Original multiwalled carbon nanotubes (O-MWCNTs) and aminofunctionalized ethylenediamine-treated multiwalled carbon nanotubes (MWCNTs-EDA) were mixed with bismaleimide (BMI) resin to prepare O-MWCNT/BMJ and MWCNT-EDA/BMI composites, respectively. Raman spectroscopy, thermogravimetric analysis, and infrared spectroscopy were used to investigate the influence of aminofunctionalization on the multiwalled carbon nanotube (MWCNT) framework. Dynamic mechanical analysis, scanning electron microscopy images of the fractured surface, and field emission scanning electron microscopy of the worn surface were used to determine the possible friction and wear mechanisms of the system. The MWCNT-EDA/BMI composite exhibited a higher friction coefficient value and a lower wear loss rate value than the O-MWCNT/BMI composite, which was attributed to the larger number of defects caused by the aminofunctionalization of the MWCNTs, the stronger interfacial adhesion formed between the MWCNTs-EDA and the BMI resin, and the better dispersive state of the MWCNTs-EDA in the BMI matrix. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 113: 3484-3491, 2009