A Spectroscopic Study of Yellowing Caused by Fatty Soil in a Cellulose-Unsaturated Fatty Acid System

The mechanism of the yellowing of cellulose fibers caused by unsaturated fatty acids such as oleic and linoleic acids was studied by IR and UV spectroscopy, using thin film of cellophane as a model fiber. The following conclusions were made.(1) No chemical bonding occurs but a weak hydrogen-bond type interaction takes place between fatty acid and cellulose, and yellowing of cellophane itself is negligible.(2) Yellowing of fatty acid is enhanced by higher temperature and light, but not so by oxygen gas, in contrast to nitrogen gas.(3) No change in the absorbance of C-H band attached to double bond takes place following strong yellowing.(4) Yellowing is proportional to the increase in 204 and 210nm bands which can be assigned to double bonds formed by polymerization of oleic and linoleic acids.(5) Finally the main mechanism of yellowing reaction is not autoxidation but possibly kind of radical polymerization reaction of the double bonds of these fatty acids.