DYNAMIC RHEOLOGICAL ANALYSIS

The solid-like properties may be measured by non-destructive dynamic rheology analysis or by destructive methods using a Penetrometer, Jelly Tester, Instron instruments, or other types of texture analyzers. The latter methods are the most useful due to their simplicity and speed. Texture analysis of whippable emulsion must always be compared with the amount of air incorporated into the foam, which is known as percentage overrun and is calculated as follows ... 

Huang, Y. Gelling temperatures of high acyl gellan as affected by monovalent and divalent cations with dynamic rheological analysis. Carbohydr. Polym. 56 (2004) 27-33. 

Cai, H., Ait-Kadi, A., and Brisson, J. (2003) Dynamic rheological analysis of a miscible blend showing strong interaction. Polymer, 44 (5), 1481-1489. 

TGA, dynamic rheological analysis and polarised light microscopy were used to assess thermal stability of PEEK. Emphasis is given to the effect of melting temperature on thermal stability. 23 refs. 

The effect of oxidative irradiation on mechanical properties on the foams of E-plastomers has been investigated. In this study, stress relaxation and dynamic rheological experiments are used to probe the effects of oxidative irradiation on the stmcture and final properties of these polymeric foams. Experiments conducted on irradiated E-plastomer (octene comonomer) foams of two different densities reveal significantly different behavior. Gamma irradiation of the lighter foam causes stmctural degradation due to chain scission reactions. This is manifested in faster stress-relaxation rates and lower values of elastic modulus and gel fraction in the irradiated samples. The incorporation of O2 into the polymer backbone, verified by IR analysis, conftrms the hypothesis of... 

An appropriate cure cycle was established based on the results obtained from the thermal analysis and cure rheology studies of the resin and cured BCB bar and dogbone shaped samples were fabricated for testing. Bar shaped specimens had the dimensions of 3.5 x 0.5 X 0.125 and were used to stake compact tension specimens for fracture toughness studies and for dynamic mechanical analysis of a torsion bar. Dogbone shaped specimens for tensile tests had a gauge area of 1 x 0.15 and were approximately 0.040 thick. 

Dynamic mechanical analysis methods are frequently used to investigate polymerization and curing processes in reactive systems. These methods allow us to obtain both relative and absolute rheological characteristics of a material. Measurements can be made in both the fluid and solid states without affecting the inherent structure of the polymerizing system. 

The miscibility of HDPE/LLDPE blends was also studied using differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA), rheological analysis, excimer fluorescence analysis, and transmission electron microscopy (TEM). Lee et al. (43) studi blends of HDPE (121,000 an 6.8 PDI)... 

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