Modeling the pyrolysis of preceramic polymers: A kinetic study of the polycarbosilane SMP-10

Key, Thomas S.; Patel, Dipen K.; Wilks, Garth B.; Cinibulk, Michael K.

doi:10.1016/j.jeurceramsoc.2021.06.011

Cited by 15 publications

(24 citation statements)

References 18 publications

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“…This comparison demonstrates the higher weight retention of GNP as compared to the linear polymer. The volume shrinkage associated with polymer-derived ceramics is a result of the intrinsic increase in density from polymer to ceramic as well as the weight loss during pyrolysis . The clear improvement in the char yield of the GNP as compared to the linear polymer points toward a material system expected to experience less volume shrinkage than particle-free preceramic polymers.…”

Section: Resultsmentioning

confidence: 99%

Impact of the Backbone Structure on the Rheological and Thermal Properties of Preceramic Polymer-Grafted Nanoparticles and Derived Ceramics

Martin

Street

Thompson

et al. 2021

ACS Appl. Nano Mater.

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Here, we demonstrate the synthesis of two novel preceramic grafted nanoparticles (GNPs) and compare their physical properties and derived ceramics to previously reported GNPs. Three variations of preceramic polymer GNPs are synthesized using hydrosilylation grafting-from chemistry, with brushes comprising poly(1,1dimethylpropylsilane) (allyl-GNP), poly(1,1-dimethylethylbenzylsilane) (styryl-GNP), and poly(1,1-dimethylethylsilane) (vinyl-GNP) on silica nanoparticles (10−15 nm in diameter). The brush structure is confirmed using FTIR, 1 H NMR, and dynamic light scattering (DLS). The rheological properties of the GNPs change depending on the brush composition, with the allyl-GNP displaying the formation of a strong interparticle network and the styryl-GNP exhibiting a weaker interparticle network. Thermal gravimetric analysis shows that after thermal treatment, the ceramic yield of all three GNPs increases at 800 °C, with the allyl-GNP and vinyl-GNP showing a significant improvement in yield as compared to the styryl-GNP. Finally, the three GNPs are pyrolyzed to 1400 °C giving ceramic composites with compositions dependent upon the precursor brush, as determined through X-ray diffraction (XRD) and Raman spectroscopy. This study demonstrates that hydrosilylation grafting-from is a robust method of anchoring ceramic precursor polymers to nanoparticles and can be employed to produce preceramic GNPs that subsequently convert to brush-dependent ceramic composites.

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Section: Resultsmentioning

confidence: 99%

Impact of the Backbone Structure on the Rheological and Thermal Properties of Preceramic Polymer-Grafted Nanoparticles and Derived Ceramics

Martin

Street

Thompson

et al. 2021

ACS Appl. Nano Mater.

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“…There was some tarry residue left after the combustion of EVA ( Figure 4 a); such tarry residue was easy to form during combustion at relatively low heat flux [ 5 ]. Unlike the residue of EVA, the aluminum foil was covered and ( Figure 4 b) torn apart by the residue of EVA/PCS 98/2, which was related to the shrinkage of the residue induced by ceramization of PCS [ 38 ] (the ceramization of PCS is a transformation process from organic linear molecules to an amorphous intermediate phase with a three-dimensional net structure, which is then pyrolyzed to inorganic silicon carbide at higher temperatures; the ceramization of PCS mentioned in this study was revealed in a previous work [ 27 ]); this revealed an excellent binding effect of PCS, and the potential to form a cohesive char. The morphology of the residue of EVA/MH/PCS 50/48/2 was different from that of EVA/MH 50/50; a large thin and cohesive char layer covered the surface of the residual char of EVA/MH/PCS 50/48/2 ( Figure 4 d), which was most likely induced by the binding effect of PCS, while there were some small bubbles in the residue of EVA/MH 50/50 ( Figure 4 c), indicating the weak binding effect of magnesium oxide.…”

Section: Resultsmentioning

confidence: 99%

Enhanced Flame Retardancy in Ethylene–Vinyl Acetate Copolymer/Magnesium Hydroxide/Polycarbosilane Blends

Zhang

Wang

et al. 2021

Polymers

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A polymer ceramic precursor material—polycarbosilane (PCS)—was used as a synergistic additive with magnesium hydroxide (MH) in flame-retardant ethylene–vinyl acetate copolymer (EVA) composites via the melt-blending method. The flame-retardant properties of EVA/MH/PCS were evaluated by the limiting oxygen index (LOI) and a cone calorimeter (CONE). The results revealed a dramatic synergistic effect between PCS and MH, showing a 114% increase in the LOI value and a 46% decrease in the peak heat release rate (pHRR) with the addition of 2 wt.% PCS to the EVA/MH composite. Further study of the residual char by scanning electron microscopy (SEM) proved that a cohesive and compact char formed due to the ceramization of PCS and close packing of spherical magnesium oxide particles. Thermogravimetric analysis coupled with Fourier-transform infrared spectrometry (TG–FTIR) and pyrolysis–gas chromatography coupled with mass spectrometry (Py–GC/MS) were applied to investigate the flame-retardant mechanism of EVA/MH/PCS. The synergistic effect between PCS and MH exerted an impact on the thermal degradation products of EVA/MH/PCS, and acetic products were inhibited in the gas phase.

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“…SiC exists in nearly 250 crystalline forms, with the most common polymorph being alpha silicon carbide (α-SiC). 3,4 The process of sintering binds grains of SiC together to form strong ceramics, and composite materials can be formed when SiC fibers are added to the polymer matrix. Adding ceramic fibers to the matrix improves fracture performance when used in monolith form.…”

Section: Silicon Carbidementioning

confidence: 99%

“…Cured ceramic polymer matrices are highly dependent on both temperature and time. 4 The work described here explored parameters near the highest possible oxide loading. Future work could explore additional oxide loading recipes with more SiCf to improve fracture resistance and homogenous incorporation at the microscale.…”

Section: Future Studies and Applicationsmentioning

confidence: 99%

Synthesis and Characterization of Silicon Carbide Ceramic Composites with CeO<sub>2</sub> Powder

Sadergaski¹,

Malmstead²,

Miskowiec³

et al. 2022

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Modeling the pyrolysis of preceramic polymers: A kinetic study of the polycarbosilane SMP-10

Cited by 15 publications

References 18 publications

Impact of the Backbone Structure on the Rheological and Thermal Properties of Preceramic Polymer-Grafted Nanoparticles and Derived Ceramics

Impact of the Backbone Structure on the Rheological and Thermal Properties of Preceramic Polymer-Grafted Nanoparticles and Derived Ceramics

Enhanced Flame Retardancy in Ethylene–Vinyl Acetate Copolymer/Magnesium Hydroxide/Polycarbosilane Blends

Synthesis and Characterization of Silicon Carbide Ceramic Composites with CeO<sub>2</sub> Powder

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