Materials

Research

16 pages, 7993 KiB

Open AccessArticle

Electrospun Nanofibers Loaded with Marigold Extract Based on PVP/HPβCD and PCL/PVP Scaffolds for Wound Healing Applications

by Magdalena Paczkowska-Walendowska, Natalia Rosiak, Tomasz Plech, Tomasz M. Karpiński, Andrzej Miklaszewski, Katarzyna Witkowska, Maciej Jaskólski, Cansu Erdem and Judyta Cielecka-Piontek

Materials 2024, 17(8), 1736; https://doi.org/10.3390/ma17081736 - 10 Apr 2024

Viewed by 684

Abstract

Marigold flower is a traditionally used plant material topically applied on the skin due to its anti-inflammatory properties and antibacterial activity. This potential of action justifies the implementation of marigold extract in nanofiber scaffolds based on poly-vinylpyrrolidone/hydroxypropyl-β-cyclodextrin (PVP/HPβCD) and polycaprolactone/polyvinylpyrrolidone (PCL/PVP) obtained by [...] Read more.

Marigold flower is a traditionally used plant material topically applied on the skin due to its anti-inflammatory properties and antibacterial activity. This potential of action justifies the implementation of marigold extract in nanofiber scaffolds based on poly-vinylpyrrolidone/hydroxypropyl-β-cyclodextrin (PVP/HPβCD) and polycaprolactone/polyvinylpyrrolidone (PCL/PVP) obtained by electrospinning for wound treatment. Using SEM, the morphology of electrospun scaffolds showed a fiber diameter in the range of 298–527 nm, with a uniform and bead-free appearance. ATR-FTIR spectroscopy confirmed the presence of marigold extracts in nanofibrous scaffolds. The composition of the nanofibers can control the release; in the case of PVP/HPβCD, immediate release of 80% of chlorogenic acid (an analytical and functional marker for marigold extract) was achieved within 30 min, while in the case of PCL/PVP, the controlled release was achieved within 24 h (70% of chlorogenic acid). All systems showed weak antibacterial activity against skin and wound-infecting bacteria Staphylococcus aureus (MIC 100 mg/mL), and Pseudomonas aeruginosa (MIC 200 mg/mL) and yeasts Candida albicans (MIC 100 mg/mL). Analysis of the effect of different scaffold compositions of the obtained electrofibers showed that those based on PCL/PVP had better wound healing potential. The scratch was closed after 36 h, compared to the 48 h required for PVP/HPβCD. Overall, the study shows that scaffolds of PCL/PVP nanofibers loaded with classic marigold extract have the best potential as wound dressing materials because of their ability to selectively modulate inflammation (via inhibition of hyaluronidase enzyme) and supportive antimicrobial properties, thereby aiding in the early stages of wound healing and repair. Full article

(This article belongs to the Special Issue Structural Design and Analysis of Fiber Composites)

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14 pages, 6906 KiB

Open AccessArticle

Facile Synthesis of Ag-Doped Urchin-like MnO₂ on Carbon Cloth for Supercapacitors

by Yanqiu Feng, Henghui Qu, Yanxiang Wang, Lanzhong Wang, Yongbo Wang, Deli Yang, Bohan Ding, Yue Sun, Jinghe Guo and Shichao Dai

Materials 2024, 17(6), 1312; https://doi.org/10.3390/ma17061312 - 12 Mar 2024

Viewed by 572

Abstract

Based on MnO₂/carbon cloth (CC) composite materials, an Ag-doped MnO₂ nanowire, self-assembled, urchin-like structure was synthesized in situ on the surface of CC using a simple method, and a novel and efficient flexible electrode material for supercapacitors was developed. The [...] Read more.

Based on MnO₂/carbon cloth (CC) composite materials, an Ag-doped MnO₂ nanowire, self-assembled, urchin-like structure was synthesized in situ on the surface of CC using a simple method, and a novel and efficient flexible electrode material for supercapacitors was developed. The morphology, structure, elemental distribution, and pore distribution of the material were analyzed using SEM, TEM, XRD, XPS, and BET. The electrochemical performance was tested using cyclic voltammetry (CV) and galvanostatic charge/discharge (GCD). In the three-electrode system, GCD testing showed that the specific capacitance of the material reached 520.8 F/g at 0.5 A/g. After 2000 cycles at a current density of 1 A/g, the capacitance retention rate was 90.6%, demonstrating its enormous potential in the application of supercapacitor electrode materials. Full article

(This article belongs to the Special Issue Structural Design and Analysis of Fiber Composites)

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15 pages, 5704 KiB

Open AccessArticle

Cellulose/Polyhydroxybutyrate (PHB) Composites as a Sustainable Bio-Based Feedstock to 3D-Printing Applications

by Lucia D’Arienzo, Stefano Acierno, Antonella Patti and Luciano Di Maio

Materials 2024, 17(4), 916; https://doi.org/10.3390/ma17040916 - 16 Feb 2024

Viewed by 759

Abstract

In this work, we have studied the potential application for 3D-printing of a polymer made from combining a biodegradable and biocompatible polymer (i.e., polyhydroxybutyrate, PHB) with natural bio-based fiber (i.e., cellulose). To this end, a masterbatch at 15 wt.% in filler content was [...] Read more.

In this work, we have studied the potential application for 3D-printing of a polymer made from combining a biodegradable and biocompatible polymer (i.e., polyhydroxybutyrate, PHB) with natural bio-based fiber (i.e., cellulose). To this end, a masterbatch at 15 wt.% in filler content was prepared by melt-blending, and then this system was “diluted” with pure PHB in a second extrusion phase in order to produce filaments at 1.5 and 3 wt.% of cellulose. For comparison, a filament made of 100% virgin PHB pellets was prepared under the same conditions. All the systems were then processed in the 3D-printer apparatus, and specimens were mainly characterized by static (tensile and flexural testing) and dynamic mechanical analysis. Thermogravimetric analysis, differential scanning calorimetry, spectroscopic measurements, and morphological aspects of PHB polymer and composites were also discussed. The results showed a significant negative impact of the process on the mechanical properties of the basic PHB with a reduction in both tensile and flexural mechanical properties. The PHB–cellulose composites showed a good dispersion filler in the matrix but a poor interfacial adhesion between the two phases. Furthermore, the cellulose had no effect on the melting behavior and the crystallinity of the polymer. The addition of cellulose improved the thermal stability of the polymer and minimized the negative impact of extrusion. The mechanical performance of the composites was found to be higher compared to the corresponding (processed) polymer. Full article

(This article belongs to the Special Issue Structural Design and Analysis of Fiber Composites)

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17 pages, 4707 KiB

Open AccessArticle

Flow Front Monitoring in High-Pressure Resin Transfer Molding Using Phased Array Ultrasonic Testing to Optimize Mold Filling Simulations

by Linus Littner, Richard Protz, Eckart Kunze, Yannick Bernhardt, Marc Kreutzbruck and Maik Gude

Materials 2024, 17(1), 207; https://doi.org/10.3390/ma17010207 - 30 Dec 2023

Cited by 1 | Viewed by 589

Abstract

During the production of fiber-reinforced plastics using resin transfer molding (RTM), various characteristic defects and flaws can occur, such as fiber displacement and fiber waviness. Particularly in high-pressure RTM (HP-RTM), fiber misalignments are generated during infiltration by local peaks in the flow rate, [...] Read more.

During the production of fiber-reinforced plastics using resin transfer molding (RTM), various characteristic defects and flaws can occur, such as fiber displacement and fiber waviness. Particularly in high-pressure RTM (HP-RTM), fiber misalignments are generated during infiltration by local peaks in the flow rate, leading to a significant reduction in the mechanical properties. To minimize or avoid this effect, the manufacturing process must be well controlled. Simulative approaches allow for a basic design of the mold filling process; however, due to the high number of influencing variables, the real behavior cannot be exactly reproduced. The focus of this work is on flow front monitoring in an HP-RTM mold using phased array ultrasonic testing. By using an established non-destructive testing instrument, the effort required for integration into the manufacturing process can be significantly reduced. For this purpose, investigations were carried out during the production of test specimens composed of glass fiber-reinforced polyurethane resin. Specifically, a phased array ultrasonic probe was used to record individual line scans over the form filling time. Taking into account the specifications of the probe used in these experiments, an area of 48.45 mm was inspected with a spatial resolution of 0.85 mm derived from the pitch. Due to the aperture that had to be applied to improve the signal-to-noise ratio, an averaging of the measured values similar to a moving average over a window of 6.8 mm had to be considered. By varying the orientation of the phased array probe and therefore the orientation of the line scans, it is possible to determine the local flow velocities of the matrix system during mold filling. Furthermore, process simulation studies with locally varying fiber volume contents were carried out. Despite the locally limited measuring range of the monitoring method presented, conclusions about the global flow behavior in a large mold can be drawn by comparing the experimentally determined results with the process simulation studies. The agreement between the measurement and simulation was thus improved by around 70%. Full article

(This article belongs to the Special Issue Structural Design and Analysis of Fiber Composites)

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11 pages, 9734 KiB

Open AccessArticle

A Simplified Method for the Preparation of Highly Conductive and Flexible Silk Nanofibrils/MXene Membrane

by Bohan Ding, Chao Teng, Yanxiang Wang, Yongbo Wang, Haotian Jiang, Yue Sun, Jinghe Guo and Shichao Dai

Materials 2023, 16(21), 6960; https://doi.org/10.3390/ma16216960 - 30 Oct 2023

Viewed by 833

Abstract

Silk nanofibers (SNF) have great applications in high-performance functional nanocomposites due to their excellent mechanical properties, biocompatibility, and degradability. However, the preparation of SNF by traditional methods often requires the use of some environmentally harmful or toxic reagents, limiting its application in green [...] Read more.

Silk nanofibers (SNF) have great applications in high-performance functional nanocomposites due to their excellent mechanical properties, biocompatibility, and degradability. However, the preparation of SNF by traditional methods often requires the use of some environmentally harmful or toxic reagents, limiting its application in green chemistry. In this paper, we successfully prepared SNF using natural silk as raw material and solvent stripping technology by adjusting the solvent concentration and solution ratio (the diameter of about 120 nm). Using the above SNFs as raw materials, SNF membranes were prepared by vacuum filtration technology. In addition, we prepared an SNF/MXene nanocomposite material with excellent humidity sensitivity by simply coating MXene nanosheets with silk fibers. The conductivity of the material can approach 1400.6 S m⁻¹ with excellent mechanical strength (51.34 MPa). The SNF/MXene nanocomposite material with high mechanical properties, high conductivity, and green degradability can be potentially applied in the field of electromagnetic interference (EMI) shielding, providing a feasible approach for the development of functional nanocomposite materials. Full article

(This article belongs to the Special Issue Structural Design and Analysis of Fiber Composites)

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13 pages, 3950 KiB

Open AccessArticle

The Effect of Chemical and Thermal Treatment for Desizing on the Properties and Chemical Functional Groups of Carbon Fiber

by Kyungeun Kim, Minsu Kim, Gyungha Kim and Daeup Kim

Materials 2023, 16(20), 6732; https://doi.org/10.3390/ma16206732 - 17 Oct 2023

Viewed by 1153

Abstract

In this paper, in order to upcycle carbon fibers (CF), the changes in their mechanical and chemical properties in accordance with time and temperature were investigated, in addition to the oxygen functional group mechanism. When acetone as a chemical desizing agent was used, [...] Read more.

In this paper, in order to upcycle carbon fibers (CF), the changes in their mechanical and chemical properties in accordance with time and temperature were investigated, in addition to the oxygen functional group mechanism. When acetone as a chemical desizing agent was used, treatment with acetone for 0.5 h at 60 °C was the optimal condition for the complete removal of the sizing agent, and there was no deterioration in tensile strength. At 25 °C, the carbonyl group (C=O) and hydroxyl group (C-O) declined in comparison to commercial CF, but a novel lactone group (O=C-O) was created. At 60 °C, the oxygen present in the sizing agent was removed and C=O, C-O, and O=C-O decreased. On the contrary, in the case of thermal desizing in an inert gas nitrogen atmosphere, by increasing the temperature, functional groups combining carbon and oxygen were reduced, because nitrogen and oxygen atoms combined with C=O and C-O on the CF surface were eliminated in the form of CO, NO, CO₂, NO₂, and O₂. When desizing via chemical and thermal methods, the amount of functional groups combining carbon and oxygen on the CF surface decreased. Desizing was performed as a pretreatment for surface treatment, so the methods and conditions were different, and related research is insufficient. In this study, we attempted to derive the optimal conditions for desizing treatment by identifying the surface characteristics and mechanisms according to chemical and thermal desizing treatment methods. Full article

(This article belongs to the Special Issue Structural Design and Analysis of Fiber Composites)

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14 pages, 3197 KiB

Open AccessArticle

Study of the Effect of Carbon Black Filling on the Mechanical Behavior of Rubber Hyper-Elasticity

by Zepeng Wang, Xiulong Yao, Fangru Hu, Chuanxiang Ma, Xinyan Li, Zhanli Miao, Junping Song, Lianxiang Ma and Wei Li

Materials 2023, 16(19), 6561; https://doi.org/10.3390/ma16196561 - 5 Oct 2023

Viewed by 706

Abstract

We have particularly investigated the correlation law of the effect of different carbon black fillings on the hyper-elastic mechanical behavior of natural rubber by conducting uniaxial tensile tests over a wide range of deformations with different volume fractions of carbon black fillings (0%, [...] Read more.

We have particularly investigated the correlation law of the effect of different carbon black fillings on the hyper-elastic mechanical behavior of natural rubber by conducting uniaxial tensile tests over a wide range of deformations with different volume fractions of carbon black fillings (0%, 4.7%, 8.9%, 12.8%, 16.4%, 19.7%, 22.7% and 25.2%). The results show that the stress-strain curve for carbon black filled rubber increases with the amount of filling, meaning that the rubber gradually becomes “harder”. We explore the correlation between the carbon black filling volume and the parameters of the Yeoh constitutive model by examining the Yeoh constitutive model to characterize the hyper-elastic mechanical behavior of rubber with different carbon black fillings. A quantitative relationship between the material parameters and the carbon black filling volume in the Yeoh constitutive model is presented. A method for calculating the material parameters of the Yeoh constitutive model is developed, and it predicts the correlation between the hyper-elastic properties of rubber and the volume fraction of the carbon black filling. Full article

(This article belongs to the Special Issue Structural Design and Analysis of Fiber Composites)

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17 pages, 17065 KiB

Open AccessArticle

Damage Imaging Identification of Honeycomb Sandwich Structures Based on Lamb Waves

by Chenhui Su, Wenchao Zhang, Lihua Liang, Yuhang Zhang and Qingmei Sui

Materials 2023, 16(13), 4658; https://doi.org/10.3390/ma16134658 - 28 Jun 2023

Viewed by 1018

Abstract

In the field of structural health monitoring, Lamb Wave has become one of the most widely used inspection tools due to its advantages of wide detection range and high sensitivity. In this paper, a new damage detection method for honeycomb sandwich structures based [...] Read more.

In the field of structural health monitoring, Lamb Wave has become one of the most widely used inspection tools due to its advantages of wide detection range and high sensitivity. In this paper, a new damage detection method for honeycomb sandwich structures based on frequency spectrum and Lamb Wave Tomography is proposed. By means of simulation and experiment, a certain number of sensors were placed on the honeycomb sandwich plate to stimulate and receive the signals in both undamaged and damaged cases. By Lamb Wave Tomography, the differences of signals before and after damage were compared, and the damage indexes were calculated. Furthermore, the probability of each sensor path containing damage was analyzed, and the damage image was finally realized. The technology does not require analysis of the complex multimode propagation properties of Lamb Wave, nor does it require understanding and modeling of the properties of materials or structures. In both simulation and experiment, the localization errors of the damage conform to the detection requirements, thus verifying that the method has certain feasibility in damage detection. Full article

(This article belongs to the Special Issue Structural Design and Analysis of Fiber Composites)

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10 pages, 3304 KiB

Open AccessArticle

Study on the Influence of Delamination Damage on the Processing Quality of Composite Laminates

by Jiali Yu, Yimeng Shan, Yiming Zhao and Ran Mo

Materials 2022, 15(23), 8572; https://doi.org/10.3390/ma15238572 - 1 Dec 2022

Cited by 1 | Viewed by 1196

Abstract

Internal delamination damage in composite connection structures can occur in the process of the overloading of a high-speed bearing, with alternating force loads, high or low temperatures, and the humid or hot environment loads. Mechanical drilling and riveting are usually used at the [...] Read more.

Internal delamination damage in composite connection structures can occur in the process of the overloading of a high-speed bearing, with alternating force loads, high or low temperatures, and the humid or hot environment loads. Mechanical drilling and riveting are usually used at the delamination position and outside its envelope, to inhibit delamination expansion. However, delamination damage can change the structural stress state of the original structure. It is difficult to achieve a better inhibition effect using conventional drilling mechanisms and process methods with intact composite panels, and new damage forms can even be introduced into the drilling process due to unreasonable parameter settings. Therefore, this paper combined finite element simulation technology and experimental processing technology, to analyze the influence of different delamination dimensions and positions on processing quality. The results showed that the feed speed and rotating speed had significant effects on the axial force of composite laminates. In particular, in the case of a low speed and high feed, the axial force will increase significantly. Full article

(This article belongs to the Special Issue Structural Design and Analysis of Fiber Composites)

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