| 1. |
- Alagumalai, Vasudevan, et al.
(författare)
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Impact response and damage tolerance of hybrid glass/kevlar-fibre epoxy structural composites
- 2021
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Ingår i: Polymers. - : MDPI. - 2073-4360. ; 13:16
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Tidskriftsartikel (refereegranskat)abstract
- The present study is aimed at investigating the effect of hybridisation on Kevlar/E-Glass based epoxy composite laminate structures. Composites with 4 mm thickness and 16 layers of fibre (14 layers of E-glass centred and 2 outer layers of Kevlar) were fabricated using compression moulding technique. The fibre orientation of the Kevlar layers had 3 variations (0, 45 and 60°), whereas the E-glass fibre layers were maintained at 0° orientation. Tensile, flexural, impact (Charpy and Izod), interlaminar shear strength and ballistic impact tests were conducted. The ballistic test was performed using a gas gun with spherical hard body projectiles at the projectile velocity of 170 m/s. The pre-and post-impact velocities of the projectiles were measured using a high-speed camera. The energy absorbed by the composite laminates was further reported during the ballistic test, and a computerised tomographic scan was used to analyse the impact damage. The composites with 45° fibre orientation of Kevlar fibres showed better tensile strength, flexural strength, Charpy impact strength, and energy absorption. The energy absorbed by the composites with 45° fibre orientation was 58.68 J, which was 14% and 22% higher than the 0° and 60° oriented composites. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.
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| 2. |
- Aminoroaya, Alireza, et al.
(författare)
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A review of dental composites : Challenges, chemistry aspects, filler influences, and future insights
- 2021
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Ingår i: Composites Part B. - : Elsevier. - 1359-8368 .- 1879-1069. ; 216
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Forskningsöversikt (refereegranskat)abstract
- Resin-based dental composites are promising tooth-resembling materials in restorative dentistry. The limited longevity of dental composite restorations due to the bulk/marginal fracture and secondary caries as well as possible health risks are the critical challenges faced by such materials. Therefore, developments of resin-based dental composites received considerable attention in academic researches for clinical applications. A comprehensive review of the recent developments in the scientific literature on resin-based dental composites is presented in this article. Firstly, in the article, the challenges in dental composites are introduced and then the chemical aspects of the systems are classified through a review of employed resins. Subsequently, the different characteristics related to the fillers employed for the development of the resin-based dental composites are described. Finally, conclusions are drawn and future insights are proposed. This article provides an insight that paves the way for tailoring and designing resin-based dental composites for clinical applications.
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| 3. |
- Babu, Karthik, et al.
(författare)
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Fire Behavior of 3D-Printed Polymeric Composites
- 2021
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Ingår i: Journal of materials engineering and performance (Print). - : Springer. - 1059-9495 .- 1544-1024. ; 30:7, s. 4745-4755
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Tidskriftsartikel (refereegranskat)abstract
- 3D printing or additive manufacturing (AM) is considered as a flexible manufacturing method with the potential for substantial innovations in fabricating geometrically complicated structured polymers, metals, and ceramics parts. Among them, polymeric composites show versatility for applications in various fields, such as constructions, microelectronics and biomedical. However, the poor resistance of these materials against fire must be considered due to their direct relation to human life conservation and safety. In this article, the recent advances in the fire behavior of 3D-printed polymeric composites are reviewed. The article describes the recently developed methods for improving the flame retardancy of 3D-printed polymeric composites. Consequently, the improvements in the fire behavior of 3D-printed polymeric materials through the change in formulation of the composites are discussed. The article is novel in the sense that it is one of the first studies to provide an overview regarding the flammability characteristics of 3D-printed polymeric materials, which will further incite research interests to render AM-based materials fire-resistant.
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| 4. |
- Capezza, Antonio Jose, et al.
(författare)
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Acylation of agricultural protein biomass yields biodegradable superabsorbent plastics
- 2021
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Ingår i: Communications Chemistry. - : Springer Nature. - 2399-3669. ; 4:1
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Tidskriftsartikel (refereegranskat)abstract
- Superabsorbent polymers (SAP) are a central component of hygiene and medical products requiring high liquid swelling, but these SAP are commonly derived from petroleum resources. Here, we show that sustainable and biodegradable SAP can be produced by acylation of the agricultural potato protein side-stream (PPC) with a non-toxic dianhydride (EDTAD). Treatment of the PPC yields a material with a water swelling capacity of ca. 2400%, which is ten times greater than the untreated PPC. Acylation was also performed on waste potato fruit juice (PFJ), i.e. before the industrial treatment to precipitate the PPC. The use of PFJ for the acylation implies a saving of 320 000 tons as CO2 in greenhouse gas emissions per year by avoiding the industrial drying of the PFJ to obtain the PPC. The acylated PPC shows biodegradation and resistance to mould growth. The possibilities to produce a biodegradable SAP from the PPC allows for future fabrication of environment-friendly and disposable daily-care products, e.g. diapers and sanitary pads.
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| 5. |
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| 6. |
- 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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| 7. |
- Ganesan, Velmurugan, et al.
(författare)
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Optimisation of Mechanical Properties in Saw-Dust/Woven-Jute Fibre/Polyester Structural Composites under Liquid Nitrogen Environment Using Response Surface Methodology
- 2021
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Ingår i: Polymers. - : MDPI. - 2073-4360. ; 13:15
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Tidskriftsartikel (refereegranskat)abstract
- Natural fibre-based composites are replacing traditional materials in a wide range of structural applications that are used in different environments. Natural fibres suffer from thermal shocks, which affects the use of these composites in cold environment. Considering these, a goal was set in the present research to investigate the impact of cryogenic conditions on natural fibre composites. Composites were developed using polyester as matrix and jute-fibre and waste Teak saw-dust as reinforcement and filler, respectively. The effects of six parameters, viz., density of saw-dust, weight ratio of saw-dust, grade of woven-jute, number of jute layers, duration of cryogenic treatment of composite and duration of alkaline treatment of fibres on the mechanical properties of the composite was evaluated with an objective to maximise hardness, tensile, impact and flexural strengths. Taguchi method was used to design the experiments and response-surface methodology was used to model, predict and plot interactive surface plots. Results indicated that the duration of cryogenic treatment had a significant effect on mechanical properties, which was better only up to 60 min. The models were found to be statistically significant. The study concluded that saw-dust of density 300 kg/m(3) used as a filler with a weight ratio of 13 wt.% and a reinforcement of a single layer of woven-jute-fibre mat of grade 250 gsm subjected to alkaline treatment for 4 h in a composite that has undergone 45 min of cryogenic treatment presented an improvement of 64% in impact strength, ca. 21% in flexural strength, ca. 158% in tensile strength and ca. 28% in hardness.
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| 8. |
- Gedde, Ulf W., et al.
(författare)
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Applied polymer science
- 2021. - 1
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Bok (övrigt vetenskapligt/konstnärligt)abstract
- This companion volume to "Fundamental Polymer Science" (Gedde and Hedenqvist, 2019) offers detailed insights from leading practitioners into experimental methods, simulation and modelling, mechanical and transport properties, processing, and sustainability issues. Separate chapters are devoted to thermal analysis, microscopy, spectroscopy, scattering methods, and chromatography. Special problems and pitfalls related to the study of polymers are addressed. Careful editing for consistency and cross-referencing among the chapters, high-quality graphics, worked-out examples, and numerous references to the specialist literature make "Applied Polymer Science" an essential reference for advanced students and practicing chemists, physicists, and engineers who want to solve problems with the use of polymeric materials.
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| 9. |
- Ghane, Nazanin, et al.
(författare)
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Regeneration of the peripheral nerve via multifunctional electrospun scaffolds
- 2021
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Ingår i: Journal of Biomedical Materials Research. Part A. - : John Wiley & Sons. - 1549-3296 .- 1552-4965. ; 109:4, s. 437-452
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Forskningsöversikt (refereegranskat)abstract
- Over the last two decades, electrospun scaffolds have proved to be advantageous in the field of nerve tissue regeneration by connecting the cavity among the proximal and distal nerve stumps growth cones and leading to functional recovery after injury. Multifunctional nanofibrous structure of these scaffolds provides enormous potential by combining the advantages of nano‐scale topography, and biological science. In these structures, selecting the appropriate materials, designing an optimized structure, modifying the surface to enhance biological functions and neurotrophic factors loading, and native cell‐like stem cells should be considered as the essential factors. In this systematic review paper, the fabrication methods for the preparation of aligned nanofibrous scaffolds in yarn or conduit architecture are reviewed. Subsequently, the utilized polymeric materials, including natural, synthetic and blend are presented. Finally, their surface modification techniques, as well as, the recent advances and outcomes of the scaffolds, both in vitro and in vivo, are reviewed and discussed.
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| 10. |
- Giorcelli, Mauro, et al.
(författare)
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A Review of Bio-Oil Production through Microwave-Assisted Pyrolysis
- 2021
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Ingår i: Processes. - : MDPI. - 2227-9717. ; 9:3
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Forskningsöversikt (refereegranskat)abstract
- The issue of sustainability is a growing concern and has led to many environmentally friendly chemical productions through a great intensification of the use of biomass conversion processes. Thermal conversion of biomass is one of the most attractive tools currently used, and pyrolytic treatments represent the most flexible approach to biomass conversion. In this scenario, microwave-assisted pyrolysis could be a solid choice for the production of multi-chemical mixtures known as bio-oils. Bio-oils could represent a promising new source of high-value species ranging from bioactive chemicals to green solvents. In this review, we have summarized the most recent developments regarding bio-oil production through microwave-induced pyrolytic degradation of biomasses.
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