Abstract
For wool and polyester fiber on which formaldehyde (HCHO) vapor was absorbed, desorption of HCHO vapor was measured under various atmospheres with different temperatures and relative humilities. The results obtained are as follows: (1) The desorption of HCHO vapor could be described by a diffusion equation which is based upon Fick's second law. Using its equation, the diffusion coefficient (D) could be obtained. (2) D of HCHO in wool increased at all the atmospheres with increasing the concentration of HCHO sorption, but D in polyester decreased at low temperatures and high relative humilities. (3) Apparent activation energy of HCHO diffusion (Ed) in wool at 50% RH was higher than that in polyester, but the former at 85% RH was a little lower than that in the latter. (4) The variation of D0with the relative humidity can be well understood for wool particularly at high relative humidities, by the free volume theory. This conclution does not contradict with previous ones which have been obtained from permeation and sorption measurements, but does support the previous conclusion.
