Mercerization theory

Mercer, E.H. 1981. The Foundation of Biological Theory. Wiley-Intersciences, New York. 

Fig. 1 illustrates the two mechanisms proposed for the processes of liquid disintegration and aerosol generation within ultrasonic nebulizers. The capillary-wave theory relates to the production of capillary waves in the bulk liquid. These waves constructively interfere to form peaks and a central geyser. When the amplitude of the applied energy is sufficiently high, the crests of the capillary waves break off, and droplets are formed. The rate of generation of capillary waves is dependent on both the physicochemical properties of the nebulized fluid and the intensity of the ultrasonic vibration. Mercer used Eq. (1) to calculate the threshold amplitude for the generation of capillary waves ... 

Water vapor adsorption isotherms have been obtained on cotton from room temperature up to 150°C [303,304]. Theoretical models for explaining the water vapor sorption isotherms of cellulose have been reviewed [303]. Only adsorption theories will be discussed here at ambient temperatures. The shape of the isotherm indicates that multilayer adsorption occurs and thus the Brunauer, Emmett and Teller (BET) or the Guggenheim, Anderson and deBoer (GAB) theory can be applied. In fact, the BET equation can only be applied at relative vapor pressures (RVPs) below 0.5 and after modification up to a RVP of 0.8 [305]. The GAB equation, which was not discussed in the chapter in the book Cellulose Chemistry and Its Applications [303], can be applied up to RVPs above 0.9 [306]. Initially as the RVP increases, a monomolecular layer of water forms in the cellulose. By a RVP of 0.19-0.22 the monomo-lecular layer is complete [303], and the moisture regain, when a monomolecular layer has just formed, for cotton and mercerized cotton is 3.27 and 4.56%, respectively [261,303]. By a RVP of 0.83 0.86, about three layers of water molecules are formed, and at higher RVPs it is thought that condensation occurs in the permanent capillary structure of the sample [307]. 

Mellor traced this idea of association of molecules by residual affinities to Mercer and Playfair it was adopted by H. E. Armstrong, and J. W. Walker. The idea of an intermediate complex appears in the work of W. Higgins (1789 see Vol. HI, p. 745) and in Dalton s note-books. Kekule s scheme of reaction (3) implies the modern theory of the intermediate complex , since he said ... 

The intermediate compound theory of catalysis was extended and clarified by Mercer and Playfair. ... 

Aveston, Mercer and Sillwood [71,72] derived crack theory for cement reinforced with continuous and short fibers and found that the tensile strength of the composite for the aligned fibers was ... 

Paper presented at the Annual Disability Research Seminar, December 2, Dubhn Oliver, M. (2004). The social model in action If I had a hammer. In C. Bames, G. Mercer (Eds.), Implementing the social model of disability Theory and research. Leeds The Disability Press Oliver, M., Barnes, C. (1998). Disabled people and social policy From exclusion to inclusion. Harlow Addison Wesley Longman... 

The transformation of cellulose I to cellulose II during mercerization has been suggested to be the result of a progressive shift of the sheets of cellulose chains within the crystallites of a microfibril from the quarter-staggered relationship in cellulose I to the complete correspondence found in cellulose II. Observed changes in lateral discnrder, cell dimensions, swellii, and AT-ray diffraction reflections of cellulose fibres support this theory. Such a shift may occur in the transformation of native celluloses with antiparallel structures as well as those with parallel polarity. 

The unattached fraction of radon decay product aerosols in ambient air should be contributed to by the short-lived decay products of Rn namely Po (T /2 = 3.05 min), " Pb (26.8 min) and (19.8 min), but not the relatively long-lived decay product of °Rn namely Pb T /2 = 10.64 h), which has such a long residence time that it will be almost entirely associated with aerosols. If it is accepted that the screen collection efficiency for the unattached fraction (which has a high diffusion coefficient of 0.06 cm s ) is 99.2% (almost 100%) for the finest screens such as 200 mesh/inch and for a low air face velocity, i.e. 10 cms as the screen diffusion theory predicts (Thomas and Hinchliffe, 1972), then " Pb should dominate the screen activity. For aerosol particles >0.5 pm, the screen eflh-ciency predicted by the diffusion theory is practically zero. However, the diffusion coefficient of the unattached particles (atoms, ions or molecules and even small clusters of atoms) is not expressed by a certain value, such as 0.06 cm s as considered by George (1972a) and Raghavayya and Jones (1974), or 0.054 cm s as considered by Chamberlain and Dyson (1956), Barry (1968), Thomas and Hinchliffe (1972), Porstendorfer et al. (1987), Reineking et al. (1985) and Mercer and Stowe (1969). Screens do not collect unattached species only. Van der Vooren et al. (1982) believed that screens always collect attached species, probably with an efficiency of 1-2%. 

The transformations now described correspond in part to the technical process of mercerization, which is expected to produce a cellulose lattice more accessible to water and other polar solvents than that of the cellulose I. The details of the intra- and intermolecular hydrogen bonding mechanism are, as in the case of cellulose I, essentially unknown. No theory has, to our knowledge, been able to give a satisfactory explanation of the cause for the irreversible chain tilting occurring during the allotropic transformation. 

Mercer, J. (1909). Functions of positive and negative type and their connection with the theory of integral equations, Philosophical Transactions of the Royal Society, London, A 209, pp. 415-446. 

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