Viscometry Ubbelohde

Dilute Solution Viscometry - The hydrogenated and hydroformyl ated (10%) PBD were completely soluble in toluene. Intrinsic viscosity measurements were carried out in toluene at 30°C using a Cannon-Ubbelohde viscometer. 

Viscometry. Intrinsic viscosity. Kinematic viscosities (v=rj/p, where tj is the viscosity) were measured in a Cannon-Ubbelohde capillary viscometer. At least four concentrations, covering the relative viscosity range where the subscript s denotes the solvent) from about 1.8 to 1.2 were used to construct Schul -Blaschke plots. These plots of versus where... 

Viscometry measurements were made in benzene at 30 °C and in TFE at 50 °C with uncalibrated Cannon-Ubbelohde dilution viscometers which gave solvent times greater than 100 seconds. The viscometers used had centistoke ranges denoted by viscometer sizes of 50 and 75 for benzene and TFE, respectively. Stock solutions were made up on gram solute/100 gram solution basis and converted to gram/deciliter via the solvent density at the temperature of measurement. The solvent densities used were d ene = 0.8686 (11a) and dlra = 1.3429 obtained from pycno-metric measurements (12). The density—temperature relationship for TFE obtained from regression analysis of the experimental pycnometric data is... 

Physical Measurements. Intrinsic Viscosities. Intrinsic viscosities were obtained using dilute solution viscometry (Cannon-Ubbelohde viscometers). 

Physical Measurements. Molecular Weight. Intrinsic viscosities were determined using dilute solution viscometry (Cannon-Ubbelohde viscometers). For the poly (methyl methacrylate) polymer the following empirical expressions were used to obtain molecular weights (4) ... 

Viscometry The specific viscosity of each polymer from the bulk polymerization was measured in acetone at 30°C using an Ubbelohde dilution viscometer. Five concentrations in the range of 1.120 to 0.242 g/d poly(vinyl acetate) and polyvinyl trideuteroacetate) and 0.385 to 0.084 g/dl (poly(trideu-terovinyl acetate)) were run. Intrinsic viscosity was calculated by extrapolation of the Tlsp/c versus c plot to zero concentration. Number average molecular weights were calculated using the equation(20) [q] =1,0 x 10 1 [Mn] 0 72 which is in the mid range of the equations listed. 

Intrinsic Viscosity. Dilute-solution viscometry of samples in toluene was carried out in a Cannon-Ubbelohde semimicrodilution viscometer (size 25) in a temperature-controlled bath (25.0 0.2 °C). At least three concentrations were measured, and the results were extrapolated to infinite dilution by using the Huggins and Kramers relations... 

Viscometry Viscoboy, Lauda, Ubbelohde, Schott Overall composition, degree of swelling... 

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. 

The use of MM-sensitive detectms has been extensively reported. Crubisic-Gallot et al. [37] applied SEC with on-line viscometry, using a discrete visccxneter (Ubbelohde type), to homopolymers and copolymers. They also used the technique to obtain a relation between viscosity and MM. The disadvantage of this method is that it cannot monitor the eluent continuously. 

Also included in Table 3 are intrinsic viscosity data from differential viscometry and Ubbelohde viscometry. There is excellent agreement between the... 

Two mobile-phase compositions of H O/CHjCN (80 20, vol/vol) and 0.10 MNaNOj/CHjCN (80 20, vol/vol) were used for SEC-viscometry of partially hydrolyzed grades (32). PEO, PEG, and PSC were used for column calibration, and universal calibration was observed (29). Molecular weights by SEC-viscometry for grades of high, medium, low, and superlow molecular weight compare favorably those from SEC-LALLS, especially with the H O/CHjCN mobile phase (Table 6). It is suspected that the nonsalt mobile phase works better to eliminate the hydrophobic interactions and maximize the size exclusion mechanism (32). Intrinsic viscosity values calculated from viscometry for the two acetonitrile mobile-phase compositions and from Ubbelohde viscometry in HjO/CH CN, are also summarized in Table 6. 

Solutions of HEC derivatives were prepared using the dry powder products at different concentrations. The suspensions were stirred gently for at least three days in order to obtain homogeneous solutions prior to viscometry measurements. Brookfield viscometry measurements were carried out at various shear rates using appropriate spindles. The apparent intrinsic viscosity of modified and unmodified HEC were also measured by using Ubbelohde viscometry. 

Intrinsic viscosities of nylon-6 polymer and nanocomposites were determined using dilute solution viscometry (ASTM D2857-95). Efflux times for 40% sulfuric acid and different concentrations of nylon-6 polymer and nanocomposite solutions were determined using a Ubbelohde-type viscometer. Four concentrations were prepared for each sample. The efflux time values were used further to determine the various terms listed in Table. 14.1, which shows the definition of the terms used in dilute solution viscometry, where... 

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