Microstructural and main mechanical properties of novalac based carbon–carbon composites as the pyrolysis heating rate

Qanati, Mahdi Valinejad; Rasooli, Ali

doi:10.1016/j.ceramint.2021.06.089

Cited by 12 publications

(1 citation statement)

References 64 publications

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“…Carbon-fiber-reinforced phenolic composites (CFRPCs) are used widely as structural materials in aeronautical and space industries due to their excellent properties such as low density, low thermal expansion, high thermal stability, high strength and stiffness, and excellent resistance to creep, fatigue, and corrosion [ 1 , 2 ]. Moreover, they can be turned into carbon-carbon composites by converting the phenolic matrix into amorphous carbon through pyrolysis [ 3 , 4 , 5 , 6 ].…”

Section: Introductionmentioning

confidence: 99%

Dynamic Impact Properties of Carbon-Fiber-Reinforced Phenolic Composites Containing Microfillers

et al. 2023

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The addition of nano- and microfillers to carbon-fiber-reinforced polymers (CFRPs) to improve their static mechanical properties is attracting growing research interest because their introduction does not increase the weight of parts made from CFRPs. However, the current understanding of the high strain rate deformation behaviour of CFRPs containing nanofillers/microfillers is limited. The present study investigated the dynamic impact properties of carbon-fiber-reinforced phenolic composites (CFRPCs) modified with microfillers. The CFRPCs were fabricated using 2D woven carbon fibers, two phenolic resole resins (HRJ-15881 and SP-6877), and two microfillers (colloidal silica and silicon carbide (SiC)). The amount of microfillers incorporated into the CFRPCs varied from 0.0 wt.% to 2.0 wt.%. A split-Hopkinson pressure bar (SHPB), operated at momentums of 15 kg m/s and 28 kg m/s, was used to determine the impact properties of the composites. The evolution of damage in the impacted specimens was studied using optical stereomicroscope and scanning electron microscope. It was found that, at an impact momentum of 15 kg m/s, the impact properties of HRJ-15881-based CFRPCs increased with SiC addition up to 1.5 wt.%, while those of SP-6877-based composites increased only up to 0.5 wt.%. At 28 kg m/s, the impact properties of the composites increased up to 0.5 wt.% SiC addition for both SP-6877 and HRJ-15881 based composites. However, the addition of colloidal silica did not improve the dynamic impact properties of composites based on both phenolic resins at both impact momentums. The improvement in the impact properties of composites made with SiC microfiller can be attributed to improvement in crystallinity offered by the α-SiC type microfiller used in this study. No fracture was observed in specimens impacted at an impact momentum of 15 kg m/s. However, at 28 kg m/s, edge chip-off and cracks extending through the surface were observed at lower microfiller addition (≤1 wt.%), which became more pronounced at higher microfiller loading (≥1.5 wt.%).

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Section: Introductionmentioning

confidence: 99%

Dynamic Impact Properties of Carbon-Fiber-Reinforced Phenolic Composites Containing Microfillers

et al. 2023

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Evolution of Electrothermal Heating and Dielectric Properties of Phenolic Resins During Pyrolysis

Wright,

Dasari,

Banavath

et al. 2024

Macro Materials & Eng

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Electrothermal heating generated via radio frequency (RF) fields is used to probe the transformation of phenolic resin to a carbon matrix during pyrolysis. Phenolic resin is a single‐stage thermoset that is popular due to its heat resistance, chemical resistance, high strength, and low creep properties. When phenolic resin is subjected to high‐temperature, low‐oxygen treatment (pyrolysis), it is converted to a carbon material useful for many structural applications. Here, neat phenolic resin is pyrolyzed at different temperatures, and the heating response of the newly formed carbon material is tracked when exposed to an RF field. The electrical conductivity of the matrix increased with increasing pyrolysis temperature, with ≈10−4 S m−1 for the neat sample prior to pyrolysis, and ≈102 S m−1 for the sample pyrolyzed at 850 °C. The material's electrothermal response to applied RF fields increases as the material pyrolyzes and becomes conductive; however, at high pyrolysis temperatures, the material becomes sufficiently conductive such that the RF fields are reflected rather than absorbed, and the heating response decreases. The findings of this work show that heating response to RF fields can be used as a quick and easy characterization technique for tracking structural changes associated with phenolic pyrolysis.

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Performance of novolac resin‐ and resole resin‐based carbon/carbon composites in relation to their fabrication conditions

Georgiou,

Kyriakopoulou,

Zoumpoulakis

2024

Polymer International

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The demands of cost‐driven industrial applications can be satisfied by manufacturing composites with a low volume fraction of carbon fibres as phenolic carbon fibre‐reinforced composites and C/C composites, both with acceptable performances, for low‐ or high‐temperature applications, respectively. Polymeric composites reinforced with a low volume fraction (7.5% v/v) of carbon fibres were fabricated using laboratory‐produced phenolic resins, novolac (N) and resole (R), as matrices after different curing/post‐curing temperature profiles. By optimising the manufacturing conditions, the N‐based polymeric composites exhibited higher flexural strength, whereas the R‐based composites showed higher shear strength. C/C composites, namely N‐based and R‐based, were manufactured by pyrolysis of the previous polymeric composites up to 1000 °C. The pyrolysed composites were then densified by impregnation with an appropriate resin solution, followed by curing and new pyrolysis, and particularly by employing 1 up to 4 consecutive cycles of ‘impregnation‐curing / pyrolysis’. Weight changes resulting from the impregnation‐curing and pyrolysis stages were determined. The curing of both resins was verified by FTIR. The apparent density and X‐ray diffraction data of the C/C composites were used to calculate their total percent porosities. The morphology and elemental analyses of C/C composites at their failure region (after flexural testing) were examined by SEM/EDS analyses. In comparison to N‐based C/C composites, R‐based ones exhibited: higher shear strength, lower flexural strength, higher Shore D hardness, slightly higher surface conductivity, and lower volume conductivity. The optimum conditions for the manufacture of C/C composites were achieved by applying two consecutive cycles of ‘pyrolysis‐impregnation‐pyrolysis’ to the polymeric composites.This article is protected by copyright. All rights reserved.

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Microstructural and main mechanical properties of novalac based carbon–carbon composites as the pyrolysis heating rate

Cited by 12 publications

References 64 publications

Dynamic Impact Properties of Carbon-Fiber-Reinforced Phenolic Composites Containing Microfillers

Dynamic Impact Properties of Carbon-Fiber-Reinforced Phenolic Composites Containing Microfillers

Evolution of Electrothermal Heating and Dielectric Properties of Phenolic Resins During Pyrolysis

Performance of novolac resin‐ and resole resin‐based carbon/carbon composites in relation to their fabrication conditions

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