Preparation, Characterization, and Pyrolysis of Polycarbosilane with High Ceramic Yield and High Viscosity

• Published in: Polymer science. Series B Vol. 64; no. 5; pp. 598 - 605
• Main Authors: Geng Su, Ban, Zifa, Li, Yongming, Li, Weijie, Zhang, Zhongwei
• Format: Journal Article
• Language: English
• Published: Moscow Pleiades Publishing 01-10-2022; Springer Nature B.V
• Subjects: Ceramics; Chemistry; Chemistry and Materials Science; Fourier transforms; Liquid chromatography; NMR spectroscopy; Polycarbosilanes; Polymer Sciences; Precursors; Pyrolysis; Reaction synthesis; Silicon carbide; Synthesis; Thermodynamic properties; Viscosity
• ISSN: 1560-0904; 1555-6123
• DOI: 10.1134/S1560090422700385

Liquid polycarbosilane substituted by allyl groups was prepared by the Grignard coupling reaction and reductive reaction synthesis with SiCl
1.25
(OCH
3
)
1.75
CH
2
Cl, Cl
2
CHSiMeCl
2
and CH
2
=CHCH
2
Cl as the starting materials. The resultant polycarbosilanes were characterized by gel permeation chromatography, Fourier transform infrared and NMR spectroscopy. Moreover, the thermal properties and processing performance of polycarbosilanes were investigated. The ceramic yield of polycarbosilanes was about 77% at 1000°C, indicating that the polycarbosilanes have great potential to be promising precursors to SiC. With the increase of Cl
2
CHSiMeCl
2
in the system, the viscosity of polycarbosilanes and C : Si ratio of ceramics increased, but the ceramic yield of polycarbosilanes decreased. Combining with its economical preparation, polycarbosilanes showed high potential as an economical SiC ceramic precursor for the fabrication of SiC matrix, coating and adhesives.