Propargyl silicon‐cyclopentadiene oligomeric resin with high temperature resistance

Multiple propargyl substituted cyclopentadiene was synthesized by phase transfer reaction between cyclopentadiene and propargyl bromide in an aqueous solution mediated by sodium hydroxide. It was found that propargylated cyclopentadiene (PCp) could be thermally cured with a mass loss of ca 28%, while the cured material showed a high char yield of ca 76% at 900°C. In order to overcome the processing problems of PCp, a condensation reaction between PCp di‐anion and dimethyldichlorosilane was performed to make a silicon‐PCp (SiPCp) oligomeric resin. SiPCp resin has an acceptable processability, attributed to its organosolubility, low viscosity, and broad processing window. SiPCp resin can readily undergo thermal cure via addition polymerization of ethynyl groups in the temperature range of 170–270°C with an exothermic maximum at ca 240°C, and the mass loss upon cure was less than 5%. Evidenced by the results of dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA) in a nitrogen atmosphere, the cured SiPCp resin exhibited stable thermo‐mechanical properties up to 320°C, and possessed an anerobic char yield of ca 77% at 900°C. The results of TGA in air atmosphere revealed the higher oxidation resistance of SiPCp resin. Copyright © 2008 John Wiley & Sons, Ltd.