“…For samples with 4-ACP and 6-ACP, linear ablation rate increased 29.3% and 51.5% as compared to that of pristine sample. Comparatively these results are better than those obtained with CNTs, 50 MWCNTs, 46 TaSi 2 51 and nano alumina 52 modified ablative composites.Figure 6.Linear ablation rates of samples with different alumina particle loadings.…”
Thermal and ablative performance of alumina-modified carbon phenolic composites has been experimentally investigated. Pristine, 2, 4, and 6wt.% alumina particles modified composites were fabricated by hand layup followed by vacuum bagging process. Linear ablation rate was determined by the oxyacetylene flame test whereas thermogravimetric analysis determined thermal stability. Furthermore, SEM and EDS were done on ablated samples for morphological and elemental analysis whereas to determine individual phases, XRD was done. It was found that the addition of alumina initially at 2wt.% enhanced the ablation resistance but with further increase in the concentration of alumina above 2wt.%, ablation resistance decreased. Thermogravimetric analysis found that char yield of alumina-modified composites increased with an increase in alumina concentration.
“…For samples with 4-ACP and 6-ACP, linear ablation rate increased 29.3% and 51.5% as compared to that of pristine sample. Comparatively these results are better than those obtained with CNTs, 50 MWCNTs, 46 TaSi 2 51 and nano alumina 52 modified ablative composites.Figure 6.Linear ablation rates of samples with different alumina particle loadings.…”
Thermal and ablative performance of alumina-modified carbon phenolic composites has been experimentally investigated. Pristine, 2, 4, and 6wt.% alumina particles modified composites were fabricated by hand layup followed by vacuum bagging process. Linear ablation rate was determined by the oxyacetylene flame test whereas thermogravimetric analysis determined thermal stability. Furthermore, SEM and EDS were done on ablated samples for morphological and elemental analysis whereas to determine individual phases, XRD was done. It was found that the addition of alumina initially at 2wt.% enhanced the ablation resistance but with further increase in the concentration of alumina above 2wt.%, ablation resistance decreased. Thermogravimetric analysis found that char yield of alumina-modified composites increased with an increase in alumina concentration.
“…Other nanoscaled fillers, such as carbon nanotubes, silica, ZrB 2 , ZrSi 2 ,TiB 2 (Figure 8D) have been also studied (Ding et al, 2019): as a representative result, TiB 2 particles included in carbon-phenolic (T/C-Ph) composites prepared by compression moulding reacted, at high temperature, with oxygen-containing molecules, by coating the residue of phenolic after pyrolysis with glassy B 2 O 3 , assuring in this way improved mechanical performance at high temperature. Nano-modified carbon fabric represents another opportunity to enhance the ablation behavior of these materials (Xu et al, 2020a;Xu et al, 2020b).…”
Section: Phenolicsmentioning
confidence: 99%
“…The current methods for manufacturing carbon fibers are slow and energy-consuming, thus making their production very expensive. Additionally, the high cost of precursors keep CF a niche market with applications restricted essentially to highperformance and structural applications (e.g., aerospace): regardless these assumptions, alternative precursors to reduce the realization cost for CF and need for no-fossil feedstock have been investigated and are still under exploration (Xu et al, 2020a). These include biomass-derived precursors such as cellulose (Zaitsev et al, 2021), lignin (Wang et al, 2021), lignin/cellulose blends (Byrne et al, 2018;Bengtsson, et al, 2020), glycerol, and lignocellulosic sugars.…”
Section: Production and Properties Of Non-oil Carbon Fibersmentioning
During last decades a plethora of high temperature materials have been developed to work as a Thermal Protection System (TPS). Carbon based materials such as graphite, which possesses low density, high heat capacity and high energy of vaporization, have been used as TPS material. However, graphite has relatively poor mechanical properties, but exhibits low resistance to the thermal shocks. Accordingly, to bypass the limitation of graphite, carbon fibers are typically introduced in a carbon matrix to produce Carbon/Carbon Composites (CCCs). Among the different families of TPS solutions, Polymeric Ablative Materials (PAMs), produced combining high char yield matrices - mainly phenolic resins - and Carbon Fibers (CFs) are used to manufacture Carbon/Phenolic Composites (CPCs) i.e. the most important class of fiber reinforced PAM. Carbon fibers are traditionally produced from Polyacrylonitrile (PAN), Rayon and Pitch. Some limited researches also aimed to use cyanate-esters, bismaleimides, benzoxazines matrices in combination with ex-PAN-CFs, ex-Rayon-CFs, and ex-Pitch-CFs. In our paper, after covering the science and technology of these state-of-the-art fiber reinforced TPS materials, a review of current challenges behind the manufacturing of new, high char yield matrices and carbon fibers derived from alternative precursors will be provided to the reader. In particular, the possibility to produce CFs from precursors different from PAN, Rayon and Pitch will be reported and similarly, the technology of non-oil based phenolics, bismaleimides, cyanate-esters and benzoxazines will be discussed. The effect of the use of nanosized fillers on these matrices will also be reported. More in detail, after a preliminary section in which the state of the art of technologies behind carbon/phenolic composites will be covered, a second part of this review paper will be focused on the most recent development related to non-oil based phenolics and biomass derived carbon fibers. Finally, an outlook focused on the maturity of the lab-scale protocols behind the researches at the base of these non-traditional raw materials from an industrial point of view will conclude this review paper.
“…[ 14 ] TaSi 2 ‐modified carbon fabric reinforced phenolic composites were prepared, when the mass fraction of TaSi 2 was 50 wt%, the linear ablation rate of modified composites was 12% lower than that of the unmodified ones. [ 15 ] Although the ablation resistance ability could be improved by adding some components into carbon/phenolic, the heat insulation capacity of it was not enough, due to that the thermal conductivity was relatively large especially under high‐temperature. Phenolic impregnated carbon ablator (PICA) had extremely low‐density and thermal conductivity attributing to its pore structures in resin, resulting its heat insulation performance rising.…”
The continuous fiber reinforced porous resin‐based composites with integrated gradient fabric (CPIGF) were successfully prepared. From the bottom to the top surface, the fiber volume fraction of the integrated fabric gradually increased, as well as the fabric architecture changed, meanwhile the porosity of the resin gradually decreased. The temperature in the inner composite increased quite slowly during ablation, and the linear ablation rate ranged from 0.019 mm/s to 0.029 mm/s. The simulation results showed that the good heat insulation capacity of CPIGFs was attributed to the anisotropy properties of the fabric architecture. The microstructure analysis showed that the good ablation resistance came from both the thermal expansion of the integrated gradient fabric and the densification of the zone with 3D orthogonal woven fabric. This work is helpful for designing thermal protection materials having both heat insulation and ablation resistance for hypersonic aircrafts.
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