Synthesis of poly [(methylsi1oxane)- co -(dimethylsilazane)] copolymers as precursors of ceramic materials

Autor:	J Carlos Aguilera, Andrónico Neira C., Mario Rodríguez-Baeza
Rok vydání:	2003
Předmět:	Condensation polymer Materials science Polymers and Plastics Cationic polymerization Silazane General Chemistry Condensed Matter Physics Ring-opening polymerization chemistry.chemical_compound Monomer chemistry Polymer chemistry Materials Chemistry Copolymer Thermal stability Chemical decomposition
Zdroj:	Polymer Bulletin. 50:25-32
ISSN:	1436-2449 0170-0839
DOI:	10.1007/s00289-003-0139-y
Popis:	A series of new crosslinked poly[(methylsiloxane)-co-(dimethylsilazane)] copolymers were synthesized by cationic ring opening polymerization of the cyclic monomers 1,3,5,7 – tetramethylcyclotetrasiloxane and 2,2,4,4,6,6 – hexamethylcyclotrisilazane. These copolymers contain different concentrations of methylsiloxane and silazane co-monomer units. The thermal stability is strongly related to the concentration of methylsiloxane co-units in the copolymers. The weight loss curve of the copolymers lies in a temperature range between its two homopolymers. FT-IR studies are in good agreement with the proposed structure, either for the copolymers or for the residual powder ceramic obtained by pyrolysis. Two cured processes (thermal and UV) were used. The pyrolysis of the copolymers were carried out under argon atmosphere at 1200°C and in air at 1000 °C. Kinetic decomposition parameters of the copolymers such as a pre-exponential factor, the decomposition reaction orders and the activation energies were determined. The molecular weights were determined by osmometry.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::ff0ec9b5c85dbe1218822fb5d7b22a63 https://doi.org/10.1007/s00289-003-0139-y Zobrazit plný text záznamu Full text from SpringerLink