This article surveys methods and mechanisms of synthesis and characterization of hydroxytelechelic polymers by the free radical process. Some practical applications have been considered.

Hydroxyl-terminated polymers obtained by free radical polymerization — Synthesis, characterization, and applications

A description is given of high resolution liquid adsorption chromatography and the application of this method for the separation of styrene oligomers according to molecular weights and for determining thermodynamic parameters of adsorption—differential heat and entropy.

Highly effective liquid adsorption chromatography of oligostyrenes using silica gel columns

The review examines the results of investigations in the last few years into the synthesis of reactive hydrocarbon oligomers with terminal functional groups with use of polymerization methods—anionic, cationic and radical. The mechanism and kinetics of the process and the link between the molecular characteristics of the oligomers obtained (molecular weights, molecular-weight distribution and the distribution by functionality) and the conditions of synthesis are analysed.

Achievements in the synthesis of reactive hydrocarbon oligomers with terminal functional groups. Review

Fsom the data on the retention of non-functional and also mono and bifunctional hydroxyl-containing polybutadienes with M = 600–7000 on Silica gel ASK and Silochrome S-3 the authors have obtained the dependence of change in the free energy ΔF during adsorption on the content of the polar component (1,2-dichloroethane, n-butanol) in a binary eluent. It is shown that the experimental data, as a whole, agree with the conclusions of the molecular-statistical theory of chromatography of macromolecules. It is concluded that it is desirable to use wide pore adsorbents on fractionation by types of functionality of polymers with a wide MWD.

Liquid chromatography of low molecular weight polybutadienes

It was found that an increase in polydispersion according to the molecular weight of oligodienes containing hydroxyl causes a deterioration in the resolution of chromatographic bands during fractionation of these oligodienes according to types of functionality. A ratio was derived between the resolution of adjacent chromatographic bands Rs and the value of Mw/Mn of corresponding oligomer fractions. A general approach is proposed to solve the problem concerning the selection of experimental conditions of determining distribution according to the type of functionality of oligodienes with a wide MWD.

Effect of molecular weight distribution of oligodienes containing hydroxyl on fractionation according to functionality

Oligomerization of isoprene on initiation by hydrogen peroxide in solutions of methyl, ethyl, propyl and carbon-labelled isopropyl alcohols is studied. The radioactive label method reveals that the functionality of the oligomers for fragments of isopropyl alcohol is about 0·5 irrespective of the molecular weight of the oligomers and degree of monomer conversion. The presence of fragments of isopropyl alcohol with the terminal tertiary OH groups in the oligomer molecule is the cause of the reduced (below 2) “effective” functionality of the oligoisoprenes obtained in solution in isopropyl alcohol. In solutions in primary alcohols oligomers containing up to 90% of molecules bifunctional in hydroxyl groups are obtained.

T.S. Dmitriyeva

Papers

Effect of molecular weight distribution of oligodienes containing hydroxyl on fractionation according to functionality

Study of oligomerization of isoprene on initiation with hydrogen peroxide