Abstract
The effects of. moisture on the sorption of formaldehyde (HCHO) vapor by various fibers were investigated under various atmospheres having different HCHO concentration and relative humidities. The results obtained are as follows: (1) The amounts of HCHO sorbed by fibers increased with increasing the moisture content. The closer the solubility parameter of fiber to that of HCHO, the amount of HCHO sorbed by the fiber became larger. (2) The amount of HCHO sorbed was constant between 30 and 70% in relative humidity, and abruptly increased with relative humidity over 85%. These are attributed to different sorption mechanisms. (3) In the former case (30-70%), the sorption can be described by Langmuir's sorption mechanisms. (4) In the latter case (>85%), the amounts of HCHO sorbed increased with increasing HCHO concentration. This increase may be caused by dissolution of HCHO molecules in water sorbed by fiber molecules. (5) The dissolution was evidenced by the fact that there was obeyed the Henry'law between the amount of monohydrated product of HCHO and the HCHO concentration in vapor phase.
