Cationic ring‐opening isomerization polymerization of spiro orthocarbonates initiated by carbon black

Abstract

AbstractThe ring‐opening isomerization polymerization of spiro orthocarbonates (SOC), such as 2,8‐dimethyl‐1,5,7,11‐tetraoxaspiro[5.5]undecane (I), 8,10,19,20‐tetraoxaspiro[5.2.2.5.2.2]‐heneicosane‐2,4‐diene (II), and 8,10,19,20‐tetraoxaspiro[5.2.2.5.2.2]heneicosane (III), initiated by carbon black was investigated. No polymerization of SOC was initiated in the absence of carbon black. But in the presence of channel black having a carboxyl group, the polymerization of SOCs was initiated at 90–150°C to give the corresponding polyether carbonates. The initiating ability of carbon black increased with an increase in its carboxyl group content. Furnace black having no carboxyl group failed to initiate the polymerization. Based on these results, it was concluded that the carboxyl group on carbon black is capable of initiating the polymerization of SOC. During the polymerization, a part of the polymers formed was grafted onto carbon black surface via the termination of growing polymer chains. The percentage of grafting increased with an increase in conversion and reached about 55%. Furthermore, polyether carbonate‐grafted carbon black was found to produce a stable colloidal dispersion in chloroform. The mechanism of initiation and grafting were discussed.