Dynamic rheological property

Redrawn from L.O. Han and M.S. Jhon, Journal of Applied Polymer Science, 1986, 32, 3809 

Redrawn from Handbook of Polyolefins Synthesis and Properties, 1st Edition, Eds., C. Vasile and R.B. Seymour, Marcel Dekker, New York, NY, USA, 1993. Copyright Marcel Dekker, 1993. 

---

Dynamic Rheological Properties of the Reconstituted Milks During the Coagulation Kinetics... 

Fig. 3.1 Examples of simple, viscometric, shear-flow rheometer geometries, la, 2a and 3 are steady while lb and 2b are dynamic rheological property... 

The viscoelastic response of polymer melts, that is, Eq. 3.1-19 or 3.1-20, become nonlinear beyond a level of strain y0, specific to their macromolecular structure and the temperature used. Beyond this strain limit of linear viscoelastic response, if, if, and rj become functions of the applied strain. In other words, although the applied deformations are cyclic, large amplitudes take the macromolecular, coiled, and entangled structure far away from equilibrium. In the linear viscoelastic range, on the other hand, the frequency (and temperature) dependence of if, rf, and rj is indicative of the specific macromolecular structure, responding to only small perturbations away from equilibrium. Thus, these dynamic rheological properties, as well as the commonly used dynamic moduli... 

In addition to the microstructural geometrical features described above, macroscopic, dynamical, rheological properties of the suspensions are derived by Brady and Bossis (1985). Dual calculations are again performed, respectively with and without DLVO-type forces. When such forces are present, an additional contribution (the so-called elastic stress) to the bulk stress tensor exists. In such circumstances, the term (Batchelor, 1977 Brady and Bossis, 1985)... 

The appropriate viscoelastic functions are the dynamic rheological properties (storage modulus G and the loss modulus G", and the dynamic viscosities f and T ") extrapolated to infinite dilution and are called the intrinsic dynamic rheological properties ... 

To examine the role of the starch granule and of the continuous phase on the dynamic rheological properties, two starches were selected (Genovese and Rao, 2003a) whose... 

Y. Hemar, D. S. Home. Dynamic rheological properties of highly concentrated protein-stabilized emulsions. Langmuir. 2000 16 3050-3057. 

Measurement of Physical Properties. The dynamic rheological properties were measured by RDS-7700 with the concentric parallel plates. The thermal properties were measured with a Du Pont Thermal Analysis 2000 equipped with a 910 DSC. The fractured surface was observed by Hitatchi scanning electron microscope S-510. The tensile properties were measured by Instron tensile tester. 

Jayanarayanan K, Jose T, Thomas S and Joseph K (2009) Effect of draw ratio on the microstructure, thermal, tensile and dynamic rheological properties of in situ microfibrillar composites, Eur Polym 745 1738-1747. 

Han Jingquan, Lei Tingzhou, and Wu Qinglin. High-water-content mouldable polyvinyl alcohol-borax hydrogels reinforced by well-dispersed cellulose nanoparticles Dynamic rheological properties and hydrogel formation mechanism. Carbohyd Polym. 

Dynamic Oscillatory Experiments The dynamic rheological properties of a polymeric solution can be determined by small-amplitude oscillation tests [2]. In small amplitude oscillatory measurements, a sinusoidally varying shear stress field is imposed on a fluid and the amplitude of the resulting shear strain and phase angle between the imposed stress and the strain is measured. The test is... 

Chen, G., Guo, S., and Li, Y. (2004) Dynamic rheological properties of high-density polyethylene/polystyrene blends extruded in the presence of ultrasonic oscillations./. Appl Polym. Scl, 92, 3153-3158. 

Dynamic rheological properties are dynamic viscosity and dynamic modulus. They depend on frequency, shear rate, time, and temperature. The parameters generally used are complex dynamic viscosity (r ) and its viscous (11 ) and elastic (ri"") components, and shear relaxation modulus (G ) and its storage modulus (G ) and loss modulus (G ) components (Figures 5.8). G for LDPE has the highest value, and G for LLDPE and mPE are very similar. The study of tan 6 = ti /ti" is of great interest for processing. 

Figure 20.9 Dynamic rheological properties of SPS/OPS nanocomposites at 280 °C. (a) Storage moduli and (b) loss moduli. In the nanocomposites, the added amount of organoclay was 3wt %. Reprinted with permission from Reference 11. Copyright (2004), with permission from Elsevier.

Dynamic rheological properties of the melt are very sensitive to the molecular structure of a polymer. It is essential to perform dynamic strain sweep test before... 

Sheriff M, Warburton B. 1974. Measurement of dynamic rheological properties using the principle of externally shifted and restored resonance. Polymer 15 253-254. Sheriff M, Warburton B. 1975. The theory of a universal oscillatory rheometer for the study of linear viscoelastic materials using the principle of normalized resonance. In Theoretical Rheology. London Applied Science Publishers, pp 299-316. Shinoda K, Yoneyama T, Tsutsumi H. 1980. Evaluation of emulsifier blending./Disper Sci Technol 1(1) 1-12. 

We will consider first the dynamical rheological properties of concentrated inverse emulsions (stabilized by Span 80 in dodecane) for various volume fractions ( ). The experimental results are given in the form of the plot G Rd/( in relation to ( ) (Figure 2.8, hollow symbols). From the value of the interfacial tension, y = 3.5mN-m measured by tensiometry, and using 3, we calculate values for a and ( )c equal to 1 and 0.66, respectively. We will therefore use this measured value of a in the subsequent analysis of concentrated multiple emulsions. 

In the presence of a selective solvent, ordered block copolymers form micelles that, at sufficiently high copolymer concentrations, serve to stabilize a diree-dimensional network and promote physical gelation. This study examines the steady and dynamic rheological properties of micellar solutions composed of AB diblock, ABA triblock and bidisperse mfactures of AB and ABA copolymer molecules. Of particular interest is the unexpected improvement in network development upon addition of an AB copolymer to an ABA copolymer at constant solution composition. This behavior is observed for ABA/solvent systems above and below the critical gelation concentration, and is interpreted in terms of the volume exclusion that occurs in bidisperse mixture of grafted chains. 

The dynamic rheological properties of both TPUs in the melt were determined with a Rheom cs ARES dynamic spectrometer with a 25 mm parallel plate configuration. Circular samples (2mm gap) were stressed at 1 Hz with a strain of 1%. Complex viscosity (t] ) was determined as a function of temperature from lOOTC to 250KC at 5fC/min. This was immediately followed by a cooling scan back to 50°C at the same rate. 

---