Oscillating-disk rheometer

Fig. 2. Cure curve from oscillating disk rheometer where A represents scorch safety B, cure rate C, state of cure D, optimum cure time and E, reversion.

Over the twentieth century, the mbber industry has developed special rheometers, essentially factory floor instmments either for checking process regularity or for quality control purposes, for instance, the well-known Mooney rheometer (1931), the oscillating disk rheometer (1962), and the rotorless rheometer (1976). All those instmments basically perform simple drag flow measurements but they share a common feature During the test, the sample is maintained in a closed cavity, under pressure, a practice intuitively considered essential for avoiding any wall slip effects. Indeed it has... 

Measuring Vulcanization. The formation of a three-dimensional structure during vulcanization increases the stiffness (modulus) of the compound. Therefore, following the modulus increase versus cure time provides a continuous picture of the vulcanization process. Oscillating disk rheometers provide a useful method to do this (17). In this test, a preweighed sample of uncured mbber is placed into a preheated cavity containing a conical rotor. The cavity is closed and the rotor is set to oscillate within the mbber sample. As vulcanization proceeds, the compound s resistance to rotor movement increases and this resistance is followed as a function of time, thereby generating a continuous profile of cure behavior. These cure curves,... 

The largest volume of fluoroelastomers (about 60% of total) is processed by compression molding. A blank (preform) is placed into a preheated mold, compressed, and cured at the appropriate temperature (see above) for a time established empirically. A good estimate for the curing time in the mold is the value of Co from the measurements by oscillating disk rheometer. In the mold design, it is necessary... 

Laboratory batches of compounded rubber samples were obtained from either Smithers Laboratories of Akron, Ohio, or Mare Island Naval Shipyard. Proper cure conditions were determined for each compound as per ASTM D 20845-79 through the use of a Monsanto lOOS oscillating disk rheometer. Samples used for experimental purposes were cured to 90% of optimum cure. Density was determined by Archimedes method. 

Addition of 2 to 5 phr of alkyl-phenol resins improve tackiness of EPDM stocks. In blends with other synthetic rubbers such as SBR, the co-curability is an important factor while designing the overall curing system while compounding. The important factors to be considered here is to synchronise the curing speed between two polymers, using studies in oscillating disk rheometer charts. However, blends with styrene-butadiene rubber do not have as much acid resistance as 100% EPDM. 

Vulcanization rate was determined by a Monsanto Rheometer. The Monsanto Oscillating Disk Rheometer is designed to measure the complete curing characteristics of a single rubber specimen, heated and maintained under continuous pressure during vulcanization. Sinusoidal oscillation of a conical disk, embedded in the vul-canizable mix confined in a heated square cavity, exerts a shear strain on the speci-... 

Decker. G. E., Wise, R. W., and Guerry. D An oscillating disk rheometer for measuring dynamic properties during vulcanization. Rubber Client. Tech... 36. 451 (1963) and Rubber World, 147, No. 3,68 (1963). Also presented at the Cleveland Rubber Division. ACS. October 17 19. 1962. 

ODR oscillating disk rheometer OTLC open tubular hydrodynamic chromatog-... 

Compounding was performed in an open two-roll mixing mill (laboratory size). NR was first masticated on the two-roll mill for about 2 3 min followed by addition of the ingredients. Cure characteristics were analysed using an oscillating disk rheometer (Monsanto R-lOO) at a temperature of 150 °C. The composites were cured at their respective cure times in a hydraulic press under a pressure of about 120 bar at 150 °C. Aged samples were prepared by keeping the samples in a hot air oven at 70 °C for 7 days. ... 

Rheometer a cure meter which determines and plots a cure curve, illustrating the state of cure for a given time and temperature typically either an oscillating disk rheometer (ODR) or a moving die rheometer (MDR). 

The same behaviour occurs with the scorch-retarded version of ZDMA and is illustrated in Table 8.1 with EPDM rubber. In this example, a 40% increase in TSj is obtained with Saret 634, the scorch-retarded version of ZDMA, without any significant loss in maximum torque (MHF). MHF is the difference between the minimum torque (Ml) and the maximum torque (M ) obtained for a rubber compound by oscillating disk rheometer (ODR). It is a measure of the crosslink density of a compound and is part of the curing characteristics of a compound. 

Cure characteristics, which include scorch time, cure rate and torque values, were measured over a 20 minute period at 160 °C using a Monsanto oscillating-disk rheometer according to ASTM method D1084 [22],... 

The Mooney Viscometer test is one of the oldest processability tests in the rubber industry. Many processors now prefer the oscillating disk rheometer (ODR) for measming cme time and cme rate, but the Mooney Viscosmeter is usually preferred for viscosity and scorch time measmements. 

Oscillating Disk Rheometer - The oscillating disk rheometer (ODR) measmes the complete cming characteristics of an elastomer compound, from a green (uncmed) stock to a fully-cured vulcanizate, at a specified temperature (ASTM D-2084). Data from the ODR are often used in conjunction with Mooney viscosity and scorch to characterize the processing... 

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