Methods of Characterisation

Characterisations of the resulting NBR-PAni.DBSA blends were performed by using  

Optical microscope (thickness of each sample, 3.0 pm and 200 x magnification) and transmission electron microscope (TEM) (microtome sample, 40,000 x magnification) at accelerating voltage, 80 kV [1]. 

Differential scanning calorimeter for 30 to 400 °C analyses (with heating rate 20 °C/min) and -60 to 0 °C analyses (with heating rate 10 C/min) each sample sealed with aluminium pan and analysed under a N2 atmosphere [1]. 

Keithley electrometer to measure the electrical resistances of pure polymers and their blends cast films (thickness of each sample, 6.0 pm) on microscope slides (6.25 cm X 0.1 cm), based on the two-probe method [1] and four-probe Van der Pauw technique [1-2]. 

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The refractive index of a liquid is recorded as where t is the temperature at which the measurement is made, and D refers to the wave length of the D line of sodium. As already pointed out, it is usual to determine both the refractive index and the density of the liquid at 20° in any case they should be determined at the same temperatme. These two constants are useful in assisting the characterisation of a pure hquid they are particularly valuable for ahphatic hydrocarbons and similar compounds where the methods of characterisation by the formation of solid derivatives are not entirely satisfactory. 

The procedures of measuring changes in some physical or mechanical property as a sample is heated, or alternatively as it is held at constant temperature, constitute the family of thermoanalytical methods of characterisation. A partial list of these procedures is differential thermal analysis, differential scanning calorimetry, dilatometry, thermogravimetry. A detailed overview of these and several related techniques is by Gallagher (1992). 

However, I believe that enough has been described to support my contention that modern methods of characterisation are absolutely central to materials science in its modern incarnation following the quantitative revolution of mid-century. That revolution owed everything to the availability of sensitive and precise techniques of measurement and characterisation. 

Bullock, K. R., Electrochemical and Spectroscopic Method of Characterising Lead Corrosion Films , J. Electroanal. Chem., 222, 347-366 (1987)... 

This second group of tests is designed to measure the mechanical response of a substance to applied vibrational loads or strains. Both temperature and frequency can be varied, and thus contribute to the information that these tests can provide. There are a number of such tests, of which the major ones are probably the torsion pendulum and dynamic mechanical thermal analysis (DMTA). The underlying principles of these dynamic tests have been covered earlier. Such tests are used as relatively rapid methods of characterisation and evaluation of viscoelastic polymers, including the measurement of T, the study of the curing characteristics of thermosets, and the study of polymer blends and their compatibility. They can be used in essentially non-destructive modes and, unlike the majority of measurements made in non-dynamic tests, they yield data on continuous properties of polymeric materials, rather than discontinuous ones, as are any of the types of strength which are measured routinely. 

One method of characterising the residence time distribution is by means of the E-curve or external-age distribution function. This defines the fraction of material in the reactor exit which has spent time between t and t -i- dt in the reactor. The response to a pulse input of tracer in the inlet flow to the reactor gives rise to an outlet response in the form of an E-curve. This is shown below in Fig. 3.20. 

J. M. Thomas, The ineluctable need for in situ methods of characterising solid catalysts as a prerequisite to engineering active sites, Chem. Fur. J., 1997, 3, 1557. 

In this chapter we illustrate a direct method of characterisation of polymer/additive dissolutions by means of (500 MHz) NMR, which takes advantage of selective signal suppression allowing elimination of unwanted signals, such as the ca. 105 x more intensive PE signal. The most effective approach to solvent suppression is the destruction of the net solvent magnetisation by pulsed... 

A method of characterising transport mechanisms in solid ionic conductors has been proposed which involves a comparison of a structural relaxation time, t, and a conductivity relaxation time, t . This differentiates between the amorphous glass electrolyte and the amorphous polymer electrolyte, the latter being a very poor conductor below the 7. A decoupling index has been defined where... 

The other methods of characterising monolayers discussed by Gaines [14] are really only effective when the layer is deposited on a solid substrate or have only come into their own with improvements of technology and are thus discussed in the next chapter. 

The reader may wonder why - given the completeness with which an X-ray analysis should reveal the structure of a crystalline solid and the extent to which the method has been automated - inorganic chemists should bother with any other method of characterisation for solid compounds. It is true that many inorganic substances are nowadays characterised by X-ray crystallography alone. There are, however, cases... 

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