Rheometer data

Specifications for soHd i7j -l,4-polyisoprenes are shown in Table 5 and include analyses for volatile matter, extractables, ash, and Mooney viscosity at 100°C. Standard method ASTM D1416 includes chemical analysis methods for volatile matter, extractables, and total ash, while ASTM D1646 includes Mooney viscosity (82). The Monsanto rheometer data for vulcanizates prepared by a standard recipe may also be specified. This formulation for vulcanizate (ASTM D3403) is mixed in a Banbury mixer in two passes with all but sulfur and accelerator added in first pass ... 

The influence of ZnCFO concentration (3,0 5,0 7,0 phr) on formation of properties complex of the unfilled rubber mixes and their vulcanizates on the basis of isoprene rubber of the following recipe, phr isoprene rubber - 100,0 sulfur - 1,0 di - (2-benzothiazolyl) -disulfide - 0,6 N, N -diphenylguanidine - 3,0 stearic acid - 1,0, was carried out in comparison with the known activator - zinc oxide (5,0 phr). The analysis of Rheometer data of sulfur vulcanization process of elastomeric compositions at 155°C (fig. 5) shows, that on crosslink density and cure rate, about what the constants of speed in the main period (k2) testify, they surpass the control composition with 5,0 phr of zinc oxide. Improvement of the complex of elastic - strong parameters of rubbers with ZnCFO as at normal test conditions, and after thermal air aging (tab. 1), probably, is caused by influence of the new activator on vulcanization network character. So, the percent part of polysulfide bonds (C-Sx-C) and amount of sulfur atoms appropriating to one crosslink (S atoms/crosslink) in vulcanizates with ZnCFO are decreased, the percent part of disulfide bonds (C-S2-C) is increased (fig. 62). 

Figur 5. Rheometer data of sulfur vulcanization process of modeling unfilled elastomeric compositions on the basis of isoprene mbber at 155°C with ZnCFO as the activator ...

Taking into account the ZnCFO positive influence on formation of the complex of the physical-mechanical characteristics of vulcanizates on the basis of various rubbers and theoretical preconditions about interrelation "recipe - structure - property", it was interested to define the morphology features of elastomeric compositions. With this purpose the percalation method of the analysis by the rheometer data of rubber mixes was used [10],... 

Fig. 9. Friction reduction effectiveness of synthetic polymers and polysaccharides during one pass through a turbulent flow rheometer (data taken from Kenis)...

Figure 6. Shows typical capillary rheometer data.

One of the main concerns is that using the torque value that the imit is reporting instead of the dynamic viscosity for calculation of Reynolds numbers renders the latter to become dimensional. Therefore, the Reynolds number calculated from torque rheometer data is referred to as pseudo-Reynolds dimensional number. Because of the fact that torque was shown to be proportional to a kinematic (rather than dynamic)... 

The capillary rheometer is a valuable tool for predicting the processability of thermoplastic resins. This is done by measuring melt viscosities at shear rates and temperatures commonly encountered in extrusion and injection molding. This procedure is difficult and time consuming due to the complex nature of rheological measurements and analyses. An automated system for acquisition and analyses of capillary rheometer data has been developed to speed up and simplify this important analytical technique. 

Melt viscosity measurements involve monitoring the pressures produced when molten polymer is forced through a capillary at various shear rates. Viscosities are calculated from capillary rheometer data using the following equations... 

Figure 3. Melt viscosity as a function of weight fraction of diluent (melt index rheometer data at 220°C r = 2.05 X 10 dyn/cm2 I" L X 0.05" D capacity -SOsNa content = 1.78 mol %. (O) base resin (0) base resin + DOP base resin + DEP (a) base resin + glycerol.

Figure 67. Comparison of Bingham plastic viscosity (in cP) obtained from a Fann concentric viscometer and an on-line pipe rheometer. (Data from reference 161.)...

ABSTRACT A rotational benchtop Rheometer with vane spindles can be used to measure the static yield stress behavior of materials. By running at different rotational speeds, the Rheometer data can be equated with the viscoelastic information determined by an oscillating rheometer. The rotational Rheometer offers a less expensive method suitable for Quality Control needs. 

Figure 6 Capillary rheometer data for change in viscosity with increasing shear rate...

Kwak SJ, Mutsuddy BC (unknown) Rheological Evalution of ceramic-binder mixtures from torque rheometer data. In Chemical Bibliography 888, Institute of Materials Processing, Michigan Technological University, Houghton, Michigan, 49931... 

If/m is the maximum packing density of the particles, which is defined as the volume fraction at which the particles touch one another, so that flow is not possible, then the actual particle volume firaction/used in injection molding is lower than/m by 5-10 vol%. This means that in a well-dispersed suspension, the particles are separated from one another by a thin layer of polymer with a thickness of about 50 nm dming the molding, so that the mixture is able to flow. Therefore, the volume fraction of particles / is determined by the particle size and distribution and the particle shape. In practice, the volume firaction of ceramic powders is determined from viscosity measurements by using a capillary rheometer. Data for the relative viscosity, i.e., the viscosity of the mixture divided by the viscosity of the unfilled polymer versus particle concentration can be well fitted by the following equation [209] ... 

One of the reasons for the popularity of melt index data is that rheometer data is significantly more expensive. Because of the higher cost of rheometry equipment and the advanced training needed by operators, most plastics manufacturers do not have a rheometer on site. Nonetheless, the data obtained from a rheometer is quite valuable to processors, so a technique has been developed to use an extruder to obtain more complete rheological data than is available from the melt index test. 

Figure 6.9 Capillary rheometer data showing viscosity vs. shear rate for three temperatures...

Fig. 5 Left VPDF of Lemon cake batter showing increased probability at high velocities. The function shows almost zero contribution at w=0, which is a hint to wall slip behaviour. Right Viscosity as a function of shear rate exhibiting shear thinning of the cake batter - the viscosity decreases with increasing shear rate. NMR (o) and rotational rheometer ( ) data.

Goodrich, J. E., and R. S. Porter. 1967. Rheological interpretation of torque—Rheometer data. Polymer Eng Science, ZOanuary), 45-51. 

Goodrich, J.E. and Porter, R5. (1%7) A rheological interpretation of torque rheometer data, Polym. Engg Sci., 7,45. 

Figur 7.10 Variation of primary normal stress difference with shear stress for calcium carbonate filled polypropylene treated with titanate surface modifier ITS. Open symbols represent Weissenberg rheogoniometer data and closed symbols represents Han slit/capillary rheometer data. (Reprinted from Ref. 34 with kind permission from Society of Plastics Engineers Inc., Connecticut, USA.)...

We will use these results for analyzing capillary rheometer data in Chapter 6. 

The amounts of HDPE in a blend and the shear rate were chosen as independent variables in this study. Experiments were carried out in the melt state at 190°C. A Goodrich method was used for determination of effective instrument dimensions, which allows one to employ the Daane et al procedure in order to relate torque-rheometer data to more fundamental rheological values. The same HDPE/LDPE ratios were used in the study of mechanical behavior of HDPE/LDPE system of injected specimens. As said previously, DSC thermograms were used to determine weight concentration of two crystalline components both in HDPE/LDPE blends and wastes. 

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