Polysulfide lower-molecular-weight

Condensation polymerization of the bis (sulfenyl) chlorides is effected by treatment with mercury or potassium iodide. However, the polymers are of lower molecular weight than the analogous products obtained directly from the cyclic polysulfides. 

An important aspect of this is the splitting of the polymer chain with thiol (eq. 5) or mercaptide ion (thiol + base catalyst). In fact, sodium sulfide or oiganic monothiols, eg, mercaptoethanol or decyknercaptan, are utilized to lower the molecular weight of polysulfides or to limit the extent of curing reactions. 

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