INDEX elastic modulus

Many relatively slow or static methods have been used to measure Tg. These include techniques for determining the density or specific volume of the polymer as a function of temperature (cf. Fig. 11-1) as well as measurements of refractive index, elastic modulus, and other properties. Differential thermal analysis and differential scanning calorimetry are widely used for this purpose at present, with simple extrapolative eorrections for the effects of heating or cording rates on the observed values of Tg. These two methods reflect the changes in specific heat of the polymer at the glass-to-rubber transition. Dynamic mechanical measurements, which are described in Section 11.5, are also widely employed for locating Tg. 

Mechanical properties, such as elastic modulus and yield point, that depend on crystallinity per se are not seriously affected by low to moderate doses of ionizing radiation. On the other hand, those mechanical properties that are sensitive to interlamellar activity are most dramatically affected by the low to moderate radiation doses. This is seen in the ultimate tensile strength and elongation at failure of the polyolefins. It is also reflected in the large change in melt index between 0 and 18 Mrad, which indicates formation of cross-links that increase with increasing... 

To compare with experimental results, the parameters corresponding to real conditions were used in our computation cases. The lubricant used in the experiment is polyglycol oil. The diameter of the steel ball is 25.4 mm, elastic modulus of the balls is 2.058 X 10 Pa, and the elastic modulus of the glass disk is 5.488 X 10 ° Pa. The circumstance temperature is 28 1 °C. The oil viscosity-pressure index is taken as 1.5 X10- Pa-. ... 

Entry Composition (daltons) (daltons) Tg ( C) Elastic Modulus (Gpa) Hardness (Mpa) Yellowness Index... 

Frost resistance is determined by the number of freeze-thaw cycles that a particular concrete can withstand before reaching a given level of degradation. In general, the loss of mass or the decrease of dynamic elastic modulus are apphed as indexes of degradation. 

The most important properties of commercial glasses are the density, refractive index, thermal expansion coefficient, glass transformation temperature, strength and elastic modulus, and chemical durability. These properties will be reviewed for each of the major categories of commercial glasses. 

Processing production of coal sample and physical mechanic parameters test are in strict accordance with the provisions of Measurement method of coal and rode physical and mechanical properties (GB/T 23561-2009), and Measurement method of coal seam impact tendency classification index (MT/T 866-2000). The experiment determined natural apparent density, compressive strength, consistent coefficient, elastic modulus, deformation modulus, wave velocity, rock burst energy index, elastic energy index, dynamic failure time, and other parameters. The determination results as shown in Table 1. 

The theoretical and practical significance of polymer dynamic/ mechanical properties is well appreciated [180,183]. The dynamic elastic modulus and mechanical losses are the most sensitive indicators for all forms of polymer molecular mobility, especially for the glasslike state. The dynamic elastic modulus is the primary index for polymer deformation properties. Apart from their purely theoretical interest, understanding of the mechanisms of molecular motion within polymers and of mechanical losses may have significant practical importance in properly defining other polymer mechanical properties. 

The loss modulus is the ability of the material to dissipate mechanical energy into heat. Tanloss modulus to elastic modulus. It is a useful index of the viscoelasticity of the test material. 

Single crystals Peculiarity Elastic modulus (GPa) Test method Brittleness Index... 

Table 8.2 summarizes the theoretical critical indices and their experimental values. The index s characterizes the divergence of the viscosity, and t characterizes the appearance of the elastic modulus. The index t is larger than because not all the chains in the connected network are elastically effective. There are many free ends near the percolation... 

Table 2. Elastic modulus, yield stress, yield strain, constants of power law fitting and indentation elasticity index obtained from stress strain curves with 3 xm radius spherical tipped indenter on GCs and silica glass.

Sakai has proposed that the ratio of hardness to elastic modulus E, that is, the elasticity index as a material parameter. " The elasticity index k/E for each the GC samples is also listed in Table 2. It is found that the GCs heat-treated at the higher temperature showed the lower elasticity index k/E. Thus, elasticity of GC decreases with the elevating HTT of GC. 

Strain-optic coefficient Index of refraction Elastic modulus Poisson s ratio... 

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