Rubber nanocomposites were obtained by melt blending synthetic poly(l,4-cis-isoprene) as the rubber and organically modified clays (OC). OC were prepared by reacting at the solid state pristine montmorillonite and dimethyl ditalloyl ammonium (2HT) chloride and by optionally adding stearic acid (SA). Different dam interlayer distances were obtained for OC by changing the amount of the compensating cation 2HT and by adding SA. In particular, dool interlayer distance was increased from 2.5 nm to 4 nm with a higher amount of 2HT and the addition of SA led to the 6 nm value. A different degree of order in the interlayer space was observed for the three OC. The same interlayer distance between two successive layers was detected upon melt blending OC with IR. Tensile and dynamic-mechanical properties of nanocomposites were found to be affected by the OC structure, namely by the interlayer distance. The higher values for stresses at given elongations and for dynamic-mechanical moduli were obtained with OC having 2.5 nm as the dam interlayer distance.
By Cipolletti Valeria, Coombs Michele, Kumar Vineet, Mauro Marco, Guerra Gaetano, Conzatti Luciae, Giannini Luca