> Donhowe and Fennema (1992) demonstrated that the water vapor permeance of beeswax films is sufficient to deliver 1.7 g of water per kg wax into the comb structure. They further pointed out that although beeswax is primarily hydrophobic, the esters, hydroxyl groups of free alcohols and the carboxyl groups of free fatty acids in beeswax are hydrophilic.

Hepburn, H. R., Pirk, C. W. W., & Duangphakdee, O. (2014). Material Properties of Honeybee Silk. In Honeybee Nests (pp. 367-382). Springer Berlin Heidelberg.

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> The water vapor (WV) permeance of lipid and lipid-hydrocolloid films exposed to relative humidity (RH) gradients of 100-0%, 100-50%, 100-65% and 100-80% RH were determined. The lipids used were beeswax (BW) or a blend of BW and acetylated monoglycerides (AG). Hydrocolloids used were methylcellulose, carboxymethylcellulose or ethylcellulose (EC). 

> All films, except those containing EC, exhibited increased water vapor permeance as the RH gradient was reduced by raising the low end RH. This increase in permeance was apparently caused by hydration and swelling across the entire film thickness, thus facilitating water movement through the film.

Donhowe, I. G., & Fennema, O. (1992). The effect of relative humidity gradient on water vapor permeance of lipid and lipid-hydrocolloid bilayer films. Journal of the American Oil Chemists’ Society, 69(11), 1081-1087.

PLB

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