A co-coagulation process was utilized to prepare carboxylated butadiene-styrene rubber (xSBR)/halloysite nanotube (HNT) nanocomposites. The interfacial interaction, morphology, and the mechanical performance of the nanocomposites were investigated. Attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS) results indicate the formation of hydrogen bonding between xSBR and HNTs. Lower content of HNTs tends to delay the vulcanization of xSBR/HNT compounds, while higher HNT loading promotes the vulcanization. It is shown that HNTs are dispersed individually and uniformly in the matrix with strong interfacial bonding. The mechanical properties, especially the modulus and hardness, are significantly increased by the inclusion of HNTs. The significant reinforcing effects of HNTs are correlated to the co-coagulation process and strong interfacial interactions via hydrogen bonding. (C) 2008 Elsevier Ltd. All rights reserved.