Thermal curing and degradation mechanism of polyhedral oligomeric octa(propargylaminophenyl)silsesquioxane

Polyhedral oligomeric octa(propargylaminophenyl)silsesquioxane (OPAPS) was synthesized and the pressed OPAPS thermally cured with a controlled temperature program. The OPAPS and its cured products were characterized by DSC, FT-IR, XRD, SEM and TGA. TG-MS was used to detect the decomposition products of OPAPS and its cured products with increasing temperature in an inert atmosphere. Curing of OPAPS commenced around 170°C and was completed by 250°C. The possible thermal curing mechanism of the OPAPS involved five- and six-membered rings which contained conjugated diene bonds connected with secondary amine. The thermal degradation of the OPAPS and the cured product differed: Alkyne, methyl, secondary amine and phenyl groups were seen in the OPAPS degradation products while five- or six-membered rings and phenyl groups were generated from the cured product. The thermal-oxidative degradation of the OPAPS involved three steps while only two were involved for the cured product.