We used real-time fluorescence microscopy to investigate the migration of latex particles in drying battery slurries. The time evolution of the fluorescence signals revealed that the migration of the latex particles was suppressed above the entanglement concentration of carboxymethyl cellulose (CMC), while it was significantly enhanced when CMC fully covered the surfaces of the graphite particles. In particular, a two-step migration was observed when the graphite particles flocculated by depletion attraction at high CMC/graphite mass ratios. The transient states of the nonadsorbing CMC and graphite particles in a medium were discussed, and the uses of this novel measurement technique to monitor the complex drying processes of films were demonstrated.

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The effect of sodium carboxymethyl cellulose (CMC) and styrene butadiene rubber (SBR) on film formation was evaluated by analyzing both drying stress and pore size distribution. We discovered that the SBR in a graphite/SBR slurry filled the voids among the graphite particles with the increase in SBR concentration. In addition, the CMC in the graphite/CMC slurry was adsorbed onto the graphite surface, which caused the graphite particles to coalesce. In the graphite/CMC/SBR slurry, a large amount of SBR was needed to increase the mechanical strength of the film in the low concentration region of CMC. However, in high concentration region of CMC, the SBR did not affect the mechanical strength of the film any longer. On the basis of the drying stress measurements, we could draw a processing window map that clearly shows the effect of CMC and SBR on the mechanical strength of the film, which will be useful in the design of anode slurries.

Preheating of dental composites improves their flowability, facilitating successful restorations. However, the flowability of dental composites is affected not only by temperature but also by the deformation conditions. In the present work, the effects of various deformation conditions upon the viscoelastic properties of a preheated dental composite were studied. The rheological properties of Z350 dental composites at 25, 45, and 60°C were measured by a strain-controlled rheometer. When a low strain (0.03%) was applied, the preheated composite exhibited greater shear storage modulus (G') and complex viscosity (η*) than a room-temperature composite. Oppositely, when a high strain (50%) was applied, G' and η* of a preheated composite were lower than those of a room-temperature composite. Preheating of dental composites might be helpful in clinical practice both to increase the slumping resistance when minimal manipulation is used (e.g., during the build-up of a missing cusp tip) and to increase flowability when manipulation entailing high shear strain is applied (e.g., when uncured composite resin is spread on a dentin surface).

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