Monomer - polymer equilibrium has been investigated for the copolymerization of 3-inethyl butene-1 and sulphur dioxide. Equilibrium (or ceiling) temperatures have been measured for comonomer mixtures of various compositions.
The activity coefficients in the various comonomer mixtures at the ceiling temperatures have been obtained by Gibbs-Duhem analyses of the total vapour pressure – mixture composition isotherms, with allowance for non-ideality of the vapour phase.
The plot of log (activity product) versus reciprocal of the ceiling temperature, derived from the ceiling temperature and activity coefficient measurements, has shown that the polymerization is thermodynamically different in "olefin-rich" and "sulphur dioxide-rich" mixtures. Possible explanations of this dissimilarity are proposed, and some have been investigated.
The initiation of some polymerizations with a chemical initiator has shown that a photo-excited species, such as a diradical, does not participate in the propagation reaction.
Chemical analyses of 3-inethyl butene-1 polysulphone have indicated that the relative proportion of olefin and sulphur dioxide units in the polymer is independent of the composition of the comonomer mixture from which it is prepared, and that there is a significant difference in the combustibility of polymer prepared from sulphur dioxide-rich and olefin-rich mixtures.