ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Modification and characterization of montmorillonite fillers used in composites with vulcanized natural rubber

Jana Hrachová, Ivan Chodák, and Peter Komadel

Institute of Inorganic Chemistry, Slovak Academy of Sciences, Dúbravská cesta 9, 845 36 Bratislava, Slovakia

E-mail: uachjana@savba.sk

Received: 11 January 2008  Revised: 10 June 2008  Accepted: 11 June 2008

Abstract: Parent Ca-montmorillonite (Jelšový Potok, Slovakia, Ca-JP) and Na-montmorillonite Kunipia-F (Japan, Na-KU) were ion-exchanged with octadecyltrimethylammonium (ODTMA) cations. Characteristics of the samples were studied by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (IR) and thermogravimetry (TG). Surface areas were measured by sorption of N₂ and ethyleneglycol monoethyl ether. Scanning electron microscopy photographs (SEM) were used to characterize the texture of samples. The XRD patterns show that, upon intercalation, the basal spacing of montmorillonite is expanded and corresponds to the pseudotrimolecular arrangement of organic cations in the interlayers. The IR spectra of organically modified montmorillonite show C-H stretching and bending bands of both CH₃ and CH₂ groups in the 3000–2800 cm⁻¹ and 1500–1400 cm⁻¹ region, respectively. Modification of montmorillonite by organic cations decreased the hydrophilicity of their mineral surface and adsorbed water evaporated at lower temperatures. The SEM photographs reveal a tendency towards lump formation and agglomeration of the ODTMA-montmorillonite particles. The modification introducing organic moiety lead to a substantial decrease in the surface area of both montmorillonites; however, it remained remarkably high, being at the level typical for silica. Completely characterized fillers were used to prepare rubber compositions with enhanced physical properties, as described in Hrachová et al. (2008).

Keywords: montmorillonite - organoclay - ODTMA - filler - nanocomposite

Full paper is available at www.springerlink.com.

DOI: 10.2478/s11696-008-0079-y

Chemical Papers 63 (1) 55–61 (2009)