Viscosity Mooney units

Compound properties Mooney scorch MS + 1 at 121°C (ASTM D1646) Minimum viscosity, Mooney units 38... 

Melvin Mooney devised an instrument to measure the stiffness of uncured compounds, also known as the compound s viscosity. The unit of measurement is expressed in Mooney units. Figure 28.1 shows an instrument set up for measuring viscosity, the Mooney viscometer, in which a knurled knob (rotor) rotates (at 2 revolutions per minute) in a closed heated cavity filled with rubber [2]. 

A shearing action grows between the compound and the rotor, and the resulting torque is measured in arbitrary units called Mooney units, which directly relate to torque. Normally, a preheat period is given to the elastomer following which the disk starts to rotate. An initial high viscosity is recorded which decreases to a minimum value. If the viscosity is more, then the Mooney unit (number) is more and viceversa. 

In the Mooney shearing disk viscometer, a serrated disk is rotated in a sample fixed in a pressurized cavity. The instalment was developed for rubber and other elastomeric materials and is a standard quality control instrument in the rubber industry (ASTM D1646). It is used to measure high viscosities given in arbitrary Mooney units, but usually ca 7.5 x 107 mPa-s at low (ca 1.5 s 1) shear rates. 

The Mooney viscometer offers a more convenient way of measuring scorch and even rate of cure, and a standard method for scorch is given in ISO 289-238 and the BS and ASTM equivalents39 40, as mentioned in Section 3.3 of this chapter. This is essentially the method of ISO 289-1 continued until the viscosity reaches a specified number of Mooney units above its minimum value, either 5 or 3 units depending on whether the large or small rotor is used. The minimum viscosity and the time to reach 5 or 3 units above minimum viscosity are reported. In earlier versions of this test the difference between times to 5 units and 35 units above minimum viscosity was taken as an indication of the rate of cure, but this measure of cure rate is now been superceded. 

Mooney viscosity is the torque of a melt of rubber determined in a Mooney rheometer. The torque is given in Mooney units (MU). It is determined on pure rubber or rubber compounds at elevated temperature (usually between 100 °C to 150 °C) after a well-defined heating procedure (usually 1 min without application of shear and subsequently 4 to 8 min with the application of shear). The method is described in detail in DIN 53523 ASTM D 1646 ISO 289... 

Compoimd viscosity variations should be kept to a minimum to guarantee a reproducible and constant amount of blowing and curing from batch to batch compound Mooney typically 2 Mooney units. 

The deflection of the U-beam is related to the torque required to turn the rotor and thus to the viscosity of the sample. The deflection can be read directly on the gauge which is calibrated in Mooney units. It can also control the linear deflection transducer whose output drives a chart recorder. 

Taiwan). It was found that the Mooney viscosity (MLl +4100 °C) of ENR was 72 (Mooney units) while that of CR was 93 (Mooney units) indicating the lower initial fluidity of CR than that of ENR (Figure 18.46). 

In the rubber industry a double parallel plate device, the Mooney Wscometer (ASTM D1646) is used to measure viscosity, Data is normally reported in Mooney units fi om 0 to 100, but these can be translated to torque and analyzed by eq. 5.5.8 (Naka-jima and Collins, 1974). Another rubber indexer is the oscillating disk curometer, which is typically a bicone oscillating at 3 Hz in a disk-shaped cavity (ASTM D2704). Peak torque is reported on a scale of 0-100, but if the amplitude is known, this can be translated to G. However, at high G levels and the usual operating conditions wall slip can occur. 

This group contains non-precrosslinked, sulfur-free, soluble, homo- and copolymers and is the most important in terms of the quantity used. It comprises the standard grades with polymer viscosities of approximately 30-140 Mooney units (ML4 at 100°C) and slight to medium crystallization types. These grades are also known as mercaptan grades. Their property profiles tend to be influenced mainly by polymer viscosity. 

Product Chlorine Content, wt% Mooney Viscosity Crystallinity (ML1 +4at121 C), Hf, J/g Mooney Units Specific Gravity Key Properties... 

On the other hand, it has been tried to assess the stability of W/O/W emulsions from the view point of the total extent of the oil layers separating the two aqueous phases in a unit volume of the sample (l ). The viscosity of the W/O/W emulsions can be expressed by the Mooney s relation (UP) in a Newtonian flow region (6, 15), as follows ... 

Buna 85 is polybutadiene (the number represents Mooney viscosity), molecular weight -80,000. Hard rubber has high softening point and excellent chemical resistance. The coefficient of vulcanisation to the ebonite stage is 39.3. The coefficient of vulcanisation is the number of unit weight of sulfur combined with 100 units by weight of unsaturated hydrocarbons. Buna S is a butadiene styrene copolymer with 70/30 to 68/32 ratio. Buna SS contains a high proportion of styrene. Perbunan are nitrile rubbers... 

Usually in the manufacture of rubber compounds for tank linings, the Mooney viscosity of the masticated rubber is maintained at 30-35 units, which is achievable, either by premastication or by the use of peptisers. The premastication normally takes about 30-40 minutes at 70 °C in the mixing mill. With the addition of peptisers this time can be reduced to 15—20 minutes. 

The quality-control shearing disk viscometer has always had only a single rotor speed (2rpm), though Mooney [M42] as early as the 1940s built a multispeed unit. The use of Eq. (81) to determine o (i ) and shear viscosity implies a multispeed instrument. 

Hydrogenated acrylonitrile-butadiene robber (HNBR)-Therban 3407, containing 34 % of acrylonitrile units and residual double bonds max 0.9 %, Mooney viscosity 70 was purchased from Lanxess. Dicumyl peroxide obtained from Aldrich was used as cross-linker. Co-agents consisted of nanostructured metal oxides magnesium, zinc or calcium oxide provided by Aldrich and unsaturated acids acrylic acid (Aldrich) or monoallyl maleate (synthesized by Department of Organic Chemistry- Technical University of Lodz). The composition of a typical elastomer blend was HNBR-100 phr, DCP- 3 phr, metal oxide- 3 phr, unsaturated acid-1 phr. 

The objects of research in this study were heterophase crosslinked BNR-EPDM (70 30) blends. At this content of the nonpolar component, a system of interpenetrating crosslinked networks appears. Commercial nitrile-butadiene rubbers (trademarks BNKS-18, BNKS-28, and BNKS-40) were used. The AN-unit contents were 18, 28, and 40 wt %, respectively, and the values of the Mooney viscosity (at 100°C) were 40-50, 45-65, and 45-70 rel. units, respectively. The content of trans-, A-, 1,2-, and cis-, A-units of butadiene was estimated via IR spectroscopy (bands at 967, 911, and 730 cm- ) [13] with the use of extinction coefficients from [14] (Table 2.1). 

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