Functional Composite Materials最新文献

In the production of polymeric drug delivery devices, dissolution profile and mechanical properties of the drug loaded polymeric matrix are considered important Critical Quality Attributes (CQA) for quality assurance. However, currently the industry relies on offline testing methods which are destructive, slow, labour intensive, and costly. In this work, a real-time method for predicting these CQAs in a Hot Melt Extrusion (HME) process is explored using in-line NIR and temperature sensors together with Machine Learning (ML) algorithms. The mechanical and drug dissolution properties were found to vary significantly with changes in processing conditions, highlighting that real-time methods to accurately predict product properties are highly desirable for process monitoring and optimisation. Nonlinear ML methods including Random Forest (RF), K-Nearest Neighbours (KNN) and Recursive Feature Elimination with RF (RFE-RF) outperformed commonly used linear machine learning methods. For the prediction of tensile strength RFE-RF and KNN achieved R² values 98% and 99%, respectively. For the prediction of drug dissolution, two time points were considered with drug release at t = 6 h as a measure of the extent of burst release, and t = 96 h as a measure of sustained release. KNN and RFE-RF achieved R² values of 97% and 96%, respectively in predicting the drug release at t = 96 h. This work for the first time reports the prediction of drug dissolution and mechanical properties of drug loaded polymer product from in-line data collected during the HME process.

The rapid growth of electronic information technology has led to an increase in electromagnetic wave radiation pollution. Therefore, it is imperative to look into shielding materials with superior electromagnetic interference (EMI) shielding capabilities. Because of its exceptional benefits, nanofibers made by electrospinning are capable of the shielding from electromagnetic radiation. This work tries to bring together the details of electrospinning, electrospun carbon and electrospun composite fibers. Furthermore, the preparation, properties and EMI shielding performance of electrospun carbon and composite fibers are presented. This article attempts to provide an overview of the advancements made in the field of carbon fibrous material prepared via electrospinning for shielding applications.

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Present work reports solution combustion synthesis (SCS) of Co_0.5Zn_0.5Fe₂O₄ spinel ferrite, its chemical modification with polymethylmethacrylate (PMMA), synthesis of polyaniline (PANI), and electromagnetic interference (EMI) shielding properties of their composites. Both as-prepared and PMMA-modified Co_0.5Zn_0.5Fe₂O₄ adopt cubic spinel structure as shown by X-ray diffraction studies. Field emission scanning electron microscopy images show the agglomerated and microporous nature of the ferrites. High resolution transmission electron microscopy image of as-prepared Co_0.5Zn_0.5Fe₂O₄ shows lattice fringes related to (311) plane of the spinel structure. X-ray photoelectron spectroscopy studies reveal the presence of Co²⁺, Zn²⁺, and Fe³⁺ in tetrahedral and octahedral coordinations in the ferrite. EMI shielding properties are evaluated for PMMA-modified Co_0.5Zn_0.5Fe₂O₄ and PANI composites in different weight ratios. Composites containing PMMA-modified ferrite and PANI with 50:50 and 10:90 weight ratios show the best performance among all the composites in 2−20 GHz frequency range. Optimized PMMA-modified Co_0.5Zn_0.5Fe₂O₄ and PANI composite with the ratio of 10:90 shows shielding effectiveness (SE) values of −16.6 to −24.2 dB in 2−20 GHz frequency region.

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The longevity of waste asphalt can be considerably improved through cold recycling techniques combined with various additives. This research investigates the cold regeneration of aged asphalt concrete using Reclaimed Asphalt Pavement (RAP), Portland cement, cationic bitumen emulsion, and additional aggregates. The primary goal is to evaluate the performance enhancements in terms of average density, compressive strength, water resistance, and swelling across different mix compositions. Three distinct mixtures were formulated and assessed. Mix No. 1, composed solely of RAP, showed the lowest average density and highest swelling, indicating poor performance due to the lack of binding agents. Mix No. 2, which incorporated RAP, Portland cement, and water, exhibited the highest density and compressive strength, highlighting the crucial role of Portland cement in improving structural integrity. Mix No. 3, a more complex mixture including RAP, aggregates, Portland cement, water, and bitumen emulsion, displayed balanced properties with enhanced moisture resistance and reduced swelling. The experimental findings emphasize the effectiveness of adding Portland cement and bitumen emulsion to improve the mechanical and durability characteristics of recycled asphalt mixtures. Specifically, Mix No. 2 and Mix No. 3 demonstrated significant performance improvements, making them suitable for road maintenance applications. This study advocates for the widespread use of cold recycling methods with additive integration to achieve sustainable and cost-effective pavement restoration solutions.

Currently, flexible capacitive sensors have a wide range of application scenarios in the field of wearable electronic devices. In order to detect more subtle joint movements of the human body, a method of fabricating stacked capacitive sensors is demonstrated. An ultrathin dielectric elastomer film of about 110 μm by the “secondary calendering” method was prepared. The shape of the electrode layers was designed, printed the electrode materials on the dielectric elastomer film by screen-printing, realized the stacked-layer technology, and connected each sensor unit in parallel by the electrode columns formed inside. A 12-layer flexible capacitive sensor with an initial capacitance of 10.2nF, good resolution (1% strain), high sensitivity (1.09) and stability under 10,000 cycles is fabricated. The sensor fabricated in this paper can recognize the motion at various joints of the human body, such as elbow and knee joints. This paper provides a new method for fabrication of stacked flexible capacitive sensors, which opens up new applications in flexible sensors, wearable electronic devices and human-computer interaction.

Active food packaging films from Carboxy methyl cellulose and starch (CMC-g-Starch) reinforced with Magnesium-oxide (MgO) NPs are created and characterized. The effect of different particle sizes, MgO NPs concentrations and different gamma irradiation doses on the preparation of (CMC-g-Starch-MgO) edible nanocomposite films were investigated to determine their properties. Several analytical methods, such as swelling behavior, FT-IR, TEM, TGA, and mechanical characteristics, are represented to investigate different characteristics of the prepared (CMC-g-Starch-MgO) edible nanocomposite films. Also, the prepared (CMC-g-Starch-MgO) edible nanocomposite films and their coating were subjected to the fresh Peaches fruits. Their effect on the Peach fruits' lifespan was evaluated. The anti-microbial property of the edible (CMC-g-Starch-MgO) nanocomposite films of gram (+ve) and gram (–ve) bacteria was reported. Results represented the thermal and mechanical characteristics of (CMC-g-Starch-MgO) edible nanocomposite films, which were enhanced by γ irradiation. Also, the irradiated (CMC-g-Starch-MgO) edible nanocomposite films and their coating extend the lifespan of Peaches fruits and exhibit resistance to pathogenic microorganisms. In conclusion, (CMC-g-Starch-MgO) edible nanocomposite films fulfilled the required behaviors for the application in the nanofood packaging era.

Researchers have recently altered their focus and have become more interested in natural fiber-reinforced polymer composites because they are more ecologically friendly and environmentally conscious than synthetic fiber-reinforced polymer composites. Among the best sources of natural fiber, Grewia ferruginea, sometimes known locally as Lenquata, is a source of natural fiber from other plant fibers. The goal of this study was to create polyester matrix composites reinforced with short Grewia ferruginea plant fibers measuring 10, 20, and 30 mm. The fibers were extracted using the traditional water-retting method and chemically treated with 5% NaOH. The findings indicated that the average tensile strength of a single fiber from Grewia ferruginea plants is 214 MPa, with a density of 1.11 g/cm³. Furthermore, the composite, which was created with a fiber length of 10 mm, fiber weight ratio of 25 %, and polyester matrix composite of 75 %, exhibited superior performance since it is stronger than any combination that was used to create the composite in this investigation, with 18.3 MPa tensile and 35.2 MPa flexural strength.

Additive manufacturing of thermoplastic elastomeric material (TPE) using direct ink writing (DIW) based printing technique opens new horizons for various applications. However, the most crucial process in DIW 3D printing is the optimization of printing parameters to obtain high-quality products both in terms of aesthetics and strength. In this work, statistical models were developed considering layer height, print speed, and, ink concentration to obtain the optimized print quality product from the blend of thermoplastic polyurethane (TPU)/ epichlorohydrin − ethylene oxide − allyl glycidyl ether elastomer (GECO) based TPE materials. Experiments were designed according to the central composite design (CCD) scheme and the influence of input printing parameters on shrinkage and tensile strength was analyzed. The significance of each parameter was systematically studied using the response surface method. For both responses, shrinkage, and tensile strength, printing speed was found to be the most significant parameter. Ink concentration significantly affected tensile strength with a contribution of ∼ 34%. On the other hand, the layer height, with a contribution of ∼ 22% significantly affected the shrinkage behaviour of the 3D printed sample. Finally, multi-objective optimization was performed using a genetic algorithm to identify the optimal 3D printing parameters of the developed TPE materials.

Multifunctional flexible conductive materials have generated significant interest in developing future portable electronic systems, including wearable electronics, implantable devices, and many more. Producing wearable electronics materials that are dependable in all-weather situations and provide high-performance electromagnetic interference (EMI) shielding remains challenging. "electromagnetic textile materials" refers to these wearable EMI shielding garments. One key material that can address the EMI problem facing systems such as wearable/flexible circuit working environments and human health is conductive polymeric nonwoven (NW) textile materials. In this review, our focus is primarily limited to the polymeric NW textile and their composites family as effective EMI shielding materials. The study provides the fundamentals of NW-based EMI shielding mechanisms, mechanisms to mitigate EM reflection, and fabrication techniques of EMI shielding NW materials. Also, the standard for future researchers to select the ideal material combination for effectively mitigating EMI waves as shields/filters is presented. Review articles exist on EMI shielding textiles in general, but no single article is dedicated to NW textile-based EMI shields. Again, no review article exists presenting the approaches employed towards mitigating EM wave reflection in NW -based EMI shield design and fabrication. In addition, the challenges encountered with the fabrication and/or application of NW-based EMI shielding materials are presented in this paper. The question of why NW selection is the primary structure for EMI shield fabrication is presented herewith for the first time in this article.

The selective distribution of filler within polymer blends presents a compelling advantage, notably manifesting as a reduced percolation threshold when compared to an individual polymer matrix with a random filler dispersion. In this context, a thermoplastic elastomeric (TPE) blend comprising ethylene propylene diene rubber (EPDM) and linear low-density polyethylene (LLDPE), denoted as EL, has been meticulously formulated. The incorporation of varying amounts of conductive carbon black (Vulcan XC 72; VCB) into this TPE matrix has been achieved through conventional melt blending, yielding a composite material with exceptional electromagnetic interference (EMI) shielding effectiveness of -27.80 dB at 50 phr (parts per hundred rubber). This success is credited to the creation of a linked structure resulting from a dual-step percolation process. The selective distribution of carbon black (CB) throughout the TPE mixture results in a decreased critical concentration for connectivity and enhanced electromagnetic interference (EMI) shielding performance. This advancement underscores the potential of EPDM-LLDPE-VCB (ELV) composites to safeguard against electromagnetic radiation. It paves the way for their utilization in various techno-commercial applications, where a balance of mechanical strength, thermal stability, and flexibility is crucial.

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