Materials

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14 pages, 5419 KiB

Open AccessArticle

Thermochromism of Highly Luminescent Photopolymer Flexible Films Based On Eu (III) Salts Confined in Polysulfone

by Mani Outis, João Paulo Leal, Maria Helena Casimiro, Bernardo Monteiro and Cláudia Cristina Lage Pereira

Materials 2020, 13(23), 5394; https://doi.org/10.3390/ma13235394 - 27 Nov 2020

Cited by 2 | Viewed by 1660

Abstract

Here we discuss the influence of two different cations on the emissive properties of the highly emissive [Eu(fod)₄]⁻ anion. The studied Eu(III) salts were [C₁₆Pyr][Eu(fod)₄] (1), and the previously reported [Chol][Eu(fod)₄]. C [...] Read more.

Here we discuss the influence of two different cations on the emissive properties of the highly emissive [Eu(fod)₄]⁻ anion. The studied Eu(III) salts were [C₁₆Pyr][Eu(fod)₄] (1), and the previously reported [Chol][Eu(fod)₄]. C₁₆Pyr stands for N-cetylpyridinium, Chol for cholinium and fod for 1,1,1,2,2,3,3-heptafluoro-7,7-dimethyloctane-4,6-dionate. 1 is classified as ionic liquid, with melting point close to 60 °C, and presented a luminescence quantum yield of (ϕ) 100%. Ultrabright emissive photopolymers were obtained for the first time using polysulfone as the host matrix. The films were prepared with incorporation of 10% (w/w) of 1 and [Chol][Eu(fod)₄] in the polymeric matrix, which improved its thermal stability. Additionally, the luminescence of CholEu(fod)₄/PSU presented a strong temperature dependence with a ratiometric thermal behavior. Full article

(This article belongs to the Special Issue Functionalization, Characterization, and Applications of Polymeric and Hybrid Materials)

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13 pages, 3054 KiB

Open AccessArticle

Physical and Mechanical Behaviour of Sugarcane Bagasse Fibre-Reinforced Epoxy Bio-Composites

by Lalta Prasad, Shiv Kumar, Raj Vardhan Patel, Anshul Yadav, Virendra Kumar and Jerzy Winczek

Materials 2020, 13(23), 5387; https://doi.org/10.3390/ma13235387 - 27 Nov 2020

Cited by 36 | Viewed by 3721

Abstract

In this study, experiments are performed to study the physical and mechanical behaviour of chemically-treated sugarcane bagasse fibre-reinforced epoxy composite. The effect of alkali treatment, fibre varieties, and fibre lengths on physical and mechanical properties of the composites is studied. To study the [...] Read more.

In this study, experiments are performed to study the physical and mechanical behaviour of chemically-treated sugarcane bagasse fibre-reinforced epoxy composite. The effect of alkali treatment, fibre varieties, and fibre lengths on physical and mechanical properties of the composites is studied. To study the morphology of the fractured composites, scanning electron microscopy is performed over fractured composite surfaces. The study found that the variety and lengths of fibres significantly influence the physical and mechanical properties of the sugarcane bagasse-reinforced composites. From the wear study, it is found that the composite fabricated from smaller fibre lengths show low wear. The chemically-treated bagasse-reinforced composites fabricated in this study show good physical and mechanical properties and are, therefore, proposed for use in applications in place of conventional natural fibres. Full article

(This article belongs to the Special Issue Functionalization, Characterization, and Applications of Polymeric and Hybrid Materials)

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13 pages, 2560 KiB

Open AccessArticle

The Characteristics of Swelling Pressure for Superabsorbent Polymer and Soil Mixtures

by Jakub Misiewicz, Arkadiusz Głogowski, Krzysztof Lejcuś and Daria Marczak

Materials 2020, 13(22), 5071; https://doi.org/10.3390/ma13225071 - 10 Nov 2020

Cited by 11 | Viewed by 2195

Abstract

Superabsorbent polymers (SAPs) are used in agriculture and environmental engineering to increase soil water retention. Under such conditions, the swelling pressure of the SAP in soil affects water absorption by SAP, and soil structure. The paper presents the results of swelling pressure of [...] Read more.

Superabsorbent polymers (SAPs) are used in agriculture and environmental engineering to increase soil water retention. Under such conditions, the swelling pressure of the SAP in soil affects water absorption by SAP, and soil structure. The paper presents the results of swelling pressure of three cross-linked copolymers of acrylamide and potassium acrylate mixed at the ratios of 0.3%, 0.5% and 1.0% with coarse sand and loamy sand. The highest values of swelling pressure were obtained for the 1% proportion, for coarse sand (79.53 kPa) and loamy sand (78.23 kPa). The time required to reach 90% of swelling pressure for each type of SAP differs. Samples of coarse sand mixed with SAP K2 in all concentrations reached 90% of total swelling pressure in 100 min, while the loamy sand mixtures needed only about 60 min. The results were the basis for developing a model for swelling pressure of the superabsorbent and soil mixtures, which is a fully stochastic model. The conducted research demonstrated that the course of pressure increase depends on the available pore capacity and the grain size distribution of SAPs. The obtained results and the proposed model may be applied everywhere where mixtures of SAPs and soils are used to improve plant vegetation conditions. Full article

(This article belongs to the Special Issue Functionalization, Characterization, and Applications of Polymeric and Hybrid Materials)

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20 pages, 5825 KiB

Open AccessArticle

The Study of Structural, Impedance and Energy Storage Behavior of Plasticized PVA:MC Based Proton Conducting Polymer Blend Electrolytes

by Shujahadeen B. Aziz, Iver Brevik, M. A. Brza, A. S. F. M. Asnawi, Elham M. A. Dannoun, Y. M. Yusof, Rebar T. Abdulwahid, M. H. Hamsan, Muaffaq M. Nofal and M. F. Z. Kadir

Materials 2020, 13(21), 5030; https://doi.org/10.3390/ma13215030 - 7 Nov 2020

Cited by 10 | Viewed by 3016

Abstract

In this study, structural characterization, electrical properties and energy storage performance of plasticized polymer electrolytes based on polyvinyl alcohol/methylcellulose/ammonium thiocyanate (PVA/MC-NH₄SCN) were carried out. An X-ray diffraction (XRD) study displayed that the plasticized electrolyte system with the uppermost value of direct [...] Read more.

In this study, structural characterization, electrical properties and energy storage performance of plasticized polymer electrolytes based on polyvinyl alcohol/methylcellulose/ammonium thiocyanate (PVA/MC-NH₄SCN) were carried out. An X-ray diffraction (XRD) study displayed that the plasticized electrolyte system with the uppermost value of direct current (DC) ionic conductivity was the most amorphous system. The electrolyte in the present work realized an ionic conductivity of 2.903 × 10⁻³ Scm⁻¹ at room temperature. The main charge carrier in the electrolyte was found to be the ions with the ionic transference number (t_ion) of 0.912, compared to only 0.088 for the electronic transference number (t_elec). The electrochemical stability potential window of the electrolyte is 2.1 V. The specific capacitance was found to reduce from 102.88 F/g to 28.58 F/g as the scan rate increased in cyclic voltammetry (CV) analysis. The fabricated electrochemical double layer capacitor (EDLC) was stable up to 200 cycles with high efficiency. The specific capacitance obtained for the EDLC by using charge–discharge analysis was 132.7 F/g at the first cycle, which is slightly higher compared to the CV plot. The equivalent series resistance (ESR) increased from 58 to 171

Ω

throughout the cycles, which indicates a good electrolyte/electrode contact. Ions in the electrolyte were considered to have almost the same amount of energy during the conduction process as the energy density is approximately at 14.0 Wh/kg throughout the 200 cycles. The power density is stabilized at the range of 1444.3 to 467.6 W/kg as the EDLC completed the cycles. Full article

(This article belongs to the Special Issue Functionalization, Characterization, and Applications of Polymeric and Hybrid Materials)

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13 pages, 4590 KiB

Open AccessArticle

Effect of Halloysite Nanotube on Mechanical Properties, Thermal Stability and Morphology of Polypropylene and Polypropylene/Short Kenaf Fibers Hybrid Biocomposites

by Piotr Franciszczak, Iman Taraghi, Sandra Paszkiewicz, Maksymilian Burzyński, Agnieszka Meljon and Elżbieta Piesowicz

Materials 2020, 13(19), 4459; https://doi.org/10.3390/ma13194459 - 8 Oct 2020

Cited by 16 | Viewed by 2372

Abstract

In this article, the effect of the addition of halloysite nanotube (HNT) on the mechanical and thermal stability of polypropylene (PP) and PP/kenaf fiber biocomposites has been investigated. Different volume contents of HNTs ranging from 1 to 10 vol.% were melt mixed with [...] Read more.

In this article, the effect of the addition of halloysite nanotube (HNT) on the mechanical and thermal stability of polypropylene (PP) and PP/kenaf fiber biocomposites has been investigated. Different volume contents of HNTs ranging from 1 to 10 vol.% were melt mixed with PP and PP/kenaf fibers. The volume content of kenaf fibers was kept constant at 30%. The morphology of HNTs within the PP matrix has been studied via scanning electron microscopy (SEM). The morphological results revealed that HNT was uniformly dispersed in the PP matrix already at a low concentration of 1 and 2 vol.%. The mechanical properties of the manufactured nanocomposites and hybrid biocomposites such as Young’s modulus, tensile strength, elongation at break, flexural modulus, flexural strength, and notched Izod strength have been measured. The results show that Young’s modulus and strengths have been improved along with the addition of low content of HNTs. Moreover, the gain of notched Izod impact strength obtained by the addition of short kenaf fibers was maintained in hybrids with low concentrations of HNTs. Finally, the thermogravimetric analysis shows that at 10% and 50% weight loss, the thermal degradation rate of the PP and PP/kenaf biocomposites decreased by the addition of HNTs. Full article

(This article belongs to the Special Issue Functionalization, Characterization, and Applications of Polymeric and Hybrid Materials)

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17 pages, 6803 KiB

Open AccessArticle

Conductance Current and Space Charge Characteristics of SiO₂/MMT/LDPE Micro-Nano Composites

by Hongtao Jiang, Xiaohong Zhang, Junguo Gao and Ning Guo

Materials 2020, 13(18), 4119; https://doi.org/10.3390/ma13184119 - 16 Sep 2020

Cited by 6 | Viewed by 1775

Abstract

Low-density polyethylene (LDPE) is one of the most comprehensive products used as insulation materials in power equipment. How to improve its dielectric properties by doping inorganic particles in LDPE has always been the focus of many researchers. In this paper, silica (SiO₂ [...] Read more.

Low-density polyethylene (LDPE) is one of the most comprehensive products used as insulation materials in power equipment. How to improve its dielectric properties by doping inorganic particles in LDPE has always been the focus of many researchers. In this paper, silica (SiO₂) particles and montmorillonite (MMT) particles were added to LDPE, the order of adding particles was changed, and different micro-nano composites was made. The crystallization characteristics of composites were analyzed, the curves of the conductance current with the change of field intensity were analyzed, and the space charge distribution of each material were investigated. The results of crystallization show that the crystalline properties and crystallinity of the composites are higher than the matrix LDPE, the addition of SiO₂ particles increases the composites’ crystallinity significantly, and the intercellular spacing of micro-nano composites is the smallest among all materials. The curve of conductance current versus electric field intensity shows that the tightness of the crystal structure can effectively hinder the movement of the molecular chain, inhibit carrier migration, while shortening the free travel of electrons, thereby reducing the electric conduction current of the material. The experimental results of the space charge accumulation curve further show that the compact crystal structure of the material is beneficial to the dissipation of space charge in the dielectric. Full article

(This article belongs to the Special Issue Functionalization, Characterization, and Applications of Polymeric and Hybrid Materials)

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21 pages, 3505 KiB

Open AccessArticle

Water Interactions in Hybrid Polyacrylate-Silicate Hydrogel Systems

by Joanna Mastalska-Popławska, Agata Stempkowska, Iwona Habina-Skrzyniarz, Artur T. Krzyżak, Paweł Rutkowski, Piotr Izak, Jakub Rudny and Tomasz Gawenda

Materials 2020, 13(18), 4092; https://doi.org/10.3390/ma13184092 - 15 Sep 2020

Cited by 3 | Viewed by 2957

Abstract

Hybrid polyacrylate-silicate hydrogels were obtained in the presence of N,N′-methylenebisacrylamide (NNMBA) as the cross-linking monomer and sodium thiosulphate/potassium persulphate (NTS/KPS) as the redox initiators. The results of the tests allowed us to conclude that a hybrid structure with a polyacrylate [...] Read more.

Hybrid polyacrylate-silicate hydrogels were obtained in the presence of N,N′-methylenebisacrylamide (NNMBA) as the cross-linking monomer and sodium thiosulphate/potassium persulphate (NTS/KPS) as the redox initiators. The results of the tests allowed us to conclude that a hybrid structure with a polyacrylate scaffolding and a silicate matrix had been obtained. The results of the rheological analysis revealed that the hydrogel sample with a 1:7 mass ratio of sodium water glass to the sodium polyacrylate is characterized by the highest complex viscosity. Thermal analysis (Thermogravimetry/Differential Scanning Calorimetry (TG/DSC)) showed that water begins to evaporate at higher temperatures, from 120 °C to even 180 °C. These results were confirmed by mid-infrared spectroscopy (MIR) and nuclear magnetic resonance spectroscopy (NMR) analysis. Differences in the intensity of the peaks derived from water in the MIR spectra indicate that most of the water is bounded. In turn, NMR results showed that the mobility of water molecules decreases as the amount of sodium water glass in the mixture increases. Full article

(This article belongs to the Special Issue Functionalization, Characterization, and Applications of Polymeric and Hybrid Materials)

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15 pages, 3889 KiB

Open AccessArticle

Modification of Collagen/Gelatin/Hydroxyethyl Cellulose-Based Materials by Addition of Herbal Extract-Loaded Microspheres Made from Gellan Gum and Xanthan Gum

by Justyna Kozlowska, Weronika Prus-Walendziak, Natalia Stachowiak, Anna Bajek, Lukasz Kazmierski and Bartosz Tylkowski

Materials 2020, 13(16), 3507; https://doi.org/10.3390/ma13163507 - 8 Aug 2020

Cited by 16 | Viewed by 3637

Abstract

Because consumers are nowadays focused on their health and appearance, natural ingredients and their novel delivery systems are one of the most developing fields of pharmacy, medicine, and cosmetics. The main goal of this study was to design, prepare, and characterize composite materials [...] Read more.

Because consumers are nowadays focused on their health and appearance, natural ingredients and their novel delivery systems are one of the most developing fields of pharmacy, medicine, and cosmetics. The main goal of this study was to design, prepare, and characterize composite materials obtained by incorporation of microspheres into the porous polymer materials consisting of collagen, gelatin, and hydroxyethyl cellulose. Microspheres, based on gellan gum and xanthan gum with encapsulated Calendula officinalis flower extract, were produced by two methods: extrusion and emulsification. The release profile of the extract from both types of microspheres was compared. Then, obtained microparticles were incorporated into polymeric materials with a porous structure. This modification had an influence on porosity, density, swelling properties, mechanical properties, and stability of materials. Besides, in vitro tests were performed using mouse fibroblasts. Cell viability was assessed with the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. The obtained materials, especially with microspheres prepared by emulsion method, can be potentially helpful when designing cosmetic forms because they were made from safely for skin ingredients used in this industry and the herbal extract was successfully encapsulated into microparticles. Full article

(This article belongs to the Special Issue Functionalization, Characterization, and Applications of Polymeric and Hybrid Materials)

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11 pages, 1422 KiB

Open AccessArticle

Application of Polymer Inclusion Membranes Doped with Alkylimidazole to Separation of Silver and Zinc Ions from Model Solutions and after Battery Leaching

by Elzbieta Radzyminska-Lenarcik, Malgorzata Ulewicz and Ilona Pyszka

Materials 2020, 13(14), 3103; https://doi.org/10.3390/ma13143103 - 11 Jul 2020

Cited by 13 | Viewed by 2428

Abstract

New materials, such as polymer inclusion membranes, can be used for water and wastewater treatment. In this paper, the selective transport of silver(I) and zinc(II) ions from nitrate solutions through the polymer inclusion membranes (PIMs), which consist of cellulose triacetate as a polymeric [...] Read more.

New materials, such as polymer inclusion membranes, can be used for water and wastewater treatment. In this paper, the selective transport of silver(I) and zinc(II) ions from nitrate solutions through the polymer inclusion membranes (PIMs), which consist of cellulose triacetate as a polymeric support, o-nitrophenyl pentyl ether as a plasticizer, and either 1-hexylimidazole (1) or 1-hexyl-2-methylimidazole (2) as an ion carrier, is studied. Both Zn(II) and Ag(I) model solutions (C_M = 0.001 M, pH = 6.5), as well as the solutions after the leaching of a spent battery with a silver–zinc cell (silver-oxide battery), are tested. The results show that Zn(II) ions are effectively transported through PIMs containing either carrier, whereas Ag(I) is more easily transported through PIMs doped with (1). In the case of the leaching solution after 24 h transport, the recovery coefficients of Ag(I) and Zn(II) for PIMs doped with (1) are 86% and 90%, respectively, and for PIMs doped with (2), 47% and 94%, respectively. The influence of basicity and structure of carrier molecules on transport kinetics is discussed as well. PIMs are characterized by using an atomic force microscopy (AFM) technique. Full article

(This article belongs to the Special Issue Functionalization, Characterization, and Applications of Polymeric and Hybrid Materials)

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16 pages, 7290 KiB

Open AccessArticle

Introducing Fractal Dimension for Interlaminar Shear and Tensile Strength Assessment of Mechanically Interlocked Polymer–Metal Interfaces

by Erik Saborowski, Philipp Steinert, Axel Dittes, Thomas Lindner, Andreas Schubert and Thomas Lampke

Materials 2020, 13(9), 2171; https://doi.org/10.3390/ma13092171 - 8 May 2020

Cited by 15 | Viewed by 2967

Abstract

The interlaminar strength of mechanically interlocked polymer–metal interfaces is strongly dependent on the surface structure of the metal component. Therefore, this contribution assesses the suitability of the fractal dimension for quantification of the surface structure, as well as interlaminar strength prediction of aluminum/polyamide [...] Read more.

The interlaminar strength of mechanically interlocked polymer–metal interfaces is strongly dependent on the surface structure of the metal component. Therefore, this contribution assesses the suitability of the fractal dimension for quantification of the surface structure, as well as interlaminar strength prediction of aluminum/polyamide 6 polymer–metal hybrids. Seven different surface structures, manufactured by mechanical blasting, combined mechanical blasting and etching, thermal spraying, and laser ablation, are investigated. The experiments are carried out on a butt-bonded hollow cylinder testing method that allows shear and tensile strength determination with one specific specimen geometry. The fractal dimension of the metal surfaces is derived from cross-sectional images. For comparison, the surface roughness slope is determined and related to the interlaminar strength. Finally, a fracture analysis is conducted. For the investigated material combination, the experimental results indicate that the fractal dimension is an appropriate measure for predicting the interlaminar strength. Full article

(This article belongs to the Special Issue Functionalization, Characterization, and Applications of Polymeric and Hybrid Materials)

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15 pages, 4917 KiB

Open AccessArticle

Effect of the Morphology of Tungsten Oxide Embedded in Sodium Alginate/Polyvinylpyrrolidone Composite Beads on the Photocatalytic Degradation of Methylene Blue Dye Solution

by Eman M. Elsayed, Mohamed S. Elnouby, M. H. Gouda, Noha A. Elessawy and D. M. F. Santos

Materials 2020, 13(8), 1905; https://doi.org/10.3390/ma13081905 - 17 Apr 2020

Cited by 36 | Viewed by 3276

Abstract

Tungsten oxide nanostructures were modified by oxygen vacancies through hydrothermal treatment. Both the crystalline structure and morphological appearance were completely changed. Spherical WO₃·H₂O was prepared from tungstic acid solution by aging at room temperature, while rod-like WO₃·0.33H [...] Read more.

Tungsten oxide nanostructures were modified by oxygen vacancies through hydrothermal treatment. Both the crystalline structure and morphological appearance were completely changed. Spherical WO₃·H₂O was prepared from tungstic acid solution by aging at room temperature, while rod-like WO₃·0.33H₂O was prepared by hydrothermal treatment of tungstic acid solution at 120 °C. These structures embedded in sodium alginate (SA)/polyvinylpyrrolidone (PVP) were synthesized as novel porous beads by gelation method into calcium chloride solution. The performance of the prepared materials as photocatalysts is examined for methylene blue (MB) degradation in aqueous solutions. Different operation parameters affecting the dye degradation process, such as light intensity, illumination time, and photocatalyst dosage are investigated. Results revealed that the photocatalytic activity of novel nanocomposite changed with the change in WO₃ morphology. Namely, the beads with rod nanostructure of WO₃ have shown better effectiveness in MB removal than the beads containing WO₃ in spherical form. The maximum degradation efficiency was found to be 98% for WO₃ nanorods structure embedded beads, while the maximum removal of WO₃ nanospheres structure embedded beads was 91%. The cycling-ability and reuse results recommend both prepared structures to be used as effective tools for treating MB dye-contaminated wastewaters. The results show that the novel SA/PVP/WO₃ nanocomposite beads are eco-friendly nanocomposite materials that can be applied as photocatalysts for the degradation of cationic dyes in contaminated water. Full article

(This article belongs to the Special Issue Functionalization, Characterization, and Applications of Polymeric and Hybrid Materials)

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11 pages, 2909 KiB

Open AccessArticle

Study of Hybrid Nanoparticles Modified Epoxy Resin Used in Filament Winding Composite

by Chengrui Di, Junwei Yu, Baoming Wang, Alan Kin Tak Lau, Bo Zhu and Kun Qiao

Materials 2019, 12(23), 3853; https://doi.org/10.3390/ma12233853 - 22 Nov 2019

Cited by 11 | Viewed by 3690

Abstract

Hybrid nanoparticles modified bisphenol A type epoxy/acid anhydride resin system applicable for filament winding forming process was studied using elastic core-shell rubber (CSR) nanoparticles with a large particle size (nearly 100 nm) and rigid nano-SiO₂ particles with a small particle size (about [...] Read more.

Hybrid nanoparticles modified bisphenol A type epoxy/acid anhydride resin system applicable for filament winding forming process was studied using elastic core-shell rubber (CSR) nanoparticles with a large particle size (nearly 100 nm) and rigid nano-SiO₂ particles with a small particle size (about 16 nm). The formulation, process properties, mechanical properties, thermal properties and microstructure of modified resin and its wound composite were studied. The results suggested that at the content of 10 phr CSR and 2 phr nano-SiO₂, the resin system achieved optimum comprehensive performance. The viscosity of modified resin system was nearly 1000 mPa·s at 25 °C and service life was over 6 h. The resin tensile strength and modulus were 89 MPa and 3.5 GPa, while flexural strength and modulus reached 128 MPa and 3.2 GPa, respectively. The impact strength was 26.6 kJ·m⁻², and the glass transition temperature (Tg) reached 145.9 °C. Modified epoxy resin enhanced the mechanical properties of carbon fiber reinforced wound composite. The tensile strength, tensile modulus and interlaminar shear strength were enhanced by 14.0%, 4.56% and 18.9%, respectively, compared with a composite based on unmodified resin. The above test results and scanning electron microscopy (SEM) analysis suggest that the hybrid nanoparticles modified resin system was suitable for carbon fiber wet filament winding products. Full article

(This article belongs to the Special Issue Functionalization, Characterization, and Applications of Polymeric and Hybrid Materials)

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14 pages, 3753 KiB

Open AccessArticle

Penetration Behavior of High-Density Reactive Material Liner Shaped Charge

by Huanguo Guo, Jianwen Xie, Haifu Wang, Qingbo Yu and Yuanfeng Zheng

Materials 2019, 12(21), 3486; https://doi.org/10.3390/ma12213486 - 24 Oct 2019

Cited by 18 | Viewed by 4243

Abstract

The traditional polytetrafluoroethylene (PTFE)/Al reactive material liner shaped charge generally produces insufficient penetration depth, although it enlarges the penetration hole diameter by chemical energy release inside the penetration crater. As such, a novel high-density reactive material liner based on the PTFE matrix was [...] Read more.

The traditional polytetrafluoroethylene (PTFE)/Al reactive material liner shaped charge generally produces insufficient penetration depth, although it enlarges the penetration hole diameter by chemical energy release inside the penetration crater. As such, a novel high-density reactive material liner based on the PTFE matrix was fabricated, and the corresponding penetration performance was investigated. Firstly, the PTFE/W/Cu/Pb high-density reactive material liner was fabricated via a cold pressing/sintering process. Then, jet formation and penetration behaviors at different standoffs were studied by pulse X-ray and static experiments, respectively. The X-ray results showed that the PTFE/W/Cu/Pb high-density reactive material liner forms an excellent reactive jet penetrator, and the static experimental results demonstrated that the penetration depth of this high-density reactive jet increased firstly and then decreased by increasing the standoff. When the standoff was 1.5 CD (charge diameter), the penetration depth of this reactive jet reached 2.82 CD, which was significantly higher than that of the traditional PTFE/Al reactive jet. Moreover, compared with the conventional metal copper jet penetrating steel plates, the entrance hole diameter caused by this high-density reactive jet improved 29.2% at the same standoff. Lastly, the chemical reaction characteristics of PTFE/W/Cu/Pb reactive materials were analyzed, and a semi-empirical penetration model of the high-density reactive jet was established based on the quasi-steady ideal incompressible fluid dynamics theory. Full article

(This article belongs to the Special Issue Functionalization, Characterization, and Applications of Polymeric and Hybrid Materials)

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15 pages, 7704 KiB

Open AccessArticle

Evaluation of Nano-Mechanical Behavior on Flax Fiber Metal Laminates Using an Atomic Force Microscope

by Zehua Qu, Xiaoxia Pan, Xiaoyue Hu, Yichun Guo and Yiou Shen

Materials 2019, 12(20), 3363; https://doi.org/10.3390/ma12203363 - 15 Oct 2019

Cited by 7 | Viewed by 2063

Abstract

The application of plant fiber-reinforced composite (PFRC) is limited due to its relatively low mechanical properties. The hybridization of a thin metal layer with plant fiber into a fiber metal laminate can largely improve the mechanical performance and the brittle fracture behavior of [...] Read more.

The application of plant fiber-reinforced composite (PFRC) is limited due to its relatively low mechanical properties. The hybridization of a thin metal layer with plant fiber into a fiber metal laminate can largely improve the mechanical performance and the brittle fracture behavior of PFRC. However, both plant fiber and metal have difficulty bonding with the polymer matrix. In this paper, several different surface treatment methods were applied on Al alloy sheets, and the influence of surface treatments on the surface morphology and nano-mechanical properties of Al alloy were studied using an atomic force microscope (AFM). After the preparation of flax fiber–metal laminates (FFMLs) with a vacuum-assisted resin transfer molding (VARTM) technique, the nanomechanical properties of different modified FFMLs were also evaluated with an AFM. It was found that the surface treatment combination of the sulfuric acid-ferric sulfate-based treatment (P2 etching) and the silane coupling agent provided the best adhesion force and modulus for Al alloy sheets at nanoscale resolution, which contributed to the surface energy increasing and strong covalent bonds between metal and polymer matrix. The resulting manufactured FFMLs also exhibited the highest nano-mechanical properties due to the great improvement of interfacial properties between metal and matrix, which was caused by mechanical interlocking mechanism and covalent bonds between metal/fiber and resin. Macromechanical performance, including tensile and flexural properties of these modified FFMLs, was also investigated. Comparison of the modulus at the nanoscale and macroscale showed reasonable agreement, and it revealed the tough interlaminar mechanisms of these types of FFMLs. Full article

(This article belongs to the Special Issue Functionalization, Characterization, and Applications of Polymeric and Hybrid Materials)

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10 pages, 4226 KiB

Open AccessArticle

Electrical Resistance Prediction for Functionalized Multi-Walled Carbon Nanotubes/Epoxy Resin Composite Gasket under Thermal Creep Conditions

by Wenlong Wang, Xia Yue, He Huang, Chao Wang, Diwei Mo, Yuyan Wu, Qingchun Xu, Chao Zhou, Houyao Zhu and Chunliang Zhang

Materials 2019, 12(17), 2704; https://doi.org/10.3390/ma12172704 - 23 Aug 2019

Cited by 4 | Viewed by 2256

Abstract

Carbon nanotube-based conductive polymer composites (CPC) showed great potentials for self-sensing and in situ structural health monitoring systems. Prediction of the long-term performance for such materials would be a meaningful topic for engineering design. In this work, the changing behavior of the long-term [...] Read more.

Carbon nanotube-based conductive polymer composites (CPC) showed great potentials for self-sensing and in situ structural health monitoring systems. Prediction of the long-term performance for such materials would be a meaningful topic for engineering design. In this work, the changing behavior of the long-term resistance of a multi-walled carbon nanotubes/epoxy resin composite gasket was studied under different temperature and loading conditions. Glass transition strongly influenced the resistance behavior of the composite during the thermal creep process. Similar to classical Kelvin–Voigt creep model, a model considering both the destruction and recovery processes of the conductive network inside the CPC was established. The long-term resistance variation can be predicted based on the model, and the results provided here may serve as a useful guide for further design of smart engineering structural health monitoring systems. Full article

(This article belongs to the Special Issue Functionalization, Characterization, and Applications of Polymeric and Hybrid Materials)

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