Poly(borosiloxanes) as precursors for carbon fiber ceramic matrix composites

Ceramic matrix composites (CMCs), constituted of a silicon boron oxycarbide (SiBCO) matrix and unidirectional carbon fiber rods as a reinforcement phase, were prepared by pyrolysis of carbon fiber rods wrapped in polysiloxane (PS) or poly(borosiloxane) (PBS) matrices. The preparation of the polymeric precursors involved hydrolysis/condensation reactions of alkoxysilanes in the presence and absence of boric acid, with B/Si atomic ratios of 0.2 and 0.5. Infrared spectra of PBS showed evidence of Si-O-B bonds at 880 cm-1, due to the incorporation of the crosslinker trigonal units of BO3 in the polymeric network. X ray diffraction analyses exhibited an amorphous character of the resulting polymer-derived ceramics obtained by pyrolysis up to 1000 °C under inert atmosphere. The C/SiBCO composites showed better thermal stability than the C/SiOC materials. In addition, good adhesion between the carbon fiber and the ceramic phase was observed by SEM microscopy

Bibliographic Details

Main Authors:	Siqueira,Renato Luiz, Yoshida,Inez Valéria Pagotto, Pardini,Luiz Claudio, Schiavon,Marco Antônio
Format:	Digital revista
Language:	English
Published:	ABM, ABC, ABPol 2007
Online Access:	http://old.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392007000200009
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