Toshinari Nakajima

Effect of polymer chain end on sorption isotherm of water by chitosan

Abstract In this study, the sorption isotherms of water vapor by chitosans with various molecular weights were measured. The BET adsorption theory was modified for the system that has several different kinds of energy levels in the water adsorption sites, i.e. a hydroxyl group, an amino group, the polymer chain end, etc. and applied it to the experimental results in order to examine the effect of the polymer chain end on the sorption isotherm of water–chitosan using the parameters which represented the total number of adsorption sites, V m , the interaction energy between water and the adsorption sites, K , and the number of adsorbed layers, n . V m and K increased as the molecular weight decreased, and n remained constant. It has been proved that the increase in V m and K were caused by the hydrophilic groups in the polymer chain end.

Effect of acetyl content on the sorption isotherm of water by cellulose acetate: comparison with the thermal analysis results

Abstract In this study, the sorption isotherms of water vapor by cellulose acetate for various acetyl contents were measured. The BET adsorption theory was modified for the system which has two different kinds of energy levels in the water adsorption sites, i.e. a hydroxyl group and an acetoxyl group, and applied it to the experimental results in order to examine the effect of acetyl content on the sorption isotherm of water using the parameters which represented the total number of adsorption sites, V m , the interaction energy between water and the adsorption sites, K , and the number of adsorbed layers, n . V m and K decreased with an increase in acetyl content and n remained constant. The apparent activation energies of the water desoption were also determined using differential thermal analysis. They are nearly constant with an increase in the acetyl content.

Effect of thermal radiation from fabrics on human body

The effectiveness of the far infrared radiation processing cloth as clothing material is discussed. Temperature rise of the irradiation plane is more rapid than the heating by heat conduction and convection for the radiant heating. Skin temperature change and thermal sensation of the examinee wearing the sweater with a plastic heater at back were examined. “The relation of the inverse proportion of heat intensity to the time needed until the extent of thermal stimulation perceived was examined. Individual examinees tested, by oral contact, the extent of the pleasant sensation produced by the warming condition. They judged the extent of the warming according to whether it felt comfortable. Individually, they differed a great extent in their opinion of what was comfortable. However, for all examinees, the relationship of warming and feeling comfortable was confined within narrow parameters. In this experiment, a unit of the radiant heat stimulation was determined by dividing mW/cm2 by the warming period, since intermittent warming was carried out.” The degree of the skin temperature perceived by the sensation was almost fixed at 33–35, even if the radiant heat strength differed. The rapid thermal stimulation by radiant heating can be perceived even for a slight temperature rise of the skin. It is also necessary to consider the temperature rise speed, except for the temperature rise of the cloth surface, when the effectiveness of the far infrared radiation processing cloth was discussed.