Molecular core binding energies have been measured by ESCA for the homopolymers of ethylene and the fluoroethylenes. The data are interpreted in terms of semiempirical all‐valence electron SCF MO calculations in the CNDO/2 formalism, in conjunction with the charge potential model. The results are used as a basis for interpreting the measured core binding energies of some Viton and Kel F type polymers. The routine application of ESCA to the determination of copolymer compositions is described.

Molecular core binding energies have been measured by ESCA for series of surface‐fluorinated high‐density polyethylene films. Detailed analysis of the results shows that the technique can be used to establish a comprehensive picture of the early stages of the surface fluorination process. Both the depth of fluorination, and stoichiometry and molecular structure as a function of depth, in the range 0–50 Å have been established. In addition, minor features such as oxidation, hydration, and hydrocarbon contamination at the surface are clearly revealed. Detailed consideration of the results allows a discussion of the dynamics of the overall fluorination process.

Rate constants and product analyses are provided for reactions of various chloropolyfluoropyridines with ammonia in dioxan-water (60 : 40 v/v) at 25 "C. Comparison of these rate constants with the values for appropriate polyfluoropyridines allows the separate effects of chlorine atoms orrho. meta, and para to the reaction centre to be established. The activating influence of chlorine decreases in the series orrho > meta >para (86 : 24 : 6.9 relative to hydrogen atom a t the same position). The rate constant ratios k,, : kB for chlorine or fluorine a t the same position are : orrho ca. 3 : 1, mera ca. 1 : 1, and para ca. 2.6 : 1. These ratios have been measured for a number of different substitutions and are remarkably constant. The results help to explain the orientation and reactivity of nucleophilic substitution in polyhalogenoaromatic compounds.

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