Characterization Of Composites Research Articles

Characterisation of new sustainable gypsum composites with low-density polyethylene waste from single-use bags

The main objective of this research is to determine the feasibility of using Low-Density Polyethylene (LDPE) waste as secondary raw material in the production of new eco-friendly gypsum composites. For this purpose, LDPE waste in crumb form has been incorporated as a partial replacement by weight of the plaster material powder at percentages of 1%, 2% and 3%. Additionally, the gypsum binder in traditional gypsum composites has been replaced for LDPE waste in granulated form, at percentages of 2.5%, 5.0% and 7.5%. The experimental campaign has involved a detailed physical and mechanical characterisation of the gypsum compounds produced to study their potential applications in the construction sector. The results show that more efficient materials are obtained with the addition of these plastic wastes, significantly reducing bulk density and thermal conductivity coefficient compared to traditional gypsum-based materials. Additionally, a considerable reduction in capillary water absorption coefficient and open porosity has been observed. Moreover, the mechanical strengths in flexion and compression surpassed the limits established by current regulations for all the prepared mixtures. In this way, these innovative gypsum composite materials can be useful for application in the production of prefabricated elements, promoting the reincorporation of these plastic wastes, which currently present a challenge from the perspective of sustainability and circular economy.

A Polymer-Derived Co(Fe)Ox Oxygen Evolution Catalyst Benefiting from the Oxidative Dehydrogenative Coupling of Cobalt Porphyrins.

Thin films of cobalt porphyrin conjugated polymers bearing different substituents are prepared by oxidative chemical vapor deposition (oCVD) and investigated as heterogeneous electrocatalysts for the oxygen evolution reaction (OER). Interestingly, the electrocatalytic activity originates from polymer-derived, highly transparent Co(Fe)Ox species formed under operational alkaline conditions. Structural, compositional, electrical, and electrochemical characterizations reveal that the newly formed active catalyst greatly benefited from both the polymeric conformation of the porphyrin-based thin film and the inclusion of the iron-based species originating from the oCVD reaction. High-resolution mass spectrometry analyses combined with density functional theory (DFT) calculations showed that a close relationship exists between the porphyrin substituent, the extension of the π-conjugated system cobalt porphyrin conjugated polymer, and the dynamics of the polymer conversion leading to catalytically active Co(Fe)Ox species. This work evidences the precatalytic role of cobalt porphyrin conjugated polymers and uncovers the benefit of extended π-conjugation of the molecular matrix and iron inclusion on the formation and performance of the true active catalyst.

PSIII-1 Effect of Cannabidiol Extraction on the Cell Wall Carbohydrate Composition of Hemp Inflorescences

Abstract Since the 2018 Farm Bill, US growers have been allowed to cultivate hemp (Cannabis sativa L.), prompting interest in exploring the use of hemp products in ruminant diets. Extraction of cannabidiol (CBD) oil from hemp biomass generates spent inflorescent material that could be upcycled as a feedstuff, yet little is known about its fiber composition. A recent study measured in vitro true digestibility and fermentation parameters of multiple hemp cultivars, some intact and some CBD-extracted (Altman et al., 2022). Both categories of hemp inflorescence material had similar or greater total digestible nutrients (TDN) than an alfalfa cube control, supporting hemp’s potential as a feedstuff. However, comparisons between non-extracted and CBD-extracted samples could not be made, and the fiber content was only described as neutral detergent fiber (NDF). Fiber composition can significantly impact ruminal digestibility, and in-depth characterizations of cell wall carbohydrate composition can provide further insight into the digestibility of a specific plant-based feed. Therefore, in the present study, we examined the effect of CBD oil extraction on the cell wall carbohydrate composition of the inflorescent material of two hemp cultivars. Intact (Biomass) and CBD-extracted (Spent) inflorescent material from two hemp cultivars, Mary and Zelios, were analyzed. The scell wall monosaccharides of the samples were released via two complementary acid hydrolyses, methanolysis and Saeman (sulfuric acid) hydrolysis, and separated and quantified using high-performance anion-exchange chromatography coupled with pulsed amperometric detection (HPAEC-PAD). Additionally, the carbohydrate linkage patterns were assessed by generating partially methylated alditol acetates (PMAAs). Student’s unpaired t-tests were run in GraphPad Prism, and no differences (P > 0.05) in monosaccharide concentrations based upon treatment (CBD extraction) or cultivar were found with either hydrolysis method except for the methanolysis glucose concentration between the biomass forms of the two cultivars where Mary Biomass possessed more glucose than Zelios Biomass (P <b0.001). In the Saeman hydrolysates, glucose was the dominant monosaccharide (38.75 ± 1.44 molar %), indicating a large amount of cellulose, supported by the presence of 1,4-Glcp in the linkage analysis. Linkage analysis also revealed the presence of xyloglucans and rhamnogalacturonan Type 1 pectins in all materials. The data showed no effect of CBD oil extraction on the monosaccharide composition, suggesting that the extraction process leaves the fiber components mostly intact, but there may be differences in glucose concentration (and consequently cellulose content) between cultivars of hemp. Future studies may benefit more from investigating the impact of hemp cultivar on fiber digestibility rather than impact of the CBD extraction process.

Fabrication and characterization of ADC-12 hybrid composites utilizing lemon grass ash and boron nitride through stir-squeeze casting method

In recent years, there has been increased interest in hybridizing metal matrix composites using agro-based-waste materials as sustainable choices. Despite the poor tribo-mechanical properties of conventional reinforcement materials, there is immense potential for using alternate reinforcing elements to enhance the mechanical features of matrix composite. In addition, conventional casting procedures present several challenges, including high costs and a lack of adequate mechanical qualities in the finished product. To combat these issues, the authors herein produce the well-known aluminium matrix composite (AMC), ADC 12 alloy, using waste lemon grass (LG) ash at a fixed rate (6 wt%) and hexagonal Boron Nitride (hBN) at variable proportions (0, 1.5, 3, 4.5, and 6 wt%) as reinforcing element against traditional reinforcement particles to enhance the tribo-mechanical properties of casted hybrid AMC. In addition, the Stir-Squeeze Casting method produces the hybrid AMC, dramatically decreasing production costs and enhancing final product qualities. The hybrid AMC formed by Stir-Squeeze Casting is examined for its mechanical, corrosion, and tribological characteristics, with the findings indicating that the addition of LG and hBN improved the mechanical, corrosion, and tribological properties of the ADC-LG-hBN composites, with 6 wt% LG and 4.5 wt% hBN reinforcements producing the optimal result. The experimental density of ADC-LG- hBN composites was reduced by 8% when compared to the ADC 12 alloy, while the composites’ tensile, hardness and compressive strength were increased by 118.9%, 36.7%, and 33.6%, respectively. Similarly, the developed composite showed an improved corrosion resistance of 43.8% for 24 h, and the wear rate decreased by 90.4%.

Micromechanical Characterization of Continuous Fiber Date Palm Composites

ABSTRACT Date palm fiber composites with aligned, continuous fibers and epoxy matrix were prepared and mechanically characterized using micromechanical models. A hydrothermal process with microwave heating was utilized to extract the date palm frond (midrib) fibers, making the process eco-friendly as opposed to the commonly reported chemical extraction method. Single fibers were then characterized and found to have an average elastic modulus and ultimate tensile strength of 17.1 ± 1.5 GPa and 333 ± 27.4 MPa, respectively. Interfacial shear strengths ranging between 6 and 12 MPa were determined using a single-fiber pull-out test. Fibers were aligned to make uniaxial tensile samples with volume fraction ranging from 11% to 56%, elastic modulus ranging from 1.72 GPa to 9.52 GPa and ultimate tensile strengths ranging from 16.9 MPa to 43.8 MPa. All the results were found to obey “Rule of Mixtures” theory. The composite’s mechanical properties are similar to or exceeding those of the commercially available wood products such as medium density fiberboard, oriented strand board, thick particle board, hard fiber board, and plywood, making the hydrothermal approach with microwave heating as a promising approach for preparation of date palm composites and further opens up similar process pathway for other natural fibers.

Fibre stacking sequence and mechanical characterization of polymer hybrid composites: An experimental study

With rapid development in the field of polymer-reinforced composites, the trend has shifted towards hybridization. Natural fibres have been found to have poor water resistance and synthetic fibres like glass fibres are hybridized to enhance the mechanical strength of individual fibres. In this regard, carbon fibre has good strength but poor damage tolerance, whereas kevlar fibre has a high strain capacity and good damage tolerance. Glass fibres have high toughness and are less expensive. Meanwhile, basalt fibre is cheaper than carbon fibre and stronger than glass fibre. To obtain optimized results of costs and superior mechanical properties, these fibres can be blended into hybrid laminates. This research work involves examining the significance of hybridization and as well as the stacking sequence of fibre-reinforced composites. The hand layup method was implemented to produce five different types of composite laminates containing ten layers each. The micro structural analysis of the fracture surface was conducted. The study revealed that the stacking sequence plays a tremendous role in enhancing the strength of polymer composites. From the test results, it was found that sample A exhibited tensile load of 15428 N, impact strength of 5.8 J and flexural strength of 677 N which was maximum compared with other samples B, C, D and E. It was found that the hybrids produced with kevlar and carbon fibres as the outer layer exhibited a significant effect on the overall composite laminate and showed more tensile, flexural, impact strength, and hardness.

Prediction of elastic wave propagation in composites using 3D CNN

Performing time-dependent finite element simulations for wave propagation in composites is a particularly complex task that consumes a lot of computational energy as it involves modeling the interactions between waves and various constituents that make up the composite material. In this study, we have developed a surrogate model of elastic wave propagation in composites based on three-dimensional conventional neural networks. The input to the model consists of a three-dimensional matrix representing the architecture of the composites and a vector representing the input waves, while the output is a vector representing the output elastic waves. After training the model using 60 000 randomly generated samples, it has shown high accuracy and efficiency in predicting the output elastic waves. This significantly reduces computational resources required to conduct simulation using commercial software, making it a more practical solution for real-world applications, such as composite optimization, nondestructive testing, and material characterization.

Water Chestnut (Eleocharis dulcis) Microfiber Reinforced Composite with NaOH Modification

This study aimed to obtain the physical and mechanical properties of a composite made from water chestnut microfiber and e-glass with a polyester matrix. Using water chestnut (Eleocharis dulcis) as reinforcement for composite materials is a good way to utilize local materials and increase the economy of local people. It would need a modified treatment to improve the mechanical properties of water chestnut fiber-reinforced composites. The water chestnut fiber was modified by treating it with 5% volume NaOH solution and continued with 5% volume H2O2 bleaching, 50% volume H2SO4 hydrolysis, and ultrasonication. Then it was washed with water and dried in the oven for 12 hours to obtain the microfiber. The size of the water chestnut microfiber obtained was about 3-9 µm. Composite was produced using the compression molding method at a pressure of 2 MPa and a temperature of 25°C. The variations in the volume fraction of the polyester composite, water chestnut microfiber, and e-glass fiber with Volume Fraction (%) were 60%:40%:0% (sample A), 60%:0%:40% (sample B), 50%:25%;25% (sample C), 60%:40%:0% (sample D) and 70%:15%:15% (sample E). The physical characterization of composites showed that the lowest composite density and water content on samples B and A were 1.22 g/cm3 and 0.59%. In contrast, the mechanical characterization of composites showed the highest MoR and MoE on samples A and C of 87.86 MPa and 10.43 Gpa, respectively. Composite made from water chestnut (Eleocharis dulcis) modified microfiber reinforcing material with 5% volume NaOH solution and e-glass with a polyester matrix at a volume fraction composition of 50%:25%:25% is recommended.

Ballistic limit and damage assessment of hybrid fibre-reinforced cementitious thin composite plates under impact loading

Impact resistance of reinforced concrete (RC) structures can be significantly improved by strengthening RC members with thin composite layers featuring high damage tolerance. Indeed, to limit the well-known vulnerability of cement-based materials against impact loading, the synergistic effects of short fibres and continuous textile meshes as hybrid reinforcement has been proved to be highly beneficial. This paper addresses the characterisation of novel cement-based hybrid composites through accelerated drop-weight impact tests conducted on rectangular plates at different impact energies. Two distinct matrices are assessed, with particular interest in a newly developed limestone calcined clay cement (LC3)-based formulation. Important parameters quantifying energy dissipation capability, load bearing capacity and damage are cross-checked to compute the ballistic limit and estimate the safety-relevant characteristics of the different composites at hand. Although textiles alone can improve the damage tolerance of fine concrete to some extent, the crack-bridging attitude of short, well-dispersed fibres in hybrid composites imparts a certain ductility to the cement-based matrices, allowing a greater portion of the textile to be activated and significantly reducing the amount of matrix spalling under impact.

Preparation and characterization of bioceramic composites based on anorthite and β-TCP from dolomitic phosphate and kaolin rocks

The current study demonstrates the possibility of producing novel economic biomaterials with biocompatible and acceptable mechanical properties for bone tissue engineering applications from dolomitic phosphate and kaolin rocks. The solid-state reaction was adapted to produce various batch compositions, through the substitution of kaolin with dolomitic phosphate rocks in which 20–30 wt% dolomitic phosphate rock was combined with kaolin material (20 PK, 25 PK and 30 PK). The fabricated ceramics composites were sintered at different temperatures ranging from 1175 to 1325 ᴼC. The phase composition, bulk density and bending strength of the sintered bioceramics were evaluated through X-ray diffraction (XRD), applying the Archimedes method, and 3-point bending test, respectively. Moreover, the in-vitro tests were estimated by immersing the samples in stimulated body fluid solution (SBF). The results showed that anorthite, β-tricalcium phosphate, and calcium magnesium phosphate were produced as primary phases during the sintering process and that their content increased with the increase in the phosphate rock content. Notably, the sample containing 20 wt% dolomitic phosphates exhibited good densification of 1.99 g/cm3 and achieved a bending strength of 45.66 MPa at 1250 °C. After immersing in the SBF for four weeks, changes in the surfaces of all the studied materials were observed, owing to the deposition of apatite particles. The pH values were in a nearby region of the natural pH levels. Such behaviour may be related to the sample's high stability, which originated from its chemical composition and dense structure. Moreover, a cytotoxicity test was carried out using osteosarcoma cells (HOS). The results demonstrated that all the studied bioceramics composites are safe for use as potential biomaterials.

Synthesis and characterization of Zn-based bimetallic microporous MOF composites for effective formaldehyde sensing at room temperature

In the present work, we fabricated 1:1 bimetallic ZnCu(NA); ZnCd(NA); and ZnCo(NA) metal organic frameworks (MOFs) using nicotinic acid (NA) as organic linker by solvothermal method. All the compounds were characterized by Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) analysis, X-ray photoelectron Spectroscopy (XPS), and scanning electron microscopy (SEM).The drop-casting method used to develop a chemiresistive sensor to sense Volatile Organic Compounds (VOCs) at room temperature. These bimetallic sensors exhibited excellent sensitivity and good linearity in detecting formaldehyde at 1 to 50 ppm range. The responses of all sensing materials towards formaldehyde gas at 50 ppm concentration are Cu(NA) 3.74, ZnCu(NA) 18.6, Cd(NA) 3.13, ZnCd(NA) 8.36 and ZnCo(NA) 28.3.The sensing times of Cu(NA), ZnCu(NA), Cd(NA), ZnCd(NA) and ZnCo(NA) are 17, 9, 15, 18 and 17 respectively. These results demonstrate the potential applications of bimetallic Zn/Cu, Zn/Cd, and Zn/Co MOFs for sensitive and specific formaldehyde detection at ambient temperature. These results show that ZnCo(NA) sensing material is an excellent selective sensor for formaldehyde sensing.

Synthesis and Characterization of Proton-Conducting Composites Prepared by Introducing Imidazole or 1,2,4-Triazole into AlPO-5 and SAPO-5 Molecular Sieves.

The present work concerns proton-conducting composites obtained by replacing the water molecules present in aluminophosphate and silicoaluminophosphate AFI-type molecular sieves (AlPO-5 and SAPO-5) with azole molecules (imidazole or 1,2,4-triazole). Both the introduction of azoles and the generation of Brønsted acid centers by isomorphous substitution in aluminophosphate materials were aimed at improving the proton conductivity of the materials and its stability. In the presented study, AlPO-5 and several SAPO-5 materials differing in silicon content were synthesized. The obtained porous matrices were studied using PXRD, low-temperature nitrogen sorption, TPD-NH3, FTIR, and SEM. The proton conductivity of composites was measured using impedance spectroscopy. The results show that the increase in silicon content of the porous matrices is accompanied by an increase in their acidity. However, this does not translate into an increase in the conductivity of the azole composites. Triazole composites show lower conductivity and significantly higher activation energies than imidazole composites; however, most triazole composites show much higher stability. The different conductivity values for imidazole and triazole composites may be due to differences in chemical properties of the azoles.

Characterization and Modelling of Composites, Volume III

The realm of composite materials continues to evolve, with researchers pushing the boundaries of understanding and application. This Special Issue published in the Journal of Composites Science encapsulates the essence of these advancements, presenting a curated collection of research articles that highlight the latest developments in the characterization and modelling of composites. The diversity of the covered topics ranges from a foundational understanding of composite behaviours to the application of cutting-edge modelling techniques. Each contribution offers a fresh perspective, expanding our knowledge of composites and setting the stage for future explorations in this dynamic domain.

Synthesis and Thermal Characterization of Solar Salt-Based Phase Change Composites with Graphene Nanoplatelets

Synthesis and Thermal Characterization of Solar Salt-Based Phase Change Composites with Graphene Nanoplatelets

Processing and Characterization of Magnesium Matrix Composites Reinforced by Nickel Particles

Metal matrisli kompozit malzemeler otomotiv endüstrisinde yaygın olarak kullanılmaktadır. Düşük 
 ağırlığın son derece önemli olduğu bu alanda magnezyum esaslıların tüketim hacimleri her geçen gün 
 artmaktadır. Fakat oda sıcaklığında gözlenen düşük süneklilikleri ve yetersiz dayanımları hem otomotiv 
 sektöründe hem de endüstride demir, çelik ve alüminyuma göre kullanımlarını önemli oranda 
 kısıtlamaktadır. Mevcut çalışmada, hacimce %0-%10 oranlarında, mükemmel süneklilik, iyi tokluk ve 
 yüksek elastik modül gibi üstün özelliklere sahip nikel mikro partiküller ile takviye edilmiş magnezyum 
 matrisli kompozit malzemeler toz metalürjisi yöntemlerinden tek eksenli sıcak presleme tekniği ile imal 
 edilmiştir. Üretim parametrelerinin optimizasyonu sonucu tüm numunelerde yaklaşık olarak tam 
 yoğunluğa ulaşılmış ve gözenek içermedikleri tespit edilmiştir. Mikroyapısal incelemelerde α (Mg) ve Ni 
 fazlarına ilaveten Mg2Ni fazı da gözlenmiştir. Bu bileşik, ayrıca, XRD analizlerinde de belirlenmiştir. 
 Güçlendirici ilavesi ile matris malzemesinin oda sıcaklığı akma ve basma dayanımlarında sırasıyla %37 
 ve %35 oranlarında iyileşmeler elde edilmiş ve tüm test sıcaklıklarında saf magnezyuma göre daha 
 yüksek değerlere sahip olduğu görülmüştür. Kompozit malzemeler gerek mekanik özellikleri gerekse de 
 düşük yoğunlukları ile otomotiv ve endüstride kullanılan geleneksel malzemelere önemli bir alternatif 
 teşkil ettiği saptanmıştır.

Optimizing Polymer-Stabilized Raw Earth Composites with Plant Fibers Reinforcement for Historic Building Rehabilitation

This research focuses on the optimization of formulation, characterization, and damage analysis of plant fiber-reinforced polyester resin composites (jute and date palm). To better understand the characteristics and mechanical behavior of these materials, this study investigates the influence of resin content and plant fibers on the physico-mechanical behavior of the resin composites. Resinous composites consisting of polyester resin and raw earth were studied using a novel formulation based on an empirical method that follows the principle of earth saturation with polyester resin. Saturation was achieved with a 28% content of polyester resin, which appeared to be an optimal blend for the earth–resin composite. Plant fibers were randomly incorporated as reinforcement in the composites at various percentages (1%, 2%, and 3%) and lengths (0.5 cm, 1 cm, and 1.5 cm). Mechanical tests including bending, compression, and indentation were conducted to evaluate the mechanical properties of the composites. Analysis of fracture morphology revealed that the deformation and rupture mechanisms in bending, compression, and indentation of these composites differ from those of traditional concrete and cement mortar. The obtained results indicate that the composites exhibit acceptable performance and could be favorably employed in the rehabilitation of historic buildings.

Strontium-Substituted Nanohydroxyapatite-Incorporated Poly(lactic acid) Composites for Orthopedic Applications: Bioactive, Machinable, and High-Strength Properties.

Traditional metal-alloy bone fixation devices provide structural support for bone repair but have limitations in actively promoting bone healing and often require additional surgeries for implant removal. In this study, we focused on addressing these challenges by fabricating biodegradable composites using poly(lactic acid) (PLA) and strontium-substituted nanohydroxyapatite (SrHAP) via melt compounding and injection molding. Various percentages of SrHAP (5, 10, 20, and 30% w/w) were incorporated into the PLA matrix. We systematically investigated the structural, morphological, thermal, mechanical, rheological, and dynamic mechanical properties of the prepared composites. Notably, the tensile modulus, a critical parameter for orthopedic implants, significantly improved from 2.77 GPa in pristine PLA to 3.73 GPa in the composite containing 10% w/w SrHAP. The incorporation of SrHAP (10% w/w) into the PLA matrix led to an increased storage modulus, indicating a uniform dispersion of SrHAP within the PLA and good compatibility between the polymer and nanoparticles. Moreover, we successfully fabricated screws using PLA composites with 10% (w/w) SrHAP, demonstrating their formability at room temperature and radiopacity when observed under X-ray microtomography (micro-CT). Furthermore, the water contact angle decreased from 93 ± 2° for pristine PLA to 75 ± 3° for the composite containing SrHAP, indicating better surface wettability. To assess the biological behavior of the composites, we conducted in vitro cell-material tests, which confirmed their osteoconductive and osteoinductive properties. These findings highlight the potential of our developed PLA/SrHAP10 (10% w/w) composites as machinable implant materials for orthopedic applications. In conclusion, our study presents the fabrication and comprehensive characterization of biodegradable composites comprising PLA and strontium-substituted nanohydroxyapatite (SrHAP). These composites exhibit improved mechanical properties, formability, and radiopacity while also demonstrating desirable biological behavior. Our results suggest that these PLA/SrHAP10 composites hold promise as machinable implant materials for orthopedic applications.

Composite optimization and characterization of dietary fiber-based edible packaging film reinforced by nanocellulose from grapefruit peel pomace

The development of edible packaging films was motivated due to resource waste and environmental damage caused by chemically produced plastic packaging. The development of edible packaging film based on grapefruit peel pomace dietary fiber has significant technological and functional potential because grapefruit processing waste is a potential source of high-quality dietary fiber. In this study, the first successful development of an edible packaging film based on dietary fiber using grapefruit soluble dietary fiber (GSDF) from grapefruit peel pomace as a substrate and nanocellulose (GNCC) as a filler was developed. Principal component analysis, membership function synthesis, and response surface methods were used to determine the optimal process to prepare the edible packaging films, and the impact of GNCC on this material was analyzed. The results showed that the overall performance score of the edible packaging film with 1 wt% GNCC was 0.764. The maximum pyrolysis temperature increased from 226.36 °C to 227.10 °C, the melting temperature (Tm) increased by 5.54 °C, the crystallinity increased by 2.95 %. The film solution exhibited non-Newtonian characteristics and a solid-like property. Our results showed that the edible packaging film developed from grapefruit peel pomace and dietary fiber could have several potential applications in the food packaging field.

Facile synthesis and characterization of polymer composites with cobalt ferrite and biomass based activated carbon for microwave absorption

In this work, flexible EMI shield materials have been prepared by the solution cast technique using AC-STG {activated carbon derived from Sal tree's gum}, CoFe2O4 nanoparticles and a polymer electrolyte {P(VDF-TrFE) + 15 wt% LiTFSI + 50 wt% EMIMTFSI}. The prepared polymer composites have been characterized for structural, morphological, thermal, ionic conductivity, dielectric, and magnetic properties. EMI shielding effectiveness has been obtained in the X-band (8.2–12.4 GHz). AC-STG particles have been characterized using XRD, FESEM EDX with elemental mapping, FTIR and RAMAN techniques. The CoFe2O4 (CF) nanoparticles have been prepared using the hydrothermal method. The highest ionic conductivity of ∼ 3.24х10−3 S.cm−1 for polymer electrolyte (PE15IL50) has been obtained at room temperature. On addition of AC-STG and CF particles to the polymer electrolyte, enhanced EMI shielding effectiveness and thermal stability of the composite films has been achieved. Also, FTIR results give the confirmation of interaction between the polymer electrolyte, AC-STG and CF particles. This study demonstrates that the EMI shielding properties of the polymer composite (PE15IL50AC-STG4CF5) get improved owing to the synergy between the properties of AC-STG and CF nanoparticles resulting in EMI shielding of ∼ 49.6 dB at 8.2 GHz (absorption ∼ 99.99%). There are three factors, viz., dielectric losses, magnetic losses and interfacial polarization which contribute majorly to this much desirable EMI performance. The studies being reported indicate PE15IL50AC-STG4CF5 polymer composite to be an excellent biomass-based composite for EM wave absorption.

Bentonite/hydroxyethylcellulose as eco-dielectrics with potential utilization in energy storage

Abstract This study deals with the preparation and characterization of novel composites accomplished by filling hydroxyethylcellulose with several amounts of bentonite. Molecular modeling enabled understanding the conformational and physicochemical features, which are responsible for the chemical reactivity parameters. Rheological analyses are made to investigate the effect of the polymer loading on the shear flow behavior. The morphology and homogeneity of each system is explored via optical microscopy. The band gap of the samples is slightly reduced by the addition of the bio-filler in the cellulosic medium, as indicated by UV-VIS spectral data. The dielectric response of these materials is extracted from refractometry experiments at several wavelengths. The electric energy density was achieved based on the dielectric properties determined at high and low frequencies. The outcome of this study offers new ways to produce alternative dielectric eco-materials having a good potential of accumulating electrical energy, as demanded for capacitor devices.