Dynamic Mechanical Analysis part 10 docx

... stress relaxation modulus, E¢ is the storage modulus from the dynamic experiment, w is the dynamic test frequency, and E≤ is the dynamic loss modulus. A similar equation exists for the compliance, ... ( )( ) ¢ ≤≤ww w w 04 04 0014 10 EtJt d t() ( )-= Ú tt 0 1 ©1999 CRC Press LLC a mixing rule. A mixing rule is a quantitative relationship that relates the observed mechanical propertie...

Ngày tải lên: 05/08/2014, 09:19

... only plot dynamic stress vs. dynamic strain, but also get E¢, E≤, E*, tan d, h*, and other dynamic properties for each cycle. This allows us to plot those properties as a function of dynamic stress ... as ©1999 CRC Press LLC FIGURE 4.15 Results from dynamic stress–strain curves showing (a) the relationship between dynamic stress and strain and (b) tan d vs. dynamic strain for tw...

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... Rheology, MIT, Cambridge, 1990. R. De le Garza, Measurement of Viscoelastic Properties by Dynamic Mechanical Analysis, Masters thesis, Univer- sity of Texas at Austin, 1994. R. Hagan, Polymer Testing, ... weight (usually 1 ¥ 10 6 Pa. s), the item is removed from its mold or form and post-cured. Post-curing involves heating the free-standing piece in an oven until full mechan...

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... Creep–Recovery Tests 3 .10 Thermomechanical Analysis Notes Chapter 4 Dynamic Testing 4.1 Applying a Dynamic Stress to a Sample ©1999 CRC Press LLC dynamic measurements were an integral part of polymer ... an introductory book on dynamic mechanical analysis. This book attempts to give the chemist, engineer, or material scientist a starting point to understand where and...

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... the molecular structure and to predict in-service performance makes it a necessary part of the modern thermal laboratory. FIGURE 1 .10 Creep–recovery testing. Creep–recovery experiments allow the determina- tion ... some or all of these curves (Figure 2.10a). This change in response with temperature leads to the need to map modulus as a function of temperature (Figure 2.10b) and represents...

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... time. In Figure 3.6a, we show the relationship of the resultant strain curve to the parts of the four-element model. This analysis is valid for materials in their linear vis- coelastic region and only ... find polymer manufacturers with a room full of parts under load that are being watched. This checks not only the polymer but also the design of the part. More accurately representative sa...

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... 3.11b). Since many materials are used in contact with a dissimilar material FIGURE 3 .10 Thermomechanical analysis test methods in common use. Dilatometry allows one to measure volumetric expansion: ... reciprocal, 13 and roughly related as (3.5) The analysis of the stress relaxation curve is shown in Figure 3.8a and is analogous to the creep analysis. One interesting application o...

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... While estimates of the relative sensitivity of DMA to DSC or DTA vary, it appears that DMA is 10 to 100 times more sensitive to the changes occurring at the T g . The T g in highly ... furnace control. I do this in one run by programming a cycle with 2-minute isothermal holds at 100 °C and 200°C and a 10 C per minute ramp between the holds. A sample of indium is loaded und...

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... region of increasing viscosity associated with curing, and both the time required to exceed 1 ¥ 10 6 Pa. s and to reach vitrification. These materials, sold for the same application, would require ... different thicknesses. As dif- ferent times are required to reach a viscosity equal to or exceeding 10 6 Pa. s, the materials will need to be held for different times before they are solid...

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... frequency of the dynamic test, and d g / dt the shear rate of the constant shear test. This rule of thumb seems to hold for most materials to within about ± 10% . Another approach, which ... method and added to the data collected by frequency scans. However, as creep is not the same as dynamic tests, sometimes the data are not even similar GN¢== ÆÆ Æ () () ()wwggyg wg g 2...

Ngày tải lên: 05/08/2014, 09:19