And moisture sorption

E. Other Methods, IR or Raman spectroscopy. X-ray diffraction, solid-state NMR, dilatometry, and moisture sorption isotherm may be used as tools for the qualitative or quantitative study of polymorphism. Brief descriptions of these techniques may be found elsewhere in this chapter. 

At this stage in the polymorph screen, enough data should be available to sort out the number and nature of solid forms obtained from crystallization experiments. As part of the characterization process, and to continue attempts to generate new forms, hot-stage microscopic and moisture sorption/desorption analyses should be carried out. 

All moisture transport processes, on the other hand, affect heat transfer significantly. Evaporation and moisture sorption have a direct impact on heat transfer, which in turn is influenced by water vapor diffusion and liquid diffusion. The temperature rise during the transient period is caused by the balance of heat released during fiber moisture sorption and the heat absorbed during the evaporation process [40],... 

FIG. 5. Diagrammatic representations of the influence of water activity upon some chemical, enzymatic, and microbiological changes and on overall stability and moisture sorption properties of food products. Source Rockland and Nishi (1980). 

It should be stressed, that a successful analysis of solvated crystal forms requires additional methods besides those mentioned with true polymorphs. Such methods are, for example, thermogravimetry or Karl-Fischer titration and moisture sorption/desorption analysis for hydrates. In order to perform studies... 

Deng, Y, J. Wu, S. Su, Z. Liu, L. Ren, and Y. Zhang, 201 la. Effect of far-infrared assisted heat pump drying on water status and moisture sorption isotherm of squid (Illex illecebrosus) fillets. Drying Technology, 29(13), 1580-1586. 

Nair, S. B. Jyothi, A. N. Sajeev, M. S. Mishra, R. Rheological, mechanical and moisture sorption characteristics of cassava starch-konjac glucomannan blend films. Starch/Starke 63 728-739 (2011). 

Besides thermal, diffractometric, and moisture sorption techniques, there are ample other techniques, as aforementioned, that are commonplace for the analysis of the various structural features of ASD. Table 14.1 lists various techniques and brief descriptions for their measuring principles relevant to ASD. The details of working principle and various other applications of these techniques are available elsewhere. Some representative and relevant references are also included in Table 14.1. Tables 14.2-14.8 portray the structural characteristics measurable by various these techniques and also possible hurdles and interferences. 

Brenier R. Stress and moisture—sorption in ozone—annealed filmes of zirconium oxide obtained from sol-gel. J. Sol-Gel Sci. Technol. 2002 25 57-63 Brenier R., Ortega L. Structure properties and stress in ZnO Films obtained from a nanocoUoidal sol. J. Sol-Gel Sci. Technol. 2004 in press... 

Tanno F., Saka S., Takabe K. Antimicrobial TMSAC-added wood—inorganic composiles prepared by the sol-gel process. Mater. Sci. Res. Int. 1997 3(3) 137—142 Toniolo L., Colombo C., Realini M., Peraio A., Positano M. Evaluation of barium hydroxide treatment efficacy on a dolomitic marble. Annali di Chimica (Rome, Italy) 2001 91(11—12) 813-821 Tshabalala M., Kingshott P., VanLandingham M.R., Plackett D. Surface chemistry and moisture sorption properties of wood coated with multifunctional alkoxysUanes by sol—gel process. J. Appl. Polym. Sci. 2003 88 2828-2841... 

The coupled heat and liquid moisture transport of nano-porous material has wide industrial applications in textile engineering and functional design of apparel products. Heat transfer mechanisms in nano-porous textiles include conduction by the solid material of fibers, conduction by intervening air, radiation, and convection. Meanwhile, liquid and moisture transfer mechanisms include vapor diffusion in the void space and moisture sorption by the fiber, evaporation, and capillary effects. Water vapor moves through textiles as a result of water vapor concentration differences. Fibers absorb water vapor due to their internal chemical compositions and structures. The flow of liquid moisture through the textiles is caused by flber-liquid molecular attraction at the surface of fiber materials, which is determined mainly by surface tension and effective capillary pore distribution and pathways. Evaporation and/or condensation take place, depending on the temperature and moisture distributions. The heat transfer process is coupled with the moisture transfer processes with phase changes such as moisture sorption and evaporation. 

In 2002 year, Li and Zhu reported a new model for simulation of coupled heat and moisture transfer processes, considering the capillary liquid diffusion process in textile [15], which developed the liquid diffusion coefficient as a function of fiber surface energy, contact angle, and fabric pore size distribution. Based on this new model, Wang et al. [16] considered more the radiative heat transfer and moisture sorption and condensation in the porous textile, achieving more accurate simulation for the reaUstic situation. The governing equations of the model are shown as follows ... 

Ch-amylase S films plasticized with polyols Blend Physical stability and moisture sorption Fernandez-Cervera et al., 2004... 

Fernandez-Cervera M, Karjalainen M, Airaksinen S, Rantanen J, Krogars K, Heinamaki J, Iraizoz-Colarte A, Yliruusi J [2004]. Physical stability and moisture sorption of aqueous chitosan-amylose starch films plasticized with polyols. EurJ Pharm Biopharm, 58,69-76. 

The structural characteristics and moisture sorption properties of two kinds of nylon-6/clay hybrids were investigated by Murase et The moisture sorption isotherms of the hybrid samples were a typical sigmoid shape similar to that of the pure nylon-6 sample, even if the extent of moisture regain of the hybrid films was comparatively low. All the isotherms obtained were explained through quantitative analysis in terms of the BET multilayer adsorption theory and complementally with the aid of the FloryHuggins solution theory. 

Murase S, Inoue A, Miyashita Y, Kimura N, Nishio Y, Structural characteristics and moisture sorption behavior of nylon-6/clay hybrid films , J. Polym. Set Part B Polymer Physics, 2002 40 479-87. 

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