Poly(methylhydrosiloxane) networks of different structure and content of Si-H groups: Physicochemical properties and transformation into silicon oxycarbide ceramics. (9th November 2017)

• Record Type: Journal Article
• Authors: Wójcik-Bania, Monika; Łącz, Agnieszka; Nyczyk-Malinowska, Anna; Hasik, Magdalena
• Is Part Of: Polymer. Volume 130(2017)
• Page Start: 170
• Page End: 181
• Publication Date: 2017-11-09
• Subjects: Polysiloxane networks -- Si-H groups -- Thermal decomposition; Polymers -- Periodicals; Polymerization -- Periodicals; Polymères -- Périodiques; Polymérisation -- Périodiques; 547.7
• DOI: 10.1016/j.polymer.2017.10.020
• Languages: English
• ISSNs: 0032-3861

Abstract

Abstract: In the work, poly(methylhydrosiloxane) was cross-linked by three vinylsiloxanes differing in molecular structure and functionality, i.e. linear difunctional Vi MM Vi, branched tetrafunctional Q(M Vi )4 and cyclic tetrafunctional D4 Vi . The cross-linking process was conducted at three molar ratios of Si-H to Si-CH=CH2 groups in order to obtain different amounts of unreacted Si-H groups in the systems. As established by swelling measurements, the applied cross-linker and molar ratio of reactive groups show the influence on the average cross-linking densities of the studied systems. Conducted thermal investigations allowed to conclude that the amount of Si-H groups present in the system affects the number of decomposition steps of the studied networks. The results of thermal studies of the cross-linked samples were complemented by FTIR and XRD analyses of the residues formed after pyrolysis of the cross-linked products conducted at different temperatures in the range between 200 and 1000 °C in Ar atmosphere. The presence of the free carbon phase in the obtained silicon oxycarbide materials was confirmed by Raman spectroscopy. Graphical abstract: Highlights: Polysiloxane networks of different structures were prepared by hydrosilylation. The obtained networks contained various amounts of Si-H groups. Amounts of Si-H groups and structure influence thermal decomposition of the systems. Pyrolysis of the obtained networks leads to SiCO materials and a free carbon phase.