| 1. |
- Babu, Karthik, et al.
(författare)
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A Review on the Flammability Properties of Carbon-Based Polymeric Composites : State-of-the-Art and Future Trends
- 2020
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Ingår i: Polymers. - : MDPI. - 2073-4360. ; 12:7
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Forskningsöversikt (refereegranskat)abstract
- Carbon based fillers have attracted a great deal of interest in polymer composites because of their ability to beneficially alter properties at low filler concentration, good interfacial bonding with polymer, availability in different forms, etc. The property alteration of polymer composites makes them versatile for applications in various fields, such as constructions, microelectronics, biomedical, and so on. Devastations due to building fire stress the importance of flame-retardant polymer composites, since they are directly related to human life conservation and safety. Thus, in this review, the significance of carbon-based flame-retardants for polymers is introduced. The effects of a wide variety of carbon-based material addition (such as fullerene, CNTs, graphene, graphite, and so on) on reaction-to-fire of the polymer composites are reviewed and the focus is dedicated to biochar-based reinforcements for use in flame retardant polymer composites. Additionally, the most widely used flammability measuring techniques for polymeric composites are presented. Finally, the key factors and different methods that are used for property enhancement are concluded and the scope for future work is discussed.
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| 2. |
- Babu, NB Karthik, et al.
(författare)
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Self‐reinforced polymer composites: An opportunity to recycle plastic wastes and their future trends
- 2022
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Ingår i: Journal of Applied Polymer Science. - : John Wiley & Sons. - 0021-8995 .- 1097-4628. ; 139:46
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Forskningsöversikt (refereegranskat)abstract
- Polymers and their composites have played an important role in industrial development. Polymer composites are becoming much stronger and more competitive than other materials as a result of ongoing research and development. This was made possible by newly developed techniques that could alter the physical and chemical properties of constituents. One of them is the self-reinforcement technique, which allows for the fabrication of high-strength thermoplastic polymer composites with reserved degradability, which is not possible with glass fiber/carbon fiber reinforcement. A self-reinforced polymer composite is made of a single polymeric material, which serves as both the matrix and the reinforcement. This review article discusses the use of self-reinforcement in various polymers and its impact on mechanical, thermal, and fire properties. Furthermore, the effects of process parameters (such as temperature and time, an), reinforcement structure, and mechanical property variation on the structure of self-reinforced composites are reviewed and presented in detail. In addition, the effect of foreign filler addition (such as flame retardants, inorganic particles, natural fibers, etc.) on self-reinforced composites is highlighted. In the end, the need for future research and its scope is presented.
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| 3. |
- Birdsong, Björn K., et al.
(författare)
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Flexible and fire-retardant silica/cellulose aerogel using bacterial cellulose nanofibrils as template material
- 2024
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Ingår i: Materials Advances. - : Royal Society of Chemistry. - 2633-5409. ; 5:12, s. 5041-5051
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Tidskriftsartikel (refereegranskat)abstract
- This study explores the possibility of using various silsesquioxane precursors such as (3-aminopropyl) triethoxysilane (APTES), methyltrimethoxysilane (MTMS), and tetraethyl orthosilicate (TEOS) to produce silsesquioxane-bacterial cellulose nanofibre (bCNF) aerogels. Each precursor allowed to customize the aerogel properties, leading to unique properties suitable for various applications requiring lightweight insulative materials. When utilizing APTES as the silsesquioxane precursor, an aerogel capable of over 90% recovery after compression was formed, making them suitable for flexible applications. When MTMS was used as the precursor, the aerogel retained some compression recovery (80%) but had the added property of superhydrophobicity with a contact angle over 160° due to the presence of CH3 functional groups, enabling water-repellence. Finally, TEOS allowed for excellent thermal insulative properties with a low Peak Heat Release Rate (PHRR), making it a promising candidate for fire-resistant applications. The customization of these aerogel materials was attributed to a combination of the chemical composition of the silsesquioxane precursors and the morphology of the coated bacterial cellulose nanofibres (bCNF), such as CH3 groups found in MTMS enabled for superhydrophobicity. Differences in morphology, such as uniform and smooth silsesquioxane coatings when using APTES or a “pearl-necklace” morphology using TEOS, enabled either compression recovery and flexibility or low thermal conduction. This investigation of silsesquioxane-bCNF provides a good understanding of the importance of the choice of precursor effect on insulating aerogel properties.
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| 4. |
- Das, Oisik, et al.
(författare)
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Flammability and mechanical properties of biochars made in different pyrolysis reactors
- 2021
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Ingår i: Biomass and Bioenergy. - : Elsevier. - 0961-9534 .- 1873-2909. ; 152
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Tidskriftsartikel (refereegranskat)abstract
- The effect of pyrolysis reactors on the properties of biochars (with a focus on flammability and mechanical characteristics) were investigated by keeping factors such as feedstock, carbonisation temperature, heating rate and residence time constant. The reactors employed were hydrothermal, fixed-bed batch vertical and fixed-bed batch horizontal-tube reactors. The vertical and tube reactors, at the same temperature, produced biochars having comparable elemental carbon content, surface functionalities, thermal degradation pattern and peak heat release rates. The hydrothermal reactor, although, a low-temperature process, produced biochar with high fire resistance because the formed tarry volatiles sealed water inside the pores, which hindered combustion. However, the biochar from hydrothermal reactor had the lowest nanoindentation properties whereas the tube reactor-produced biochar at 300 °C had the highest nanoindentation-hardness (290 Megapascal) and modulus (ca. 4 Gigapascal) amongst the other tested samples. Based on the inherent flammability and mechanical properties of biochars, polymeric composites’ properties can be predicted that can include them as constituents.
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| 5. |
- Das, Oisik, et al.
(författare)
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Functionalised biochar in biocomposites: The effect of fire retardants, bioplastics and processing methods
- 2023
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Ingår i: Composites Part C: Open Access. - : Elsevier. - 2666-6820. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- Fire retardants, although can impart fire-safety in polymeric composites, are detrimental to the mechanical properties. Biochar can be used, in conjunction with fire retardants, to create a balance between fire-safety and mechanical performance. It is possible to thermally dope fire retardants into the pores of biochar to make it functionalised. Thus, the current work is intended in identifying a composite having the combination of the most desirable fire retardant, bioplastic, and a suitable processing method. A comparison was made between two fire retardants (lanosol and ammonium polyphosphate), bioplastics (wheat gluten and polyamide 11), and composite processing methods (compression and injection moulding). It was found that wheat gluten containing ammonium polyphosphate-doped biochar made by compression moulding had the best fire-safety properties with the lowest peak heat release rate (186 kW/m2), the highest fire performance index (0.6 m2s/kW), and the lowest fire growth index (1.6 kW/ms) with acceptable mechanical properties compared to the corresponding neat bioplastic. Thus, for gluten-based polymers, the use of ammonium polyphosphate thermally doped into biochar processed by compression moulding is recommended to both simultaneously improve fire-safety and conserve the mechanical strength of the resulting biocomposites.
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| 6. |
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| 7. |
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| 8. |
- Gawusu, Sidique, et al.
(författare)
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Exploring distributed energy generation for sustainable development : A data mining approach
- 2022
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Ingår i: Journal of Energy Storage. - : Elsevier. - 2352-152X .- 2352-1538. ; 48
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Forskningsöversikt (refereegranskat)abstract
- This study explores how data mining may be used to uncover patterns and trends in the area of distributed generation (DG). It employs the usage of the bibliometric approach. Bibliometric analysis is an increasingly common and rigorous approach for analysing huge datasets in the scientific community. It explains the evolution of a given discipline while highlighting new developments in the sector. To this purpose, this research examines the link between publishing patterns and the underlying technology trends and advances that influence these trends. Also included are key advances in the most recent findings in DG's research. The review finds that past research on system performance and optimization has built a solid conceptual framework for this research domain. The incorporation of new technologies, and the consideration of sustainability issues, are additional areas of concern. The overall strategy and methodologies utilized in this study may be applied to a wide range of research disciplines. Researchers will benefit from this study as a guide for future studies on DG integrating concerns.
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| 9. |
- Gawusu, Sidique, et al.
(författare)
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Spatial analysis and predictive modeling of energy poverty: insights for policy implementation
- 2024
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Ingår i: Environment, Development and Sustainability. - : Springer Nature. - 1387-585X .- 1573-2975.
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Tidskriftsartikel (refereegranskat)abstract
- Understanding and alleviating energy poverty is critical for sustainable development. This study harnesses a suite of Machine Learning (ML) algorithms to predict Multidimensional Energy Poverty Index (MEPI) and to highlight the spatial distribution of energy poverty. We assess the predictive accuracy of Random Forest (RF), Support Vector Machine (SVM), Artificial Neural Network (ANN), Multiple Linear Regression (MLR), and XGBoost models. The RF model outperforms others, achieving an R2 value of 0.92 and a Pearson Correlation Coefficient (PCC) of 0.97 on the testing dataset, indicative of a highly accurate prediction capability. XGBoost also demonstrates strong predictive power with corresponding values of 0.88 and 0.94, respectively. Our spatial analysis, revealing significant clustering of energy poverty with a Global Moran’s I value of 150.39, indicates that energy poverty is not only geographically concentrated but also intricately linked to socio-economic factors such as income levels, access to education, and nutritional status. These insights underscore the necessity of region-specific and socio-economically informed policy interventions. The results inform targeted interventions, particularly highlighting the critical roles of education and nutrition in mitigating energy poverty. The RF model’s accuracy rate of 92% on the testing set suggests that improvements in these sectors could significantly influence MEPI scores. The integration of ML and spatial analysis offers a nuanced and actionable understanding of energy poverty, paving the way for targeted, evidence-based policy formulation aimed at achieving SDG7: ensuring access to affordable, reliable, sustainable, and modern energy for all.
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| 10. |
- Jiang, Lin, et al.
(författare)
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Developing an artificial intelligent model for predicting combustion and flammability properties
- 2022
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Ingår i: Fire and Materials. - : John Wiley & Sons. - 0308-0501 .- 1099-1018. ; 46:5, s. 830-842
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Tidskriftsartikel (refereegranskat)abstract
- While there have been various attempts in establishing a model that can predict the flammability characteristics of polymers based on their molecular structure, artificial intelligence (AI) presents a promising alternative in tackling this pressing issue. Therefore, a novel approach of adopting AI methods, extreme learning machines (ELMs) and group method of data handling (GMDH) in estimating heat release capacity, total heat release and char yield from thermophysical properties of polymers were addressed. GMDH showed a clear indication of overfitting whereby the models generated excellent training results but could not provide similar performance during testing. The superior generalisation performance of ELM during testing makes it the standout method. ELM produced HRC predictions having R and RRMSE of 0.86 and 0.405 for training, 0.94 and 0.356 for testing. For THR estimates from ELM, the R and RRMSE scores were 0.9 and 0.195 for training, 0.93 and 0.131 for testing. While char yield ELM model generated 0.88 and 0.795 for training, 0.93 and 0.383 for testing. The potential of ELM was demonstrated as it estimated the flammability parameters of 105 polymers having little or no empirical test results.
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| 11. |
- Lin, Chia-Feng, et al.
(författare)
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Fire Retardancy and Leaching Resistance of Furfurylated Pine Wood (Pinus sylvestris L.) Treated with Guanyl-Urea Phosphate
- 2022
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Ingår i: Polymers. - : MDPI. - 2073-4360. ; 14:9
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Tidskriftsartikel (refereegranskat)abstract
- Guanyl-urea phosphate (GUP) was introduced into furfurylated wood in order to improve fire retardancy. Modified wood was produced via vacuum-pressure impregnation of the GUP–furfuryl alcohol (FA) aqueous solution, which was then polymerized at elevated temperature. The water leaching resistance of the treated wood was tested according to European standard EN 84, while the leached water was analyzed using ultra-performance liquid chromatography (UPLC) and inductively coupled plasma–sector field mass spectrometry (ICP-SFMS). This new type of furfurylated wood was further characterized in the laboratory by evaluating its morphology and elemental composition using optical microscopy and electron microscopy coupled with energy-dispersive X-ray spectrometry (SEM-EDX). The chemical functionality was detected using infrared spectroscopy (FTIR), and the fire resistance was tested using cone calorimetry. The dimensional stability was evaluated in wet–dry soaking cycle tests, along with the mechanical properties, such as the Brinell hardness and bending strength. The fire retardancy of the modified furfurylated wood indicated that the flammability of wood can be depressed to some extent by introducing GUP. This was reflected in an observed reduction in heat release rate (HRR2) from 454.8 to 264.9 kW/m2, without a reduction in the material properties. In addition, this leaching-resistant furfurylated wood exhibited higher fire retardancy compared to conventional furfurylated wood. A potential method for producing fire-retardant treated furfurylated wood stable to water exposure has been suggested.
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| 12. |
- Lin, Chia-Feng, et al.
(författare)
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High Leach-Resistant Fire-Retardant Modified Pine Wood (Pinus sylvestris L.) by In Situ Phosphorylation and Carbamylation
- 2023
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Ingår i: ACS Omega. - : American Chemical Society (ACS). - 2470-1343. ; 8:12, s. 11381-11396
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Tidskriftsartikel (refereegranskat)abstract
- The exterior application of fire-retardant (FR) timber necessitates it to have high durability because of the possibility to be exposed to rainfall. In this study, water-leaching resistance of FR wood has been imparted by grafting phosphate and carbamate groups of the water-soluble FR additives ammonium dihydrogen phosphate (ADP)/urea onto the hydroxyl groups of wood polymers via vacuum-pressure impregnation, followed by drying/heating in hot air. A darker and more reddish wood surface was observed after the modification. Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, solid-state 13C cross-polarization magic-angle-spinning nuclear magnetic resonance (13C CP-MAS NMR), and direct-excitation 31P MAS NMR suggested the formation of C–O–P covalent bonds and urethane chemical bridges. Scanning electron microscopy/energy-dispersive X-ray spectrometry suggested the diffusion of ADP/urea into the cell wall. The gas evolution analyzed by thermogravimetric analysis coupled with quadrupole mass spectrometry revealed a potential grafting reaction mechanism starting with the thermal decomposition of urea. Thermal behavior showed that the FR-modified wood lowered the main decomposition temperature and promoted the formation of char residues at elevated temperatures. The FR activity was preserved even after an extensive water-leaching test, confirmed by the limiting oxygen index (LOI) and cone calorimetry. The reduction of fire hazards was achieved through the increase of the LOI to above 80%, reduction of 30% of the peak heat release rate (pHRR2), reduction of smoke production, and a longer ignition time. The modulus of elasticity of FR-modified wood increased by 40% without significantly decreasing the modulus of rupture.
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| 13. |
- Lin, Chia-Feng, et al.
(författare)
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Phosphorylated and carbamylated Kraft lignin for improving fire- and biological-resistance of Scots pine wood
- 2024
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Ingår i: International Journal of Biological Macromolecules. - : Elsevier. - 0141-8130 .- 1879-0003.
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Tidskriftsartikel (refereegranskat)abstract
- In this study, Kraft lignin was modified by ammonium dihydrogen phosphate (ADP) and urea for achieving phosphorylation and carbamylation, aiming to protect wood against biological and fire attack. Scots pine (Pinus sylvestris L.) sapwood was impregnated with a water solution containing Kraft lignin, ADP, and urea, followed by heat treatment at 150 °C, resulting in changes in the properties of the Kraft lignin as well as the wood matrix. Infrared spectroscopy, 13C cross-polarisation magic-angle-spinning (MAS) nuclear magnetic resonance (NMR), and direct excitation single-pulse 31P MAS NMR analyses suggested the grafting reaction of phosphate and carbamylate groups onto the hydroxyl groups of Kraft lignin. Scanning electron microscopy with energy dispersive X-ray spectroscopy indicated that the condensed Kraft lignin filled the lumen as well as partially penetrating the wood cell wall. The modified Kraft lignin imparted fire-retardancy and increased char residue to the wood at elevated temperature, as confirmed by limiting oxygen index, microscale combustion calorimetry, and thermogravimetric analysis. The modified wood exhibited superior resistance against mold and decay fungi attack under laboratory conditions. The modified wood had a similar modulus of elasticity to the unmodified wood, while experiencing a reduction in the modulus of rupture.
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| 14. |
- Liu, Dongyun, et al.
(författare)
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Correlation between early- and later-age performance indices of early frost-damaged concrete
- 2022
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Ingår i: IABSE Symposium Prague 2022: Challenges for Existing and Oncoming Structures - Report, International Association for Bridge and Structural Engineering. - Zurich, Switzerland : International Association for Bridge and Structural Engineering. ; , s. 934-941
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Konferensbidrag (refereegranskat)abstract
- Freeze‐thaw cycles can lead to serious damage of early‐age concrete and influence its behaviour at later ages. In this study, the later‐age compressive strength, resistance to chloride penetration and resistance to freeze‐thaw of early frost‐damaged concrete were experimentally studied and the relationship between its early‐ (i.e., strength and resistivity) and later‐age (i.e., strength, chloride ion electric flux and freeze‐thaw durability factor) performance indices were analysed. Results show that the later‐age performance of the concrete subjected to freeze‐thaw cycles at early age was generally worse than that of the control samples, which had not undergone early frost damage. This was especially significant for the concrete subjected to freeze‐thaw cycles before the age of 24 h. The compressive strength after early frost action had a higher linear correlation with the later‐age indices of the concrete than the compressive strength before early frost action. Results also showed that the early‐age resistivity is a good indicator for the later‐age performance of early frost‐damaged concrete if the pre‐curing time before frosting is at least 24 h.
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| 15. |
- Liu, Hao, et al.
(författare)
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Insights into wood species and aging effects on pyrolysis characteristics and combustion model by multi kinetics methods and model constructions
- 2023
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Ingår i: Renewable energy. - : Elsevier Ltd. - 0960-1481 .- 1879-0682. ; 206, s. 784-794
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Tidskriftsartikel (refereegranskat)abstract
- Considering the extensive application of wood materials in the construction and manufacturing, waste wood has potential of converting into new natural energy sources. In this study, cypress, pine and fir woods commonly used in China, as well as old samples for above each species (more than 200 years old) have been used to study the aging and species effects on their thermal stability and combustion models. To obtain the kinetic triplets of the pyrolysis process, all samples have been heated in a nitrogen atmosphere with heating rates of 5, 10, 15, and 20 K min−1. The kinetics parameters of pyrolysis throughout the conversion process were then calculated using isoconversional method, Coats-Redfern (CR), and masterplots methods. The reconstructed theoretical models have been then adjusted using the accommodation functions. The results of this study contribute to an increased understanding of the fire mechanism of waste woods, and implications concerning to provide scientific theoretical guidance for its feasibility as a new energy fuel more efficiently.
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| 16. |
- Mani, Megavannan, et al.
(författare)
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Nano-enhanced epoxy sandwich composites: Investigating mechanical properties for future aircraft construction
- 2024
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Ingår i: Polymers for Advanced Technologies. - : John Wiley & Sons. - 1042-7147 .- 1099-1581. ; 35:6
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Tidskriftsartikel (refereegranskat)abstract
- The aviation sector is continually seeking ways to reduce the weight of aircraft structures without compromising their mechanical integrity. Lightweight materials, such as advanced epoxy sandwich composites with hybrid nanostructures, have the potential to significantly contribute to fuel efficiency, thereby addressing environmental concerns and operational costs. This research investigates the mechanical properties of hybrid sandwich polymer composites filled with silica nanoparticles (SNiPs). Epoxy isocyanate (PU) foam sandwich composites were fabricated with kevlar fiber, carbon fiber, and glass fiber, constructed by alternating inclined interply bidirectional fiber and foam layers. SNiPs were introduced into the composite system at varying percentages, such as 0, 2, 4, and 6 wt%. The study employs a systematic approach, incorporating experimental testing, to assess key mechanical parameters, including tensile strength, flexural strength, and shear strength. The test results indicate that the incorporation of SNiPs improved the mechanical properties of the composites, leading to enhanced strength, toughness, and modulus of elasticity. Incorporation of composite laminates with 4 wt% SiNPs resulted in improved three-point bending, tensile, shear, and torsional strengths, with maximum values of ca. 64, ca. 5, ca. 2 MPa, and ca. 22 Nm, respectively. The findings contribute to the ongoing pursuit of materials that can meet the stringent demands of modern aviation, ultimately paving the way for advancements in aircraft construction and design.
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| 17. |
- Mensah, Rhoda Afriyie, et al.
(författare)
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A review of sustainable and environment-friendly flame retardants used in plastics
- 2022
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Ingår i: Polymer testing. - : Elsevier. - 0142-9418 .- 1873-2348. ; 108
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Tidskriftsartikel (refereegranskat)abstract
- The progressive transition from conventional structural designs to lightweight and more complex structures has led to the increase in the quantity of plastic materials in buildings. However, plastics have a major flaw: their low fire performance characterised by shorter ignition times and higher heat release rates. This has necessitated the incorporation of flame retardants (FRs) in plastics. Nevertheless, not all FRs are environmentally safe, hence, there is an urgent need for the development of sustainable biobased FRs that reduce environmental footprints while simultaneously improving the fire performance of plastics. This article addresses the negative connotation of FRs and reviews the most extensively used biobased FRs in plastics, their preparation (synthesis) and mode of application, performance evaluation as well as the leaching of FRs, and environmental fate. Some interesting observations in the review are the reduction of ignition times of plastics by the addition of FRs due to the rapid volatilisation of samples. In addition, the leaching rate of FRs is found to be higher in finer particles (micro and nanoparticles) compared to larger-sized ones and has the potential to dissolve in humic matter hence endangering the lives of humans and animals.
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| 18. |
- Mensah, Rhoda Afriyie, et al.
(författare)
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Application of Adaptive Neuro-Fuzzy Inference System in Flammability Parameter Prediction
- 2020
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Ingår i: Polymers. - : MDPI. - 2073-4360. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- The fire behavior of materials is usually modeled on the basis of fire physics and material composition. However, significant strides have been made recently in applying soft computing methods such as artificial intelligence in flammability studies. In this paper, multiple linear regression (MLR) was employed to test the degree of non-linearities in flammability parameter modeling by assessing the linear relationship between sample mass, heating rate, heat release capacity (HRC) and total heat release (THR). Adaptive neuro-fuzzy inference system (ANFIS) was then adopted to predict the HRC and THR of the extruded polystyrene measured from microscale combustion calorimetry experiments. The ANFIS models presented excellent predictions, showing very low mean training and testing errors as well as reasonable agreements between experimental and predicted datasets. Hence, it can be inferred that ANFIS can handle the non-linearities in flammability modeling, making it apt as a modeling technique for accurate and effective flammability assessments.
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| 19. |
- Mensah, Rhoda Afriyie, et al.
(författare)
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Biochar-Added Cementitious Materials—A Review on Mechanical, Thermal, and Environmental Properties
- 2021
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Ingår i: Sustainability. - : MDPI. - 2071-1050. ; 13:16
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Forskningsöversikt (refereegranskat)abstract
- The enhanced carbon footprint of the construction sector has created the need for CO2 emission control and mitigation. CO2 emissions in the construction sector are influenced by a variety of factors, including raw material preparation, cement production, and, most notably, the construction process. Thus, using biobased constituents in cement could reduce CO2 emissions. However, biobased constituents can degrade and have a negative impact on cement performance. Recently, carbonised biomass known as biochar has been found to be an effective partial replacement for cement. Various studies have reported improved mechanical strength and thermal properties with the inclusion of biochar in concrete. To comprehend the properties of biochar-added cementitious materials, the properties of biochar and their effect on concrete need to be examined. This review provides a critical examination of the mechanical and thermal properties of biochar and biochar-added cementitious materials. The study also covers biochar’s life cycle assessment and economic benefits. Overall, the purpose of this review article is to provide a means for researchers in the relevant field to gain a deeper understanding of the innate properties of biochar imparted into biochar-added cementitious materials for property enhancement and reduction of CO2 emissions.
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| 20. |
- Mensah, Rhoda Afriyie, et al.
(författare)
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Fire behaviour of biochar-based cementitious composites
- 2024
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Ingår i: Composites Part C: Open Access. - : Elsevier. - 2666-6820. ; 14
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Tidskriftsartikel (refereegranskat)abstract
- The study aimed to test the hypothesis that biochar's unique properties, such as its microporous structure, can enhance concrete's resilience to high temperatures. Despite expectations of reduced crack formation and enhanced fire resistance, the experimental results revealed a limited impact on concrete's fire behaviour. The investigation involved the use of two biochar types, fine and coarse biochar as replacements for cement and aggregates, respectively. Fine biochar exhibited higher water absorption and Young's modulus than coarse biochar, but both resisted ignition at 35 kW/m2 radiative heat flux and had peak heat release rates below 40 kW/m2. Incorporating these biochars at varying weight percentages (10, 15, and 20 wt.%) into concrete led to a gradual decline in compressive and tensile strength due to reduced binding ability with increased biochar content. Exposure to 1000 °C compromised mechanical properties across all the samples. However, the biochar concrete maintained compressive strength (compared to the control) with up to 20 wt.% biochar as a fine aggregate substitute after exposure to 600 °C, and as a cement replacement after exposure to 200 °C. This substitution also yielded a significant reduction in CO2 emissions (50 % reduction as the biochar loading amount doubled) from concrete manufacturing, showcasing biochar's potential for sustainable construction practices. Despite not fully supporting the initial hypothesis, the study demonstrated biochar's viability in reducing carbon footprint while maintaining concrete strength under certain fire conditions.
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| 21. |
- Mensah, Rhoda Afriyie, et al.
(författare)
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Influence of biochar and flame retardant on mechanical, thermal, and flammability properties of wheat gluten composites
- 2022
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Ingår i: Composites Part C: Open Access. - : Elsevier. - 2666-6820. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- The use of environmentally friendly materials such as bio-sourced plastics is being driven by increased awareness of environmental issues caused by synthetic plastics. However, bio-sourced plastics have poor fire behaviour that limits their application. The addition of a flame retardant to these plastics is one effective way to increase the fire resistance property; however, the flame retardant should not interfere with the mechanical performance of the plastic. Most flame retardants act as stress concentration points, reducing tensile strength. Hence, to create a balance between tensile strength and fire resistance, biochar (to conserve strength) and lanosol (to improve fire resistance) were added to wheat gluten bioplastic in various ratios and the optimal ratio was identified. Wheat gluten composites were fabricated using compression moulding at four different concentrations of lanosol (2, 4, 6, and 8 wt.%) and biochar (2, 4, 6, and 8 wt.%). From the test results, the composite with 4 wt.% lanosol and 6 wt.% biochar exhibited a good balance between the mechanical and fire properties; it conserved the strength and improved the fire properties (39 % reduction in peak heat release rate).
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| 22. |
- Mensah, Rhoda Afriyie, et al.
(författare)
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The effect of infill density on the fire properties of polylactic acid 3D printed parts: A short communication
- 2022
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Ingår i: Polymer testing. - : Elsevier. - 0142-9418 .- 1873-2348. ; 111
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Tidskriftsartikel (refereegranskat)abstract
- The use of 3D printing technology for manufacturing construction materials is gaining popularity, however, only a few studies have reported the fire behavior of such parts. In this research, the fire properties of 3D printed polylactide acid (PLA) parts with varying infill densities along with the tensile properties were analysed. The results from the fire tests showed that increasing the infill density increased the fuel load, which sustained combustion. Hence, the peak heat release rate and total heat release increased with an increment in infill density percentage. It was also observed that the increasing infill density had no effect on the flammability rating of the parts due to the constant shell thickness used for all the parts. In addition, the tensile strength and ductility of the parts increased with density as a porous part is more susceptible to failure than a solid homogeneous part.
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| 23. |
- Paladugu, Sri Ram Murthy, et al.
(författare)
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A Comprehensive Review of Self-Healing Polymer, Metal, and Ceramic Matrix Composites and Their Modeling Aspects for Aerospace Applications
- 2022
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Ingår i: Materials. - : Mdpi. - 1996-1944. ; 15:23
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Forskningsöversikt (refereegranskat)abstract
- Composites can be divided into three groups based on their matrix materials, namely polymer, metal and ceramic. Composite materials fail due to micro cracks. Repairing is complex and almost impossible if cracks appear on the surface and interior, which minimizes reliability and material life. In order to save the material from failure and prolong its lifetime without compromising mechanical properties, self-healing is one of the emerging and best techniques. The studies to address the advantages and challenges of self-healing properties of different matrix materials are very limited; however, this review addresses all three different groups of composites. Self-healing composites are fabricated to heal cracks, prevent any obstructed failure, and improve the lifetime of structures. They can self-diagnose their structure after being affected by external forces and repair damages and cracks to a certain degree. This review aims to provide information on the recent developments and prospects of self-healing composites and their applications in various fields such as aerospace, automobiles etc. Fabrication and characterization techniques as well as intrinsic and extrinsic self-healing techniques are discussed based on the latest achievements, including microcapsule embedment, fibers embedment, and vascular networks self-healing.
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| 24. |
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| 25. |
- Perroud, Théo, et al.
(författare)
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Testing bioplastic containing functionalised biochar
- 2022
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Ingår i: Polymer testing. - : Elsevier. - 0142-9418 .- 1873-2348. ; 113
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Tidskriftsartikel (refereegranskat)abstract
- Although flame retardants are very effective in reducing the fire hazard of polymeric materials, their presence may be detrimental to mechanical strength. Hence, in order to have a holistic improvement of performance properties, a new approach has been developed wherein biochar is used to host a naturally-occurring flame retardant (lanosol). The issue of loss in mechanical strength of a polymer host is alleviated by the use of biochar. Three different doping procedures were investigated, namely, dry mixing, and chemical and thermal-based doping, to integrate lanosol into the biochar pores. The doped biochar was used to develop wheat gluten-based blends. The mechanical and flammability properties of the blends were assessed. It was found that thermal doping was the most effective in introducing significant amounts of lanosol particles inside the biochar pores. The bioplastic containing chemically, and thermally doped biochar had equal tensile strength (5.2 MPa), which was comparable to that of the unmodified material (5.4 MPa). The thermally doped biochar displayed the lowest cone calorimeter peak heat release rate (636 kW m−2) for combustion and the highest apparent activation energy (32.4 kJ mol−1) for decomposition. Thus, for flame retarding protein-based matrices, the use of additives thermally doped into biochar is recommended to both simultaneously improve fire-resistance and conserve mechanical strength.
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| 26. |
- Raja, Pradeep, et al.
(författare)
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A Review of Sustainable Bio-Based Insulation Materials for Energy-Efficient Buildings
- 2023
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Ingår i: Macromolecular materials and engineering. - : John Wiley and Sons Inc. - 1438-7492 .- 1439-2054. ; 308:10
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Forskningsöversikt (refereegranskat)abstract
- The surge towards a sustainable future in the construction industry requires the use of bio-based insulation materials as an alternative to conventional ones for improving energy efficiency in structures. In this article, the features of bio-based insulation materials, including their thermal conductivities, moisture buffering value, fire performance, and life cycle evaluations are examined. It is clear from the review that pre- and post-treatment of the bio-based materials used for insulation materials optimize their properties. The life cycle analysis reveals a significant reduction in global warming potential (GWP) compared to conventional foams. In addition, it is envisaged that producing bio-based insulation materials on a larger scale will further decrease the net GWP. The article, therefore, proposes the implementation of policies that will promote the commercialization of bio-based insulation materials.
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| 27. |
- Renner, Juliana Sally, et al.
(författare)
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Fire behavior of wood-based composite materials
- 2021
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Ingår i: Polymers. - : MDPI. - 2073-4360. ; 13:24
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Forskningsöversikt (refereegranskat)abstract
- Wood-based composites such as wood plastic composites (WPC) are emerging as a sustainable and excellent performance materials consisting of wood reinforced with polymer matrix with a variety of applications in construction industries. In this context, wood-based composite materials used in construction industries have witnessed a vigorous growth, leading to a great production activity. However, the main setbacks are their high flammability during fires. To address this issue, flame retardants are utilized to improve the performance of fire properties as well as the flame retardancy of WPC material. In this review, flame retardants employed during manufacturing process with their mechanical properties designed to achieve an enhanced flame retardancy were examined. The addition of flame retardants and manufacturing techniques applied were found to be an optimum condition to improve fire resistance and mechanical properties. The review focuses on the manufacturing techniques, applications, mechanical properties and flammability studies of wood fiber/flour polymer/plastics composites materials. Various flame retardant of WPCs and summary of future prospects were also highlighted.
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| 28. |
- Rezvani Ghomi, Erfan, et al.
(författare)
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The Flame Retardancy of Polyethylene Composites : From Fundamental Concepts to Nanocomposites
- 2020
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Ingår i: Molecules. - : MDPI. - 1431-5157 .- 1420-3049. ; 25:21
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Forskningsöversikt (refereegranskat)abstract
- Polyethylene (PE) is one the most used plastics worldwide for a wide range of applications due to its good mechanical and chemical resistance, low density, cost efficiency, ease of processability, non-reactivity, low toxicity, good electric insulation, and good functionality. However, its high flammability and rapid flame spread pose dangers for certain applications. Therefore, different flame-retardant (FR) additives are incorporated into PE to increase its flame retardancy. In this review article, research papers from the past 10 years on the flame retardancy of PE systems are comprehensively reviewed and classified based on the additive sources. The FR additives are classified in well-known FR families, including phosphorous, melamine, nitrogen, inorganic hydroxides, boron, and silicon. The mechanism of fire retardance in each family is pinpointed. In addition to the efficiency of each FR in increasing the flame retardancy, its impact on the mechanical properties of the PE system is also discussed. Most of the FRs can decrease the heat release rate (HRR) of the PE products and simultaneously maintains the mechanical properties in appropriate ratios. Based on the literature, inorganic hydroxide seems to be used more in PE systems compared to other families. Finally, the role of nanotechnology for more efficient FR-PE systems is discussed and recommendations are given on implementing strategies that could help incorporate flame retardancy in the circular economy model.
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| 29. |
- Rodrigues, Quentin, et al.
(författare)
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Using X-Ray Computed Tomography To Measure Fire Degradation Of A Timber Connection
- 2023
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Ingår i: World Conference on Timber Engineering (WCTE 2023). - Oslo : World Conference on Timber Engineering 2023 (WCTE 2023). ; , s. 1519-1525
-
Konferensbidrag (refereegranskat)abstract
- The charring behaviour of timber elements under fire is well understood, however, the effects of fire and heat on connections are not equally well known. Timber connections often use steel fasteners, like screws or angle brackets, which conduct heat much better than wood. Moreover, these fasteners lose their mechanical resistance and capacity under elevated temperatures. X-ray computed tomography (CT) can be used to reconstruct the internal structure of wood non-destructively. It should therefore be possible to use this technology to also study the progressive degradation due to fire of a timber connection. The goal of the present study is to investigate how CT can be used to analyse the degradation of a timber connection due to fire. Samples of Norway spruce with self-tapping screws were scanned before and after a fire exposure, and mechanical tests were performed. The results indicate that the degradation due to fire in a timber connection can be observed in CT scans, but that certain measures need to be taken to minimise the effects of image artefacts due to X-ray scattering and photon starvation.
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| 30. |
- Sanned, Ellinor, et al.
(författare)
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The curious case of the second/end peak in the heat release rate of wood: A cone calorimeter investigation
- 2023
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Ingår i: Fire and Materials. - : Wiley. - 0308-0501 .- 1099-1018. ; 47:4, s. 498-513
-
Tidskriftsartikel (refereegranskat)abstract
- The reasons behind the occurrence of a second/end peak heat release rate (PHRR) during wood combustion under radiative heating were determined. Effects of the type of rear material, wood thickness, char progression, and its microstructure, as well as moisture content/transport in spruce wood, were studied. Rear materials used were insulating Kaowool, conducting steel, and the same wood but physically separated from test specimen by aluminium foil. The intensity of the second/end PHRR with Kaowool was almost 50% more than that of the sample with steel. Thus, the second/end peak is governed by the boundary condition defined by the rear material, which determines the heat losses at the rear side of the specimen and consequently the temperature of the specimen. Higher specimen temperature enhances the pyrolysis rate, thereby causing the second/end PHRR. The appearance times and values of the second/end PHRR for 30, 20, and 10 mm wood were 1740 s/78 kWm−2, 685 s/134 kWm−2, and 450 s/160 kWm−2, respectively. Char progressed to the rear of the samples even with a thin (8 mm) conductive steel substrate. Cracks in char grew almost three times wider during the second/end PHRR compared to the sample with no second/end peak. Char cracking had no significance on the time of occurrence of the second/end PHRR but affected the overall heat release. High moisture content reduced the charring rate and delayed the time of occurrence of the second/end PHRR as more water was needed to undergo a phase change, requiring a higher amount of energy.
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| 31. |
- Shankar, Adith Narayan, et al.
(författare)
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Microscale combustion calorimetry assessment of green composites made with chicken feather-modified soy protein resins and jute fabric
- 2023
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Ingår i: Composites Part C: Open Access. - : Elsevier B.V.. - 2666-6820. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- Biodegradable, and sustainably produced, ‘green’ plastics are actively being researched to replace conventional, environmentally harmful petroleum-based plastics. However, before these green plastics get adopted, they must match the properties of their conventional counterparts. In many applications, fire-safety can be a key parameter where naturally derived green materials could potentially outcompete petroleum-based plastics. In the present research, green resins and composites were fabricated using soy protein isolate (SPI), waste chicken feather fibers (CFF), jute fabric (JF), and glutaraldehyde (GA), and evaluated for their critical fire-safety parameters through Microscale Cone Calorimetry (MCC) characterization. The loading of CFF from 0 to 30 wt% increased the specific peak heat release rate (pHRR) from 101 to 120 W/g for CFF/SPI resins without GA and from 94.5 to 114 W/g for GA crosslinked CFF/SPI resins. GA was thus shown to improve fire-safety for CFF/SPI resins. However, for JF/(CFF/SPI) composites, CFF did not show a proportional relationship with fire-safety. Rather, at 20 wt% CFF, the pHRR was minimized to 81.1 W/g for JF/(CFF/SPI) composites without GA and to 86.0 W/g for GA-crosslinked JF/(CFF/SPI) composites. This demonstrated that the addition of JF improved fire-safety despite its known combustibility, and even removed the need of the toxic crosslinker GA. Results also indicated that all variations of the fabricated CFF/SPI resins and JF/(CFF/SPI) composites had lower specific pHRR than typical petroleum-based plastics, clearly demonstrating the benefits of switching to SPI based green resins and composites. These green composites would be suitable for many applications including housing and transportation where fire-safety can be critical.
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| 32. |
- Shanmugam, Vigneshwaran, et al.
(författare)
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A Review of the Synthesis, Properties, and Applications of 2D Materials
- 2022
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Ingår i: Particle & particle systems characterization. - : John Wiley & Sons. - 0934-0866 .- 1521-4117. ; 39:6
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Forskningsöversikt (refereegranskat)abstract
- In the modern age of nanotechnology, the discovery of graphene has opened up the way to study and develop of several novel 2D materials. The unique physical and chemical properties of 2D materials have enhanced their research, making them superior to the commercial bulk materials used in various applications. Efforts have been made in the current study to present an overview of the intrinsic properties of these materials. Furthermore, synthesis and applications are also reviewed and discussed. Finally, the future outlook of 2D materials is discussed to enhance the research and performance of these materials, which can result in broader applications benefitting the electrical and electronics industries and society. Intensive research into 2D materials is expected to lead to the discovery of new materials with enhanced properties that will benefit the industry and society at large.
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| 33. |
- Shanmugam, Vigneshwaran, et al.
(författare)
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A Review on Combustion and Mechanical Behaviour of Pyrolysis Biochar
- 2022
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Ingår i: Materials Today Communications. - : Elsevier. - 2352-4928. ; 31
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Forskningsöversikt (refereegranskat)abstract
- Biochar has unique physical and chemical properties, making it a viable and sustainable future generation material for a variety of applications. The applications include power generation, composite production, construction (as a reinforcement), and soil amendment. The inherent good mechanical and combustion (or fire) resistance properties of biochar are attractive, however, there are limited reports, despite its effects on bulk material properties being well-documented. Comprehending these innate properties of biochar is critical for tailoring the mechanical and fire properties of biochar-based materials and structures. Therefore, an attempt has been made in this article to garner and analyse literatures reported on the mechanical and combustion properties of biochar without being integrated with a material or structural system (e.g. composite). Biochar produced at high pyrolysis temperatures (>500 ℃) showed high fire resistance property, because of the absence of the volatile matters and development of strong C-C covalent bonds. The mechanical and combustion properties of biocharcan be controlled by varying the biochar size, porus nature, and pyrolysis temperature. The information presented in this article is crucial and can be used as a guide to develop biochar-based materials and structures for mechanical and fire resistance applications.
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| 34. |
- Shanmugam, Vigneshwaran, et al.
(författare)
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Circular economy in biocomposite development : State-of-the-art, challenges and emerging trends
- 2021
-
Ingår i: Composites Part C: Open Access. - : Elsevier. - 2666-6820. ; 5
-
Forskningsöversikt (refereegranskat)abstract
- Biocomposites being environmentally-friendly alternative to synthetic composites are gaining increasing demand for various applications. Hence, biocomposite development should be integrated within a circular economy (CE) model to ensure a sustainable production that is simultaneously innocuous towards the environment. This review presents an overview of the state-of-the-art technologies for the adoption of the CE concept in biocomposite development. The study outlined the properties, environmental and economic impacts of biocomposites. A critical review of the life-cycle assessment of biocomposite for evaluating greenhouse gas emissions and carbon footprints was conducted. In addition, the opportunities and challenges pertaining to the implementation of CE have been discussed in detail. Recycling and utilisation of bio-based constituents were identified as the critical factors in embracing CE. Therefore, the development of innovative recycling technologies and an enhanced use of novel biocomposite constituents could lead to a reduction in material waste and environmental footprints. This article is one of the first studies to review the circularity of biocomposites in detail that will stimulate further research in enhancing the sustainability of these polymeric materials.
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| 35. |
- Shanmugam, Vigneshwaran, et al.
(författare)
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Introduction to lightweight materials
- 2022. - 1
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Ingår i: Materials for Lightweight Constructions. - Boca Raton : CRC Press. - 9781003252108 ; , s. 1-15
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 36. |
- Shanmugam, Vigneshwaran, et al.
(författare)
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The thermal properties of FDM printed polymeric materials: A review
- 2024
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Ingår i: Polymer degradation and stability. - : Elsevier Ltd. - 0141-3910 .- 1873-2321. ; 228
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Forskningsöversikt (refereegranskat)abstract
- Fused Deposition Modelling (FDM), a prevalent additive manufacturing technique utilising polymeric materials, facilitates intricate geometric customisation and rapid prototyping. The ongoing development of FDM technology emphasises the importance of the thermal characteristics of FDM-printed polymeric materials, which are essential for various applications, including aerospace and biomedical engineering. The thermal properties of FDM-printed polymeric materials, covering a wide range of thermoplastic polymers and composites, were examined in this review. Despite the versatility of FDM technology, thermal challenges persist in 3D printed parts, manifesting as anisotropy, voids, and sub-optimal conductivity, thereby impeding performance. Achieving precise control over printing parameters such as nozzle temperature, layer height, and speed is pivotal for optimising thermal properties. Additionally, controlled thermal treatments, like annealing, offer avenues for manipulating the crystalline structure of printed components to enhance the thermal conductivity. By elucidating the effects of reinforcements, this article aims to provide insights into potential enhancements and adjustments for developing thermally resistant FDM-based polymeric materials.
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| 37. |
- Vijaybabu, T. R., et al.
(författare)
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High Thermal Conductivity Polymer Composites Fabrication through Conventional and 3D Printing Processes: State-of-the-Art and Future Trends
- 2023
-
Ingår i: Macromolecular materials and engineering. - : John Wiley & Sons. - 1438-7492 .- 1439-2054. ; 308:7
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Forskningsöversikt (refereegranskat)abstract
- The lifespan and the performance of flexible electronic devices and components are affected by the large accumulation of heat, and this problem must be addressed by thermally conductive polymer composite films. Therefore, the need for the development of high thermal conductivity nanocomposites has a strong role in various applications. In this article, the effect of different particle reinforcements such as single and hybrid form, coated and uncoated particles, and chemically treated particles on the thermal conductivity of various polymers are reviewed and the mechanism behind the improvement of the required properties are discussed. Furthermore, the role of manufacturing processes such as injection molding, compression molding, and 3D printing techniques in the production of high thermal conductivity polymer composites is detailed. Finally, the potential for future research is discussed, which can help researchers to work on the thermal properties enhancement for polymeric materials.
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| 38. |
- Wang, Dong, et al.
(författare)
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Optimized fire resistance of alkali-activated high-performance concrete by steel fiber
- 2024
-
Ingår i: Journal of thermal analysis and calorimetry (Print). - : Springer Nature. - 1388-6150 .- 1588-2926.
-
Tidskriftsartikel (refereegranskat)abstract
- The behavior of alkali-activated ultra-high-performance concrete (A-UHPC) at elevated temperatures is unknown. This study addresses this gap by investigating the behavior of A-UHPC under varying temperatures with steel fiber additions (1%, 2%, and 3%), and considering target temperatures (20 °C, 200 °C, 400 °C, 600 °C, and 800 °C) as design variables. As the results, A-UHPC with steel fibers showed improved fire resistance, suffering less compressive strength loss at 800 °C than fiber-free A-UHPC. High temperatures initially optimized A-UHPC’s microstructure at 200 °C but later caused damage through microstructure propagation. Steel fibers enhanced A-UHPC’s ductility, resulting in ductile failure even at 800 °C. A-UHPC exhibited a unique mechanical degradation pattern under elevated temperatures, distinct from ordinary cement-based concrete. Empirical models accurately predicted its behavior, offering valuable insights for engineers dealing with heavy loads and high temperatures.
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| 39. |
- Xiao, Jie, et al.
(författare)
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Ablation behavior studies of charring materials with different thickness and heat flux intensity
- 2021
-
Ingår i: Case Studies in Thermal Engineering. - : Elsevier. - 2214-157X. ; 23
-
Tidskriftsartikel (refereegranskat)abstract
- Surface ablation and in-depth temperature distribution of the charring material are the key properties of the thermal protection system in re-entry vehicles subjected to aerodynamic heating. To investigate the factors affecting the ablation performance of charring materials, the influence of decomposition reaction and surface recession on ablation was added to the heat conduction and surface energy balance equation, to comprehend the phenomenon of surface material removal. The model developed in this study was verified by comparing with results from traditional finite difference method. Furthermore, the effects of external constant heat flux, initial material thickness, and heating time on ablation were determined and discussed on temperature, surface recession, and density distribution. The change trend of the external heat flux significantly affects the change trend of the surface temperature. The material thickness and heating time have great influence on the bottom temperature. This paper contributes to the understanding of the heat transfer and ablation of the charring materials, thereby providing a basis for the selection of the thermal protection material for re-entry vehicles.
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| 40. |
- Xu, Qiang, et al.
(författare)
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Wood Dust Flammability Analysis by Microscale Combustion Calorimetry
- 2022
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Ingår i: Polymers. - : MDPI. - 2073-4360. ; 14:1
-
Tidskriftsartikel (refereegranskat)abstract
- To study the practicability of a micro combustion calorimeter to analyze the calorimetry kinetics of wood, a micro combustion calorimeter with 13 heating rates from 0.1 to 5.5 K/s was used to perform the analysis of 10 kinds of common hardwood and softwood samples. As a microscale combustion measurement method, MCC (microscale combustion calorimetry) can be used to judge the flammability of materials. However, there are two methods for measuring MCC: Method A and Method B. However, there is no uniform standard for the application of combustible MCC methods. In this study, the two MCC standard measurement Methods A and B were employed to check their practicability. With Method A, the maximum specific heat release rate, heat release temperature, and specific heat release of the samples were obtained at different heating rates, while for Method B, the maximum specific combustion rate, combustion temperature and net calorific values of the samples were obtained at different heating rates. The ignition capacity and heat release capacity were then derived and evaluated for all the common hardwood and softwood samples. The results obtained by the two methods have significant differences in the shape of the specific heat release rate curves and the amplitude of the characteristic parameters, which lead to the differences of the derived parameters. A comparison of the specific heat release and the net calorific heat of combustion with the gross caloric values and heating values obtained by bomb calorimetry was also made. The results show that Method B has the potentiality to evaluate the amount of combustion heat release of materials.
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| 41. |
- Zhao, Shu-Na, et al.
(författare)
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Insights into thermochemistry, kinetics, and pyrolysis behavior of green gas generator 5- aminotetrazole by experiment and theoretical methods
- 2023
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Ingår i: Case Studies in Thermal Engineering. - : Elsevier Ltd. - 2214-157X. ; 49
-
Tidskriftsartikel (refereegranskat)abstract
- Green gas generator 5-aminotetrazole(5-AT) has been widely used as a kind of energetic material with excellent properties, and it is crucial to understand its pyrolysis process and mechanism. The present study comprehensively investigated the thermochemistry, kinetics, and pyrolysis mechanism of green gas generator 5-AT, using a combination of experimental analysis and theoretical calculation. Thermogravimetric analysis (TGA) and fourier transform infrared spectroscopy (FTIR) were used to investigate the pyrolysis behavior of 5AT and energy barriers of transition states for different pyrolysis paths of three isomers of 5AT were also calculated at a high and reliable level of theory CCSD(T)/cc-pvtz. The results showed that the pyrolysis of 5-AT had five reaction stages and kinetic parameters in each stage were determined by Kissinger method and Criado method. Furthermore, the elimination of N2 from the tetrazole ring occurred before that of HN3, and N2 elimination had lower energy than HN3 elimination for 1-hydrogen-5-aminotetrazole and 2-hydrogen-5-aminotetrazole, but HN3 elimination had lower energy for 5-iminotetrazole. The results of the study provide useful insights into the pyrolysis mechanism and kinetics of 5-AT and could contribute to its efficient utilization in various applications.
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| 42. |
- Öhrn, Olina, et al.
(författare)
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Surface coated ZnO powder as flame retardant for wood: A short communication
- 2023
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Ingår i: Science of the Total Environment. - : Elsevier B.V.. - 0048-9697 .- 1879-1026. ; 897
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Tidskriftsartikel (refereegranskat)abstract
- In the present study, the ability of a coating of zinc oxide (ZnO) powder to improve the fire-safety of wood exposed to radiative heat flux was examined, focusing on the ignition time of the wood. To test ZnO's efficiency on the wood substrate, two different amounts of ZnO (0.5 and 1 g ZnO per dm2) were applied to the wood surface and exposed to radiative heat from a cone calorimeter wherein a pristine piece of wood with no ZnO treatment was taken as control. The experiments were conducted at three different irradiation levels i.e., 20, 35, and 50 kWm−2. The results showed that applying ZnO on the surface of the wood significantly increased the ignition time (TTI). For the three different heat fluxes, using 0.5 g ZnO per dm2 coating on the wood surface increased the TTI by 26–33 %. Furthermore, the application of 1 g of ZnO per dm2 generated a TTI increment of 37–40 %. All three irradiation levels showed similar trends in TTI. The micrographs taken before and after combustion showed no significant disparity in the morphology of ZnO. The agglomerated ZnO particles on the wood surface remained intact after combustion. This study demonstrates a facile method of using ZnO to delay the ignition of wood. This could potentially impart fire-safety to wooden structures/façades in wildland-urban interfaces and elsewhere by reducing flame spread.
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