Development of Si-O-C Based Ceramic Matrix Composites Produced via Pyrolysis of a Polysiloxane

Abstract

Abstract. Pyrolytic conversion of a preceramic polymer, poly(phenyl)siloxane has been investigated to develop ceramic matrix composites (CMCs) at low temperatures with high dimensional stability. Furthermore, the thermal transformation of the polymer precursor under inert atmosphere was monitored. For this purpose, poly(phenyl)siloxanes were cured at about 200 °C for 2 hours under air and pyrolysed at various temperatures in the range of 900 -1500 °C for 1 hour under inert argon atmosphere. The products of the pyrolytic conversion were analyzed using X-ray diffraction (XRD), thermal analysis (TG and DTA) and scanning electron microscopy (SEM) coupled with EDX analyzer. It was found that pyrolysis under inert atmosphere up to 1300 °C led to amorphous silicon oxycarbide (SiO x C y ) ceramics. Conversions at higher temperatures caused the transformation into the crystalline β-SiC phases. Moreover, to obtain composite monoliths inert Al 2 O 3 and active Ti and Si particulates were incorporated into the polymer as fillers employing compressive moulding at moderate temperatures. During pyrolysis, cross-linked green compacts of the particulate/polymer system were converted into ceramic body and the microstructural parameters and the effects of the filler type on the microstructure were investigated.

Processing of Polymer‐Derived Ceramic Composite Coatings on Steel

“…Precursor routes offer the potential of near‐net shape production of complex geometries at temperatures lower than traditional ceramic processing 1–4 . Preceramic polymers are now commercially available for a variety of ceramics and have been used for a range of applications including chemical and wear‐resistant coatings, 5 ceramic fibers, 6,7 joining of ceramics, 8–10 porous ceramics and ceramic foams, 11–13 MEMS devices, 14,15 and ceramic matrix composites 16–18 . One of the most promising areas of polymer‐derived ceramics is in low‐dimensional applications such as coatings 19–21 .…”

Preparation and characterization of novel poly(glycidyl methacrylate) beads carrying amidoxime groups

“…3,4 Therefore, numerous studies have either introduced low-molecular-mass ligands to various synthetic [5][6][7] and natural polymeric matrices, [8][9][10] or synthesized a copolymer containing conventional chelating vinyl monomer to form a chelating resin. [11][12][13] Previous studies 14 prepared a chelating vinyl monomer, glycidyl methacrylate-iminodiacetic acid (GMA-IDA), via an epoxy group reaction of GMA with IDA. This monomer has the hydrophilic nature of hydroxyl and iminodiacetate groups and has an adequate affinity to metal ions.…”

Crosslinking effects on hybrid organic-inorganic proton conducting membranes based on sulfonated polystyrene and polysiloxane

“…Finally, the loss observed between 500 and 600°C (~30%) combines the evolution of carbon monoxide from the residues of the polymeric backbone, as well as the cleavage of the C―Si bonds of the PDMS, to the evolution of CH 4. In the second loss, it was observed that the degradation of the polystyrene rings in the HSPSØ‐20 membrane occurs approximately 20°C higher than for the HSPS membranes with crosslinkers, which is most likely because of a stronger interaction among the aromatic groups of SPS and PDMS. In contrast, for the third loss, the degradation of HSPSØ‐20 membrane starts before (538°C, 567°C and 578°C for HSPSØ‐20, HSPST‐20‐10 and HSPSP‐20‐10 respectively), indicating that cleavage of the Si―C bonds of PDMS is easier in the absence of crosslinkers.…”