Layered Nanofillers for Rubbers

LAYERED NANOFILLERS FOR RUBBERS

Galimberti Maurizio¹, Cipolletti Valeria^1, Coombs Michele², Kumar Vineet³, Mauro Marco⁴, Guerra Gaetano⁴,  Conzatti Lucia⁵, Giannini Luca²

¹ Politecnico di Milano, Dipartimento di Chimica, Materiali e Ingegneria Chimica “G. Natta”, Via Mancinelli 7, 20131 Milano (I)

² Pirelli Tyre, Viale Sarca 222, 20126 Milano (I)

³ Università degli Studi di Milano-Bicocca, Dipartimento di Scienza dei Materiali, Via R. Cozzi 53, 20125 Milano (I)

⁴ Università degli Studi di Salerno, Dipartimento di Chimica, via Ponte don Melillo, 84084 Fisciano (SA), Italy

⁵ CNR-ISMAC UOS Genova, Via De Marini 6, Genova (I)

Nanofillers play a role of increasing importance, also on a commercial scale, for the reinforcement of rubbers. It is well known that layered fillers such as clays were first used, in the 90’s, for the preparation of polymer nanocomposites and are, still nowadays, the most applied nanofillers in the rubber field¹, in spite of the large interest for carbon nanotubes (CNT)² and of the increasing number of studies on graphene and on nanofillers made by few layers of graphene. ³

Clays are characterized by structural features that are particularly suitable to bring about substantial improvements of rubber properties, namely barrier and mechanical properties. The aspect ratio, the availability of a space between two opposite layers, the hydrophilic or hydrophobic nature as a function of the compensating cation appear as the most relevant clay characteristics in view of their use in a rubber composite. Moreover, studied developed in the last years^1,4showed that the order in the interlayer space can be tuned by appropriately selecting the compensating cation and the optional guest(s).

As mentioned above, an increasing interest is dedicated by the scientific community to nanofillers made by few layers of graphene. They are layered and can propose the features reported above for clays.

There is thus the chance of investigating the effect of layered fillers in rubber composites, trying to attempt a correlation between the nanocomposite properties and the filler structure. This work present a study of layered nanofillers for rubber composites. Layered fillers were prepared starting from pristine clays and nano-graphites and their structure was assessed through X-ray diffraction (XRD) analysis. Rubber nanocomposites were prepared and characterized through electron microscopy and XRD and by determining quasi-static and dynamic-mechanical properties. A rationalization of the obtained results is proposed.

¹ M. Galimberti, Ed.. Rubber Clay Nanocomposites - Science, Technology and Applications, Wiley and Sons, New York, , pp 601, 2011

² L. Bokobza, Polymer 48: 4907-4920 (2007).

³ J. R. Potts, D. R. Dreyer, C. W. Bielawski, R. S. Ruoff Polymer52(1): 5-25 (2011)

⁴ M. Galimberti, S. Giudice, V. Cipolletti, G. Guerra Polymers for Advanced Technologies 21: 679–684 (2010)