Study On Carbon Black/Polyurethane Antistatic Foams

The dispersion of carbon black (CB) in polyether polyol and CB/polyurethane (PU) foams was improved by optimizing the dispersing process and the surface modifications of CB. The effect of surface modifications on the dispersion of CB in polyether polyol and CB/PU foams and the properties of the CB/PU composite foams was investigated. The result of comparisons showed that the push type and interlaced-vane type stirring paddles have better on dispersing tiny particles in liquid system. Pristine CB (p-CB) was oxidized in nitric acid to obtain oxidized CB (o-CB), and then by the esterification reaction between the carboxyl groups of o-CB and the hydroxyl groups of polyether polyol, polyol grafted CB (g-CB) was obtained. Optical microscopy observation of the CB suspensions showed that surface modifications effectively improved the dispersion of CB in polyether polyol. Scanning and transmission electron microscopy observations showed that surface modifications effectively improved the dispersion of CB in the composite foams. Compared with the p-CB/PU foams, the o-CB/PU and g-CB/PU composite foams exhibited improved conductivities, storage moduli and increased glass-transition temperatures. The cell sizes of the modified CB/PU (especially g-CB/PU) composite foams were smaller and more uniform than those of p-CB/PU foams. The compressive strengths of the p-CB/PU and o-CB/PU composite foams decreased with the increase of filler contents, but g-CB had no negative effect on the compressive strength even at the filler content as high as 8 phr.