Creep viscosity

Thus, measuring rheological properties of dispersions of low-molecular-weight (with viscosity about 60 Pa s) and high-molecular-weight poly(isobutilene) (with viscosity about 10s Pa s) with the same content of filler we see that the values of creep viscosity r c of these systems are practically equal, in spite of the difference of the viscosity of the dispersion medium more than 1000 times [3],... 

The durability of the particle network structure imder the action of a stress may also be time-dependent. In addition, even at stresses below the apparent yield stress, flow may also take place, although the viscosity is several orders of magnitude higher than the viscosity of the disperse medium. This so-called creeping flow is depicted in Fig. 11 where r (. is the creep viscosity. In practice this phenomenon is insignificant in the treatment of filled polymer melts, but may be relevant, for example, in consideration of cold flow of filled elastomers. 

The simplest physical situation that involves both chemistry and deformation is a cylinder that is being thinned radially and elongated axially in a uniform way by slow viscous deformation. The cylinder is in two parts that meet in the middle at an interface. First we suppose that the two materials are polymorphs, both capable of slow continuous deformation (creep) with different viscosities but the same composition. Then we extend to a situation where the materials are like sphalerite and wurtzite— both having formula (Fe, Zn)S but having different structures and hence different creep viscosities, and also having different Fe/Zn ratios. 

Melt creep viscosity by according to procedure MVS Patent i By capillary rheometer ASTM D 2116 15) Melt flow rate by ASTM D 2116 By capillary rheometer ASTM D 3307... 

Melt Creep Viscosity - A viscosity value measured for polytetrafluoroethylene using a dynamic mechanical analyzer (DMA). 

Figure 21 Segmental relaxation times and shift factors for global chain dynamics of atactic polypropylene. Segmental relaxation i>, NMR v, dielectric spectroscopy , light scattering o, mechanical dynamic spectroscopy 0, creep compliance measurements. Shift factors for global chain dynamics

Table 1 Some steady-state creep viscosities of solid-like materials.

Figure 1 Creep viscosity versus shear stress for magnesium oxide at 1000 °C, for various values of grain size.

Figure 2 Creep viscosity versus shear stress for olivine...

Kriechprobe, Creep-Test creep viscosity Kriechviskositat,... 

Rouxel T., Soraru G.D., Vicens J. Creep viscosity and stress relaxation of gel-derived silicon oxycarbide glasses. J. Am. Ceram. Soc. 2001b 84 1052-1058 Singh A.K., Pantano C.G. The role of Si-H functionality in oxycarbide glass synthesis. Mater. Res. Soc. Symp. Proc. 1992 271 795-800... 

Melt creep viscosity by according to procedure MVS Patent. 

---