The gel time, measured under isothermal conditions, may be taken as a measure of the overall rate of polymerization of a given system under certain circumstances. This enables us to estimate the Arrhenius activation energy from such measurements. A simple piece of apparatus is described which has been used to measure the overall activation energy of some epoxy resin polymerizations. The agreement with previously published data is reasonable.
Several techniques have been investigated for studying the transfer to skin of chemicals from a durable press finish on cotton-containing fabric, under normal wearing conditions. Using flameless atomic absorption spectroscopy, it has been found that the transfer of solid resin to skin was below the sensitivity of the technique (less than about 200 μg of resin per gram of fabric). By differential pulse polarography, it was found that the release of free formaldehyde from shirts did not exceed 10 ng/g in the laboratory air that was drawn over the samples.
Several operating and sample handling conditions were used to study their effect on spectral subtraction results using Fourier transform infrared spectroscopy. Purge rate, orientation of a heterogeneous sample and sample pathlength were varied to determine under what conditions and to what degree subtraction artifacts can be produced. To some degree, all of the conditions evaluated produced spectral subtraction artifacts although sample pathlength was found to have the greatest effect. Also under certain conditions, concentration differences taken from identical pathlength cells could not be totally nulled by subtraction manipulation.
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