کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5177601 | 1502476 | 2017 | 12 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Poly(methylhydrosiloxane) networks of different structure and content of Si-H groups: Physicochemical properties and transformation into silicon oxycarbide ceramics Poly(methylhydrosiloxane) networks of different structure and content of Si-H groups: Physicochemical properties and transformation into silicon oxycarbide ceramics](/preview/png/5177601.png)
- 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.
In the work, poly(methylhydrosiloxane) was cross-linked by three vinylsiloxanes differing in molecular structure and functionality, i.e. linear difunctional ViMMVi, branched tetrafunctional Q(MVi)4 and cyclic tetrafunctional D4Vi. 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.
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Journal: Polymer - Volume 130, 9 November 2017, Pages 170-181