An investigation on the dispersibility of carbon nanotube in the latex nanocomposites using rheological properties

This study focuses on the preparation and rheological investigations of carboxylated styrene butadiene rubber latex (XSBR) - multiwall carbon nanotube (CNT) nanocomposites. Two types of non-functionalized CNT and hydroxyl functionalized multiwall carbon nanotube (CNTOH) were used. A new approach based on concurrent ball milling of CNT and XSBR latex was applied to embed the nano material into the carboxylated latex. To do so, first of all, the effect of ball milling on the colloidal stability of the carboxylated latex was examined by the use of Dynamic Light Scattering (DLS) method. The results of DLS revealed that the particle size of the carboxylated latex did not seriously alter during ball milling, implying that the milling process had no significant impact on the aggregation of particles. The study of rheological properties of nanocomposites showed that the simultaneous milling of the latex and CNT can lead to a relatively better dispersion of CNT in the latex compared to the dispersion obtained by ultrasonication which provides a new opportunity to produce latex nanocomposites in large scales using industrial ball mills. The hydroxyl functionality of CNT led to an enhanced dispersion of CNTOH into the polymer matrix through reaction with carboxyl group of the latex. These findings were also confirmed by infrared spectroscopy. Finally, ZnO was proposed as a Lewis catalyst for the improvement of CNT dispersion in the carboxylated latex and an improved dispersion was gained.