Diffusion Behavior of Water at Infinite Dilution in Hydroxypropyl Xylan Films with Sorbitol and Cellulose Nanocrystals

作者：Bayati Fatemeh; Boluk Yaman; Choi Phillip^*

来源：ACS Sustainable Chemistry and Engineering, 2014, 2(5): 1305-1311.

DOI：10.1021/sc500133p

• Inverse gas chromatography
• Hydroxypropyl xylan
• Plasticizer
• Cellulose nanocrystal
• Water diffusivity

Inverse gas chromatography (IGC) was used to measure the infinite dilution diffusion coefficients of water in hydroxypropyl xylan (HPX) films containing sorbitol, a commonly used plasticizer, and cellulose nanocrystals (CNC) at temperatures above their glass transition temperatures (T-g). HPX forms transparent but relatively rigid films and has the potential to be used for certain food-packaging applications. Sorbitol and CNC were added to HPX films to reduce T-g and to reduce the water diffusivity, respectively. It was found that almost 40 wt % of sorbitol was needed to yield a HPX film to have the desired flexibility, as quantified by its T-g, and that addition of a small amount of CNC (1-5 wt %) while maintaining the total concentration of sorbitol and CNC at 40 wt % (39-35 wt % of sorbitol) slightly increased the T-g but significantly decreased the diffusivity of water. In particular, the infinite dilution diffusion coefficient of water for the HPX film with 35 wt % of sorbitol and 5 wt % CNC was comparable to that of the bare HPX film. The diffusion data suggest that effects of sorbitol and CNC on the water diffusivity follow the free volume theory.

• 出版日期2014-5