clay Colloid Chemistry , 1977 .

[18]  E. Giannelis,et al.  Synthesis and properties of new poly(dimethylsiloxane) nanocomposites , 1995 .

[19]  C. Cohen,et al.  Reinforcement of Poly(dimethylsiloxane) Elastomers by Chain-End Anchoring to Clay Particles , 1999 .

[20]  G. Sandí,et al.  Characterization of Montmorillonite Surfaces After Modification by Organosilane , 2001 .

[21]  E. Giannelis,et al.  On The Origins of Silicate Dispersion in Polysiloxane/Layered‐Silicate Nanocomposites , 2006 .

[22]  T. M. El-akkad,et al.  Nitrogen and water vapour adsorption on monovalent and divalent montmorillonite derivatives and their heats of immersion in polar liquid , 1982 .

[23]  Daniel I. Kaplan,et al.  Iodide Sorption to Subsurface Sediments and Illitic Minerals , 2000 .

[24]  W. Fan,et al.  Influence of Fe‐MMT on crosslinking and thermal degradation in silicone rubber/clay nanocomposites , 2006 .

[25]  J. Gérard,et al.  Surface modifications of montmorillonite for tailored interfaces in nanocomposites , 2002 .

[26]  H. Ishida,et al.  Concentration-Dependent Conformation of Alkyl Tail in the Nanoconfined Space: Hexadecylamine in the Silicate Galleries , 2003 .

[27]  C. A. Walker,et al.  Swelling of Silicone Elastomers , 1956 .

[28]  C. Volzone,et al.  Modified bentonitic clay minerals as adsorbents of CO, CO2 and SO2 gases , 2002 .

[29]  E. Riande,et al.  Effect of silica and rice husk ash fillers on the modulus of polysiloxane networks , 2003 .

[30]  R. Wibulswas.  Batch and fixed bed sorption of methylene blue on precursor and QACs modified montmorillonite , 2004 .

[31]  C. Nah,et al.  Preparation and properties of EPDM/organomontmorillonite hybrid nanocomposites , 2002 .

[32]  J. Bottero,et al.  Study of the Structure of Dimethyldioctadecylammonium-Montmorillonite by Small Angle X-Ray Scattering , 1995 .

[33]  E. Giannelis,et al.  Nanostructure and properties of polysiloxane‐layered silicate nanocomposites , 2000 .

[34]  G. Camino,et al.  Thermal polydimethylsiloxane degradation. Part 2. The degradation mechanisms , 2002 .