Films drying

Lineham,J. H., M. Petrick, and M. M. El-Wakil, The Condensation of A Saturated Vapor on a Subcooled Film Drying Stratified Flow, AlChE Sym. on Heat Transfer, V. 66, No. 102. 

These dispersions thus obtained are mixed together, and after the introduction of other additives, coated (at about 5-10g/m2 as dry solid) on a substrate such as paper, synthetic paper, or plastic film, dried, and calendered to give thermosensitive recording paper. 

E. Mei, A.M. Bardo, M.M. Collinson, and D.A. Higgins, Single-molecule studies of sol-gel-derived silicate films. Microenvironments and film-drying conditions J. Phys. Chem., B 104, 9973-9980 (2000). 

Researchers who have focused more on understanding cause-effect relationships in solution processing have given attention to film drying and pyrolysis behavior, densification processes, and nucleation and growth into the desired crystalline state. Both thermodynamic and kinetic factors associated with the phase transformation from the amorphous state to the crystalline state have been considered.11 119 Control of these factors can lead to improvements in the ability to influence the microstructure. It is noted that in the previous sentence, influence has been carefully chosen, since the ability to manipulate the factors that govern the nature of the phase transformation to the extent that full control of the microstructure is possible remains to be demonstrated. However, trends in characteristics such as film orientation and columnar versus uniaxial grains have certainly already been achieved.120... 

Data have been published by Baelz [48] concerning the retention of solvent by a 50 p thick film dried at 25°C to a constant weight in air at 60% R.H. The results are shown in Fig. 97. 

Figure 4. FT-IR spectra of (a) neat Epon 828 resin, (b) the reaction product of APS film dried at 25°C and Epon 828, and (c) the reaction product of APS film dried at 170°C and Epon 828.

Hansen, C.M. (1968) A mathematical description of film drying by solvent evaporation. Journal of Oil and Color Chemists Association, 51, 27-43. 

Figure 9 Schematic showing liquid film "dry-out" on a rotating disc.

Below we give the dielectric characteristics of polymethyldimethylsi-lazane film dried for 24 hours at room temperature (the measurements... 

From the area of thermal process engineering, the mass and heat transfer in stirred vessels and in bubble columns is treated. In the case of mass transfer in the gas/liquid system, coalescence phenomena are also dealt with in detail. The problem of simultaneous mass and heat transfer is discussed in association with film drying and in continuous electrophoresis. 

A drum dryer (Fig. 6.4) consists of one or more heated metal rolls on which solutions, slurries or pastes are dried in a thin film. The thin film dries in less than one revolution of the slowly revolving rolls and is scraped off by a doctor blade to form a product in flake, chip or granular form. Drum dryers are widely used in chemical processing frequently to dry hydrates, carbonates, arsenates, acetates, phosphates, clays and food products [11]. 

Poly (vinyl alcohol)/Water. When distilled water is poured onto the surface of poly (vinyl alcohol) films dried onto the impedometer bar, the initial response is not the expected decrease in stiffness caused by the solvating effect of the water, but rather a marked increase in stiffness followed by a slow relaxation as shown in Figure 2. (The A db scale on this and most following graphs has been adjusted to read as change in A db from the initial value. Thus, the zero point is for the dried polymer film. The absolute value A db for dried polymer films ranged from 1 to 16 A db depending on film thickness and polymer type.)... 

The same curious effects occur when the moisture sequence is reversed. An experiment of this sort is shown in Figure 3, where we equilibrated a PVA film with a 100% relative humidity atmosphere and then recorded the A db change as this film dried out in a 50% relative humidity atmosphere. 

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