Depolymerization of polysulfide polymers by dithionite ions

The action of sodium dithionite, Na₂S₂O₄ on desulfurized tetrasulfide polymers leads to their depolymerization. Our studies showed that successful depolymerization can be initiated only in an alkali medium when 1.9–3.2 mole of sodium hydroxide per mole of dithionite is used, and that this leads to the cleavage of disulfide bonds and the formation of polymers of lower molecular weight with ? SH end groups. Liquid polymers of 1000–5000 molecular weight are obtained when 0.388–0.155 mole sodium dithionite per segment of polymer is used for depolymerization in the presence of the above-mentioned quantity of sodium hydroxide per mole of dithionite. The depolymerization of poly-sulfide polymers with sodium dithionite in the presence of sodium hydroxide was followed by determination of the molecular weight and sulfur content of the polymer and analysis of the mother liquid.