Automatic viscometer

One of the simplest methods of examining this effect is by capillary viscometry, although automatic viscometers are commercially available. In a U-tube viscometer such as the Ubbelohde suspended level dilution model shown in Figure 9.8, the flow times of pure solvent and a polymer solution t are recorded. This is done by pipetting an aliquot of solution of known volume into bulb D. The solution is then pumped into E. The flow time t is the time taken for the solution meniscus to pass from X to y in bulb E. 

Continuous measurement of viscosity. The accuracy of the Mark-Houwink equation will be improved if the intrinsic viscosity of a fraction at each retention volume can be measured continuously. An automatic viscometer having a capillary of 0.5 mm in diameter and a length of 200 mm was constructed and applied to the estimation of molecular mass of di- and triblock copolymers of polystyrene-polyisoprene P(S-IP) and di-block copolymer of P(S-MMA) [32]. In the case of copolymers which have homogeneous... 

A similar type of automatic viscometer, with a capillary diameter of 0.4 or 0.5 mm and a length of 200 mm, was applied to copolymers of vinyl chloride (VC), methyl acrylate, and MMA with vinylidene chloride (VDC) [33]. At the peak maximum the viscosity was not very different from that of the whole polymer. The viscosities increased with the decrease in VDC content. From the plot of [fj ] and the slope a and intercept K were obtained and corrections were made according to ... 

A series of random, block and graft copolymers of VC with styrene (S), butadiene (B), MMA, VAc, and VDC was characterized with the help of three consecutive detectors a differential refractometer (RI), an ultraviolet absorption detector (UV) and an automatic viscometer [33]. Figure 5.2 summarizes the relation between solution viscosity and molecular mass for these copolymers. 

Viscometric Methods.—Dilute Solution Viscosity [ij]. Ubbelohde and Fica automatic viscometers are among the apparatus which are frequently used to obtain thermodjmamic data from dilute solution viscosity measurements. The method suffers from vagaries of interpretation in... 

ROUSSEL, G. and DU PARQUET, J. Development of a fully automatic viscometer for oil rheology in a broad range of shear rates , SAE 1982, Paper No. 82121)9. 

Melt Index Tester MTS Capillary Viscometer Automatic Capillary Rheometer ProcessibiLity Tester... 

HVA 6 Automated CapiUary/Sht Viscometer MFM Melt Flow Rheometer Automatic Melt Flow Indexer AK Continuous Capillary Rheometer Han Slit Rheometer... 

More recent developments in the rolling ball area include an automated micro viscometer, the Paar AMV 200, from Paar Physica. The specimen to be measured is introduced into a glass capillary down which a gold-covered steel ball roUs. The rolling time is measured automatically. The shear stress may be varied by changing the inclination angle of the capillary tube. The shear rate range is 10 1000, which makes the instmment useflil for... 

Rheological and processability behaviors were studied in a Monsanto processability tester (MPT), which is an automatic high-pressure capillary viscometer. The entire barrel and capillary are electrically heated with a microprocessor-based temperature controller [14], The... 

The screening capillary viscometer can be operated manually as well as automatically. If manual operation is desired, an interactive program is available to aid with data collection. Program-operator interaction takes place through terminal input and also with a push-button data collection indicator on the instrument itself. The immediate on-line analysis of results and the ease of data storage and retrieval are just some of the benefits realized by using this program 1n conjunction with manual operation of the instrument. 

Zimmerman, E. (1967). Automatic recording of viscosity changes with the Ostwald capillary viscometer. Anal. Biochem. 21, 81—85. 

IL. Dilute solution viscosity measurements were done at 30 with the appropriate Ostwald-Fenske capillary viscometers. The water content of all organic solvents, used as the liquid phase in solid-liquid PTC runs was analyzed by potentiometric Karl Fischer titration using a Metrohm AG CH 9100 model automatic titrator. 

Irradiation Studies in Solution. The degradation studies on both PIPTBK and PMIPK in solution were carried out in an automatic UV irradiation-viscometer apparatus that has been described elsewhere (10). Each solution was irradiated at 313 nm for a fixed time period and then automatically transferred to a viscometer, where nine repetitive measurements of the efflux time were performed. The solution was then returned to the UV cell for further irradiation, and the cycle was repeated seven times. The intrinsic viscosity of... 

Meyerhoff (4) and Goedhart and Opschoor (5) have measured the viscosity of each eluting GPC fraction by coupling an automatic capillary tube viscometer with the GPC syphon. The low polymer concentration in each fraction necessitated an extremely accurate efflux time measurement to 0.01 second since the flow time of each fraction containing polymer has flow times, th greater than that of pure solvent, t0, by at most 2.00 seconds. The specific viscosity sv. of the ith polymer fraction is calculated from the flow times of the pure solvent and the polymer fraction. 

Most mills control the cooking cycle by automatic time-temperature controllers and recorders. The rate of temperature rise to the conversion plateau must be slow to prevent hot pockets or cold areas. The rate of temperature increase to the inactivation plateau must be rapid to prevent excessive depolymerization in the intermediate temperature range. The viscometers operate according to different mechanisms time to expel paste from a sample device (Norcross) vibration of a probe in the paste (Dynatrol) torque readings (Brookfield) or pressure drop on passage through an orifice (Escher Wyss). Potential errors in viscosity can result from variations in starch solids due to differences in moisture content of the starch, errors in slurry preparation and the quantity of condensate added by the steam. The process yields a maximum paste concentration of about 32%. 

Chromatography. Filtered polysaccharide solutions were analyzed using an SEC system consisting of an automatic sampler (Waters WISP, Waters, Milford, MA) with a high-performance liquid chromatography pump (Waters model 590), pulse dampener (Viscotek, Houston, TX), viscometer... 

The Brookfield DV-II+-series rotational viscometers and DV-IIl-series rheometers have a built-in Time-to-Torque feature. The selected instrument is run in stand-alone mode, at one constant speed with one spindle. The motor rotation automatically stops at a user-selected torque reading that is a percent of full-scale range or "FSR." The elapsed time and the setpoint torque are then shown on the instrument s display. This system can therefore be used as a type of gel timer - the instrument monitors the torque increase to 90 % of full-scale range, for example, as the sample s viscosity increases during gelation. However, it is a "one-point" test - that is, only one data point is acquired. If the instrument s "continuous printing" mode is selected and a... 

Dilute solution viscosities used for determining the intrinsic viscosity of the polymer systems in 2.0 wt % NaCl were obtained in a capillary viscometer (Ubbe-lohde) by using standard methods (iO, 11). Some of the measurements were obtained fi om an automatic capillary viscometer (Schott AVS/G). A conventional Huggins relationship 11) in which reduced viscosity is a linear function of polymer concentration was used to fit the data. A regression analysis was used to yield the intrinsic viscosity (the intercept) and the Huggins interaction coefficient, K, (the slope divided by the square of the intrinsic viscosity). 

The indicated above importance of polymer melts viscosity causes the appearance of a considerable number of theoretical treatments, describing this property on the basis of either representations, mainly fiom the point of view of free volume [3], In the present chapter polymer melts viscosity is treated within the framework of fractal analysis [5]. This is due to the fact, that the macromolecular coil in polymer solutions and melts is a fiactal [6] that creates prerequisites for the polymer melt viscosity prediction quite at the synthesis stage. The authors of Ref [7] demonstrated the possibility of polymer melts viscosity description and prediction within the fiamework of fiactal analysis on the example of two polymers of different classes—aromatic poly-ethersulfonoformals (APESF) and high-density polyethylene (HOPE). MFI values were determined on the automatic capillary viscometer IIRT-A at temperatures and loads, listed in Table 1. The fiactal dimension of a macromo-... 

Apparatus Latex irradiator with activity 110 kCi Co for producing irradiated latex, automatic dipping machine for examination gloves with capacity 7.0(X) gloves/hour, pH meter, viscometer, Instron tester type 1122 apparatus for measuring the quality of latex and its film were used in this trial... 

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