Synthesis, characterization, and properties of novel phenylene-silazane-acetylene polymers

New phenylene-silazane-acetylene polymers, P1 and P2, have been synthesized using Sonogashira cross-coupling reactions with a new designed ethynyl-ended silylenediamine, N,N′-bis(4-ethynylphenyl)-1,1-diphenylsilylenediamine (1), as the key monomer. This also represents the first example that construction of polymers containing silazane unit with Sonogashira coupling reaction. The structures of monomer and polymers were well characterized. Their thermal properties were studied by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Both polymers had good thermal stability with their temperatures at 5% weight loss (T_d5) being higher than 394 °C under nitrogen and higher than 385 °C in air, respectively. Their char yields at 1000 °C under N₂ were above 70%. The fundamental photophysical properties in solution were also investigated. Both polymers showed fluorescence in ultraviolet region with moderate quantum yields. These polymers had potential to be used as high-temperature resistant resins and light-emitting materials with good thermal stability.