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The accelerated aging of unplasticized Cellophane film specimens was conducted at tempe:atures ranging from 80 to 150 °C in a dry, forced-air convection oven for various periods of time. Colorimetric evaluation showed increasing discoloration which could be partially reversed by rinsing in deionized water. The infrared spectra of samples aged within this temperature range show the same changes, dependent upon aging time. This indicates that the species formed in the films at temperatures above and below the boiling point of water are the same, and that the moisture content of the films may affect the reaction rate, but not the mechanisms. The observed data in the visible region fit the standard pseudofirst-order kinetics model and are in excellent agreement with those determined for both the color change of cotton and the UV absorbance of Cellophane under similar conditions.

The kinetics of the disappearance of propagating butadiene radicals produced in the grafting of butadiene to poly(vinyl chloride) was followed by electron spin resonance measurements. The radical species observed in the temperature range 213-298/sup 0/K is the conjugated allylic radical: --CH/sub 2/--CH==CH--CH/sub 2/ reversible --CH/sub 2/--CH--CH==CH/sub 2/. The reaction conditions were adjusted to provide a highly viscous medium in which the propagation reaction took place. Under these conditions the radicals were stabilized and a precise ESR spectrum was obtained. Arrhenius plots of the second-order decay rate constants yield an activation energy of 5 kcal/mole. This suggests that the bimolecular termination reaction is controlled by the segmental motion of the grafted side chains.