Water-vapor permeation in semicrystalline and molten poly(octadecyl acrylate)

The water-vapor permeability of poly(octadecyl acrylate) (PA-18) was measur ed as a function of temperature in the region traversing its melting point (50 degreesC). The molten-state permeability of PA-18 is comparable to that of shorter side-chain methacrylate polymers. Water permeability in the sem icrystalline state of PA-18 is similar to that of polyethylene at comparabl e crystallinity levels. The permeation switch, or change in permeability wi th the traversing of the melting point, for water is discussed in the conte xt of previous results for other penetrants in this and other side-chain cr ystalline polymers. (C) 2001 John Wiley & Sons, Inc. J Polym Sci B: Polym P hys 39: 979-984, 2001.