Étude de la Distribution des Compositions au Sein de Copolymères Préparés Par Voie Radicalaire

The instantaneous composition of a radically prepared copolymer is a function of the composition of the monomer mixture. Thus, if a copolymerization is carried out to give a high yield, the obtained copolymer is not homogeneous in composition. In the present paper, it has been tried to relate the fluctuations in composition within a copolymer sample with the copolymerization yield, knowing the reactivity ratios of the two corresponding monomers. Integration of the Skeist equation, which expresses in a differential form the copolymer composition as a function of copolymer yield, has been performed by means of an electronic computer, for three different monomer systems: styrene—methyl‐methacrylate, styrene—p‐bromostyrene, and styrene—α‐vinyl‐naphthalene. Copolymerization experiments were carried out to various yields, and followed by careful characterization of the obtained products, by analysis, fractionation and UV spectroscopy. The obtained results concerning composition distribution within the samples and the average composition of the copolymers as well are in satisfactory agreement with the corresponding data theoretically established in the first part of the work.