27
Recent Advancements In Rubber Nanocomposites
Galimberti Maurizio,1 Cipolletti Valeria1, Musto Sara1, Cioppa Serena,1 Giulia Peli,1 Mauro Marco2, Guerra Gaetano2, Agnelli Silvia,3 Riccò Theonis,3 Kumar Vineet4
1 Politecnico di Milano, Dipartimento di Chimica, Materiali e Ingegneria Chimica “G. Natta”, Via Mancinelli 7, 20131 Milano (I)
2 Salerno University, Dipartimento di Chimica, Università di Salerno, via Ponte don Melillo, 84084 Fisciano (SA), Italy
3 Università degli Studi di Brescia, Via Branze 38, 25123 Brescia, Italy
4 Università degli Studi Milano-Bicocca, Via R. Cozzi 53, 20125 Milano
Most investigated nanofillers (NF) for rubber nanocomposites (RNC) are organically modified clays (OC), carbon nanotubes (CNT) and nano-graphite (nano-G). Their primary particles have at least one dimension of one or few nanometers and can be individually dispersed in the polymer matrix. NF have thus a great effect on the rubber properties, provided that even distribution and dispersion are achieved. In fact, most research efforts are aimed at exfoliating layered fillers such as OC and nano-G and at debundling CNT. NF particles, thanks to their high surface area, form filler networks at very low NF concentrations, giving also rise to hybrid filler networks with a nano-structured filler such as carbon black (CB).
This work attempts a rationalization of the phenomena that steer the formation of RNC, discussing in particular the efficient dispersion of NF particles, the exfoliation of layered fillers and the NF networking phenomenon.
The interaction of NF with chemicals traditionally employed to modify NF, such as ammonium cations and fatty acids, is studied. OC and intercalate compounds of graphite oxide1,2 were prepared with the help of solvents, at the solid state and in the rubber matrix, by using a variety of ammonium salts, fatty acids and amides. Characterization of NF and RNC was performed through thermogravimetric, X-ray diffraction, infrared and differential scanning calorimetry analyses. Behaviour of sulphur based vulcanization, static and dynamic-mechanical properties of RNC were investigated.
The NF networking phenomenon is discussed examining RNC either with NF in neat matrices or based on the hybrid CNT-CB3 and nano G-CB4 filler systems. Overall correlation between the RCN mechanical properties, in particular the storage modulus, and NF surface area is proposed.
The control of NF structure is aimed at reducing the non linearity of dynamic-mechanical properties of RNC, particularly in view of their application in tyre compounds.
1 M. Mauro, M. Maggio, V. Cipolletti, M. Galimberti, P. Longo, G. Guerra, Carbon, in press
2 M. Galimberti, V. Cipolletti, M. Mauro, L. Conzatti, Macromolecular Chemistry and Physics, in press
3 M. Galimberti, M. Coombs, V. Cipolletti, P. Riccio, T. Riccò, S. Passera, S. Pandini, L. Conzatti, A. Ravasio, I. Tritto, Macromol. Mater. Eng. 2012, 298(2), 241-251
4 M. Galimberti, V. Kumar, M. Coombs, V. Cipolletti, S. Agnelli, S. Pandini, L. Conzatti, Rubber Chem. Technol. in press