Nanofiller Content Research Articles

Evaluating the properties of starch/chitosan films with the incorporation of various nanoclays for use in food packaging.

This study evaluates the properties of starch/chitosan films (SCF) produced via the casting method, incorporating 40% (w/w) plasticizers (glycerol and sorbitol) and various concentrations (0, 3, 5, and 10% (w/w)) of nanoclays (Cloisite 20A, Cloisite 30B, and K-10). The effects of each nanofiller on the films were thoroughly investigated. Films containing nanoclays exhibited reduced water solubility and enhanced thermal stability compared to films without nanofillers. A higher nanoclay concentration (10% (w/w)) led to a reduction in the solubility of the starch/chitosan films, with a decrease of approximately 15% relative to the SCF sample. Incorporating the three types of nanoclays improved tensile strength at break, particularly in samples with 3% and 5% (w/w) nanoclay content, achieving an approximate 68% increase in tensile strength at break compared to the SCF sample. Atomic Force Microscopy (AFM) analysis revealed that increasing nanofiller content significantly heightened surface roughness. Films incorporating Cloisite 30B demonstrated lower surface roughness than those with Cloisite 20A and K-10 nanoclays, especially at concentrations of 3% and 5% (w/w), with a reduction of approximately 40%. X-ray diffraction (XRD) analysis indicated superior interaction in films containing Cloisite 20A and 30B, while films with 10% (w/w) K-10 exhibited a diffraction peak at 8.88°, suggesting inadequate incorporation. These findings align with the AFM analysis results for this film. Consequently, the integration of nanoclays improves the properties of starch/chitosan films, with formulations utilizing 20A and 30B nanoclays at 3% and 5% (w/w) showing the most promising potential for future applications in food packaging.

Improved dielectric performance of graphene oxide reinforced plasticized starch.

High dielectric constants with less dielectric loss composites is highly demandable for technological advancements across various fields, including energy storage, sensing, and telecommunications. Their significance lies in their ability to enhance the performance and efficiency of a wide range of devices and systems. In this work, the dielectric performance of graphene oxide (GO) reinforced plasticized starch (PS) nanocomposites (PS/GO) for different concentrations of GO nanofiller was studied. The surface morphology, and chemical and structural properties of the PS/GO nanocomposites were investigated by field emission scanning electron microscopy (FESEM), Fourier-transform infrared spectrometry (FTIR), and X-ray diffractometer (XRD). The FESEM study showed a uniform dispersion of the GO nanofiller in the nanocomposites. The XRD analysis showed a reduction in d-space due to the incorporation of GO nanofiller in the nanocomposites. The FTIR data exhibits the formation of hydrogen bonds among PS and GO nanofillers, suggesting the presence of strong interaction between them. The dielectric properties of the nanocomposites were studied at room temperature in the frequency range 100 Hz‒1 MHz. The dielectric constant was found to improve due to the incorporation of GO. This composite nanomaterial also provides low dielectric loss at low frequency. Moreover, an increasing trend is observed for the AC conductivity of the composites. From the complex impedance study, the changes in various impedances with low to high-frequency ranges have been calculated and explained in the equivalent circuit diagram. The complex impedance spectra analysis shows the change in resistance and constant phase element (CPE): grain boundary resistance, R2 decreases from 4.3 KΩ to 1.9 KΩ, and CPE increases from 0.59 μF to 0.72 μF for PS/GO (0.5%) nanocomposite. This study will provide a potential route for the fabrication of biocompatible dielectric device fabrication.

NANOCOMPOSITES BASED ON A HEAT RESISTANT POLYCYANURATE MATRIX

The review article is devoted to a promising and rapidly developing class of thermosetting polymers – polycyanurates created from cyanate ester resins (CER), in particular, to the synthesis and characterization of the structure and physical properties of their nanocomposites obtained by in situ method using inorganic nanoparticles with an organo-functionalized surface. Cyanate ester resins are very easy to use, and the technology of their processing is close to the technology of manufacturing materials based on traditional epoxy resins. Due to their high heat resistance, cyanate ester resins are increasingly replacing epoxy materials, especially in high-tech industries. An important feature of the synthesis of nanocomposites based on polycyanurates is that almost all functionalized nanoparticles used in the published studies catalyze the high-temperature polycyclotrimerization of dicyanates into polycyanurates. Nanoparticles with reactive groups on a surface, such as hydroxy, phenolic, amine, epoxy, etc. are covalently embedded in the forming polymer network during the synthesis process due to their easy chemical interaction with cyanate groups of the cyanate ester resin. The chemical reactions to such hybridization have been thoroughly studied. This phenomenon prevents an aggregation of nanoparticles and leads to their effective distribution in a polymer matrix, which in turn ensures high performance of the resulting nanocomposites. A specific effect of ultra-low (<1 wt.%) nanofiller concentrations on the glass transition temperature, heat resistance and mechanical strength of the resulting nanocomposites has been established: the glass transition temperature of polycyanurate increases by 40–60 °C with the introduction of 0.01 to 1.00 wt.% of epoxy-functionalized polyhedral oligomeric silsesquioxane (POSS), amino-SiO2, amino-POSS or amino-functionalized montmorillonite (MMT). Increasing the content of nanoparticles above ~2 wt.% usually leads to the opposite effect due to the formation of their aggregates. The areas of industrial application of nanocomposites based on polycyanurates are described. It has been shown that the valuable complex of thermal, dielectric, mechanical, and chemical properties of polycyanurates, as well as their ability for nanostructuring and all kinds of chemical modifications, due to the high reactivity of the cyanate groups of CER, contribute to the wide application of CER, polycyanurates and nanocomposites based on them in various fields of industry instead of traditional epoxy resins. In recent years, the use of CER, its composites and nanocomposites has increased significantly in the aerospace and defense industries, in the manufacture of electrical products and electronics, etc. CER-based products are used as potting resins, binders for carbon, glass and organic plastics, coatings, adhesives in aircraft, helicopters, satellites, antennas, gas turbines, microchips, etc.

Morphology and thermal properties of a nanocomposite based on polypropylene PP/MnO2

This research study investigated the thermal stability and morphology of PP/MnO2 nanocomposite as a function of volume content of polypropylene (PP) and manganese nanooxide nanofiller using atomic force microscopy (AFM), X-ray diffraction (XRD) and differential scanning calorimetry (DSC). Polymer nanocomposites obtained by hot pressing method were formed into 120 μm thick layers. The effect of MnO2 nanoparticles on polypropylene polymer was determined by determining the degree of crystallization, melting enthalpy and structural properties. The importance of this paper is that besides using PP/ MnO2 based nanocomposites as microelectronics for making memory cells, it is also possible to make new sensors based on these sample.

Key factors enhancing the electrical properties of nanofluids. A mini-review of the applications in the energy-related sectors

The article presents a mini-review of key factors significantly affecting the electrical properties of nanofluids. One-step and two-step approaches, together with examples of vacuum sputtering-based techniques, chemical reduction, and mechanical mixing techniques, were explained. The crucial factors enhancing the electric and dielectric responses, such as nanofiller concentration, its type, geometry, uniformity of distribution in the base liquid as well as the base liquid’s type, temperature, chemical stability, etc., were analyzed. Special attention was paid to the impact of the parameters on electrical conductivity, permittivity, and dielectric losses. The selected models for nanofluid’s conductivity prediction have been presented. The potential and implemented applications of nanofluids in the energy-related industry branches with reference to their electrical properties have been reviewed. Examples of applications in power transformers, solar cell production processes, nanoelectrofuel flow batteries, and other electrotechnologies have been analyzed.

Optimizing polylactic acid composites: Role of sodium lignosulfonate-modified carbon nanotubes in mechanical and interfacial performance

In this study, researchers synthesized sodium lignosulfonate (LS) modified multi-walled carbon nanotubes (L-MWCNTs) using a deep eutectic solvent (DES) method and incorporated them into polylactic acid (PLA) composite films using a solvent evaporation method. The nanofiller content ranged between 0.5 % and 1.5 % by mass. Transmission electron microscopy (TEM) confirmed the uniform dispersion of LS on the surface of MWCNTs, while scanning electron microscopy (SEM) revealed that L-MWCNTs were homogeneously distributed within PLA matrix without notable aggregation. Thermogravimetric analysis (TGA) demonstrated enhanced thermal stability, with an 8.4 % increase in residue at 800 °C. Fourier-transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) confirmed the successful integration of L-MWCNTs into the composite films, while X-ray diffraction (XRD) analysis showed a significant increase in crystallinity (Xc) from 47.4 % to 68.9 %. With increasing L-MWCNT content, ultraviolet-visible (UV–vis) transmittance decreased from 75.9 % to 28.9 %, and oxygen (O2) permeability was reduced by 22.4 %. At an L-MWCNT content of 1.5 %, the composite films exhibited an increase of 49.7 % and 194.5 % in tensile strength and elongation at break compared to pure PLA. These results unveil that PLA/L-MWCNT composite films possess excellent mechanical strength, thermal resistance, and barrier properties, enabling their suitability for advanced applications in packaging, medical, and electronic industries.

Impact of adding bismuth oxide nanoparticles functionalized with graphene oxide nanosheet on the polyvinyl chloride shielding properties

This study investigates the enhancement of polyvinyl chloride (PVC) by incorporating Bi2O3-GO nanocomposites. We produced nanocomposites with varying concentrations (1, 2.5, 5, and 10 wt%). The prepared samples were characterized using scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). X-ray diffraction (XRD) and thermogravimetric analysis (TGA) were also used. As well as the shielding effectiveness against ultraviolet rays and gamma radiation from 137Cs and ⁶⁰Co sources at energies of 662, 1173, and 1275 keV. Results indicate that the addition of Bi2O3-GO significantly improves the thermal stability of PVC, as evidenced by higher decomposition temperatures from TGA. The absorption coefficient increases, while energy gap values decrease with increased nanofiller weight concentrations. The linear attenuation coefficient (LAC) also rises with increasing nanofiller content and decreases with higher gamma-ray energies. Results were consistent with Phy-X software simulations. The sample with 10% wt of Bi2O3-GO composite demonstrated a highly fast neutron removal cross section (FNRC) and reduced mean free path (MFP). This indicates strong potential for use as a safe, environmentally friendly alternative to lead-based shielding materials. These PVC/Bi2O3-GO nanocomposites could be effectively utilized in radiation barriers and protective screens in settings involving neutron and low-energy gamma radiation, such as in radiography and radioactive material management.

Development of surface modified SiO2 nanoparticles incorporated clearcoats for automotive industry

Evaluating organic-inorganic hybrid coatings containing modified nanoparticles may open up opportunities for the automotive industry. In this study, vinyltrimethoxysilane (VTMO) modified SiO2 nanoparticles were synthesized to develop two-component High Solid (2K HS) hybrid clearcoats (CC) which require low-temperature curing. Hansen Solubility Parameters (HSP) and Design of Experiment (DOE) studies provided better optimization in terms of reaction parameters and suitable solvent prediction. Several characterization techniques like FTIR, SEM, and DLS techniques were performed to prove the successful modification of SiO2 nanoparticles with silane agent, VTMO. HS Hybrid CC formulations were designed for the automotive industry with 1.75 and 3.00 phr (per hundred acrylic polyol resin) VTMO modified SiO2 nanoparticles. Dynamic Mechanical Analysis (DMA) tests showed that toughness values increase with the nanofiller amount, in contrast to Young's modulus and yield strength due to the various interactions between nanofiller and the polyurethane polymer matrix. The free volume formed between VTMO ligands of the SiO2 nanoparticles and the polymer matrix provides a low-density region which results in a decrease in time, temperature, and frequency dependent modulus values and glass transition temperature (Tg) of HS Hybrid CC system. Static and dynamic surface tension measurements, water uptake, and cure monitoring result that 1.75 phr nanofiller content in HS Hybrid CC enhances the performance of clearcoats significantly due to the formed low-density region between the nanofiller and the polymer matrix. However, further increase of the nanofiller causes agglomeration and consequently worse clearcoat performance. VTMO modified SiO2 nanoparticles provide significant compatibility up to 1.75 phr and enhance the clearcoat performance in terms of mechanical strength for further usage in the automotive industry.

Enhanced Thermal Conductivity of Thermoplastic Polyimide Nanocomposites: Effect of Using Hexagonal Nanoparticles.

Thermoplastic polyimides have garnered significant interest in the electronic and electrical industries owing to their performance characteristics. However, their relatively low thermal conductivity coefficients pose a challenge. To address this issue, this study focused on the properties of nanocomposites comprising two thermoplastic semicrystalline polyimides R-BAPB and BPDA-P3, one amorphous polyimide ULTEMTM, and hexagonal nanoparticles. Polyimide R-BAPB was synthesized based on 1,3-bis-(3',4-dicarboxyphenoxy)benzene (dianhydride R) and 4,4'-bis-(4'-aminophenoxy)biphenyl (BAPB diamine); polyimide BPDA-P3 was synthesized based on 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA) and diamine 1,4-bis[4-(4-aminophenoxy)phenoxy]benzene (P3); and amorphous polyimide ULTEMTM was commercially produced by Sabic Innovative Plastics. Using microsecond-scale all-atom molecular dynamics simulations, the effects of incorporating hexagonal nanoparticles with enhanced thermal conductivity, such as graphene, graphene oxide, and boron nitride, on the structural and thermophysical characteristics of these materials were examined. The formation of stacked aggregates was found for graphene and hexagonal boron nitride nanoparticles. It was observed that graphene oxide nanoparticles exhibited a dispersion in polyimide binders that was higher than those in graphene and hexagonal boron nitride nanoparticles, leading to reduced translational mobility of polymer chains. Consequently, the decrease in polyimide chain mobility correlated with an increase in the glass transition temperature of the nanocomposites. Aggregates of nanoparticles formed a pathway for phonon transport, resulting in improved thermal conductivity in polyimide nanocomposites. An increase in the thermal conductivity coefficient of polyimide nanocomposites was observed when the concentration of graphene, graphene oxide, and hexagonal boron nitride nanofillers increased. The enhancement in thermal conductivity was found to be strongest when graphene nanoparticles were added.

Polyurethane Nanocomposites with Open-Cell Structure Modified with Aluminosilicate Nano-Filler.

Nanocomposite flexible polyurethane foams (nFPUfs) were obtained by modifying the polyurethane formulation by adding a halloysite nano-filler in the amount of one to five parts by weight per hundred parts of used polyol (php). Flexible polyurethane (PU) foams with an open-cell structure and with a beneficial SAG factor were obtained. Premixes with nano-filler had a lower reactivity than the reference PU system. This favored the production of smaller cells, but with a more rounded shape in comparison with the REF foam without the nano-filler. During the study, the morphology and physical and mechanical properties were characterized, including apparent density, compressive stress, rebound flexibility, SAG factor, closed-cell content, and thermal stability, and compared with the properties of the unmodified reference foam. Scanning electron microscopy (SEM) showed that the cell structures of all prepared foams were open, and the cell size decreased with increasing nano-filler content. Apparent densities, SAG factors and rebound flexibilities of the foams increased with the increase of nano-filler content, while the resistance to permanent deformation showed the opposite trend. The proper selection of raw materials and optimally developed polyurethane formulations allow for obtaining environmentally friendly foams with favorable functional properties, taking into account price and the needs of sustainable development in the synthesis of flexible foams dedicated to the upholstery industry.

Energy harvesting through the triboelectric nanogenerator (TENG) based on polyurethane/cellulose nanocrystal

This study investigates how physical and mechanical properties affect the performance of triboelectric nanogenerators (TENGs). Polyurethane (PU) was prepared using two methods: (i) one-step PU (non-chain extended polyurethane) and (ii) two-step PU (chain extended polyurethane) via the prepolymer method; both types were filled with different concentrations of nanocrystalline cellulose. Mechanical properties significantly influence the deformation at the material interface that occurs during contact or friction. Key surface characteristics, including surface energy, geometry, and physicochemical properties, affect the effective contact area and potential distribution. One-step PU with 0.1 % CNC demonstrates a maximum capacitance of 29.20 pF, a voltage of 2.04 V, an electric current of 0.43 µA and power of 0.89 µW, representing a 74.5 % increase in power compared to the neat one-step PU, exhibits significant potential for TENG applications. Performance improvements are associated with lower concentrations of cellulose nanocrystals, enhanced hydrogen bonding, and beneficial surface energy. The observed enhancements in output are attributed to improved internal polarization from well-dispersed crystalline nanocellulose, increased crystallinity of the soft segment, and reduced charge transfer mechanisms due to amino groups in the chain extender. However, the impact of the molecular structure and conformation of polyurethanes on triboelectrification remains unclear, highlighting the need for theoretical models and experimental data. This research provides a practical approach for developing stretchable triboelectric materials with enhanced mechanical properties, emphasizing the importance of considering factors such as mechanical parameters, nanofiller content, and surface physicochemical properties to optimize TENG design.

Optimizing the structural, optical, dielectric, and electrical properties of polyvinyl alcohol/polyvinyl pyrrolidone/zinc manganite nanocomposites for optical and energy storage applications

This study investigates the structural, dielectric, optical, and electrical properties of eco-friendly polyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP) matrices embedded with zinc manganite nanoparticles (ZnMn2O4NPs). The nanocomposites films were prepared using a casting method for potential applications in flexible electrochemical devices. FTIR spectroscopy confirmed the successful incorporation of ZnMn2O4NPs into the polymeric matrix. UV–Vis absorption analysis revealed an increase in absorbance with increasing ZnMn2O4 nanoparticle content. Among the various blend nanocomposites, the lowest bandgap energy was observed for the sample containing 2.5 %ZnMn2O4 NPs. Measurements of electrical conductivity, dielectric characteristics, and complex impedance were made for all prepared films. The findings showed that as frequency and nanofiller concentration increased, so did AC conductivity and dielectric characteristics. Overall, the PVA/PVP-2.5 % ZnMn2O4 nanocomposite exhibited superior properties compared to the pure polymer blend. This sample demonstrated optimal electrical conductivity and dielectric constant. These findings suggest that by carefully adjusting the ZnMn2O4 concentration, it is possible to fine-tune the dielectric, optical, and electrical properties of these nanocomposite films. This versatility offers promising potential for applications in optoelectronic devices, energy storage devices, and nanodielectric materials.

Dielectric, Photoluminescence, Thermal and Mechanical Properties of CuO Nanoparticles Filled Polyvinyl Alcohol/Polyvinyl Pyrrolidone Blends for High Frequency Device Applications

This study involves synthesizing blends of polyvinyl alcohol (PVA) and polyvinylpyrrolidone (PVP) in 1:1 ratio using solution casting technique. The blends were then mixed with different concentrations of copper oxide (CuO) nanofiller, ranging from 0 to 16 wt% (0, 2, 4, 8, 12, and 16 wt%). Fourier transform infrared spectra and x-ray diffraction studies provide evidence of the structural modifications occurring within nanocomposites. Fluorescence spectroscopy revealed that the highest photoluminescence intensity occurred at a concentration of 8 wt% CuO in the blend which specifies that this particular concentration of nanofillers had a substantial impact on luminescence properties of the material. The morphology and texture of film’s surface was examined by means of atomic force microscopy. The dielectric plot demonstrated that dielectric constant of the film increased up to a CuO filler concentration of 12 wt%. This indicates that there is an optimal concentration of CuO nanofillers that enhances dielectric properties of the material. The mechanical studies carried out using universal Testing Machine reveals enhancement in the mechanical properties after the addition of nanofillers. The promising characteristics of these nanocomposites are suitable for high-frequency device applications and optical sensing applications.

Study on the effect of halloysite nanotubes on the mechanical properties and swelling resistance of ethylene-propylene diene monomer (EPDM)/nitrile butadiene rubber (NBR) blend nanocomposites

Abstract Research was undertaken to explore the alteration of natural halloysite nanotubes (HNTs) using a blend of resorcinol and hexamethylenetetramine (RH), (γ-aminopropyl) triethoxysilane (APTES), and diethoxydimethyl silane (DMS). This investigation delved into the impact of incorporating various proportions of RH-modified HNTs (RH-HNTs), APTES-modified HNTs (APTES-HNTs), DMS-modified HNTs (DMS-HNTs), and unmodified HNTs into ethylene propylene diene monomer (EPDM) and nitrile butadiene rubber (NBR) for their potential as seal materials. The study assessed key properties such as tensile strength, stress at 100% elongation, elongation at break, compression set, hardness, and swelling and abrasion resistance to gauge the influence of HNT additions. As nanofiller content increased, the crosslinking rate rose, while scorch time and optimum cure time decreased. Findings indicated that incorporating nanofillers at 6 phr compositions notably enhanced composite strength initially, with a subsequent slight reduction. However, rebound resilience diminished with increasing filler content, though composite hardness experienced a slight improvement. Mole percent uptake decreased, particularly at higher filler loadings. Notably, systems containing 6 phr RH-HNTs exhibited a 140% increase in tensile strength. FESEM micrographs depicted a rough fracture surface with well-dispersed nanofillers within EPDM/NBR. Additionally, compression set data illustrated enhanced composite performance under compression, crucial for seal applications.

Green synthesis of boehmite-reinforced cashew gum/polypyrrole biopolymer blend for advanced biomaterials

Electrically conducting biopolymer blend nanocomposites based on different contents of boehmite (BHM) reinforced cashew gum (CG) /polypyrrole (PPy) blend is synthesized by an in situ polymerization technique using water as a green solvent. The resulting bio-blend nanocomposites underwent comprehensive analysis concerning their structural, morphology, thermal, and electrical properties, such as dielectric constant, dielectric loss, electric modulus, and AC conductivity. The Fourier transform infrared spectroscopy (FTIR) spectra revealed the presence of metal oxide stretching in the blended nanocomposite at 512 cm−1. Field emission scanning electron microscopy (FE-SEM) confirmed the attachment and uniform dispersion of BHM within the CG/PPy blend at 7 wt% loading, and beyond this loading, the nanoparticles get agglomerated in the biopolymer blend. The glass transition temperature and thermal stability of all the blended nanocomposites are higher than that of the pure CG/PPy blend and these thermal properties increase with the loading of nanoparticles. Conductivity experiments demonstrated that as the nanofiller content increases up to 7 wt%, there is a concurrent rise observed in AC conductivity, dielectric loss, and dielectric constant. There is a substantial difference of 1.21 Scm−1 between the maximum and minimum AC electrical conductivity, at 102 Hz. However, a decrease in electrical properties is observed at the highest loadings of BHM due to the agglomeration of nanoparticles in the polymer blend matrix. The lowest activation energy value (0.049 × 10−4 eV) is also exhibited by 7 wt% BHM nanocomposites. Furthermore, the electrical properties of both CG/PPy and CG/PPy/BHM nanocomposites exhibited a temperature-dependent behavior, progressively increasing until reaching maximum values. This study suggests that such bio-based polymer dielectrics could be promising materials for various applications, offering enhanced thermal and electrical properties through careful control of nanofiller content and dispersion.

Use of nanocelluloses from orange peel and ZnO as hybrid nanofiller in developing functionalized starch nanocomposite for edible coatings

AbstractThis study explores the formulations of orange peel nanocelluloses (NC) with tailored dimensions for the development of functionalized nanocomposites coatings on green chilies. In the present century, the valorization of agro‐waste, specifically orange peel for developing NC facilitated sustainable packaging such as edible films and coatings with improved properties has received importance. As, this approach aligns with the sustainable development goals, including reduced food waste and agro waste. For the work, the derived orange peel celluloses were acid hydrolyzed using sulfuric acid (H2SO4) and hydrochloric acid (HCl) to deliver cellulose nanofibers (CNF) and cellulose nanoparticles (CNP), respectively. The fabricated CNP and CNF were characterized using Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), and thermogravimetric analysis (TGA). The FESEM morphology showed the formation of CNP with diameter ranges from 42.4 to 108 nm and formation of CNF with diameter ranged from 27.4 to 50.5 nm. The creation of the functionalized nanocomposite was done by reinforcing with hybrid nanofillers consisting CNF, CNP consecutively with ZnO in corn starch for tailormade packaging properties in terms of mechanical, physicochemical, optical, thermal properties, and so on. The results reveal improved tensile strength, and reduced water vapor transmission rates of nanocomposite with the addition of hybrid nanofillers. Additionally, green chilies were coated with the functionalized nanocomposites prepared by different concentrations of nanofillers. The storage analysis was performed in terms of weight loss, total chlorophyll content, and microbiological analysis. The developed coatings were found to be effective in extending the shelf life of green chilies. The control samples showed significantly higher weight loss compared to coated ones. The coated samples showed significantly better firmness and total chlorophyll content after 20 days of storage. In comparison to other coatings, NC and ZnO incorporated starch‐based coating was found to be the most effective in maintaining the quality of fresh green chilies throughout the storage. Thus, incorporating NC and ZnO in starch‐based films and coatings presents a promising avenue for sustainable packaging and preservation.Highlights Agro‐waste orange peel was valorized to develop sustainable food packaging. Orange peel‐based nanocellulose was developed using H2SO4 and HCl. Nanocomposite film was developed using hybrid nanofillers. Nanocomposites provide tailored properties due to the nanofillers. Developed nanocomposite was used as edible coatings on green chilies.

Tuning Dielectric Properties with Nanofiller Dimensionality in Polymer Nanocomposites.

Polymer nanocomposites hold great potential as dielectrics for energy storage devices and flexible electronics. The structural architecture of the nanofillers is expected to play a crucial role in the fundamental mechanisms governing the electrical breakdown and dielectric properties of the nanocomposites. However, the effect of nanofiller structure and dimensionality on these properties has not been studied thoroughly to date. This study explores the critical relationship between nanofiller dimensionality and dielectric properties in polymer nanocomposites. We fabricated polyvinylidene fluoride (PVDF) nanocomposites by incorporating a range of carbon-based nanofillers separately, including zero-dimensional (0D) carbon black (CB), one-dimensional (1D) multiwalled carbon nanotubes (MWCNT), 1D single-walled carbon nanotubes (SWCNT), two-dimensional (2D) reduced graphene oxide (rGO), and three-dimensional (3D) graphite. The frequency-dependent (1 kHz to 1 MHz) dielectric permittivity (k) of the nanocomposites at the same concentration of nanofillers demonstrated a hierarchical order, with MWCNT showing the highest permittivity (∼400%), succeeded by rGO (∼360%), CB (∼290%), SWCNT (∼230%), and graphite (∼70%), respectively. The temperature-dependent (50-150 °C) dielectric spectroscopy revealed high k with increasing temperature due to the enhanced dipole movement. However, their dielectric breakdown strength and energy densities were not correlated to k and exhibited the following order: SWCNT > MWCNT > CB > rGO > graphite. As the electrical breakdown depends upon the nanocomposites' mechanical strength, we correlated the mechanical properties with the nanofiller dimensionality, and Young's modulus followed the 1D ≈ 2D > 0D > 3D order. These findings will provide fundamental insights into designing tunable, conducive nanofiller-based nanocomposites in next-generation flexible electronics and capacitive energy storage devices.

Composite Materials Used for Dental Fillings.

This article explores the properties of composite materials employed in dental fillings. A traditional nano-hybrid composite containing nanofiller particles exceeding 82% by weight served as a benchmark. The remaining samples were fabricated from ormocer resin, maintaining an identical nanofiller content of 84%. In all specimens, the nanoparticles were dispersed randomly within the matrix. This study presents findings from investigations into surface geometry, hardness, wettability, and tribological behavior. The microscopic observations revealed that ormocer-based samples exhibited greater surface roughness than those composed of the traditional composite. Hardness testing indicated that both ceramic addition and sample preparation significantly influenced mechanical properties. Ceramic-enhanced samples demonstrated superior hardness, surpassing the reference composite by 30% and 43%, respectively. Contact angle measurements revealed hydrophilic characteristics in the classic composite, contrasting with the hydrophobic nature of ceramic-containing samples. Tribological evaluations revealed the superiority of the classic composite in terms of friction coefficients and volumetric wear compared to ormocer-based materials.

Tribological and mechanical behaviors of Fe3O4NPs reinforced UHMWPE biocomposite

Ultra high molecular weight polyethylene (UHMWPE) filled with diverse contents of magnetite nanoparticles (Fe3O4NPs) were produced via hot compression molding. The effect of Fe3O4NPs on the tribological and mechanical properties of the UHMWPE matrix was studied. Wear and friction behaviors were studied using a reciprocating pin-on-disc tribometer under a sliding speed of 0.03 m.s−1 and an applied normal load of 20N. Mechanical behavior was investigated using tensile and hardness tests. SEM technique was used to explore the surface morphology and to investigate wear mechanisms. Results showed that reinforcement with Fe3O4NPs improved UHMWPE matrix hardness and wear resistance. A maximum hardness and wear resistance in addition to a good mechanical behavior in traction were obtained when adding 1 wt% of magnetite nanofiller. Reinforcement increased the coefficient of friction but there is no obvious correlation between nanofiller contents and friction. SEM analysis showed that the reinforcing rate of UHMWPE influences wear mechanisms.

Agglomeration phenomenon in graphene/polymer nanocomposites: Reasons, roles, and remedies

The addition of low-loading content of nanofillers may improve the material properties of polymer-based nanocomposites. This improvement directly corresponds to the density of well-dispersed nanofillers in the matrix. However, for higher nanofiller loadings, the nanocomposites' material properties not only may not be improved but also may be degraded due to agglomeration. This complex phenomenon, where nanofillers tend to form agglomerates with the enhancement of volume fraction, poses significant challenges in materials science and nanotechnology. It has been proven that agglomerations hinder the performance of the nanocomposites and thwart the unique properties of nanofillers in most aspects. Graphene, one of the most used nanofillers, plays a remarkable role in nanotechnology. Therefore, the key focus of the current review is to provide insight into the impact of agglomeration on the various material properties such as tensile, flexural, fracture, fatigue, thermal, electrical, and barrier characteristics of the polymer nanocomposites reinforced by graphene-based structures. A comprehensive review of the factors leading to the agglomeration of graphene in the nanocomposites was presented. It was concluded that agglomeration could be a barrier to developing polymer-based nanocomposites, and the challenges of controlling the nanofiller agglomerations were discussed in depth, highlighting the issue's complexity.