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crystallization behavior of fat is influenced also by various dynamic factors, such as cooling rate, mixing and crystallization temperature ( Metin and Hartel, 2005 ). Important characteristics of both chocolate and coating is their rheological properties such as

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Progress in Agricultural Engineering Sciences
Authors: Karina Ilona Hidas, Csaba Németh, Anna Visy, Adrienn Tóth, László Ferenc Friedrich, and Ildikó Csilla Nyulas-Zeke

. Herald et al. (1989) examined the rheological behaviour of heat-treated liquid whole egg at −24 °C for 80 days. Thixotropic behaviour was found in all samples examined, and their rheological properties were completely altered, with near Newtonian

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Abstract  

Hydrogels prepared by crosslinkage of gelatin with dextran dialdehyde have been characterized by dynamic shear oscillation measurements at small strain. Isothermal as well as temperature scan measurements were performed. The results obtained demonstrated that the final polymer network is a result of a chemical gelatin-dextran dialdehyde interaction as well as a gelatin-gelatin (physical association) and a polymer-solvent interaction. This balance is strongly dependent on the composition of the system, the polymer concentration, the storage temperature and the storage time. We found that a short cryogenic treatment at −20°C of physically structured gels, significantly increases the chemical crosslinkage. DSC measurements at low cooling rate confirm these results and demonstrate a chemical reaction enthalpy contribution.

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Abstract  

The high concentration 17 wt% triblock copolymer poly(ethylene oxide)100–poly(propylene oxide)65–poly(ethylene oxide)100 Pluronic F127 aqueous solutions with the addition of laponite is investigated as a novel temperature-sensitive hydrogel system. The critical micelle temperature (cmt) and the sol-to-gel transition were characterized by rheological experiments and differential scanning calorimetry. Experimental results showed that laponite particles have no significant influence on the cmt. On the other hand, viscoelastic measurements have highlighted an increase of the sol-to-gel transition temperature for mixtures with 2 and 3 wt% of laponite particles. This additive can be used to adjust the gelation temperature close to physiological temperature in medical applications.

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Abstract  

The rheological behaviour of the materials diglycidil ether of bisphenol A (n = 0), 1, 2 diamine-cyclohexane and the epoxy reactive diluent vinylcyclohexane dioxide have been studied both separately and mixed before the beginning of the curing reaction. Different kinds of tests such as: preshear and time sweep, flow curve and stress sweep experiments were carried out. From these experiments, interesting information about: viscosity-shear stress and viscosity-shear rate dependences, storage modulus and the linear viscoelastic region were found out. Relationships between concentration of diluent and the final viscosity of the mixed sample and also between percentage of diluent and storage modulus were studied.

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Three types of wheat were submitted to two different milling procedures, giving rise to six flours which differed by some physico-chemical characteristics such as particle size, level of damaged starch and protein content. Differential scanning calorimetry was used for monitoring heat-induced structural changes in flour aqueous dispersions 80% water and in doughs 45% water. Differences between the thermal behaviour of the flour dispersions and doughs were explained mainly by differences in protein content. This result was confirmed after partial substitution of flour by gluten. Dynamic mechanical analysis performed at 20°C on the flour doughs indicated, as expected, a linear increase in the elastic modulus with increasing protein content. The results did not bring any evidence that, under these experimental conditions, starch damage might affect gluten hydration.

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Abstract  

Three types of commercially available organophilic Montmorillonite (Cloisite 30B, 25A and 15A) were used to prepare VARTM epoxy resin nanocomposites in order to study the effect of the nanoclay organophilic modification on the epoxy matrix. The morphology of the dispersions was investigated through XRD and TEM analyses. The thermal stability of the nanocomposites was studied by means of HI-RES TG measurements and the influence of the nanoclay on the viscosity of the resin was investigated through rheological measurements. It was found that the nanoclay modification had no significant influence on the dispersion and on the thermal properties of the nanocomposites. Areas of exfoliated and intercalated morphology were observed. The viscosity of the resin furthermore did not exceed the critical value of the infusion process.

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Journal of Thermal Analysis and Calorimetry
Authors: N. A. Santos, R. Rosenhaim, M. B. Dantas, T. C. Bicudo, E. H. S. Cavalcanti, A. K. Barro, I. M. G. Santos, and A. G. Souza

composition of three mixtures of fats was also investigated by Bell et al. [ 5 ], who studied rheological properties during cooling and observed that the crystallization temperature was dependent on composition. Differential scanning calorimetry (DSC) has also

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of compatibility can be reached [ 5 , 14 – 17 ]. The aim of this work was to investigate the effect of PC with different melt flow rates and cobalt catalyst as modifier agents of thermal and rheological properties of PET/PC reactive blending

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Abstract  

Coal-tar pitch was modified by addition of polystyrene, poly(ethylene terephthalate), unsaturated polyester and coumarone-indene resin. The optimum conditions for production of homogeneous binary pitch-polymer blends containing 10% w/w of the polymer were established. Softening points, contents of toluene and quinoline-insoluble matters and rheological properties of the blends were determined. The yield of solid fraction in semi-coking the blends was also found. The effect of polymers on the coal-tar pitch blend properties was evaluated. Some pitch-polymer blends were then carbonized to carbon sorbents used for purification of water and wastewater.

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