Nanofilled Composites Research Articles

Spectrophotometric Evaluation of the Color Stability of Nanofilled Composites With and Without a Dentin Bonding Agent as a Surface Sealer Following Exposure to Common Beverages

Spectrophotometric Evaluation of the Color Stability of Nanofilled Composites With and Without a Dentin Bonding Agent as a Surface Sealer Following Exposure to Common Beverages

Optimal Tungsten Inert Gas Welding Parameters of Dissimilar Aluminum Alloys Al 7075 and Al 6061 Using Ultrasonic Vibration and Nanocomposite Filler (Al 5356/ZrB2) to Alleviate Hot Cracking Phenomenon

Abstract In this study, the welding of dissimilar aluminum alloys, Al 7075 and Al 6061, was investigated using Al 5356 filler rods reinforced with ZrB2 particles. The welding process was conducted using tungsten inert gas (TIG) welding, with and without ultrasonic vibration, to enhance weld quality and reduce hot cracking. Optimization of process parameters for dissimilar TIG welding was performed through Response Surface Methodology (RSM), which generated a design matrix to analyze the influence of process parameters on response variables. Numerical and graphical optimization was applied to minimize hot cracking sensitivity and maximize microhardness. The RSM-based models suggested an optimal welding current of 93 A, the use of Al 5356/ZrB2 nanocomposite filler, and the application of ultrasonic vibrations. Experimental validation of the identified solution demonstrated improvements in weld quality, including increased yield strength and ductility. The combination of nano-reinforced fillers and ultrasonic vibrations was found to enhance weldability and mitigate hot cracking in dissimilar aluminum joints. The mechanism of hot cracking reduction involved grain refinement, degassing, and homogenization due to ultrasonic vibrations, as well as the modification of weld pool chemistry and control of dilution by the nanocomposite filler, which collectively minimized solidification shrinkage and stress. Under these optimized conditions, no hot cracking was observed experimentally.

Effect of Charcoal-containing Mouthwashes on Color Stability of Nanofill and Microhybrid Composites

Effect of Charcoal-containing Mouthwashes on Color Stability of Nanofill and Microhybrid Composites

Preparation and investigation of structural, optical, and dielectric properties of PVA/PVP blend films boosted by MWCNTs/AuNPs for dielectric capacitor applications

With the rising global energy demands, there is a pressing need for the invention of efficient and reliable energy storage systems. This research centers on the creation and analysis of flexible dielectric capacitors composed of polymer nanocomposites (PNCs), incorporating a blend of polyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP) as the base polymer, with multi-walled carbon nanotubes (MWCNTs) and gold nanoparticles (AuNPs) serving as nanofillers. The AuNPs were produced through an environmentally friendly synthesis method. Films made from PVA/PVP blended with MWCNTs and AuNPs were fabricated using the casting approach. Various characterization methods, including TEM, XRD, FTIR, and UV–Vis spectroscopy, were utilized to evaluate the samples. A detailed analysis of their electrical/dielectric characteristics was conducted. XRD analysis revealed a significant decrease in crystallinity from 55% for the pure PVA/PVP blend to 37% for the 1.6 wt% nanofiller composite, indicating increased amorphous content, which facilitates better ion mobility. FTIR confirmed strong interactions between the polymer matrix and nanofillers, with intensified vibrational peaks pointing to enhanced molecular dynamics. UV–Vis spectroscopy demonstrated a red shift in the absorption edge, and Tauc plot analysis showed a reduction in the indirect/direct optical band gap from 4.84 eV/5.68 eV for the pure blend to 4.26/5.35 eV for the nanocomposite with 1.6 wt% nanofillers. The addition of nanofillers resulted in improvements in their dielectric features, which exhibited a significant performance improvement, with the dielectric constant (ε′) reaching approximately 1100 at low frequency for the 1.6 wt% nanofiller sample, compared to 9 for the pure blend. Additionally, the dielectric loss (ε'') and tangent loss (tan δ) were reduced, with tan δ showing a decrease from 15 for the pure blend to 2 for the 1.6 wt% nanofiller composite at low frequency, indicating enhanced dielectric efficiency and reduced energy dissipation. The capacitors' functionality was assessed through capacitance-frequency and conductance-frequency analyses. The capacitors exhibited stable high capacitance across a broad frequency spectrum, making them alternatives for energy storage solutions.

Evaluation of Marginal Adaptation of SDR Plus, Fiber-Reinforced and Nanofilled Composites in Endodontically Treated Teeth: A Scanning Electron Microscopic Study.

Endodontically treated teeth (ETT) undergo structural changes, including a reduction in water content and loss of dentin elasticity, which can compromise their mechanical properties. One critical factor influencing the long-term prognosis of a restored ETT is the marginal adaptation of the restorative material. The present study compared the marginal adaptability of Smart Dentin Replacement (SDR) Plus, fiber-reinforced, and nanofilled composites in ETT using scanning electron microscopy (SEM). Cavities were made in 30 recently extracted maxillary premolars distributed into three experimental groups depending on the restorative material used: group 1 as SDR Plus (Dentsply Sirona, Charlotte, North Carolina, USA), group 2 as fiber-reinforced composite (EverX, GC Corp., Tokyo, Japan), and supra nanofilled composite (Estelite Sigma Quick, Tokuyama Dental Corp., Tokyo, Japan). Standardized access openings were performed, and endodontic treatment was completed in all teeth. Specific composite restoration techniques were applied according to the manufacturer's instructions. After thermocycling for 30 days, the restored teeth were sectioned and viewed using SEM (Labindia Instruments Pvt. Ltd., Maharashtra, India) to measure the width of the marginal gap. The data were analyzed using statistical software. The mean marginal gap width varied significantly among the groups. Group 1 had a lower mean marginal gap of 2.99 μm, group 2 exhibited the highest mean marginal gap of 10.24 μm, and group 3 had a mean marginal gap of 5.51 μm. Overall, group 2 consistently showed significantly larger marginal gaps than the other groups. Within the limitations of this study, SDR Plus demonstrated better marginal adaptation than fiber-reinforced and supra-nanofilled resins in the coronal restoration of ETT. Fiber-reinforced composites demonstrated the maximum marginal gap, followed by nanofilled composites. Thus, SDR Plus may be recommended as a suitable restorative material to enhance the longevity and success of endodontic treatments.

Wear, microhardness, water sorption, and solubility of conventional glass ionomer cement modified with precured nanofilled composite.

Wear, microhardness, water sorption, and solubility of conventional glass ionomer cement modified with precured nanofilled composite.

Innovating a EVOH composite coating towards outstanding H2 barrier and anti-corrosion properties

Concerning the mitigating leakage and hydrogen-induced embrittlement during the conveyance of hydrogen (H2), we have developed an innovative dual-layer composite coating that exhibits exceptional hydrogen gas barrier properties and good resistance to corrosion. Using a bottom-top approach combining hot pressing with spin-coating techniques, the bottom Ethylene-vinyl alcohol copolymer (EVOH) layer with glass flakes (GF) serves as an effective hydrogen gas barrier and the top fluorosilicone resin (FSR) layer with composite nanofiller possesses good corrosion resistance, ensuring the functional integrity of the EVOH layer. The composite coating shows an exemplary low hydrogen gas transmission rate (H2 GTR) value of 2.858 cm3/(m2·24 h·0.1 MPa), representing a substantial decrease of 99.98 % compared to the FSR coating and 15 times more effective than commercial gas barrier films. Moreover, even after a 90-day immersion in 3.5 wt% NaCl solution, the coating maintains an impressive impedance at 0.01 Hz (|Z|0.01 Hz) of 1.0 × 1011 Ω·cm2. The composite coating is exposed to 2 MPa hydrogen for 7 days, and we find that it still sustains outstanding hydrogen gas barrier and anti-corrosion properties.

A COMPARATIVE CLINICAL EVALUATION OF THE AESTHETICS AND BIOCOMPATIBILITY OF COMPOSITE VENEER RESTORATIONS WITH DIRECT AND INDIRECT TECHNIQUES

In recent years, dental aesthetics have garnered significant attention, prompting the advancement of noninvasive and minimally invasive techniques to preserve natural dental tissues while addressing aesthetic concerns. This study aims to evaluate and compare the clinical performance and biocompatibility of prefabricated componeers and direct composite veneers by assessing changes in color, surface texture, marginal integrity, and gingival response. Emphasizing the modern landscape of dental materials, the study addresses the challenges associated with tooth wear and advocates for minimally invasive approaches. The utilization of contemporary nanofilled and nanohybrid composites provides a broad spectrum of aesthetic solutions while highlighting the critical importance of biocompatibility. Study Design and Methodology: This investigation is structured as an in vivo, comparative clinical study involving a sample size of 72 teeth from patients aged between 20 and 60, with equal representation of both genders. Conducted under real-life conditions, the study systematically divides participants into two distinct groups for comprehensive comparative analysis. Objective: The primary objective of this study is to assess and compare the clinical performance and biocompatibility of prefabricated componeers versus direct composite veneers.

Novel poly(2-ethyl-2-oxazoline) and poly(diallyldimethylammonium chloride) polymer functionalized montmorillonite: Physicochemical aspects and near-IR study of hydration properties

The novel functionalized montmorillonites (Mts) with non-ionic poly(2-ethyl-2-oxazoline) (PEtOx) and cationic poly(diallyldimethylammonium) (PDDA) were created via an intercalation method with different loading ratio of both polymers. A comprehensive investigation into their physicochemical properties was conducted using Carbon analysis (CA), Powder X-ray diffraction (PXRD), Fourier-transform infrared spectroscopy (FTIR), Simultaneous thermal analysis (TGA/DSC) and BET-N2 adsorption analysis. The impact of hydration on PEtOx-Mts and PDDA-Mts was assessed through gravimetric analysis and near-infrared spectroscopy (NIR) spectroscopy. PXRD analysis revealed a significant increase in 001 diffraction of PDDA-Mt corresponding to a PDDA interlayer with a basal spacing ranging from 1.47 to 1.49 nm. Conversely, the basal spacing exceeding 2 nm for PEtOx suggested, that the PEtOx polymer was intercalated in a larger amount and packed in a less compact manner compared to PDDA. After modification of Na-Mt with PEtOx polymer, FTIR spectroscopy confirmed the presence of the carbonyl CO group (3265 and 1641 cm-1) and the stretching (2982, 2942 and 2883 cm-1) and bending (1480–1200 cm-1) vibrations of the CH2 and CH3 groups. The vibrations of CH groups were further verified following PDDA modification. NIR spectroscopy also confirmed the vibrational bands attributed to both modifiers after intercalation of PEtOx and PDDA. The results of BET-N2 adsorption revealed a significant decrease in the specific surface area (SSA) after intercalation with a non-ionic PEtOx polymer. On the contrary, in the case of saturation of Na-Mt with polycation PDDA, SSA increased slightly in two instances. TGA analysis confirmed greater weight loss for PEtOx-Mts compared to PDDA-Mts. Derivative thermogravimetry (DTG) revealed the release of physisorbed bound water around 100 °C, decomposition of the organic phase within the 250–550 °C range and dehydroxylation of OH groups around 550–800 °C in both cases. The results obtained from the gravimetry and NIR analysis indicated a greater hydrophobic nature for PEtOx-Mts compared to PDDA-Mts. These findings hold substantial potential for enhancing the properties of novel organo-montmorillonites, thereby facilitating their application as adsorbents for pollutants, surface coatings, biodegradable materials, fillers in polymer nanocomposites, drug carriers, anticancer agents and various other significant applications.

A comparison of physical, morphological, and mechanical properties of bio‐polyester hybrid nanocomposites

AbstractIt is imperative to improve the physical, morphological, and mechanical properties of biodegradable polymers like polylactic acid (PLA), poly (butylene adipate‐co‐terephthalate) (PBAT), and polycaprolactone (PCL) in order to employ them on a larger scale. The development of hybrid nanocomposite materials using nano inclusions can improve desired qualities. Here we introduced an interactive nano reinforcement approach to improve the properties by combining graphene oxide (GO) and carboxyl functionalized MWCNT (f‐MWCNT), to provide for their chemical bonding for synergic reinforcement. A constant filler 2 wt.% was added to the biopolyesters by melt blending process and examined the different physical properties like water absorption, intrinsic viscosity, and hardness. To completely evaluate the functionalization of the nanofillers, wide‐angle X‐ray diffraction (WAXD), Raman spectroscopy and Fourier transform infrared radiation (FTIR) analyses were used. The paired nanoparticles and polymer matrix appear to mix well together, as shown by electron microscopy, which also reveals good dispersion and the creation of a reinforcing network microstructure across the matrix layer. A thorough analysis of the results showed that effective stress transmission, delaying the start of faults and generating microcracks, and dissipating additional mechanical energy all contributed to efficient hybrid network formation, which improved the mechanical properties of hybrid filler nanocomposites except some nanocomposites. These findings offer a viable technique for chemically altering biodegradable polymers, like PLA, PBAT, and PCL for use in biomedical, wastewater management, and agricultural applications.

Neutron Reflectivity Study on the Adsorption Layer of Polyethylene Grown on Si Substrate.

To investigate the structure of the interface between polyethylene films and substrates, the neutron reflectivity (NR) of deuterated polyethylene (dPE) thin films deposited on Si substrates was measured, demonstrating water accumulation at the interface, even under ambient conditions. After leaching the thermally annealed dPE films in hot p-xylene, NR measurements were conducted on the layers remaining on the substrate, clearly revealing that the adsorption layer of dPE grew during annealing and consisted of two layers, an inner adsorption layer and an outer adsorption layer, as previously proposed for amorphous polymers. The inner adsorption layer was approximately 3.7 nm thick with a density comparable to that of the bulk. The outer adsorption layer was several nanometers thick and appeared to grow insufficiently on top of the inner adsorption layer under the annealing conditions examined in this study. This study clarifying the growth of the adsorption layer of polyethylene at the interface with an inorganic substrate is useful for improving the performance of polymer/inorganic filler nanocomposites due to the wide utility of crystalline polyolefins as polymer matrix materials in nanocomposites.

An experimental study on jute/banana fiber reinforced poly(vinyl alcohol) composites with nanofiller

AbstractThe incorporation of nanoparticles into natural fiber composites has the potential to alter the characteristics of natural fiber composites. In this study, various properties of jute and banana fiber reinforced poly(vinyl alcohol) (PVA) composites with different nanofillers incorporation were investigated. Samples were prepared using the vacuum bagging technique. Inorganic nanoparticles (Al2O3, ZnO, MgO, CuO, and TiO2) were synthesized using a ball milling machine and in each sample, 3 wt.% of nanofillers were incorporated. The maximum ultimate tensile strength and elongation percentage is found for TiO2, which is 90.433% higher than pure PVA whereas MgO incorporated samples provides maximum flexural strength, which is 162.59% higher than PVA. The sample with Al2O3 provides strongest impact resistance, 17.3 J/cm2. It was found that the decomposition temperatures were slightly higher for MgO and CuO doping than the undoped PVA composite. The FT‐IR spectra exhibited notable hydroxyl groups and minor shifts indicating a reduction in hydrophilicity upon the introduction of nanoparticles. The water absorption exhibited a reduction of up to 36% in conjunction with an increase in density across all samples. The highest crystallinity is found for CuO nanofiller composite, validated by x‐ray diffraction analysis. Additionally, morphological changes in the composites were seen through scanning electron microscopy and EDX shows a strong peak at 2.1 keV indicate some impurities present in the samples.Highlights Jute/banana/PVA composites were prepared with 3 wt% nanoparticles incorporation. Metal oxides such as Al2O3, ZnO, MgO, CuO, and TiO2 were used as nanoparticle. The use of nanoparticle improved the tensile, flexural, and impact properties. Decomposition temperatures were found higher for MgO and CuO incorporated composites. Upon nanoparticle incorporation, water absorption exhibited a reduction of upto 36%.

Advancing anti-corrosion performance of composite coating: Self-aligned fluorinated graphene for multifunctional electronic packaging

Fluorinated graphene (FG) is considered an ideal filler for polymer nanocomposites to enhance anti-corrosion performance due to its hydrophobicity and electrical insulation properties. A key objective in advanced anti-corrosion design is to create a structure where FG sheets are stacked and aligned, forming an ultra-long, circuitous path to impede the diffusion of active corrosion species. Additionally, integrating aligned FG sheets with polymers prevents the formation of electrical percolation paths, making the coating suitable for electronic passivation. However, achieving a high degree of alignment of FG within the polymer matrix has been a challenge. In this study, we employ a straightforward electrophoretic deposition method to align FG sheets in a polyurethane (PU) matrix for anti-corrosion coatings on copper. The optimized coating exhibits outstanding corrosion resistance for copper, with a stable corrosion rate of 4.0 × 10−3 μm/year in a 3.5 wt% NaCl solution. Moreover, the FG composite coating significantly enhances thermal conductivity, increasing it by 97 % compared to pristine PU, while also providing high electrical resistance. This results in a high breakdown electric field of 28 kV/cm and an extremely low current density of 1.32 × 10−8 A/cm2, which is advantageous for electronic packaging. This multifunctional coating meets industrial standards for large-scale production, uniformity, and controllable thickness, offering a promising approach to improving anti-corrosion protective coatings.

Enhancing the performance of flexible pipeline materials through polyethylene of raised temperature resistance (PE-RT) nanocomposites reinforced with reduced graphene oxide

Due to its superior mechanical properties compared to many other materials, reduced graphene oxide (rGO) shows great promise as a filler in polymer matrix nanocomposites. Through experimental investigation, this study explores the influence of rGO on the thermal and mechanical properties of high temperature resistance polyethylene (PE-RT). PE-RT/rGO nanocomposites were prepared by the melting method at 180 °C and screw speed of 100 rpm, with a residence time of 6 min. The results showed that there was an increase in the thermal stability of the nanocomposite at 8 °C. The DSC analysis did not reveal any substantial effect on the melting and crystallization temperatures or the degree of crystallinity of PE-RT; however, the XRD analysis revealed a higher crystallinity index for the sample with lower rGO content. SEM images showed that the GO nanoparticles have a good interface with PE-RT without agglomeration. The water contact angle values increased from 97.5° in the pure matrix to 102° in the nanocomposite, indicating that the nanoparticles increased the hydrophobicity of the material. Permeability assessments for CO2 showed an increase in time-lag of 6.01 hours. The aging test showed that rGO improves the performance of the PE-RT matrix against swelling. Hardness increased from 50 to 57 Shore D with 2.0 wt% rGO. Finally, the incorporation of 1.0 wt% rGO showed an increase in Young's modulus from 329±37 MPa to 419±40 MPa. The results suggest a potential gain in the use of rGO as reinforcement for PE-RT, which is beneficial for riser applications.

Evaluation of thermal conductivity models and dielectric properties in metal oxide-filled poly(butylene succinate-co-adipate) composites

This study examines how various nanofillers impact thermal conductivity, dielectric characteristics, and electromagnetic interference (EMI) shielding potential of bio-based and biodegradable poly(butylene succinate-co-adipate) (PBSA). TiO2, NiFe2O4, Fe2O3, and Fe3O4 were selected as fillers for nanocomposites at 4–50 vol.% (12–81 wt.%). The nanocomposites were analyzed in three domains: structural (scanning electron microscopy, energy dispersive X-ray spectroscopy mapping, density, tensile testing), thermal (light flash analysis, literature models), and dielectric (AC conductivity, permittivity, EM shielding effectiveness (SE)). The investigated fillers showed good dispersion and compatibility with the PBSA matrix. LFA was analyzed according to literature models, where Bruggeman and Agari models showed the best fit at high concentrations. The dielectric analysis revealed that most of the nanocomposites did not reach percolation; thus, producing thermally conductive plastics that are electrically insulating. EMI shielding was limited to frequencies below 10 Hz, with the notable exception of Fe3O4 (100 nm and loading of > 25 vol.%), which showed shielding at frequencies up to 105 Hz. The investigated composites based on a biodegradable polyester and abundant metal oxide nanofillers are suitable for the production of cheap, ecological, and electrically insulating heat dissipation solutions required for modern and lightweight applications.

Influence of particle size on the magnetic and microwave absorption properties of magnetite via mechano-mechanical methods for micro-nano-spheres

The demand for innovative electromagnetic wave absorbers stems from the pressing need to mitigate electromagnetic interference and pollution emanating from electronic devices and communication technologies, which pose risks to human health and disrupt the functionality of electronic equipment. This study investigates how particle size influences the magnetic and microwave absorption properties of magnetite micron-nano-spheres. Utilizing ball milling (BM) and mechanochemical alloying (MA), particle sizes were controlled by varying the milling times, resulting in a reduction of magnetite's average particle size from 3 µm to 43 nm. The research uncovers the unique effects of blending micron and nano-sized particles, a phenomenon previously undocumented. It was observed that saturation magnetization and coercivity increase with larger particle sizes due to the small size effect. The complex permittivity, dielectric loss and attenuation constant of the magnetite nanocomposites were influenced by the larger interface area and increased defects in smaller-sized nano-filler composites. Decreasing the magnetite particle size leads to a lower frequency shift and a broader bandwidth of the reflection loss (RL) peak in the fixed absorber, with maximum RL achieved for thinner absorber layers. Notably, the mixed micron-nano magnetite composite exhibits promising microwave absorption capabilities, achieving a maximum RL of −35.36 dB at 16.8 GHz with a 1 mm thickness, making it suitable for lightweight microwave absorption. Resonance frequencies corresponding to RL below −20 dB extend to 3.63 GHz, meeting the 99 % wave absorption requirement due to the high loss tangent of antiferromagnetic resonance and significant magnetic relaxation peak over the 8–18 GHz frequency range. This study underscores the significant impact of adjusting the particle size on microwave absorption properties, where decreasing the size broadens the absorption bandwidth, shifts the RL peak to lower frequencies and maximizes RL with thinner thicknesses. Increasing the nano-filler content enhances the absorption bandwidth and microwave absorber performance by augmenting the dielectric loss, attenuation constant and impedance matching. Overall, controlling the particle size proves effective in tailoring microwave absorption, highlighting the potential of magnetite composites as ultra-thin, lightweight materials capable of absorbing a wide range of microwave frequencies. These composites find applications in microwave absorption, stealth technology and managing electromagnetic interference, leveraging the magnetic properties of ferrites and exploiting super-exchange interactions in microparticles-sized materials. Moreover, they benefit from the amplified dielectric or/magnetic losses resulting from the characteristics of nanoparticle-sized materials, including high surface area, greater surface atoms and multiple reflections, resulting in exceptional microwave absorption performance exceeding 99 % across an exceptionally broad bandwidth.

Comparative Evaluation of Shear Bond Strength of Bonded Space Maintainers Using Ormocers, Nanofilled and Glass Fiber-reinforced Adhesive Composites.

Space maintainers (SMs) are used to preserve the space created by premature loss of primary teeth. The most commonly used is the band and loop (B&L) SM. As this SM has several drawbacks, such as poor esthetics and gingival health, laboratory procedures for fabrication, and multiple seating procedures, various bonded SMs were introduced. This study aims to compare the shear bond strength of bonded SMs using ormocer, nanofilled, and short glass fiber-reinforced adhesive composites with the conventional B&L SM luted with type I glass ionomer cement (GIC). Sixty intact extracted primary molars were randomly divided into four groups (n = 15). In group I (control), conventional B&L SMs were luted with type I GIC, whereas ormocer, nanofilled, and glass fiber-reinforced composites (GFRC) were used to bond the SMs in groups II, III, and IV, respectively. Shear bond strength of all the specimens was analyzed using a universal testing machine, and the obtained data were subjected to statistical analysis. The highest shear bond strength, that is, 68.82 ± 16.81 MPa, was exhibited by GFRC, followed by 51.04 ± 23.28 MPa with nanofilled composite, 45.3 ± 18.27 MPa with ormocer, and the least in the control group, that is, 42.17 ± 17 MPa. Glass fiber-reinforced resin composite has better resistance against shear force than the other three study materials, and this was significantly higher (p = 0.001) than conventional B&L SMs. Barathi D, Jampanapalli SR, Patloth T, et al. Comparative Evaluation of Shear Bond Strength of Bonded Space Maintainers Using Ormocers, Nanofilled and Glass Fiber-reinforced Adhesive Composites. Int J Clin Pediatr Dent 2024;17(6):695-701.

Comparative Evaluation of Fracture Resistance of Composite Core Buildup Materials: An In Vitro Study.

Aim This study aimed to compare the fracture resistance of different materials used in composite core buildups, including conventional filler composite, nanofiller composite, and short fiber-reinforced composite (SFRC). Methods This in vitro study was conducted on 30 freshly extracted premolars. The teeth were treated using a uniform endodontic procedure, and Fiber Posts (REFORPOST, Angelus) were placed. The teeth were then divided into three groups and restored using different materials. Group 1 was restored using SFRC(everX Posterior, GC, Europe), Group 2 using microfiller composite (Te-Econom Flow, Ivoclar Vivadent), and Group 3 using nanofiller composite (Tetric N-Flow, Ivoclar Vivadent). The restoration materials were then light-cured for 40 seconds. The teeth were placed in a Universal Testing Machine (Instron) and a load was applied with a stainless-steel ball (4 mm diameter) until the tooth fractured. The fracture load for each tooth was recorded, and after the mechanical test, the experimental groups were examined for failure modes. Statistical analysis was performed using SPSS version 21.0 software. A one-way ANOVA test was conducted to compare more than two groups, followed by Tukey's test for post hoc pairwise comparison. Results The mean fracture resistance of the microfiller composite (346.94±44.63) was the lowest among the three groups. When analyzed using Tukey's test at p<0.05, fracture resistance was significantly higher in the SFRC, followed by nanofillers and microfiller composites. Conclusion Due to the increasing demand for aesthetic restorations in recent years, composites have become important in modern restorative dentistry. The development and implementation of composite dental restorative materials rely on a comprehensive understanding of each composite component and consideration of methods for modifying each component. As a result, the findings of this study will be beneficial in determining which material to use based on specific cases.

Polymer blending and nanophotocatalyst loading synergy in visible light‐driven photocatalytic PES/SPSf mixed matrix membranes

AbstractThe synergy of polymer blending and loading photocatalytic titania–amorphous carbon nanotubes (TiO2–aCNT) in tailoring the morphological, surface, and optoelectrical properties of membranes is investigated. High energy band gap (Eg) polyethersulfone (PES), and low Eg sulfonated polyethersulfone (SPSf) polymer blends were loaded with TiO2–aCNT nanocomposite fillers. SEM reveals membranes consisting of a selective layer, a dense sublayer and a spongy layer with the latter two consisting of a network of nanofibers whose diameters decrease with increasing TiO2–aCNT loading. The downshifting in the wavenumbers of sulfonyl and sulfone peaks in Fourier transform infrared and Raman spectra confirms bonding of TiO2–aCNT with PES/SPSf via these groups. Blending PES with SPSf decreases the Eg of the membranes while loading TiO2–aCNT produces a second band edge corresponding to = 2.8 eV. Suppression of charge recombination in membranes is realized at 1.2 filler wt.%. Charge separation occurrs via shuttling of the positive holes to the aCNTs and valence band of TiO2 while electrons are shuttled to the conduction bands of PES and SPSf. Electron impedance spectroscopy shows TiO2–aCNT loading reduces polymer membrane resistance to charge transport. Dye degradation up to 85% is realized under direct sunlight irradiation accompanied by mineralization.

Anisotropic Semicrystalline Homopolymer Dielectrics for High‐Temperature Capacitive Energy Storage

AbstractHigh‐temperature dielectric polymers are in high demand for powering applications in extreme environments. Here, we have developed high‐temperature homopolymer dielectrics with anisotropy by leveraging the hierarchical structure in semicrystalline polymers. The lamellae have been aligned parallel to the surface in the dielectric films. This structural arrangement resembles the horizontal alignment of nanosheet fillers in polymer nanocomposites and nanosheet‐like lamellae in block copolymers, which has been proven to provide the optimal topological structure for electrical energy storage. The unique ordering of lamellae in our dielectric films endue a significantly increased breakdown strength and a reduced leakage current compared to amorphous films. This novel approach of enhancing the capacitive energy storage properties by controlled orientation of lamellae in homopolymer offers a new perspective for the design of high‐temperature polymer dielectrics.