IGC study of filler-filler and filler-rubber interactions in silica-filledcompounds

A modification of the existing methods for evaluating the dispersive and sp ecific components of surface free energy (gamma (d) and gamma (s), respecti vely) was made to investigate filler-rubber and filler-filler interactions by inverse gas chromatography. Four silicas as fillers and various probes t hat mimic elastomers were employed in this study. It was shown that the pre treatment of silicas with helium could increase gamma (d) and decrease gamm a (s). Modification of the silica surface with silane could enhance the dis persive interaction and weaken the specific interaction. The temperature de pendence of the interfacial interaction was also investigated, and it was f ound that lower temperatures favored filler-rubber interactions and mixing efficiency. Tests on different sizes of agglomerates demonstrated the exist ence of a filler-rubber and filler-filler network. It was also found that g amma (d) played a role in agglomeration or filler-filler interaction. Our s tudy showed that the larger the specific surface area was, the stronger the dispersive and specific interactions were. The effectiveness of various fi llers and elastomer probes was also compared. (C) 2001 John Wiley & Sons, I nc.