Correlation of cross-linked structures and properties in the characterization of dimethyl-diphenylethynyl-silane using DSC, TGAÂ and Py-GC/MS analysis

Hybrid monomer with reactive CC linkages, dimethyl-diphenylethynyl-silane (DMPES), is conveniently synthesized and its structure is characterized. The cross-linking behavior of the monomer and its cross-linked structures are inferred from DSC and FTIR. A large exothermic peak is observed in the DSC curve, which indicates that cross-linking occurs during heating to 430 °C via the Diels-Alder and trimerization reactions. The results also supported by the FTIR spectra. After that, pyrolysis-gas chromatography combined with mass spectroscopy (Py-GC/MS) is carried out to identify characteristic products of the pyrolysis (750 °C) of the cross-linked DMPES. A qualitative analysis of the pyrolyzates reveals a pronounced dependence of the cross-linked structures, which presents a good agreement with the results of DSC and FTIR. Furthermore, TGA and SEM measurements are also used to study the thermal properties, which indicate that the cross-linked DMPES exhibits excellent thermal stability and resistance to oxidation. The temperature corresponding to 5% weight loss and the residue at 1000 °C under nitrogen are 610.8 °C and 85.6%, respectively, which is attributed to the highly cross-linked network structures of the cross-linked DMPES. This analytical method is proposed for studying the cross-linked structures of polymer or monomer and gaining insight into understanding the structure-property relationship, which can also be used to design and predict high performance polymer and monomer for advanced materials.