Synthesis, structure and thermogravimetric analysis of α,ω-telechelic polydimethylsiloxanes of low molecular weight

• Main Authors: Tasić Aleksandra M., Pergal Marija V., Antić Mališa P., Antić Vesna V.
• Format: Article
• Language: English
• Published: Serbian Chemical Society 2017-01-01
• Series: Journal of the Serbian Chemical Society
• Subjects: a,w-telechelic PDMS; siloxane equilibration; thermal and thermo-oxidative degradation
• Online Access: http://www.doiserbia.nb.rs/img/doi/0352-5139/2017/0352-51391700082T.pdf

A series of α,ω-telechelic polydimethylsiloxanes (PDMS), with predetermined molecular weights of about 2500 g mol-1, was synthesized by siloxane equilibration reaction. Syntheses were performed using octamethylcyclotetrasiloxane (D4) and various disiloxanes: hexamethyldisiloxane (HMDS), 1,1,3,3-tetramethyldisiloxane (TMDS), 1,3-divinyltetramethyldisiloxane (DVTMDS), 1,3-bis(3-carboxypropyl)tetramethyldisiloxane (DCPTMDS) and 1,3-bis(3-aminopropyl)tetramethyldisiloxane (DAPTMDS). The role of the disiloxane was to introduce terminal functional groups at the end of the polymer chains and to control the molecular weight of the polymers. Polymers with trimethyl, hydrido, vinyl, carboxypropyl and aminopropyl end-groups were obtained in this way. The structure of the α,ω-telechelic PDMSs was confirmed by NMR and IR spectroscopy. The molecular weights of the polymers were determined by 1H-NMR, gel permeation chromatography (GPC) and dilute solution viscometry. Thermogravimetric analysis (TGA) under nitrogen and air showed that the type of the terminal groups significantly influenced the thermal and thermo-oxidative stability, as well as the degradation mechanism of the α,ω-telechelic PDMSs. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. 172062]