Rheology Fourier-transform

M. Wilhelm, Fourier-Transform rheology, Macromol. Mater. Eng., 287(2), 83-105, 2002. 

G. Eleury, G. Schlatter, and R. Muller, Non linear rheology for long branching characterization, comparison of two methodologies Fourier transform rheology and relaxation, Rheol. Acta, 44, 174—187, 2004. 

M. Wilhelm, D. Maring, and H.-W. Spiess, Fourier-transform rheology, Rheol. Acta, 37, 399 05, 1998. 

For the continuous mode, we utilized a dynamic rheological technique, Fourier transform mechanical spectroscopy (FTMS) (77,75), which provided a powerful method for monitoring, simultaneously, the evolving dynamic moduli at several frequencies during the course of photo-cross-linking. In this technique, an oscillatory strain, y, was applied to the sample, such that... 

It is not possible to discuss all the methods available for characterizing foods critically and systematically in a single volume. Methods pertaining to interfaces (food emulsions, foams, and dispersions), fluorescence, ultrasonics, nuclear magnetic resonance, electron spin resonance, Fourier-transform infrared and near infrared spectroscopy, small-angle neutron scattering, dielectrics, microscopy, rheology, sensors, antibodies, flavor and aroma analysis are included. 

Fourier transform rheology is a new technique, which has as yet not been widely employed. In the future, it will provide quantitative information on non-linear viscoelasticity, in particular on the onset of nonlinearity. Combined with structural probes such as small angle scattering, this will enhance enormously our understanding of nonlinear viscoelasticity in soft polymeric materials. 

Kleinebudde (140) suggested that with MCC the process of extrusion induced a microcrystallite-ger state in the MCC/water system, which aided the process. Chopra et al. (15) found that for certain formulations, good quality pellets could be prepared without extrusion of the wet mass. Kleinebudde (140) offered no direct experimental evidence that the extrusion in any way changed the crystallinity of the MCC, nor that the system had different rheological properties, nor, for that matter, it was a gel. Thus the whole concept is seriously flawed and, even in a later paper, it was concluded that the use of Fourier transform Raman spectroscopy did not confirm the existence of a microcrystallite-gel (141). The water holding capacity is not the sole property involved, the consistency of the wet mass must also be important, as discussed previously. 

The investigation of non-linear behaviour is an active field for many other polymer systems. For example Payne (1962) interpreted a maximum in G" (with respect to strain) in the non-linear behaviour of filled suspensions, which has been denoted the Payne effect. Maier and Goritz (1996) and Wilhelm et al. (2000) examined the use of Fourier-transform analysis of non-sinusoidal waveforms produced by materials exhibiting non-linear behaviour. This concept of using Fourier-transform rheology to characterize the non-linear... 

Copolymers with sites for association in aqueous solutions were pre-pared by copolymerizing acrylamide with N-alkylacrylamides or with the ampholytic monomer pairs sodium 2-acrylamido 2 methylpro-panesulfonate (NaAMPS) and 2-acrylamido-2-methylpropane-dimethylammonium chloride (AMPDAC). The copolymers were characterized by elemental analysis, NMR and Fourier transform infrared spectroscopy, and lowhangle laser and quasielastic lightscattering measurements. Rheological properties were studied as a function of microstructure, molecular weight, polymer concentration, electrolyte concentration, and shear rate. On the basis of those results, a conceptual model that is based on microheterogeneous domain formation in aqueous solutions is proposed. 

Fourier transform rheology (FTR) [Wapner and Forsman, 1971] was used for the analysis of CPNCs. The experiments were performed in the ARES using the software developed by Wilhelm [2002]. It was expected that the method may be suitable for characterization of the nonlinear viscoelastic response of CPNC. The FTR analysis is based on the expression... 

Debbaut, B., and Burhin, H., Large amplitude oscillatory shear and Fourier-transform rheology for a high-density polyethylene experiments and numerical simulation, J. Rheol., 46,1155-1176 (2002). 

Carotenuto, C., Grosso, M and MafFettone, P.L, (2008) Fourier transform rheology of dilute immiscible polymer blends a novel procedure to probe blend morphology. Macromolecules, 41 (12), 4492- 500. 

Polymer Blends.—In addition to the work on polyester—polyamide blends reported in Section 2, several other papers describe the characteristics of various polymer formulations with polyamides. Biconstituent fibres have been formed from nylon-6 and poly(ethylene terephthalate). The same polyamide and nylon-12 have been blended with acrylonitrile-butadiene-styrene copolymer and the temperature and the concentration dependence of the dynamic modulus evaluated. The rheological properties of acrylonitrile-styrene copolymer/nylon-6 mixture have also been reported. Fourier transform infrared studies of nylon-6 and PVC have indicated the presence of specific interactions between the two polymers in both the molten and solid states. Finally X-r y studies carried out on injection-moulded blends of nylon-6, -12, and -66, have revealed that the addition of small amounts of the second component initiates formation of the y-crystalline phase within the nylon-6 polymer matrix. ... 

The interfacial tension response to transient and harmonic area perturbations yields the dilational rheological parameters of the interfacial layer dilational elasticity and exchange of matter function. The data interpretation with the diffusion-controlled adsorption mechanism based on various adsorption isotherms is demonstrated by a number of experiments, obtained for model surfactants and proteins and also technical surfactants. The application of the Fourier transformation is demonstrated for the analysis of harmonic area changes. The experiments shown are performed at the water/air and water/oil interface and underline the large capacity of the tensiometer. 

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