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A process of the graft polymerisation of 2-methyl-5-vinylpyridine induced by plasma on the surface of poly(ethylene terephthalate) track membranes (PET TM) was investigated. The surface properties and hydrodynamic properties of the composite membranes produced in this case have been studied. It is shown that the water permeability of the obtained polymeric membranes can be controlled by changing the filtrate pH.

The basic laws governing phase separation in solutions of the synthetic polyampholytes formed by acrylic acid and 2-methyl-5-vinylpyridine have been studied. A reversible equilibrium transition from true solution to a polymeric dispersion is observed when the pH of the medium or the polymer concentration is changed. The pH region for phase separation of solutions of the polyampholytes is determined by the composition and compositional non-uniformity of the copolymer but it does not depend on the molecular-mass distribution. Structure-formation occurs above a critical polymer concentration, whose value depends on the pH of the medium and the copolymer's composition.

Copolymers of 2-methyl-5-vinylpyridine with acrylic acid have been studied by spectrophotometric titration in the UV region. It was found that the basic strength of the methylvinylpyridine groups increases as the proportion of acrylic acid units in the copolymer is increased, and the molar extinction coefficient, e, of these groups varies as the composition of the copolymer is varied. It is suggested that the change in the coefficient is brought about by change in the intramolecular distribution of the units in the copolymer.

The molecular and compositional heterogeneity of polyampholytes formed by acrylic acid and 2-methyl-5-vinylpyridine having various compositions and molecular masses have been assessed by spectroturbidimetric titration. Fractionation of the copolymers has been carried out in the system methanol-toluene. It has been established that, in the system methanol-diethyl ether, precipitation of the copolymers occurs principally with respect to composition and, in the system methanol-toluene, with respect to molecular mass.

The emulsion polymerization of 2-methyl-5-vinylpyridine (MVP) initiated by potassium persulphate in the presence of two anionic emulsifiers, sodium lauryl sulphate (NaLS) and sodium oleate, was investigated. The effects of persulphate and emulsifier concentration on the rate of polymerization are not those predictable on the basis of the theories of Harkins and Smith-Ewart. MVP polymerizes with a high rate in water solution and in emulsion even in the absence of emulsifier. A few emulsion polymerizations carried out with various NaLS concentrations near the critical micelle concentration showed that the presence of emulsifier in micellar form does not substantially increase the rate of polymerization, as predicted by the above theories. The behaviour of MVP is probably related to its moderate water solubility, which is 1·04 per cent by weight at 60°. Some experiments with seeded latexes confirmed that the water phase plays a predominant is not exclusive role as locus of polymerization.

In previous communications [1, 2] it was shown that polyampholytes based on two unsaturated, stereo-isomeric acids (maleic and fumaric) and 2-methyl-5-vinylpyridine are substantially different in their behaviour in titration. This was associated with the different spatial configurations of the carboxyl groups in these copolymers. Another important feature of polyampholytes of this type, also associated with the use of an ethylene-1,2-dicarboxylic acid as one of the comonomers, is that the acidic component units in the copolymer will alternate with a definite number of units of the basic component. The purpose of the present work was to extend the study of the behaviour of these polyampholytes in potentiometric titration. In contrast to the earlier work attention here was directed mainly to study of the effect of change in the ratio of acidic and basic groups in the copolymers on their behaviour in titration.

1. I. P. LOSEV, O. V. SMIRNOVA and Ye. V. KOROVINA, Vysokomol. soyed. 5: 1941, 1963 2. S. B. YEROFEYEVA, Dissertation, 1963 3. EL SAID ALI KKASAN, Dissertation, 1964 4. O. V. SMIRNOVA, EL SAID ALI KHASAN, I. P. LOSEV and G. S. KOLESNIKOV, Vysokomol. soyed. 7: 503, 1965 5. J. VAN-BRAUN, Liebig's Ann. Chem. 472: 1, 1929 6. E. KHORVAT, Dissertation, 1961 7. G. S. KOLESNIKOV, EL SAID ALI KHASAN and O. V. SMIRNOVA, Vysokomol. soyed. 7: 129, 1965