Academic literature on the topic 'Composite PEKK/FC'
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Journal articles on the topic "Composite PEKK/FC"
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Liu, Qing Suo, Cui Min Lu, Xu Ma, X. M. Lu, and X. Y. Gao. "Preparation and Damping Capacities of the NiTiSMA/FC Composites." Advanced Materials Research 97-101 (March 2010): 1601–6. http://dx.doi.org/10.4028/www.scientific.net/amr.97-101.1601.
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NiTiSMA/FC composites have been prepared by depositing ferroelectric ceramics films on NiTi shape memory alloy substrate with the sol-gel method. Heterojunction structure of the composites has been characterized by using X-ray diffraction and scanning electron microscope. The differences of the damping capacities between NiTiSMA/FC composites and NiTiSMA substrates have been tested by the Dynamic Mechanical Analyzer. The results show pure perovskite structure could be obtained in the FC films part of NiTiSMA/FC composites sintered at 650oC. The transitional TiO2 layer produced in-situ by the oxidation of the surface of the NiTiSMA substrate improves the combined function between the ceramic film and NiTiSMA substrate. When the temperature is lower than 20oC, the tanδ of NiTiSMA/FC composites is stabilized at 3.5%, the vibration frequencies (within 0.33-10Hz) have a small effect on damping capacities. Within the temperature of 20-40oC, there is a tanδ peak up to 5.0%.The damping capacities of NiTiSMA/FC composites are better than the pure NiTiSMA materials.
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Kolev, Svetoslav, Petya Peneva, Kiril Krezhov, Tanya Malakova, Chavdar Ghelev, Tatyana Koutzarova, Daniela Kovacheva, et al. "Structural, Magnetic and Microwave Characterization of Polycrystalline Z-Type Sr3Co2Fe24O41 Hexaferrite." Materials 13, no. 10 (May 20, 2020): 2355. http://dx.doi.org/10.3390/ma13102355.
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We report results on the structural and microwave properties and magnetic phase transitions in polycrystalline Sr3Co2Fe24O41 hexaferrite synthesized by sol-gel auto-combustion and acting as a filler in a composite microwave absorbing material. The zero-field-cooled (ZFC) and field-cooled (FC) magnetization curves revealed a change in the magnetization behavior at 293 K. The reflection losses in the 1–20 GHz range of the Sr3Co2Fe24O41 powder dispersed homogeneously in a polymer matrix of silicon rubber were investigated in both the absence and presence of a magnetic field. In the latter case, a dramatic rise in the attenuation was observed. The microwave reflection losses reached the maximum value of 32.63 dB at 17.29 GHz in the Ku-band. The sensitivity of the microwave properties of the composite material to the external magnetic field was manifested by the appearance of new reflection losses maxima. At a fixed thickness tm of the composite, the attenuation peak frequency can be adjusted to a certain value either by changing the filling density or by applying an external magnetic field.
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Li, Wenqian, Yanli Dou, Xuefei Li, Shengbo Fang, Jian Li, and Quanming Li. "A Highly Effective, UV-Curable, Intumescent, Flame-Retardant Coating Containing Phosphorus, Nitrogen, and Sulfur, Based on Thiol-Ene Click Reaction." Materials 15, no. 9 (May 7, 2022): 3358. http://dx.doi.org/10.3390/ma15093358.
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In this paper, a flame-retardant, UV-cured coating was prepared on the fiber composites’ (FC) surface via a thiol-ene click reaction using pentaerythritol tetra(3-mercaptopropionate) (PETMP), triallyl cyanurate (TAC), and 2-hydroxyethyl methacrylate phosphate (PM-2). The synergistic effectiveness of phosphorus (P), nitrogen (N), and sulfur (S) was studied in detail by changing the proportion of these reactants. Sample S4(N3P2)6, with a molar ratio of N and P elements of 3:2, and the thiol and vinyl groups of 4:6 had the highest LOI value (28.6%) and was self-extinguishing in the horizontal combustion test. It had the lowest peak heat release rate (PHRR) value (279.25 kW/m2) and total smoke production (2.18 m2). Moreover, the thermogravimetric analysis (TG) showed that the decomposition process of the coated composites was delayed. The conversion rate of the double bond and the thiol of S4(N3P2)6 was 100% and 92.0%, respectively, which showed that the cross-linked network structure was successfully formed. The tensile strength and the flexural strength of coated composites improved, and the transparency of the coating can reach 90%. These characteristics showed that the UV-cured coatings could be used in industrial production to effectively prevent fires.
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Kostishin, V. G., R. I. Shakirzyanov, I. M. Isaev, E. S. Savchenko, and B. M. Skibo. "Analysis of the electromagnetic properties of 2000NN/2000NM composites with ferroelectric and polymer matrices." Industrial laboratory. Diagnostics of materials 89, no. 12 (December 18, 2023): 44–52. http://dx.doi.org/10.26896/1028-6861-2023-89-12-44-52.
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The results of studying the electrical properties of ferrite-dielectric composites containing inclusions of Mn-Zn and Ni-Zn spinel ferrites with the same initial magnetic permeability (grades 2000NM and 2000NN, respectively) and different electrical resistance are presented. Four matrix materials, polymer and ceramic dielectrics with a different dielectric permittivity were used in the experiments: polystyrene (PS525), polyvinylidene fluoride (grade F2MB), lead zirconate titanate (ZTS-21), and barium titanate (TBK-3). Experimental samples of composites were obtained by hot (for a polymer matrix) or cold pressing with a binder (in case of ferroelectric ceramic matrix). It has been shown that the microwave-absorbing properties of the resulting composites significantly depend on the electrical properties of the dielectric matrix and the electrical resistivity of the filler. The highest attenuation of electromagnetic waves of 25 – 27 dB in the frequency range 4 – 5 GHz is observed for ferrite-polymer composites with a semiconductor filler of 2000NM with a thickness of microwave-absorbing material of 6 mm. For composites with Mn-Zn ferrite filler, a pronounced shift in the dispersion region of magnetic permeability is also observed, which in turn changes the frequency position of peak radio absorption. For the composites with a ferroelectric matrix, the operating frequency range for both fillers shifted to the low-frequency region 1 – 4 GHz with a maximum attenuation of up to 22 dB at the same thickness. It was experimentally confirmed that at a concentration of ferrite Cm = 40 % wt., the value of the frequency of absorption peal center fc and the minimum value of the reflection loss Kref for a filler with high electrical resistance of 2000NN decrease with an increase in the dielectric constant of the matrix. As for the composites with a 2000NM filler, the (ε’ of the matrix) dependence passes through a minimum. The obtained composites can be considered as effective microwave-absorbing materials for the frequency range 1 – 6 GHz with peak attenuation of the electromagnetic wave in the range 14 – 27 dB and frequency band (less than 10 dB) in the range 1.1 – 2.5 GHz.
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Zhao, Dongmei, Jizhen Li, Fuqiang Bi, Yahui Yang, Xiaoni Gao, Weiqiang Zhang, Guofang Zhang, and Ziwei Gao. "Ionic binuclear ferrocenyl compounds containing 1,1,3,3-tetracyanopropenide anions – synthesis, structural characterization and catalytic effects on thermal decomposition of main components of solid propellants." Zeitschrift für Naturforschung B 70, no. 5 (May 1, 2015): 317–26. http://dx.doi.org/10.1515/znb-2014-0251.
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AbstractAlkyl-substituted ferrocenes are typical burning-rate catalysts in composite solid propellants, but their high migration tendency and volatility has impeded their extensive applications. By introducing the concept of ionic energetic compounds, eight new ionic binuclear ferrocenyl compounds, [FcCH2N(CH3)2(CH2)nN(CH3)2CH2Fc]2+ (X–2) (Fc = ferrocenyl; X– = 1,1,3,3-tetracyano propenide; n = 3–10; the compounds being numbered consecutively 1–8), were prepared and characterized. The molecular structures of 1, 2, and 4 were determined by single-crystal X-ray diffraction, and their cations were studied by density functional theory calculations (DFT). Compounds 1–5 show high thermal stability but 6–8 are slightly volatile. The results of cyclic voltammetry studies suggest that each salt exhibits a quasireversible redox system. Catalytic effects of the new salts on thermal degradation of ammonium perchlorate (AP), 1,3,5-trinitro-1,3,5-triaza-cyclo-hexane (RDX), and 1,2,5,7-tetranitro-1,3,5,7-tetraazacyclooctane (HMX), have been investigated by DSC and/or TG methods. The results show that the new compounds can bring the peak temperatures of both AP and RDX down significantly and enhance their heat release dramatically, indicating that the ferrocenyl salts possess high catalytic efficiency for the thermal decomposition of AP and RDX. Their catalytic activities are nearly equal to or higher than that of the corresponding nitrates and picrates, as well as their mononuclear counterparts. Compound 6 also efficiently catalyzes the thermal decomposition of hydroxyl-terminated polybutadiene (HTPB) and 1:1 mixtures of HTPB and AP.
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Li, Zhi, Shengjie Yao, Guichao Wang, Xi Deng, Fang Zhou, Xiaoxu Wu, and Qiong Liu. "Enhancing Water Resistance in Foam Cement through MTES-Based Aerogel Impregnation." Gels 10, no. 2 (February 1, 2024): 118. http://dx.doi.org/10.3390/gels10020118.
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The propensity of foamed concrete to absorb water results in a consequential degradation of its performance attributes. Addressing this issue, the integration of aerogels presents a viable solution; however, their direct incorporation has been observed to compromise mechanical properties, attributable to the effects of the interface transition zone. This study explores the incorporation of MTES-based aerogels into foamed cement via an impregnation technique, examining variations in water–cement ratios. A comprehensive analysis was conducted, evaluating the influences of MTES-based aerogels on the thermal conductivity, compressive strength, density, chemical composition, and microstructure of the resultant composites across different water–cement ratios. Our findings elucidate that an increment in the water–cement ratio engenders a gradual regularization of the pore structure in foamed concrete, culminating in augmented porosity and diminished density. Notably, aerogel-enhanced foamed concrete (AEFC) exhibited a significant reduction in water absorption, quantified at 86% lower than its conventional foamed concrete (FC) counterpart. Furthermore, the softening coefficient of AEFC was observed to surpass 0.75, with peak values reaching approximately 0.9. These results substantiate that the impregnation of MTES-based aerogels into cementitious materials not only circumvents the decline in strength but also bolsters their hydrophobicity and water resistance, indirectly enhancing the serviceability and longevity of foamed concrete. In light of these findings, the impregnation method manifests promising potential for broadening the applications of aerogels in cement-based materials.
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Kuryliszyn-Kudelska, I., W. Dobrowolski, M. Arciszewska, N. Romcevic, M. Romcevic, B. Hadzic, D. Sibera, U. Narkiewicz, and W. Lojkowski. "Transition metals in ZnO nanocrystals: Magnetic and structural properties." Science of Sintering 45, no. 1 (2013): 31–48. http://dx.doi.org/10.2298/sos1301031k.
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Currently, wide-gap ZnO nanoparticles bear important potential application in electro-optical devices, transparent ultraviolet protection films, and spintronic devices. We have studied the magnetic properties of nanocrystals of ZnO(Fe, Co, Mn) prepared by two methods of synthesis. We have used the microwave assisted hydrothermal synthesis and traditional wet chemistry method followed by calcination. The detailed structural characterization was performed by means of X-ray diffraction and micro-Raman spectroscopy measurements. The morphology of the samples was studied by means of SEM and TEM microscopy. The results of systematic measurements of AC magnetic susceptibility as a function of temperature and frequency as well as SQUID magnetization are presented. The SQUID magnetization measurements revealed a clear bifurcation of the FC and ZFC plots. Such behavior suggested superparamagnetic behavior above the blocking temperature. The dynamic magnetic measurements were performed at small AC magnetic field with amplitude not exceeding 5 Oe and different frequency values (from 7 Hz to 9970 Hz). For ZnO(Fe) and ZnO(Mn), the AC susceptibility maxima has been found for in-phase susceptibility Re(?) and for out of phase susceptibility Im(?). We analyzed the observed frequency dependence of the peak temperature in the AC susceptibility curve using the empirical parameter ? that is a quantitative measure of the frequency shift and is given by the relative shift of the peak temperature per decade shift in frequency, as well as Vogel- Fulcher law. We observed two different types of magnetic behavior, spin-glasslike behavior or superparamagnetic behavior, depending on the synthesis process. For ZnO(Co) nanocrystalline samples high temperature Curie-Weiss behavior in AC magnetic susceptibility was observed. We observed that the determined negative values of the Curie- Weiss temperature ? depend strongly on the nominal content of cobalt oxide. It was shown that for calcination method the values of ? increase with the increase of magnetic ion content indicating enhancement of predominance of antiferromagnetic interactions. For hydrothermal method the opposite effect was observed indicating the breakdown of predominance of aniferromagnetic coupling with the increase of nominal magnetic ion content. This paper gives an in-depth discussion of the structural and magnetic properties of ZnO nanocrystals in addition to the technological issues such as different methods of wet chemical synthesis.
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Sharma, Rashmi, Rahul Sharma, and Minakshi Kaushik. "Fuel Economy Optimisation by Utilising Hybrid Energy Storage Systems." Journal of Futuristic Sciences and Applications 1, no. 1 (2018): 12–16. http://dx.doi.org/10.51976/jfsa.111803.
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The onboard energy-storage system (ESS) of hybrid electric vehicles (HEVs) has a significant impact on their fuel efficiency and all-electric range (AER). Energy-storage Devices charge when there is little demand for electricity and discharge when high power requirements that operate as catalysts to boost energy. In ground vehicles, batteries serve as the main energy storage mechanism. Vehicles with an AER of 15% or more almost twice the added expense of the ESS. As the result ESS requires more peak power while maintaining high energy density of HEVs. In comparison to batteries, ultracapacitors (UCs) are the solutions with better power densities. For more advanced hybrid vehicular ESSs, a hybrid ESS made of batteries, UCs, and/or fuel cells (FCs) would be a better choice. Modern energy-storage architectures for HEVs and plug-in HEVs are presented in this work (PHEVs). In this paper, battery, UC, and FC technologies are examined and contrasted. Additionally, different hybrid Also discussed are different hybrid ESSs that integrate two or more storage devices.
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Erlandsson, M., K. M. Andersson, N. Nair, A. Damdimopoulos, S. Töyrä Silfverswärd, R. Pullerits, A. Barton, and M. I. Bokarewa. "OP0127 TRANSCRIPTIONAL ACTIVITY OF SURVIVIN CONTRIBUTES TO MATURATION AND FUNCTION OF THE INTERFERON-GAMMA PRODUCING T CELLS IN RHEUMATOID ARTHRITIS." Annals of the Rheumatic Diseases 79, Suppl 1 (June 2020): 83.1–84. http://dx.doi.org/10.1136/annrheumdis-2020-eular.4325.
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Background:Interferon gamma (IFNg) signalling and downstream effects make important contribution in pathogenesis of rheumatoid arthritis (RA). Here, we propose a mechanism by which oncoprotein survivin participates in development of IFN-dependent repertoire of T cells in RA patients.Objectives:We study the role of survivin in the phenotype of CD4 T cells of RA patients.Methods:CD4 cells of RA patients and healthy controls were purified from blood, activated and subjected to RNAseq, ChIPseq with antibodies to survivin (BIRC5) was performed on CD4+ cells. Histone H3 ChIPseq was performed using antibodies to H3K27ac, H3K27me3 and H3K4me3. Statistical analysis was performed In R-studio using the Bioconductor package DESeq2, clustering using Spearman and Ward.D2.Results:Unsupervised clustering of CD4 samples by expression of 48 core Th cell markers identified subsets of CD28hiCD27hiIFNnegcentral memory cells (Tcm), CD28loCD27loIFNloeffector memory cells (Tem) and CD28nullCD27nullIFNhiterminal effector cells (Tte). Tte cells showed classical features of Th1 cells including high levels of TBX21, TNFa and IL32 and signs of activation in IFN signalling machinery. Interestingly, they combined the features of peripheral Tregs CD25hiFoxp3hiIKZF2negand IL10 producing cells together with type 1 regulatory cells, which rely on transcription factors BATF and IRF1 for the differentiation and produced high amounts of perforin and granzyme B. Importantly, Tte CD4 cells had also high transcription of BIRC5 (p=1.15e-18).To study if BIRC5 is a part of IFN signalling, CD4 cells were cultured with survivin inhibitor YM155 and activated with IFNg. RNAseq analysis revealed 2033 (FC<2.0, n=336) differentially expressed genes in the IFN stimulated cultures. Interestingly, a substantial number of these IFN-dependent genes was significantly reduced in the survivin-deficient cultures and included among others CD28, FoxP3, IKZF2, ICOS, BATF, PRDM1, CXCR3, IRF4 and IRF8. Analysis of the peak sequences identified enrichment for composite motifs for IRFs (ETS:IRF, p1.0e-124; bZIP:IRF, p=1.0e-640), indicating that survivin is important for IFNg signalling. Numerically, the peaks containing ETS:IRF motifs were most prevalent and identified in total within 49.7% of all survivin-ChIP peaks. Frequent was co-localisation of the IRF:bZIP and IRF:ETS motifs within the survivin peaks. Among the IRF motifs dominated those suitable for IRF1 (p=1,0e-127) and IRF8 (p=1,0e-84). However, the DNA binding motifs of these two are alike.Encouraged by the survivin ChIPseq results, we wanted to know its relation to histone marks. We observed that 50% of survivin peaks containing both IRF:bZIP and IRF:ETS motifs are co-localized with the H3K27ac marks. In total, 16 of 48 core Th cell markers used for patients clustering were identified by survivin ChIPseq, co-localized with IRF composite motifs and histone marks. They were also dependent of survivin for expression.Conclusion:his study showed that survivin binds to DNA and regulates the core gene expression contributing to maturation and function of the IFNg producing Th1 cells.References:-Disclosure of Interests:Malin Erlandsson: None declared, Karin ME Andersson: None declared, Nisha Nair: None declared, Anastasius Damdimopoulos: None declared, Sofia Töyrä Silfverswärd: None declared, Rille Pullerits: None declared, Anne Barton Consultant of: AbbVie, Maria I Bokarewa: None declared
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Al-Absi, Rana S., Mohammed H. Abu-Dieyeh, Radhouane Ben-Hamadou, Mustafa S. Nasser, and Mohammad A. Al-Ghouti. "Novel composite materials of modified roasted date pits using ferrocyanides for the recovery of lithium ions from seawater reverse osmosis brine." Scientific Reports 11, no. 1 (September 23, 2021). http://dx.doi.org/10.1038/s41598-021-98438-2.
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AbstractIn this paper, novel composite materials from modified roasted date pits using ferrocyanides were developed and investigated for the recovery of lithium ions (Li+) from seawater reverse osmosis (RO) brine. Two composite materials were prepared from roasted date pits (RDP) as supporting material, namely potassium copper hexacyanoferrate-date pits composite (RDP-FC-Cu), and potassium nickel hexacyanoferrate-date pits composite (RDP-FC-Ni). The physiochemical characterization of the RO brine revealed that it contained a variety of metals and salts such as strontium, zinc, lithium, and sodium chlorides. RDP-FC-Cu and RDP-FC-Ni exhibited enhanced chemical and physical characteristics than RDP. The optimum pH, which attained the highest adsorption removal (%) for all adsorbents, was at pH 6. In addition, the highest adsorption capacities for the adsorbents were observed at the initial lithium concentration of 100 mg/L. The BET surface area analysis confirmed the increase in the total surface area of the prepared composites from 2.518 m2/g for RDP to 4.758 m2/g for RDP-FC-Cu and 5.262 m2/g for RDP-FC-Ni. A strong sharp infrared peak appeared for the RDP-FC-Cu and RDP-FC-Ni at 2078 cm−1. This peak corresponds to the C≡N bond, which indicates the presence of potassium hexacyanoferrate, K4[Fe(CN)6]. The adsorption removal of lithium at a variety of pH ranges was the highest for RDP-FC-Cu followed by RDP-FC-Ni and RDP. The continuous increase in the adsorption capacity for lithium with increasing initial lithium concentrations was also observed. This could be mainly attributed to enhance and increased lithium mass transfer onto the available adsorption active sites on the adsorbents’ surface. The differences in the adsorption in terms of percent adsorption removal were clear and significant between the three adsorbents (P value < 0.05). All adsorbents in the study showed a high lithium desorption percentage as high as 99%. Both composites achieved full recoveries of lithium from the RO brine sample despite the presence of various other competing ions.
Dissertations / Theses on the topic "Composite PEKK/FC"
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Lesimple, Gwladys. "Interaction du PEKK et des composites PEKK/FC avec l'eau et le Skydrol." Electronic Thesis or Diss., Paris, HESAM, 2023. http://www.theses.fr/2023HESAE016.
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Alléger les avions reste une problématique majeure pour l’industrie aéronautique. Le développement de composites à matrices thermoplastiques, en remplacement des thermodurcissables, permet d’obtenir des matériaux soudables et recyclables, avec une température de service supérieure. Cette thèse s’inscrit dans le cadre du projet PSPC HAICoPAS, porté par Hexcel et Arkema, dont le but est de concevoir des nappes de composites à matrices thermoplastiques hautes performances. L’objectif de cette thèse est d’évaluer l’impact de l’eau et du Skydrol (un fluide hydraulique utilisé en aéronautique) sur les propriétés des composites PEKK/FC (polyéthercétonecétone renforcé en fibres de carbone) et d’identifier les mécanismes responsables des potentielles pertes de propriétés. Pour répondre à cette problématique, l’étude porte à la fois sur la matrice PEKK seule et sur le composite PEKK/FC. Les mécanismes de transport de l’eau dans la matrice ainsi que dans le composite sont mis en évidence par gravimétrie. Les différents paramètres de transport de l’eau sont déterminés dans une gamme de températures de 30°C à 70°C, à la fois en immersion dans l’eau et par DVS pour des humidités relatives entre 10% et 90%. La diffusion de l’eau dans le PEKK seul suit une loi de Fick tandis qu’une déviation de cette loi est observée aux temps long pour le composite PEKK/FC immergé dans l’eau. La solubilité de l’eau dans le PEKK suit une loi d’Henry. Cependant, l’absorption d’eau dans le composite, en fonction de l’humidité relative, est modélisée par une loi d’Henry couplée à une loi de puissance attribuée à un phénomène de « clustering » ayant lieu dans les micro cavités. Les propriétés mécaniques de la matrice et du composite sont peu impactées par l’eau qui induit essentiellement une plastification de la matrice et qui ne semble pas impacter l’interface fibre/matrice. L’immersion de composite PEKK/FC dans le Skydrol révèle une quantité de fluide absorbé par le composite croisé [0/90] dix fois plus importante que pour l’unidirectionnel. Ce résultat est la conséquence de cavités de taille submicronique créées dans le composite [0/90] sous la forme de décohésions à l’interface fibre/matrice. Ces décohésions sont présentes uniquement au niveau des interplis des composites d’empilements croisés (0/90, ±45° ou quasi-isotropes). Leur formation est attribuée au différentiel de retrait thermique qui existe entre les fibres de carbone et la matrice PEKK, causant un champ de contraintes résiduelles post-consolidation, lors du refroidissement. Ces endommagements, très localisés, n’impactent pas les propriétés mécaniques déterminées en ILSSLightening aircraft remains a major issue for the aeronautics industry. The development of composites with thermoplastic matrices, replacing thermosetting ones, makes it possible to obtain weldable and recyclable materials, with a higher service temperature. This thesis is part of the PSPC HAICoPAS project, led by Hexcel and Arkema, whose goal is to design high-performance thermoplastic matrix composite tapes. The objective of this thesis is to evaluate the impact of water and Skydrol (a hydraulic fluid used in aeronautics) on the properties of CF/PEKK composites (carbon fiber reinforced polyetherketoneketone) and to identify the mechanisms responsible for potential loss of property. To answer this problem, the study concerns both the PEKK matrix alone and the CF/PEKK composite. The water transport mechanisms in the matrix as well as in the composite are determined by gravimetry. The different water transport parameters are measured in a temperature range of 30°C to 70°C, both in water immersion and by DVS, for relative humidities between 10% and 90%. The diffusion of water in the PEKK alone follows a Fick's law while a deviation from this law is visible at long times for the CF/PEKK composite immersed in water. The solubility of water in PEKK follows Henry's law. However, water absorption in the composite, as a function of relative humidity, is modeled by Henry's law coupled with a power law attributed to a “clustering” phenomenon taking place in the microcavities. The mechanical properties of the matrix and of the composite are little affected by water, which essentially induces plasticization of the matrix and which does not seem to affect the fibre/matrix interface. The immersion of CF/PEKK composite in the Skydrol reveals a quantity of fluid absorbed by the crossed composite [0/90] ten times greater than for the unidirectional layup. This result is the consequence of cavities of submicronic size created in the [0/90] composite in the form of decohesions at the fibre/matrix interface. These decohesions are present only at the level of the interply of the cross-ply composites (0/90, ±45° or quasi-isotropic). Their formation is attributed to the thermal shrinkage differential that exists between the carbon fibers and the PEKK matrix, causing a post-consolidation residual stress field upon cooling. These very localized damages do not affect the resulting mechanical properties in ILSS
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Arquier, Raphaël. "Etude des phénomènes physico-chimiques en jeu lors de la consolidation hors autoclave de composites PEKK/FC." Electronic Thesis or Diss., Paris, HESAM, 2023. http://www.theses.fr/2023HESAE017.
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Les composites à fibres de carbone continues et matrice thermoplastique haute performance présentent un intérêt fort pour l’industrie aéronautique comparés aux traditionnels composites à matrice thermodurcissable, pour la diminution des temps de procédé ainsi que pour leur potentielle aptitude à être soudés et recyclés. C’est dans ce contexte que le projet collaboratif HAICoPAS (Highly Automatized Integrated Composites for Performing Adaptable Structures) porté par Hexcel et Arkema et regroupant un consortium industriel et académique, a vu le jour. Il a pour but de développer toute la chaîne de production, allant de la pré-imprégnation de la nappe jusqu’au démonstrateur, permettant de mettre en œuvre un composite fibres de carbone continues à matrice PEKK (Polyetherketoneketone) de la famille des PAEK (Polyaryletherketone) capable de répondre aux exigences industrielles, notamment de produire des pièces consolidées hors autoclave avec un taux de porosité inférieur à 1 %.Sachant que la résorption des porosités intra ou interplis demande un écoulement, certes local, mais d’ensemble du composite, des essais de rhéologie en squeeze flow ainsi que leur modélisation ont permis de mieux appréhender le comportement visqueux complexe du système fortement renforcé en fibres. Les paramètres de viscosité en loi de puissance du composite à 1 bar ont pu être identifiés, ainsi que leur augmentation avec la pression appliquée, corrélée au phénomène de shear banding. Puis, la mise en place d’essais de consolidation sous bâche à vide en étuve couplée à des essais modèles sous rhéomètre reproduisant le même cycle temps-température-pression, ont permis de mettre en évidence les relations procédé / microstructure / propriétés mécaniques induites. Une bonne dispersion de fibres et a fortiori peu de porosités confinées dans des zones très sèches en résine, est nécessaire pour faciliter la consolidation hors autoclave du composite. Aussi, une augmentation de la résistance au cisaillement interpli (ILSS), observée avec le temps de consolidation, s’est avérée être liée à l’homogénéisation de la répartition {fibres + matrice} aux interplis plutôt qu’au taux de porosité généralement considéré comme critère discriminant de la qualité de consolidation. Enfin, le rôle non négligeable joué par les volatils et le taux d’humidité en particulier, dans la consolidation du composite a pu être identifiéCarbon Fiber/High performance thermoplastic matrix composites are of great interest for the aeronautical industry, for the reduction of process times as well as for their potential ability to be welded and recycled compared to their thermoset matrix-based composites counterparts. In this context, the HAICoPAS (Highly Automatized Integrated Composites for Performing Adaptable Structures) collaborative project, built around an industrial and academic consortium and led by Hexcel and Arkema, aims to develop the entire production chain of a continuous carbon fiber reinforced composite with a PEKK (Polyetherketoneketone) matrix. This goes from the pre-impregnation of the tape to the welding of real parts capable of meeting industrial requirements, in particular, consolidate parts in out-of-autoclave (OOA) system with a porosity rate inferior to 1%.As the resorption of intra or interply voids requires a local flow of the whole composite, squeeze flow rheological tests have been modeled to understand the viscous behavior of this highly filled system. The power law viscosity parameters have been identified at 1 bar, as well as an unexpected increase of these parameters with the applied pressure which has been related to "shear banding". Then, consolidation experiments under vacuum bag in an oven, coupled with model rheological tests reproducing the same time-temperature-pressure cycle, have highlighted the process / microstructure / mechanical properties relationships induced. A good dispersion of fibers along with few porosities confined in dry areas is necessary to facilitate the out of autoclave consolidation of the composite. Also, an increase in the interlaminar shear strength (ILSS), observed with consolidation time, was found to be related to the homogenization of the {fibers + matrix} distribution at the interplies rather than to the more usually considered porosity rate. Finally, the important role played by the volatiles and the moisture content in particular, in the consolidation of the composite was identified
Conference papers on the topic "Composite PEKK/FC"
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RICKS, TRENTON M., ROBERT K. GOLDBERG, and J. MICHAEL PEREIRA. "HIGH-ENERGY DYNAMIC IMPACT MODELING OF AN AS4D/PEKK-FC COMPOSITE USING LS-DYNA MAT213." In Proceedings for the American Society for Composites-Thirty Eighth Technical Conference. Destech Publications, Inc., 2023. http://dx.doi.org/10.12783/asc38/36552.
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As part of the NASA Hi-Rate Composite Aircraft Manufacturing (HiCAM) Project, multiple thermoplastic composite systems are being considered as candidates for enabling a more rapid production of composite aircraft components. Various analysis methods are being explored to evaluate their capabilities and applicability to simulating the progressive failure of thermoplastic composites. One of these approaches is based on using the MAT213 material model, a tabulated composite material model recently integrated into the commercial release of Ansys LS-DYNA. For this study, a Solvay APC AS4D/PEKK-FC unidirectional tape composite system was analyzed. A MAT213 input deck was generated for this composite utilizing data from standard composite coupon tests. A series of singleelement verification exercises were performed to evaluate the correct performance of MAT213. These model inputs were then implemented into a high energy dynamic impact (HEDI) ply-by-ply model of a flat 32-ply quasi-isotropic specimen. A tie-break contact model, implemented separately from MAT213, was used to simulate delamination between individual plies. Comparisons, including deformations, damage/delamination sizes, and penetration threshold, are made to test data for a variety of impact velocities. The results demonstrate that MAT213 is a viable option for simulating progressive failure in thermoplastic composite systems under HEDI loads.
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Pereira, Mike, Sandi G. Miller, Duane M. Revilock, Charles R. Ruggeri, and Richard E. Martin. "High Energy Dynamic Impact Testing of APC AS4D/PEKK-FC and TC1225 LMPAEK T700G Thermoplastic Composite Materials." In AIAA SCITECH 2023 Forum. Reston, Virginia: American Institute of Aeronautics and Astronautics, 2023. http://dx.doi.org/10.2514/6.2023-1903.
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CUTTING, REBECCA, WADE JACKSON, PRABHAKAR RAO, and BRIAN JUSTUSSON. "PROGRESSIVE DAMAGE AND FAILURE ANALYSIS OF THERMOPLASTIC COMPOSITES IN LOW VELOCITY IMPACT USING MAT299." In Proceedings for the American Society for Composites-Thirty Eighth Technical Conference. Destech Publications, Inc., 2023. http://dx.doi.org/10.12783/asc38/36561.
Full textAbstract:
As part of NASA’s Hi-Rate Composite Aircraft Manufacturing (HiCAM) Project, state-of-the-art progressive damage and failure analysis (PDFA) tools developed for use with thermosets are being evaluated for use in modeling alternative material systems, like thermoplastics. This work presents experimental low-velocity impact data of a thermoplastic material system, AS4D/PEKK-FC, including characterization of the impact damage mechanisms as well as associated load and displacement data from testing. Following the presentation of experimental results, two simulation approaches using the PDFA tool MAT299 in the commercial off-the-shelf finite element software LS-DYNA are employed to predict damage area and forcedisplacement responses of thermoplastic panels subjected to various impact energies. The first modeling method uses solid elements with a high-density mesh and a ply-byply modeling approach similar to previously published work for thermosets. This method has the capability of capturing individual crack development, progression, and delamination on a per ply basis. The second modeling method uses TSHELL elements that have in-plane dimensions that are an order of magnitude larger than the elements used in the solid element approach and reduces the number of elements through the thickness of the laminate. This produces a lower-fidelity model with reduced run times that is incapable of monitoring every delamination plane and damage within each ply. Results from both simulation methods are compared to experiment, and limitations of the methods are discussed.
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JACKSON, WADE, CHERYL ROSE, and FRANK LEONE. "CHARACTERIZATION OF LOW-VELOCITY IMPACT DAMAGE IN THERMOPLASTIC LAMINATED COMPOSITESThe impact damage response of two thermoplastic material systems were compared over a range of impact energies. Eight-inch-square impact specimens with a 24-ply quasi-isotropic layup were manufactured from TC1225 LMPAEK T700G from Toray Industries and APC AS4D/PEKK-FC from Solvay. The effect of the degree of crystallinity (DOC) on the damage response was also investigated using a third set of specimens from the Toray material manufactured with reduced crystallinity. Using a combination of data obtained from X-ray computed tomography (CT) scans and ultrasonic testing (UT), detailed damage maps were created for every interface and ply for selected specimens. Using these damage maps, the delamination size, shape, and area were evaluated at each interface. The presence of fractured fibers was also identified on each ply. The LMPAEK material was found to have fewer and smaller delaminations than the PEKK specimens for impacts at the same energy. However, the LMPAEK specimens contained a larger number of fiber breaks. A similar trend was observed when comparing the baseline LMPAEK specimens with the low-crystallinity LMPAEK specimens. The low-crystallinity specimens had very little delamination but had a large number of plies with fiber breaks. In addition, the LMPAEK specimens often contained lines of fiber fractures in near-surface plies emanating from the contact region that were not present in the PEKK specimens." In Proceedings for the American Society for Composites-Thirty Eighth Technical Conference. Destech Publications, Inc., 2023. http://dx.doi.org/10.12783/asc38/36557.
Full textAbstract:
The impact damage response of two thermoplastic material systems were compared over a range of impact energies. Eight-inch-square impact specimens with a 24-ply quasi-isotropic layup were manufactured from TC1225 LMPAEK T700G from Toray Industries and APC AS4D/PEKK-FC from Solvay. The effect of the degree of crystallinity (DOC) on the damage response was also investigated using a third set of specimens from the Toray material manufactured with reduced crystallinity. Using a combination of data obtained from X-ray computed tomography (CT) scans and ultrasonic testing (UT), detailed damage maps were created for every interface and ply for selected specimens. Using these damage maps, the delamination size, shape, and area were evaluated at each interface. The presence of fractured fibers was also identified on each ply. The LMPAEK material was found to have fewer and smaller delaminations than the PEKK specimens for impacts at the same energy. However, the LMPAEK specimens contained a larger number of fiber breaks. A similar trend was observed when comparing the baseline LMPAEK specimens with the low-crystallinity LMPAEK specimens. The low-crystallinity specimens had very little delamination but had a large number of plies with fiber breaks. In addition, the LMPAEK specimens often contained lines of fiber fractures in near-surface plies emanating from the contact region that were not present in the PEKK specimens.