Novolac‐Polydimethyl Siloxane networks through click chemistry: Thermal and Thermophysical characterization

Abstract Polydimethyl siloxane combs projecting from a novolac stem were synthesized using click reaction of azide‐terminated polydimethylsiloxane (AZ‐PDMS), and novolac propargyl ether (NPE) under ambient (30°C) conditions. Dynamic mechanical analyses (DMA) indicated the transition of soft segments at nearly −100°C and that of the hard segments in the range of 25°C‐30°C. The hybrid novolac‐siloxane networks have been found to possess an elongation at break of 100%–260%. Thermal degradation behavior of the networks of different crosslink densities was studied using TGA and pyrolysis GC‐MS. Thermogravimetry revealed an anaerobic char residue of 23%–40% at 900°C. Further rise in temperature up to 1500°C has been observed to result in hardly 1% reduction in the char yield/ceramic residue, thus attributing to the presence of high char‐yielding aromatic part. The ceramic residue obtained at 1500°C under argon atmosphere was analyzed using FTIR, Raman, and XRD. XRD studies implied formation of βSiC, and SiO ₂ . Morphology of the ceramics conformed to nanowires with diameters in the range of 20‐100 nm. The nanowire consisted of mainly SiOC as attested by EDS analysis.