Synthesis and thermal properties of conjugated poly[(silylene)diacetylene silazanes]

A series of novel conjugated polymers, poly[(silylene)diacetylene silazanes] having different substituents on silicon were prepared by ammonolysis of the corresponding α,ω-dichlorodiorganosilylenediacetylene oligomers. The polymers had the number-average molecular weight between 700 and 2800, and the polydispersity index between 1.07 and 1.43. The polymers showed good solubility in common organic solvents. The structures of the poly[(silylene)diacetylene silazanes] were characterized by Fourier transform infrared, 1H, 13C, 29Si NMR, elemental analyses, and gel permeation chromatography. The thermal properties were measured with thermogravimetric analysis and differential scanning calorimetry. The resulting polymers had good thermal stability, and the DSC showed lower glass-transition temperature (Tg). They had good processability due to non-crystallization. Treatment of these polymers at appropriate temperature led to thermal polymerization of the acetylene unit to form a new cross-linking network system. These polymers have the potential to be used as precursors for Si/C/N-based ceramics.