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Some filler effects on diffusion in silicone rubber
Author(s) -
Most C. F.
Publication year - 1970
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1970.070140412
Subject(s) - fumed silica , silicone rubber , filler (materials) , materials science , diffusion , composite material , adsorption , silicone , natural rubber , solubility , precipitated silica , chemical engineering , polymer chemistry , chemistry , organic chemistry , thermodynamics , physics , engineering
The diffusion of ethyl p ‐aminobenzoate in silicone rubber membranes containing varying amounts of a high surface area fumed silica filler is described, as is a new apparatus for assaying multiple samples. It is shown that increased filler loading results in what appears to be a linear decrease in transmission rate, but that apparent diffusivities fall off drastically as a result of adsorption of the permeant on the filler. Distribution coefficient measurements suffer from the same result. The results suggest that neither an unmodified time lag technique nor a direct solubility method can be used to determine diffusivities of polar or unsaturated molecules in silicone rubbers, since they generally contain silica fillers.