Viscosity measurement oscillating plate method

With rubbers a similar situation is met, but now with the aid of a rotation viscometer. The Mooney viscosity is measured as the torque needed to rotate two parallel plates, between which the rubber mass is present, with respect to each other. This provides a rough indication of the viscosity, and thus of the molar mass. This measurement can also be used to characterize the vulcanization behaviour under vulcanization conditions the increase of the Mooney viscosity indicates the onset of network formation. When the network develops further, a continuous rotation can, of course, no longer be applied because the viscosity increases unlimitedly therefore an oscillation method is mostly used with a cone-and-plate geometry. Initially, the viscosity is being measured, and later on the build-up of the E-modulus of the network. Another characterization of the viscosity of unvulcanized rubbers is the Hoekstra method. The rubber is present between two parallel plates, which are moved towards each other with a certain speed the force needed to do so is an indication of the viscosity. 

The experimental methods for the determination of liquid viscosity are similar to those used for gases ( 8.VII F) (i) transpiration, through capillaries, (ii) torque on rotating cylinders, or the damping of oscillating solid discs or spheres, in the liquid, (iii) fall of solid spheres through the liquid, (iv) flow of liquid through an aperture in a plate, (v) capillary waves. Methods (i) and (ii) are mostly used for absolute, the others for comparative, measurements. 

In this method the liquid crystal is filled in a container having a circular or rectangular cross-section (Fig. 5). A thin plate suspended from a wire or glass rod is submerged in the liquid crystal. The force on the suspension during an upward or downward movement of the container or the damping of an oscillation of the plate gives a measure of the viscosity of the liquid crystal [13-16]. 

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