| Abstract: | Polymerization under the influence of boron trifluoride of 2-oxa-6-thia3,3]spiroheptane gives two products: a linear polyether containing oxetane groups and a crosslinked polyether polysulfide. When the polymerization was carried out at ?3°C., up to 60% of soluble polysulfide is obtained. This does not prove that the thietane group polymerizes more rapidly than the oxetane group but rather that oxetane polymerization is inhibited by the presence of thietane groups. Polymerization under the influence of boron trifluoride etherate of 3,3-bis(mercaptomethyl)oxetane leads to a polyether containing free thiol groups. The degree of polymerization of the polymer, however, is low. In order to obtain higher degrees of polymerization several compounds with masked thiol groups were polymerized. 2-Oxa-6,7-dithia-6-thio3,4]spirooctane and 2-oxa-6,8-dithia-7,7-dimethyl3,5]-spirononane gave crosslinked products. The diacetate of 3,3-bis(mercaptomethyl)oxetane gave a linear polyether containing thiolacetate groups. Hydrolysis of this polymer leads to poly-3,3-bis(mercaptomethyl)oxetane with a softening temperature of 125–135°C. |
