Wide-angle light-scattering analysis

The typical results of the wide-angle light-scattering (WALS) analysis on the latex particles that were presumed to be cores are given in Table I where the theoretical model to be fitted was either S = sphere or CS = core-shell, the variance measured the goodness of fit, the modal size parameter is given by aM = 27rr/A, aQ is the log normal breadth parameter, DM is the core diameter in ym, mi the relative refractive index of the core and m2 the relative refractive index of the shell of indicated thickness. 

The concentration of the polymer molecules eluting from SEC columns is continuously monitored by a detector. The most widely used detector in SEC is the differential reftactometer (DRI), which measures the difference in refractive index between solvent and solute. Other detectors commonly used for SEC are functional group detectors ultraviolet (UV) and infrared (IR), and absolute molecular weight detectors low angle laser light scattering (LALLS) and in-line continuous viscometers. Applications of these detectors to SEC analysis will be discussed later in the Multiple Detectors Section. Other detectors also being used are the densimeter (11-19) and the mass detector (20-23). 

Several simple relations have been proposed for the determination of the fractal dimensions from the results of such experiments as gas molecular probe method, transmission electron microscopy (TEM), small-angle X-ray scattering, neutron scattering, and laser light scattering.63,66,113 116 Among those techniques, gas molecular probe method and image analysis method have been widely used for the calculation of the surface... 

The dispersion structure of the blends both in the melt and in the solid state was imaged partly by light microscopy (LM), and partly by scanning (SEM) and transmission electron microscopy (TEM). Wide-angle X-ray scattering (WAXS), Infrared (IR) measurements, and torsional pendulum analysis at IHz were performed too. 

Instrumentation used in the measurement of polymer crystallinity includes light scattering, positron annihilation lifetime spectroscopy, differential scanning calorimetry, differential thermal analysis, infrared spectroscopy, NMR spectroscopy and wide and small angle x-ray diffraction (Chapter 14). 

Fraunhofer scattering has become a popular optical sizing tool for particles substantially larger than a micrometre in diameter. In this case each particle behaves similarly to a pinhole aperture, and the low angle scattered light is a superposition of Fraunhofer diffraction patterns. This technique is widely used for the analysis of commercial food-based emulsions and sauces. 

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