Low density cellulose foams for buffering between zones with different relative humidity
摘要
In this work, water vapor adsorption and water vapor diffusion through low-density cellulose fiber foams of different thicknesses (10, 20, and 30 mm) were studied. The moisture sorption isotherm of the cellulose foam was determined, showing a moisture content ranging from 1.7 ± 0.1 to 15.1 ± 0.9% within a relative humidity range of 10 to 90% at 23 °C, respectively, following the GAB model for moisture adsorption. Moreover, the moisture adsorption kinetics of the cellulose foams exhibits exponential increase behavior. Adsorption kinetics depend on thickness, with the adsorption rate (k) decreasing as thickness increases. In addition, water vapor transmission rate (WVTR) experiments conducted on cellulose foams showed that water vapor diffusion flux through the structure is influenced by thickness, with WVTR values decreasing from 484 to 380 g/m2·day for thicknesses ranging from 10 to 30 mm. An innovative buffer capacity experiment has been designed and has demonstrated that cellulose foam acts as a moisture transmission retarder, functioning as a buffering (scavenger) system whose effect slightly increases with foam thickness.