No abstract

For solutions containing rod‐shaped polyelectrolytes and their counterions only, the Poisson‐Boltzmann equation can be solved explicity without the usual assumption of the Deybe‐Hückel theory. At charge densities corresponding to half‐neutralized polyacrylic acid a large proportion of monovalent counterions is located close to the polyion even in solutions as dilute as 1/800 base molar.

The mechanism of catalytic copolymerization of two monomers A and B is treated with the the aid of steady state approximation. Two initiation and two termination rates are assumed, one for each monomer. Four propagation rates are considered, corresponding to the four possibilities of addition, namely, addition of monomer A to a chain ending in A* or to a chain ending in B* and addition of monomer B to a chain ending in A* or to a chain ending in B*. Over-all rate and number average molecular weight are calculated. The composition of the polymer and the number distribution curves of groups of submolecules a and of submolecules b are calculated as functions of the monomer composition and two rate constant ratios. These last results are of general character and independent of the nature of the initiation and termination processes provided that the average degree of polymerization is ``high.''

From data in the literature on relative rates of copolymerization it has been possible to evaluate two constants, Q and e, characteristic of an individual monomer, which appear to account satisfactorily for its behavior in copolymerization. The constant Q describes the “general monomer reactivity” and is apparently related to possibilities for stabilization in a radical adduct. The constant e takes account of polar factors influencing copolymerization.

In this study of side chain crystallinity, methacrylate and acrylate monomers, with «-alkyl groups containing from 12 to 18 carbon atoms, were synthesized, polymerized and copolymerized; dilatometric measurements were made on these polymers to determine the changes in specific volume with temperature and time; spacings were obtained from Debye-Scherrer patterns taken at small and wide angles. The following results were noted: the specific volume-temperature plots were S-shaped, typical of first-order transitions; crystallization was rapid and accompanied by very little supercooling; melting ranges were short except for the mixed long chain copolymers; long and short spacings were found in the X-ray patterns. The melting ranges of the polymers did not depend on the temperature of the cooling bath.