Models for assessment of volatile organic compound diffusivities in leather or leather imitates by mercury intrusion porosimetry test

Abstract

Recent studies have been conducted on the characteristics of volatile organic compound emissions; most of them are focused on wood-based building materials, scarcely mentioned about leather or leather imitates. The volatile organic compound emissions of these products may cause poor indoor (vehicle cabins included) air quality. This article takes formaldehyde as an example to study its diffusion in leather. The porous structure of leather was characterized by carrying out mercury intrusion porosimetry test. The formaldehyde diffusivities in leather was assessed by Blondeau et al.'s, Ataka et al.'s, and Xiong et al.'s models which represent parallel, equivalent, and series interconnection of pores, respectively, and validated through independent liquid inner tube diffusion film emission experiments. The results demonstrated that the fractal dimension of leather is 2.19, which indicated it is a porous medium with self-similar pore structure. Most of the pores in leather were macro pores with average diameter 16.56 μm which contributed to 95.9% of whole porosity and the meso pore with average diameter 0.60 μm which contributed to 4.1%. As far as the liquid inner tube diffusion film emission experiment shows, the Xiong model agrees much better with the experimental results than the other two. The two kinds of pores were considered to be serially connected. It is useful for predicting volatile organic compounds diffusion coefficient in a short time and can be applied to the design and development of low volatile organic compound emission leather or leather imitates within further research.