The ring-opening polymerization of a series of organosilylcyclophosphazenes of formula gem-N3P3Cl4(CH2SiMe3)(R), where R = C2H5, i-C3H7, n-C4H9, t-C4H9, neo-C5H11, and C6H5, is described and is compared with the polymerization behavior of the non-silylated counterparts, gem-N3P3Cl4(CH3)(R). Polymerization is markedly favored by the presence of the organosilicon group. In the organosilyl derivatives, geminal t-C4H9or neo-C6H11cosubstituent groups retard polymerization compared to CH3, C2H5, n-C4H9, or C6H5groups. The i-C3H7group has an intermediate effect. It is speculated that the t-C4H9, neo-C6H11, and i-c3H7groups give rise to polymerization-inhibiting side reactions. The polymers prepared by the polymerization of gem-N3P3Cl4(CH2SiMe3)(R) were subjected to chlorine replacement reactions by treatment with sodium trifluoroethoxide. Reactions carried out in toluene solution allowed replacement of chlorine without concurrent attack on the organosilyl groups. In THF solvent, CH2-Si bond cleavage occurred to replace the (trimethylsilyl)methylene units by methyl groups.
All Science Journal Classification (ASJC) codes
- Organic Chemistry
- Polymers and Plastics
- Inorganic Chemistry
- Materials Chemistry