Rheology of linear and gelled carbon black thermoplastics composites

Abstract

This study was initiated to understand what effect polymer structure has on the fusing properties of dry toner in electrophotography and to define the rheological properties of carbon containing thermoplastics. The polymer systems studied span a range of crosslinking density and molecular weight distribution. Various types and molecular weight ranges of resins have been shown to effect the viscoelastic properties of toner materials. The authors examine the effects of processing, shear history, crosslink density, molecular weight distribution, and carbon black filler on the rheological properties of the composite. Polymer composites, typical of those employed as toners for hot roll fusing in electrophotography, were studied using the cone/plate geometry at temperatures ranging between 100°C and 180°C. It is shown that the melt rheology of the carbon composites is strongly influenced by (1) the structure of the initial resin, and (2) the method used to disperse the carbon black into the polymer matrix. It was found that the character of the melt at 160°C in time less than one second with the partially crosslinked resins was changed from liquid-like to solid-like after shearing at 50s-1 for 0.5 s.