Rheological effects, consequence

As outlined earlier (Chapter 3), electrically charged colloidal particles are surrounded by an electrical double layer. This leads to important rheological effects. The primary electroviscous effect is a consequence of the fact that the electrical double layer [Figure 8.10(a)] is deformed from its spherical shape by the shear field. Construction of the double layer ahead of the particle and its disintegration behind the particle take a finite time [Figure 8.10(b)], This causes an increase in the intrinsic viscosity, which for low zeta-potentials ( < 25 mV) is proportional to the square of this potential ... 

Though nano-sized fillers did not make increments in the rheological, mechanical and physical properties, there were no deteriorating effects. Consequently, this study leads to a conclusion that nano-sized fillers, if uniformly dispersed can be successfully used in thin wall tubing applications. 

In another study [31] it has been reported that haze of LLDPE is mainly a consequence of light scattered by the spherulites. Thus, origin of poor clarity is not the same in LLDPE as in HP LDPE. In HP LDPE the haze is produced by surface defects coming from processing rheology [48,54,55]. Processing variables, therefore, do not have the same effect on LLDPE as they do on HP LDPE. 

Figure 7.10 shows typical Arrhenius plots for rheological parameters from each mechanical test. The rate constants of the first mechanisms at 60°C (3-10 K ) were the least linear this effect is mainly apparent in plots of maximum compression and tension forces (in plots, rate constants at 60° C are circled). This could be another consequence and evidence of the fact that in the experimental potato variety the optimum temperature for activation of the PME enzyme is close to 60° C. 

One convenient strategy to interpret these results is to review the molecular characteristics of binary blends as extracted from polymer melt rheology [40]. The influence of short chains (M < Me) is to effectively decrease the plateau modulus and the terminal relaxation times as compared to the pure polymer. Consequently, the molecular weight between entanglements... 

Sebert P, Andrianoff N, Roller M. Effect of gamma irradiation on hydroxypropylmethylcellulose powders consequences on physical, rheological and pharmacotechnical properties. Int ] Pharm 1993 99 37 2. 

In most food systems, pectin is present together with other biopolymers, such as protein and other polysaccharides. The mixture of these polymers may produce synergistic effects and generate novel rheological and textural properties. Consequently,... 

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