Novel surface-modified kaolin with liquid-like behavior was prepared. The characteristics of the solvent-free kaolin fluid were evaluated by using Fourier transform infrared spectroscopy, WAXD, thermogravimetric analysis, and transmission electron microscopy. The polyvinyl chloride (PVC)/solvent-free kaolin fluid composites were also fabricated via melt mixing. Owing to the novel surface modification, the hydrophilic kaolin surface grafted long organic chains, which made that the solvent-free kaolin fluid could be well dispersed in PVC matrix and firmly integrated with the PVC matrix. The resulted composites exhibited better heat resistance and mechanical properties than neat PVC resins. POLYM. ENG. SCI., 2012. (C) 2012 Society of Plastics Engineers