Dibutylamine reacts with benzophenone oxime carbamates to give the corresponding dibutylureas. This reaction, with a polymeric bis (oxime carbamate) derived from a toluene-2,4-diisocyanate-polypropylene oxide adduct, was studied in toluene solution using kinetic techniques. The reaction exhibited first-order kinetics and had entropy of activation of -1.86 eu and enthalpy of activation of 24.8 kcal/mol, and the rate was insensitive to added tertiary amine. The reaction was favored by electron-releasing substituents on the oxime moiety with p = -0.45. An intramolecular, cyclic transition state is postulated for the rate-determining dissociation step.Blocked polyurethanes are those polymers whose reactive isocyanate groups have been treated (eq 1)with a thermally removable active hydrogen compound, BH. The term "unblocking" may refer to dissociation of the unstable adduct or to the reaction of a blocked polyurethane with some monomeric or polymeric coreactant. In this paper, unblocking will be used to indicate the latter (eq 2), whereas the reverse reaction in eq 1 will be referred to as dissociation.RNHCOB + B'H -> RNHCOB ' + BH (2)

total pressure of 0 2 above the reaction was just the total pressure minus 50 Torr. The stirring speeds were adjusted to avoid making the rates diffusion controlled. In rates higher than about 150 M min-l diffusion rates of oxygen begin to compete as ratelimiting steps. All kinetic studies were done below this limiting rate.Products.-Reaction solutions were quenched by pouring into cold 1 M HCl. The mixture was extracted with two portions of benzene and the benzene extracts were washed several times with water. The benzene solutions were dried and analyzed by gas chromatography. Fluorene, fluorenone, and fluorenol were determined on an XE-60 column a t 230' using chloronaphthalene as an internal standard. No fluorenol was found in any reactions.9,9'-Bifluorenyl was analyzed on an XE-60 column (seasoned overnight a t 275') at 24j0. Spectra.-Visible spectra were done using a Cary 14 spectrophotometer. A Varian Aerograph instrument was used for esr spectra except for liquid helium temperatures, where a super heterodyne spectrometer operating near 9200 MHz was used.

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Poly(methyl isopropenyl ketone) (PMIPK) degrades upon exposure to 5 keV electrons. Using a scanning electron microscope to expose fine‐line raster patterns in thin films of this polymer and subsequently solvent‐developing the thus‐degraded regions, sharp walled troughs are observed, the width of which is a measure of the sensitivity to degradation. Copolymers with several vinyl monomers were prepared and the sensitivities of these were similarly determined. Information relevant to the mechanism of depolymerization was obtained by comparing homopolymers with copolymers and by the use of additives in the irradiated polymer films. Examples of potential device‐fabrication techniques using PMIPK resist are given.