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Raimondo, M., S. Russo, L. Guadagno, P. Longo, S. Chirico, A. Mariconda, L. Bonnaud, O. Murariu et Ph Dubois. « Effect of incorporation of POSS compounds and phosphorous hardeners on thermal and fire resistance of nanofilled aeronautic resins ». RSC Advances 5, no 15 (2015) : 10974–86. http://dx.doi.org/10.1039/c4ra11537f.
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Barra, Giuseppina, Liberata Guadagno, Luigi Vertuccio, Bartolome Simonet, Bricio Santos, Mauro Zarrelli, Maurizio Arena et Massimo Viscardi. « Different Methods of Dispersing Carbon Nanotubes in Epoxy Resin and Initial Evaluation of the Obtained Nanocomposite as a Matrix of Carbon Fiber Reinforced Laminate in Terms of Vibroacoustic Performance and Flammability ». Materials 12, no 18 (16 septembre 2019) : 2998. http://dx.doi.org/10.3390/ma12182998.
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Different industrial mixing methods and some of their combinations ((1) ultrasound; (2) mechanical stirring; (3) by roller machine; (4) by gears machine; and (5) ultrasound radiation + high stirring) were investigated for incorporating multi-walled carbon nanotubes (MWCNT) into a resin based on an aeronautical epoxy precursor cured with diaminodiphenylsulfone (DDS). The effect of different parameters, ultrasound intensity, number of cycles, type of blade, and gear speed on the nanofiller dispersion were analyzed. The inclusion of the nanofiller in the resin causes a drastic increase in the viscosity, preventing the homogenization of the resin and a drastic increase in temperature in the zones closest to the ultrasound probe. To face these challenges, the application of high-speed agitation simultaneously with the application of ultrasonic radiation was applied. This allowed, on the one hand, a homogeneous dispersion, and on the other hand, an improvement of the dissipation of heat generated by ultrasonic radiation. The most efficient method was a combination of ultrasound radiation assisted by a high stirring method with the calendar, which was used for the preparation of a carbon fiber reinforced panel (CFRP). The manufactured panel was subjected to dynamic and vibroacoustic tests in order to characterize structural damping and sound transmission loss properties. Under both points of view, the new formulation demonstrated an improved efficiency with reference to a standard CFRP equivalent panel. In fact, for this panel, the estimated damping value was well above the average of the typical values representative of the carbon fiber laminates (generally less than 1%), and also a good vibroacoustic performance was detected as the nanotube based panel exhibited a higher sound transmission loss (STL) at low frequencies, in correspondence with the normal mode participation region. The manufactured panel was also characterized in terms of fire performance using a cone calorimeter and the results were compared to those obtained using a commercially available monocomponent RTM6 (Hexcel composites) epoxy aeronautic resin with the same process and the same fabric and lamination. Compared to the traditional RTM6 resin, the panel with the epoxy nanofilled resin exhibits a significant improvement in fire resistance properties both in terms of a delay in the ignition time and in terms of an increase in the thermal resistance of the material. Compared to the traditional panel, made in the same conditions as the RTM6 resin, the time of ignition of the nanotube-based panel increased by 31 seconds while for the same panel, the heat release rate at peak, the average heat release rate, and the total heat release decreased by 21.4%, 48.5%, and 15%, respectively. The improvement of the fire performance was attributed to the formation of a non-intumescent char due to the simultaneous presence of GPOSS and carbon nanotubes.
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FAINLEIB, A. M. « BIO-BASED CYANATE ESTER RESINS AND THERMOSTABLE POLYMER NETWORKS DERIVED THEREOF. MINI REVIEW ». Polymer journal 44, no 2 (20 juin 2022) : 93–100. http://dx.doi.org/10.15407/polymerj.44.02.093.
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This article is devoted to a review of the literature on a very promising direction in the chemistry of macromolecular compounds: the synthesis and study of polymers, more specifically, high performance polycyanurates based on bis(poly)phenols) of natural origin. Cyanate Ester Resins (CER) are characterized by a very regular structure of the polymer networks, namely polycyanurates (PCNs), obtained by their polycyclotrimerization. They have received much attention because of their unique combination of physical properties, including high thermal stability (> 400 °C), high glass transition temperature (> 270 °C), high fire-, radiation and chemical resistance, low water absorption and low outgassing, high adhesion to different substrates and excellent dielectric properties (ε=2,64−3,11). As a result, CER are currently used as structural or functional materials in aeronautics, space (composite strakes, fins, nose radomes, heat shields), printed circuit boards, adhesives etc. It has to be noted here that CER thermosetting resins, expanding the high-temperature operations regimes, are produced from synthetic petroleum-derived bisphenols, such as bisphenol A, which are toxic and dangerous for environment. In the past decade, naturally occurring phenolic derivatives have arisen as attractive precursors for developing new materials from renewable bio-sources for use in eco-friendly processes. Resins have been prepared utilizing either the whole liquid product or a phenolic-enriched fraction obtained after fractional condensation or further processing, such as solvent extraction or use of greener extraction methods. However, to date, none of the phenolic production and fractionation techniques has been utilized to allow for substitution of 100% of the phenol content of the resin without impacting its effectiveness compared to commercial formulations based on petroleum-derived phenol. The variable nature of the percentage of phenolic compounds in terms of purity from different batches of crops from one season to another and geographical influence does not allow from the reproducibility of phenolic compounds, and hence the resulting polymers. However, the direction that needs to be explored should be oriented towards complete replacement of petro-based phenolics with bio-based ones in the face of an urgent petroleum crisis. In addition, there is a necessity for materials showing enhanced applicability and improved performance. It is a beginning of the era of such a step, which requires further exploration of natural phenolic sources aimed at their enhanced utilization.
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Grange, Nathan, Pietro Tadini, Khaled Chetehouna, Nicolas Gascoin, Guillaume Bouchez, Samuel Senave et Isabelle Reynaud. « Experimental determination of fire degradation kinetic for an aeronautical polymer composite material ». International Journal of Structural Integrity 9, no 1 (5 février 2018) : 76–92. http://dx.doi.org/10.1108/ijsi-03-2017-0021.
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Purpose The purpose of this paper is to evaluate the fire resistance of an innovative carbon-reinforced PEKK composite for aeronautical applications. To this end, thermal degradation analysis under inert and oxidative atmosphere is carried out. Moreover, a linear model fitting approach is compared to a generally used isoconversional method to validate its reliability for kinetic triplet estimation. Design/methodology/approach Thermogravimetric analysis carried out under inert and oxidative atmospheres, between 25 and 1000°C for three different heating rates (5, 15, 25°C/min), followed by a qualitative SEM observation of the samples before and after thermal treatment. After the reaction identification by TG/DTG curves, an isoconversional analysis is carried out to estimate the activation energy as a function of the reaction conversion rate. For the identified reactions, the kinetic triplet is estimated by different methods and the results are compared to evaluate their reliability. Findings In inert case, one global reaction, observed between 500-700°C, seems able to describe the degradation of carbon-PEKK resin. Under oxidative atmosphere, three main reactions are identified, besides the resin degradation, the other two are attributed to char and fiber oxidation. Good agreement achieved between isoconversional and linear model fitting methods in activation energy calculation. The achieved results demonstrate the high thermal resistance of PEKK associated with the ether and ketone bonds between the three aromatic groups of its monomer. Originality/value This paper provides a possible degradation model useful for numerical implementation in CFD calculations for aircraft components design, when exposed to high temperatures and fire conditions.
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Chtourou, Halim, Abdelatif Atarsia et Bo Fisa. « Prediction of Thermal and Fire Resistance of Phenolic Resins by Dynamic TG Analysis ». Journal of Reinforced Plastics and Composites 18, no 4 (mars 1999) : 339–45. http://dx.doi.org/10.1177/073168449901800404.
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De Aloysio, Giulia, Mattia Morganti, Luca Laghi, Matteo Scafè, Enrico Leoni, Claudio Mingazzini et Stefano Bassi. « Characterization in expected working environments of recyclable fire-resistant materials ». MATEC Web of Conferences 349 (2021) : 01009. http://dx.doi.org/10.1051/matecconf/202134901009.
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This study focuses on the development of multi-material solutions for fire-resistant structural materials for transport and thermal insulation in the construction field. Special attention was paid to combining recyclable and bio-mass derived raw materials without interfering with an easy end-of-life separation, recycling and reuse. Fire-resistant biomass derived resins were associated with basalt derived Mineral Fibres (BDMF) in the form of prepregs, which were studied as semi-finished materials. Fire-resistance was obtained by associating these prepregs with thin gres tiles in the case of fire-resistant thermal insulating facades and with aluminum layers (giving origin to Fibre Metal Laminates-FML) in the case of structural components for transport applications. Thermophysical characterization of the solutions was carried out to assess both thermal conductivity and thermal diffusivity. Fire resistance tests were performed on FML to determine the number of Al layers needed to ensure fire resistance. Results suggest that fire resistance depends primarily on the number of Al layers, rather than on their thickness. Accelerated ageing tests (salty mist and freeze-thaw) were executed to predict durability in the expected working conditions. Results suggest a durability issue in FML with preceramic interface in salty environments.
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Zielecka, Maria, Anna Rabajczyk, Krzysztof Cygańczuk, Łukasz Pastuszka et Leszek Jurecki. « Silicone Resin-Based Intumescent Paints ». Materials 13, no 21 (27 octobre 2020) : 4785. http://dx.doi.org/10.3390/ma13214785.
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Silicone resins are widely applied as coating materials due to their unique properties, especially those related to very good heat resistance. The most important effect on the long-term heat resistance of the coating is connected with the type of resin. Moreover, this structure is stabilized by a chemical reaction between the hydroxyl groups from the organoclay and the silicone resin. The novel trends in application of silicone resins in intumescent paints used mostly for protection of steel structures against fire will be presented based on literature review. Some examples of innovative applications for fire protection of other materials will be also presented. The effect of silicone resin structure and the type of filler used in these paints on the properties of the char formed during the thermal decomposition of the intumescent paint will be discussed in detail. The most frequently used additives are expanded graphite and organoclay. It has been demonstrated that silicate platelets are intercalated in the silicone matrix, significantly increasing its mechanical strength and resulting in high protection against fire.
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Nguyen, Tuan Anh, et Thi Thu Trang Bui. « Study the Effects of Carbon Nanotubes and Graphene Oxide Combinations on the Mechanical Properties and Flame Retardance of Epoxy Nanocomposites ». Journal of Nanomaterials 2021 (27 décembre 2021) : 1–9. http://dx.doi.org/10.1155/2021/1437929.
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Carbon-based fillers have attracted a lot of interest in polymer composites because of their ability to alter beneficial properties at low filler concentrations, good surface bonding with polymers, availability in different forms, etc. Carbon-based materials (such as fullerene, CNTs, graphene, and graphite) have been studied as fillers with enhanced fire resistance to epoxy resins. In order to reduce the flammability and improve the thermal stability of epoxy resin-based nanocomposite materials, which can be achieved by a simultaneous combination of graphene oxide and multiwall carbon nanotubes, the graphite oxide (GO) epoxy nanomaterial was developed by 1% wt.% GO combined with 0.02 wand 0.04 wt.% MWCNT. The homogeneous dispersion of GO and MWCNTs in epoxy resins is supported by ultrasonic vibrations. The results showed that when nanocomposite materials were present at the same time MWCNTs and GO, their mechanical properties and fire resistance were significantly improved. Nanomaterials are characterized by FT-IR spectroscopy and SEM imaging, mechanical strength, and flame retardant properties (LOI, UL94).
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Dowbysz, Adriana, Mariola Samsonowicz et Bożena Kukfisz. « Recent Advances in Bio-Based Additive Flame Retardants for Thermosetting Resins ». International Journal of Environmental Research and Public Health 19, no 8 (15 avril 2022) : 4828. http://dx.doi.org/10.3390/ijerph19084828.
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Thermosetting resins are used in many applications due to their great mechanical properties, chemical resistance, and dimensional stability. However, the flammability of thermosets needs to be improved to minimize fire risk and meet fire safety regulations. Some commercially available flame retardants have an adverse effect on people’s health and the environment. Thus, the development of novel, more sustainable flame retardants obtained or derived from biomass has become an objective of contemporary research. The objective of this study is to summarize recent progress on bio-based flame retardants for thermosetting resins so as to promote their prompt development. Groups of biomass compounds with a potential for flame retardant industrial applications were introduced, and their thermal degradation was investigated. The authors focused mostly on the thermal degradation of composites containing bio-based flame retardants determined by thermogravimetric analysis, their tendency to sustain a flame determined by a limiting oxygen index, and fire behavior determined by a cone calorimeter test. The results showed that the mode of action is mostly based on the forming of the char layer. However, in many cases, there is still a necessity to input a high amount of additive to achieve significant flame retardancy effects, which may adversely impact mechanical properties.
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Sayin, Baris, et Erdem Damcı. « A Numerical Evaluation of Insulated CFRP-Strengthened RC Beams Exposed to Fire ». Advanced Materials Research 742 (août 2013) : 62–69. http://dx.doi.org/10.4028/www.scientific.net/amr.742.62.
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There are mainly two approaches to improve the fire resistance of FRP systems. While the most common way is to protect or insulate the FRP systems, the other way is to use fibers and resins with better fire-performance. In this paper a numerical investigation for evaluating the fire behavior of insulated CFRP-strengthened RC beams is presented.The effects of external loading and thermal expansion of materials in both the structural and the thermal behavior of composite elements due to loading and elevated temperatures are taken into consideration in a finite element model. The validity of the numerical model isdemonstrated withthe results from an existing experimental study on insulated CFRP-strengthened RC beam. The conclusions of this investigation have been employed to predict the structural behavior of concrete structures successfully.
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Manfredi, Liliana B., Exequiel S. Rodríguez, Maria Wladyka-Przybylak et Analía Vázquez. « Thermal degradation and fire resistance of unsaturated polyester, modified acrylic resins and their composites with natural fibres ». Polymer Degradation and Stability 91, no 2 (février 2006) : 255–61. http://dx.doi.org/10.1016/j.polymdegradstab.2005.05.003.
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Liang, Bing, Tie Zhu Bao, Jun Cao et Xiao Dong Hong. « Preparation and Properties of Halogen-Free Flame Retardant Epoxy Resins with Aryl Phosphinate Dianhydride Hardener ». Advanced Materials Research 328-330 (septembre 2011) : 1335–38. http://dx.doi.org/10.4028/www.scientific.net/amr.328-330.1335.
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Two halogen-free flame retardant epoxy resins were prepared by diglycidyl ether of bisphenol A (DGEBA) epoxy with two compound hardeners. The aryl phosphinate dianhydride BPAODOPE was used as a hardener and flame retardant when coupled with two curing agents, such as methylhexahydrophthalic anhydride (MeHHPA) and maleic anhydride (MA). The effect of the BPAODOPE contents on the fire resistance, thermal properties and mechanical properties of halogen-free flame-retardant epoxy resins were investigated in detail. The results showed that the phosphorus-containing epoxy resin composites had a higher UL-94 grade and char yield, furthermore, the flame retardation and the char yield of the cured epoxy resins increased with an increase of the phosphorus content, the phosphorus content of 1.75% was enough to achieve UL-94 V-1 grade and the best combination properties for the two composites with different hardeners.
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Vidal, Julio, David Ponce, Alice Mija, Monika Rymarczyk et Pere Castell. « Sustainable Composites from Nature to Construction : Hemp and Linseed Reinforced Biocomposites Based on Bio-Based Epoxy Resins ». Materials 16, no 3 (2 février 2023) : 1283. http://dx.doi.org/10.3390/ma16031283.
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The present manuscript describes the use of natural fibers as natural and sustainable reinforcement agents for advanced bio-based composite materials for strategic sectors, for example, the construction sector. The characterization carried out shows the potential of both natural hemp and linseed fibers, as well as their composites, which can be used as insulation materials because their thermal conductivity properties can be compared with those observed in typical construction materials such as pine wood. Nevertheless, linseed composites show better mechanical performance and hemp has higher fire resistance. It has been demonstrated that these natural fibers share similar properties; on the other hand, each of them should be used for a specific purpose. The work also evaluates the use of bio matrixes in composites, demonstrating their feasibility and how they impact the final material’s properties. The proposed bio-resin enhances fire resistance and decreases the water absorption capacity of the natural fibers, enabling the use of composites as a final product in the construction sector. Therefore, it has been demonstrated that it is possible to manufacture a biocomposite with non-woven natural fibers. In fact, for properties such as thermal conductivity, it is capable of competing with current materials. Proving that biomaterials are a suitable solution for developing sustainable products, fulfilling the requirements of the end-user applications, as it has been demonstrated in this research with the non-woven fibers for the non-structural components.
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Sarika, P. R., Paul Nancarrow, Abdulrahman Khansaheb et Taleb Ibrahim. « Bio-Based Alternatives to Phenol and Formaldehyde for the Production of Resins ». Polymers 12, no 10 (28 septembre 2020) : 2237. http://dx.doi.org/10.3390/polym12102237.
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Phenol–formaldehyde (PF) resin continues to dominate the resin industry more than 100 years after its first synthesis. Its versatile properties such as thermal stability, chemical resistance, fire resistance, and dimensional stability make it a suitable material for a wide range of applications. PF resins have been used in the wood industry as adhesives, in paints and coatings, and in the aerospace, construction, and building industries as composites and foams. Currently, petroleum is the key source of raw materials used in manufacturing PF resin. However, increasing environmental pollution and fossil fuel depletion have driven industries to seek sustainable alternatives to petroleum based raw materials. Over the past decade, researchers have replaced phenol and formaldehyde with sustainable materials such as lignin, tannin, cardanol, hydroxymethylfurfural, and glyoxal to produce bio-based PF resin. Several synthesis modifications are currently under investigation towards improving the properties of bio-based phenolic resin. This review discusses recent developments in the synthesis of PF resins, particularly those created from sustainable raw material substitutes, and modifications applied to the synthetic route in order to improve the mechanical properties.
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Gadow, Weichand et Jiménez. « Process Technology, Applications and Thermal Resistivity of Basalt Fiber Reinforced SiOC Composites ». Ceramics 2, no 2 (17 avril 2019) : 298–307. http://dx.doi.org/10.3390/ceramics2020025.
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Promising lightweight composite materials, bridging the gap between Polymer and Ceramic Matrix Composites, are manufactured as polymer derived ceramics by the use of polysiloxanes and basalt fibers. Such competitive free formable Hybrid Composites are supposed to be capable for lightweight applications in a temperature range between 300 °C and 850 °C and short time exposure up to over 1000 °C, even in oxidative atmosphere. Cheap raw materials like basalt fibers and siloxane resins in combination with performing manufacturing technologies can establish completely new markets for intermediate temperature composites. These attributes enable the Hybrid Composites as ideal material for fire retardant applications in automotive engineering and public transportation, as well as in fire protection systems in electrical and civil engineering applications. In this study, the most prominent fields of application and engineering solutions for Hybrid-CMC are reviewed and the results of the thermal resistivity analysis effectuated on basalt fiber reinforced SiOC samples are presented. This study consisted of several air exposures between 1 h and 50 h and temperatures in the range of 650 °C to 1100 °C. Remaining mechanical resistance was characterized by Impulse Excitation Technique (IET) and Interlaminar Shear Strength (ILSS) tests. Basalt fiber reinforced samples exhibited a decent level of mechanical performance even after the most demanding exposures. Due to the poor oxidation resistance of carbon fibers, Cf/SiOC composites were completely degraded after long-term exposure at 500 °C in air.
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Burdonov, А. Е., V. V. Barakhtenko et Е. V. Zelinskaya. « The Technology of Creating Composite Materials on the Ground of Phenolformaldehyde Oligomers and Heat-power Engineering Waste Products ». Ecology and Industry of Russia 22, no 12 (4 décembre 2018) : 22–27. http://dx.doi.org/10.18412/1816-0395-2018-12-22-27.
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The process of TPP fly ash treatment for production of efficient thermal protection composite materials with improved operational characteristics has been presented. One of the methods of rational using fly ash that is formed during coal combustion at thermal power plants is its application as a filler in composite materials. The developed composites based on fly ash and polymer resins form a new class of heat insulating materials that boast higher fire resistance, low density, lower moisture absorption compared with analogues, and high strength. The materials have a broad application range as heat insulators: from small diameter pipelines to industrial facilities. The data obtained by the authors indicate the possibility for safe application of these materials as modern heat retainers for heat insulation of pipeline systems and buildings.
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Fürst, Richard, Petr Hejtmánek, Tomáš Vlach, Jakub Řepka, Vladimír Mózer et Petr Hájek. « Experimental Evaluation of Carbon Reinforced TRC with Cement Suspension Matrix at Elevated Temperature ». Polymers 14, no 11 (27 mai 2022) : 2174. http://dx.doi.org/10.3390/polym14112174.
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Textile-reinforced concrete (TRC) is a new composite material comprising high-performance concrete and textile reinforcement from textile yarns with a matrix, usually consisting of epoxy resins (ER). The most significant advantage of ER is the homogenization of all filaments in the yarn and full utilization of its tensile potential. Nevertheless, ER matrix is a critical part of TRC design from the perspective of the fire resistance due to its relatively low resistance at temperatures of approximately 120 ∘C. This work expands the previously performed mechanical tests at normal temperatures with cement suspension (CS) as a non-combustible material for the yarn matrix. Here, the mechanical properties of CS matrix at elevated temperatures were verified. It was found that the addition of polypropylene fibers into HPC negatively affected the mechanical results of CS matrix specimens. Simultaneously, thermal insulation effect of the covering layers with different thicknesses did not significantly influence the residual bending strength of specimens with CS matrix and achieved similar results as reference specimens. Furthermore, all specimens with ER matrix progressively collapsed. Finally, CS as a textile reinforcement of yarn matrix appears to be a suitable solution for increasing the temperature resistance of TRC structures and for substituting synthetic resins.
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Petrakova, Viktoria V., Vyacheslav V. Kireev, Denis V. Onuchin, Igor A. Sarychev, Vyacheslav V. Shutov, Anastasia A. Kuzmich, Natalia V. Bornosuz et al. « Benzoxazine Monomers and Polymers Based on 3,3′-Dichloro-4,4′-Diaminodiphenylmethane : Synthesis and Characterization ». Polymers 13, no 9 (28 avril 2021) : 1421. http://dx.doi.org/10.3390/polym13091421.
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To reveal the effect of chlorine substituents in the ring of aromatic amine on the synthesis process of benzoxazine monomer and on its polymerization ability, as well as to develop a fire-resistant material, a previously unreported benzoxazine monomer based on 3,3′-dichloro-4,4′-diaminodiphenylmethane was obtained in toluene and mixture toluene/isopropanol. The resulting benzoxazine monomers were thermally cured for 2 h at 180 °C, 4 h at 200 °C, 2 h at 220 °C. A comparison between the rheological, thermal and fire-resistant properties of the benzoxazines based on 3,3′-dichloro-4,4′-diaminodiphenylmethane and, for reference, 4,4′-diaminodimethylmethane was made. The effect of the reaction medium on the structure of the oligomeric fraction and the overall yield of the main product were studied and the toluene/ethanol mixture was found to provide the best conditions; however, in contrast to most known diamine-based benzoxazines, synthesis in the pure toluene is also possible. The synthesized monomers can be used as thermo- and fire-resistant binders for polymer composite materials, as well as hardeners for epoxy resins. Chlorine-containing polybenzoxazines require more severe conditions for polymerization but have better fire resistance.
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Toldy, Andrea, Gábor Szebényi, Kolos Molnár, Levente Tóth, Balázs Magyar, Viktor Hliva, Tibor Czigány et Beáta Szolnoki. « The Effect of Multilevel Carbon Reinforcements on the Fire Performance, Conductivity, and Mechanical Properties of Epoxy Composites ». Polymers 11, no 2 (12 février 2019) : 303. http://dx.doi.org/10.3390/polym11020303.
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We studied the effect of a multilevel presence of carbon-based reinforcements—a combination of conventional load-bearing unidirectional carbon fiber (CF) with multiwalled carbon nanotubes (CNT) and conductive CNT-containing nonwoven carbon nanofabric (CNF(CNT))—on the fire performance, thermal conductivity, and mechanical properties of reference and flame-retarded epoxy resin (EP) composites. The inclusion of carbon fibers and flame retardant reduced the peak heat release rate (pHRR) of the epoxy resins. The extent to which the nanoreinforcements reduced the pHRR depended on their influence on thermal conductivity. Specifically, high thermal conductivity is advantageous at the early stages of degradation, but after ignition it may lead to more intensive degradation and a higher pHRR; especially in the reference samples without flame retardant. The lowest pHRR (130 kW/m2) and self-extinguishing V-0 UL-94 rating was achieved in the flame-retarded composite containing all three levels of carbon reinforcement (EP + CNF(CNT) + CNT + CF FR). The plasticizing effect of the liquid flame retardant impaired both the tensile and flexural properties; however, it significantly enhanced the impact resistance of the epoxy resin and its composites.
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Xia, Wenjing, Suying Fan et Tao Xu. « Inhibitory action of halogen-free fire retardants on combustion and volatile emission of bituminous components ». Science Progress 104, no 3 (juillet 2021) : 003685042110352. http://dx.doi.org/10.1177/00368504211035215.
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The objective of this study is to quantitatively evaluate inhibitory action of halogen-free fire retardants (HFR) on combustion properties and volatile emission of such bituminous components as saturates, aromatics, resins, and asphaltenes (SARA). Thermogravimetry-Fourier transform infrared spectroscopy (TG-FTIR) tests were performed on SARA fractions containing matched fire retardants, respectively, and thermal kinetics parameters based on TG curves and functional and structural indices from FTIR spectra were calculated, respectively. The selected fire retardants have not affected the combustion process of SARA fractions, but the combustion temperature intervals are elevated and combustion progresses are retarded. Also, the char yields of SARA fractions are obviously increased by the matched fire retardants, improving their heat stability. The activation energy is elevated because of the added fire retardants, indicating combustion resistance of SARA fractions become larger. Additionally, the matched fire retardants inhibit the toxic gas emission in the combustion process of SARA fractions, but have few effects on gaseous product constituents. H2O and CO2 are identified as two typical released gases in various combustion phases of each SARA fraction. Finally, the added hydroxide play a role of fire retardants through cooling, dilution, adsorption, and neutralization, and the generated active oxide facilitates the expandable graphite (EG) and matrix to form densified and thick carbon layer. These suppress the volatile emission, and hinder the heat conduction and oxygen supply. Fire retardant composite exhibits the synergistic effect of fire retardancy and smoke inhibition in the combustion process of SARA fractions.
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Varganici, Cristian-Dragos, Liliana Rosu, Dan Rosu, Corneliu Hamciuc, Irina Rosca et Ana-Lavinia Vasiliu. « Effect of Hardener Type on the Photochemical and Antifungal Performance of Epoxy and Oligophosphonate S–IPNs ». Polymers 14, no 18 (9 septembre 2022) : 3784. http://dx.doi.org/10.3390/polym14183784.
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Due to their highly reactive character and multiple crosslinking capacity, epoxy resins are one of the worldwide market-dominating classes of thermosetting polymers and are present in a wide range of technical applications, including structural adhesives, coatings and polymer matrices for composite materials. Despite their excellent features, epoxy resins are known to be highly flammable and possess low thermal stability and a brittle character and crack easily under impact forces. An efficient approach towards eliminating such drawbacks resides in obtaining epoxy-based semi-interpenetrating polymer networks, which possess excellent control over the morphology. The article describes the comparative effect of three hardeners (aromatic, cycloaliphatic and aliphatic) in the presence of an oligophosphonate (–R–O–PO(C6H5)–O–) (2 wt.% phosphorus) on the photochemical, fire and antifungal performance of bisphenol A diglycidyl ether semi-interpenetrating polymer networks. The networks are designed as future potential outdoor protective coatings for different substrates. The fire resistance capacity of the networks was undertaken with microscale combustion calorimetry before and after photochemical aging. Structural changes during photoirradiation were monitored via color modification studies, Fourier-transform infrared spectroscopy, differential scanning calorimetry, morphological assessment through scanning electron microscopy and mass loss measurements in order to propose the action mode of the hardeners and the oligophosphonate on the material properties. Microbiological testing was also undertaken with the aid of three specific wood decaying fungi as a first substrate.
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Xu, Miao-Jun, Yue Ma, Min-Jie Hou et Bin Li. « Synthesis of a cross-linked triazine phosphine polymer and its effect on fire retardancy, thermal degradation and moisture resistance of epoxy resins ». Polymer Degradation and Stability 119 (septembre 2015) : 14–22. http://dx.doi.org/10.1016/j.polymdegradstab.2015.04.027.
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Dai, Kang, Zhenzhen Deng, Guyue Liu, Yutong Wu, Wenbin Xu et Yuan Hu. « Effects of a Reactive Phosphorus–Sulfur Containing Flame-Retardant Monomer on the Flame Retardancy and Thermal and Mechanical Properties of Unsaturated Polyester Resin ». Polymers 12, no 7 (27 juin 2020) : 1441. http://dx.doi.org/10.3390/polym12071441.
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A novel reactive phosphorus and sulfur-containing monomer (bis(acryloxyethyldiphenylphosphate)sulfone, BADPS) was synthesized to enhance the comprehensive performance of unsaturated polyester resin (UPR), and corresponding flame-retardant unsaturated polyester resins (FR-UPRs) with various amounts of BADPS were prepared by radical bulk polymerization. The flame retardancy and thermal and mechanical properties of the UPR samples were investigated by limiting oxygen index (LOI) measurements, cone calorimetry, differential scanning calorimetry (DSC), a thermogravimetric analysis (TGA), and a tension test. The results showed that the introduction of BADPS remarkably enhanced the flame resistance and high-temperature stability, as well as the tensile performance of UPR. Scanning electron microscopy (SEM), Fourier transform infrared (FTIR), and Raman spectroscopy studies revealed that BADPS can efficaciously promote the formation of UPR char residue with an improved microstructure and increased graphitization degree, which enhancedthe high-temperature stability and char yield of UPR. Additionally, a thermogravimetry-Fourier transform infrared (TG-FTIR) analysis corroborated that the evolution of combustible volatiles from UPR decomposition was substantially restrained by the incorporation of BADPS, which is beneficial for the suppression of fire hazards in UPR.
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Bazzad, Priyanka, et J. B. Dahiya. « Effect of Functionality of Organophosphorus Flame Retardants on Flammability and Thermal Stability of DGEBA-Based Epoxy Resin Nanocomposites ». Current Applied Polymer Science 4, no 3 (décembre 2021) : 217–26. http://dx.doi.org/10.2174/2452271604666211104091336.
Texte intégralRésumé :
Background: Epoxy resins have been extensively used in fire hazard environments, such as printed circuit boards, electrical isolation materials, adhesives, construction, and transportation due to their economically viable, simple processing. Therefore, the development of thermally stable and flame-retardant epoxy resin systems is essential. Objective: The aim of the present study was to study the effect of the functionality of organophosphorus flame retardants on DGEBA-based epoxy resin nanocomposites on thermal stability and flame retardancy. Method: DGEBA (diglycidyl ether of bisphenol-A)-based epoxy resin nanocomposites having 2.0 wt% phosphorus were prepared with organophosphorus flame retardants with different functionalities by using an in-situ polymerization method. The flame retardant compounds uni-functional 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and bi-functional 2-(6-oxid-6Hdibenz [c, e] [1, 2] oxaphosphorin 6-yl) 1, 4-benzenediol (DOPO-HQ) were prepared. The thermal behavior of composites was studied by TG and DTA techniques. The flammability behavior was investigated by UL-94 and limiting oxygen index (LOI) tests. Results: The XRD and TEM results showed the mixed dispersion of nanoclay platelets in an epoxy matrix. The thermal stability of the epoxy composite (EPDOPO-HQ) containing bi-functional DOPOHQ is increased by 16°C in comparison to the epoxy composite (EPDOPO) containing uni-functional DOPO. According to the TG analysis, the addition of nanoclay was observed to be more effective and synergistic with bi-functional DOPO-HQ as the EPDOPO-HQ/NC sample gains more resistance to degradation after around 450°C and also gave rise to a high char yield. Epoxy resin samples containing reactive flame retardants gave UL-94 V-0 rating, but further addition of 2.0 wt% nanoclay lowered the rating from V-0 to V-1. Conclusions: TG analysis of the epoxy composite samples showed that the addition of nanoclay were observed to be synergistic with bi-functional flame retardant (DOPO-HQ) as the EPDOPO-HQ/NC sample gained more resistance to degradation after around 450°C due to the formation of mixed intercalated and exfoliated structure. The EPDOPO-HQ sample gave a high char yield with increased onset degradation temperature, high thermal stability as well as high flame retardancy.
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Volponi, R., P. Spena, F. De Nicola et L. Guadagno. « Multiscale Composites : Assessment of a Feasible Manufacturing Process ». International Journal of Aerospace Engineering 2019 (13 mai 2019) : 1–8. http://dx.doi.org/10.1155/2019/6845310.
Texte intégralRésumé :
A very interesting field of research on advanced composite materials is the possibility to integrate new functionalities and specific improvements acting on the matrix of the composite by means of a nanocharged resin. In this way, the composite becomes a so-called “multiscale composite” in which the different phases change from nano to macro scale. For example, the incorporation of nanoscale conductive fillers with intrinsically high electrical conductivity could allow a tailoring of this property for the final material. The properties of carbon nanotubes (CNT) make them an effective candidate as fillers in polymer composite systems to obtain ultralight structural materials with advanced electrical and thermal characteristics. Nevertheless, several problems are related to the distribution in the matrix and to the processability of the systems filled with CNT. Existing liquid molding processes such as resin transfer molding (RTM) and vacuum-assisted resin transfer molding (VARTM) can be adapted to produce carbon fiber reinforced polymer (CFRP) impregnated with CNT nanofilled resins. Unfortunately, the loading of more than 0.3-0.5% of CNT can lead to high resin viscosities that are unacceptable for such kind of processes. In addition to the viscosity issues that are related to the high CNT content, a filtration effect of the nanofillers caused by the fibrous medium may also lead to inadequate final component quality. This work describes the development of an effective manufacturing process of a fiber-reinforced multiscale composite panel, with a tetra-functional epoxy matrix loaded with carbon nanotubes to increase its electrical properties and with GPOSS to increase its resistance to fire. A first approach has been attempted with a traditional liquid infusion process. As already anticipated, this technique has shown considerable difficulties related both to the low level of impregnation achieved, due to the high viscosity of the resin, and to the filtration effects of the dispersed nanocharges. To overcome these problems, an opportunely modified process based on a sort of film infusion has been proposed. This modification has given an acceptable result in terms of impregnation and morphological arrangement of CNTs in nanofilled CFRP. Finally, the developed infiltration technique has been tested for the manufacture of a carbon fiber-reinforced panel with a more complex shape.
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Khalaj Asadi, Amir, Morteza Ebrahimi et Mohsen Mohseni. « Microencapsulation of a sunlight-curable silicon-based resin in the presence of polyvinylpyrrolidone ». Pigment & ; Resin Technology 47, no 3 (8 mai 2018) : 272–78. http://dx.doi.org/10.1108/prt-04-2017-0040.
Texte intégralRésumé :
Purpose The purpose of this investigation is to develop a facile method to encapsulate a sunlight-curable silicone-based resin into a melamine–urea–formaldehyde (MUF) shell in the presence of polyvinylpyrrolidone (PVP) as an emulsifier. These microcapsules can be used in self-healing coating formulations. Design/methodology/approach MUF microcapsules containing a sunlight-curable core (methacryloxypropyl-terminated polydimethylsiloxane, MAT-PDMS) have been fabricated by means of in situ polymerisation of an oil-in-water emulsion using PVP as an efficient and environmentally advantageous stabiliser. The effects of agitation rate and PVP concentration on the microencapsulation process have been investigated using optical microscopy (OM) and scanning electron microscopy (SEM). The chemical structure and thermal stability of the microcapsules have been studied using Fourier transform infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA). The solvent resistance of the microcapsules has been determined as well. Findings It has been revealed that the pH of the reaction mixture remained almost constant during the reaction, which simplified the process. It has also been observed that the microencapsulation yield improved and the microcapsules’ surface morphology became smoother when a high PVP content was used. With an increase in stirring rate from 600 to 1,200 rpm, the surface roughness and the average particle size decreased. The mean diameter of the prepared microcapsules ranged from 32.1 to 327.1 µm depending on the synthesis conditions. It was demonstrated that the microcapsules had a high capacity for MAT-PDMS encapsulation (more than 88 Wt.%). The solvent stability of the microcapsules against different polar, semi-polar and non-polar solvents was also evaluated. Research limitations/implications This research is limited to the encapsulation of a hydrophobic and sunlight curable liquid (such as MAT-PDMS) by means of in situ polymerisation of amino resins. Practical implications The results can be used by researchers working on the fabrication of microcapsules for applications such as drugs, electrophoretic inks, electrophoretic displays, intumescent fire-retardant coatings and self-healing materials. Social implications In self-healing coatings, healing agents which can be cured by UV irradiation or sunlight are envisaged attractive because they are catalyst-free, environmentally friendly and relatively inexpensive. PVP is an environmentally friendly emulsifier. The prepared microcapsules can be used in self-healing coatings to help in reducing maintenance costs for buildings and steel structures. Originality/value The novel aspect of this work is the development of a sunlight-curable silicone-based resin that was encapsulated in a MUF shell in the presence of PVP. A simple method was used to fabricate MUF microcapsules containing MAT-PDMS without the need to control pH during the reaction. Conventional methods for the preparation of amino resin microcapsules require an intensive and precise pH control to obtain favourable microcapsules. MAT-PDMS can be cured by sunlight and is catalyst-free, environmentally friendly and relatively inexpensive.
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Gurchumelia, Lali, Murman Tsarakhov, Tengiz Machaladze, Dali Dzanashvili, Feliks Bezhanov et Olga Chudakova. « PRODUCING OF NEW TYPES, FIRE-PROTECTIVE COATINGS BY THE USE OF HIGH DISPERSED COMPOSITE POWDERS OF LOCAL MINERAL RAW MATERIALS ». InterConf, 19 juin 2021, 315–25. http://dx.doi.org/10.51582/interconf.7-8.06.2021.033.
Texte intégralRésumé :
The aim of this research is the fabrication of new types, environmentally safe, highly efficient and inexpensive fire-protective coatings by the use of high-dispersed composite powders (with high inhibitory properties) of local mineral raw materials, which in fire-protective coatings will play the role as binders as well as efficient inert flame retardants. Fire-protective coating was prepared only by mechanical mixing of binders and fillers, does not require addition of expensive phosphorus and halogen-containing flame retardants. On the one hand it simplifies technological process of production of materials and on the other hand decreases price cost of fire-protective coatings. Polyurethane resins were selected as binders, popularity of which is due to low price and simple technological process of production, high performance properties and low combustion capacity (in comparison with binders, used in series). High-dispersed composite powders of local mineral raw materials: zeolites, perlites, dolomites and clay shales are used as fillers, which are characterized by high inhibition properties and fire-extinguishing ability. Thus, produced coatings will be environmentally safe and much cheaper compared to imported analogues. Due to their performance properties and fire resistance, they will fully meet the requirements set by the normative documentation for building materials. The performance properties of the obtained fire–protective coatings were determined by laboratory standard methods. Thermogravimetric analysis method allows us to study the thermal stability of the material and determine the relative combustion capacity of the material. The effectiveness of the obtained coating was evaluated by the determine the relative combustion capacity - Oxygen Index (OI) and by of studying combustibility of materials. In the course of studying combustibility of materials in an initial stage was established combustible group by the method of "fire tube”- ГОСТ 1708-71.
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Müller-Pabel, Michael, Daniel Wohlfahrt, Sirko Geller et Maik Gude. « Qualification of an Epoxy Resin System for Use in Secondarily Formable CFRP Rebars ». ESAFORM 2021, 1 avril 2021. http://dx.doi.org/10.25518/esaform21.4252.
Texte intégralRésumé :
The use of reinforcing bars has been known for more than 150 years in construction sector, in order to compensate the limited tensile strength of concrete. Steel is the most widespread and standardized rebar material. As industry targets a reduction of resource consumption and increased freedom of design, novel materials come into the scope of current research efforts. In this context, carbon fiber reinforced polymers (CFRP) have become a promising candidate for rebar materials as they offer excellent corrosion resistance and mechanical properties. Their use enables significant reduction of concrete cover in future buildings and cost-efficient maintenance of bridges. The resin system used for manufacturing of CFRP rebars dictates possible applications. Thermoplastic polymers offer the advantage of formability in a molten state. On the other hand, they provide limited heat and fire resistance, what hinders further industrialization. In contrast, thermosets deliver high mechanical and thermal properties due to their polymeric network structure. This is also the reason for their restricted formability after gelation has occurred. However, it is known that epoxy resins may sustain substantial plastic deformation when being deformed at elevated temperatures and in a partial cure state. In this work, a commercially available resin system is selected and qualified for potential use in thermoset-based CFRP rebars. Based on the resin characterization comprising reaction kinetics as well as tensile and compressive tests at partial cure, general guidelines and limits for secondary forming are derived. The feasibility is demonstrated by bending tests on CFRP stripes with varied fiber orientation.