Search Results (115)

This study reports the impact of a silver nanoparticles/reduced graphene oxide@titanium dioxide nanocomposite (Ag/rGO@TiO₂) on the mechanical and biocompatibility properties of poly(styrene-co-methylmethacrylate)/poly methyl methacrylate (PS-PMMA/PMMA)-based bone cement. The chemical, structural, mechanical, and thermal characteristics of Ag/rGO@TiO₂ nanocomposite-reinforced PS-PMMA bone cement ((Ag/rGO@TiO₂)/(PS-PMMA)/PMMA) were evaluated using Fourier Transform Infrared spectroscopy (FT-IR), X-ray diffraction (XRD), nano-indentation, and electron microscopy. FT-IR, XRD, and transmission electron microscopy results confirmed the successful synthesis of the nanocomposite and the nanocomposite-incorporated bone cement. The elastic modulus (E) and hardness (H) of the ((Ag/rGO@TiO₂)/(PS-PMMA)/PMMA) bone cement were measured to be 5.09 GPa and 0.202 GPa, respectively, compared to the commercial counterparts, which exhibited E and H values of 1.7 GPa to 3.7 GPa and 0.174 GPa, respectively. Incorporating Ag/rGO@TiO₂ nanocomposites significantly enhanced the thermal properties of the bone cement. Additionally, in vitro studies demonstrated that the bone cement was non-toxic to the MG63 cell line. Full article

To promote environmental sustainability, this research investigated the potential of utilizing recycled polymethylmethacrylate (PMMA) as raw material in material extrusion (MEX) additive manufacturing (AM). To enhance its mechanical response, carbon black (CB) was employed as the filler in nanocomposite formation. Filament extrusion of the mixture at different concentrations produced printable feedstocks for MEX AM. Rheological analysis (viscosity and material flow rate) showed that the CB introduction to the matrix was beneficial for consistent layer deposition, while differential scanning calorimetry and thermogravimetric analyses verified the thermal stability of the nanocomposites during processing. Mechanical properties were optimized, with increases in modulus (27.8% and 25.8%, respectively, in tensile and bending loadings) and tensile strength at optimal CB loadings. Dynamic mechanical analysis revealed the viscoelastic response of the nanocomposites. Raman and energy dispersive spectroscopy provided element-related insights. Surface morphology and parts structure were observed employing scanning electron microscopy and micro-computed tomography, respectively, revealing a positive impact on the AM parts due to the CB presence in the nanocomposites. The 4 wt.% in CB content nanocomposite was the optimum one. This research pioneers the development of new sustainable nanocomposite filaments and highlights the potential of next-generation MEX-based AM. Full article

Diblock copolymers (BCP) consisting of poly(methyl methacrylate) (PMMA) and poly(1H,1H,2H,2H-perfluorodecyl methacrylate) (PsfMA) blocks are employed as templates for controlled dispersion and localization of multi-walled carbon nanotubes (MWCNT). Short MWCNT are modified with perfluoroalkyl groups to increase the compatibility between MWCNT and the semifluorinated (PsfMA) phase and to promote a defined arrangement of MWCNT in the BCP morphology. Thin BCP and BCP/MWCNT composite films are prepared by dip-coating using tetrahydrofuran as solvent with dispersed MWCNT. Atomic force microscopy, scanning and transmission electron microscopy reveal a strong tendency of the BCP to form micelle-like domains consisting of a PMMA shell and a semifluorinated PsfMA core, embedded in a soft phase, containing also semifluorinated blocks. MWCNT preferentially localized in the embedding phase outside the micelles. Perfluoroalkyl-modification leads to significant improvement in the dispersion of MWCNT, both in the polymer solution and the resulting nanocomposite film due to increased interaction of MWCNT with the semifluorinated side chains in the soft phase outside the micelle domains. As a result, reliable electrical conductivity is observed in contrast to films with non-modified MWCNT. Thus, well-dispersed, modified MWCNT provide a defined electrical conduction path at the micrometer level, which is interesting for applications in electronics and vapor sensing. Full article

To address the environmental hazards posed by oil spills and the limitations of conventional hydrocarbon monitoring techniques, a cost-effective and user-friendly gas sensor system was developed for the real-time detection and quantification of hydrocarbon contaminants in soil. This system utilizes carbon black (CB)-filled poly(methyl methacrylate) (PMMA) and poly(vinyl chloride) (PVC) nanocomposites to create chemoresistive sensors. The CB-PMMA and CB-PVC composites were synthesized and deposited as thin films onto interdigitated electrodes, with their morphologies characterized using scanning electron microscopy. The composites, optimized at a composition of 10% w/w CB and 90% w/w polymer, exhibited a sensitive response to hydrocarbon vapors across a tested range from C₂₀ (99 ppmV) to C₈ (8750 ppmV). The sensor’s response mechanism is primarily attributed to the swelling-induced resistance change of the amorphous polymer matrix in hydrocarbon vapors. These findings demonstrate the potential use of CB–polymer composites as field-deployable gas sensors, providing a rapid and efficient alternative to traditional gas chromatography methods for monitoring soil remediation efforts and mitigating the environmental impact of oil contamination. Full article

This study investigates the development of advanced radiation shielding materials incorporating bismuth oxide (Bi₂O₃) nanoparticles (NPs) into polymethyl methacrylate (PMMA) composites, comparing efficacy against I-131 gamma radiation. The NPs exhibit a 1.53-fold reduction in z-average diameter and a significantly higher surface area than Bi₂O₃, ensuring superior dispersion and structural uniformity within the PMMA matrix. These characteristics, validated through SEM, EDX, and XRD analyses, contribute to enhanced gamma radiation attenuation, leveraging the high atomic number and density of Bi₂O₃. Mechanical evaluations reveal that increasing Bi₂O₃-NPs concentrations enhances ductility but reduces tensile strength, likely due to nanoparticle agglomeration and stress concentration. Radiation shielding performance, assessed using XCOM and Phy-X/PSD simulations, demonstrates a direct correlation between Bi₂O₃ content and attenuation efficiency. Notably, composites with 75% Bi₂O₃ content exhibit attenuation properties comparable to, or exceeding, those of PbO₂, achieving superior shielding efficacy at reduced thicknesses across various photon interaction mechanisms. These findings position Bi₂O₃ NPs-enhanced PMMA composites as promising lightweight high-performance alternatives to lead-based shields. By addressing toxicity and environmental concerns associated with lead, this work emphasizes the potential of high-Z nanomaterials in advancing radiation protection applications. This study highlights a transformative approach to designing safer and more efficient shielding solutions, contributing to the next generation of radiation protection materials. Full article

Poly(methyl methacrylate) (PMMA) is a thermoplastic widely utilized in civilian-, defense-, and medicine-related applications. Therefore, inducing antibacterial properties is an additional asset when infection control is prioritized. To counter this, PMMA was mixed, for the first time, with antibacterial agents (antibacterial blend nanopowder, AP) to curb bacterial proliferation and therefore reduce the chances of infection. The reinforcing efficacy of the blend in PMMA was also assessed. Nanocomposites were developed with various nanopowder concentrations for 3D printing material extrusion (MEX). PMMA/AP nanocomposites were evaluated for their mechanical and rheological properties, thermal stability, morphological, structural, and chemical characteristics, and bacterial resistance (against Staphylococcus aureus and Escherichia coli (E. Coli) using the well diffusion method). The effect on quality metrics, such as the geometrical accuracy and pores of the 3D-printed structure was examined with micro-computed tomography. The modified PMMA had improved properties, such as increased tensile (~20% increase at 2 wt.%) and flexural strength (~10.8% at 4 wt.%), while also having strong antibacterial properties against Staphylococcus aureus and mild antibacterial properties against E. Coli. Such improvements add to the expanding portfolio of biomaterials, such as their use in the demanding defense sector and the medical field. Full article

This study presents a simple, high-throughput synthesis approach for fabricating palladium (Pd) nanomaterials with anisotropic shapes, specifically Pd nanorods, via a self-assembly process. This method avoids the use of reducing agents, surface functionalization, and stabilizing agents. Palladium–poly(methyl methacrylate) (Pd-PMMA) nanocomposites were successfully synthesized using a vapor-induced phase separation (VIPS) method. The formation of Pd nanorods was controlled by tuning key parameters, such as the Pd precursor concentration, choice of solvents, and spin coating speed. Notably, the resulting nanorods exhibited high reproducibility and ultrasensitivity as a surface-enhanced Raman scattering (SERS) platform, achieving an enhancement factor of approximately 1.8 × 10⁵, despite the relatively weak plasmonic properties of Pd. This work represents a novel, facile strategy for Pd nanorod synthesis, offering new potential for the design of Pd-based nanosensors for chemical sensing applications. Full article

Polymer networks were synthesized using the condensation method between PMMA and melamine as cross-linkers. CuO nanoparticles (NPs) and activated carbon (AC) were used as a filler. The final products PMMA/Mel, PMMA/Mel-CuO, and PMMA/Mel-AC were tested for antibacterial activities against E.coli and S. aureus. The chemical structure and composition, thermal properties, and surface morphology of the new PMMA/Mel-based nanocomposites were investigated by various techniques. The XRD and EDX results showed the successful incorporation of CuO NPs and AC into the polymer matrix. Also, the thermal stability of the PMMA/Mel polymer was significantly enhanced after adding CuO nanoparticles. This finding showed that the PMMA/Mel-CuO and PMMA/Mel-AC nanocomposites have greater activity against both bacteria than PMMA/Mel. The PMMA/Mel-CuO and PMMA/Mel-AC polymers showed high activity against S. aureus bacteria, with inhibition zones of 22.6 mm and 11.3 mm, respectively. This confirms that small-sized nanoparticles have an effective role in killing bacterial cells. Full article

Incorporating nanoparticles into denture materials shows promise for the prevention of denture-associated fungal infections. This study investigates the antifungal properties of acrylic modified with microwave-sintered ZnO-Ag nanoparticles. ZnO-Ag nanoparticles (1% and 2.5% wt.) were synthesized via microwave solvothermal synthesis (MSS). Nanoparticles were characterized for phase purity, specific surface area (SSA), density, morphology, and elemental composition. ZnO and ZnO-Ag nanoparticles were added to acrylic material (PMMA) at concentrations of 1% and 2.5% and polymerized. Pure PMMA (control) and obtained PMMA-nanocomposites were cut into homogeneous 10 × 10 mm samples. Antifungal activity of nanoparticles and PMMA-nanocomposites against C. albicans was tested using minimal inhibitory concentration (MIC) determination, and biofilm formation was assessed using crystal violet staining followed by absorbance measurements. Laboratory tests confirmed phase purity and uniform, spherical particle distribution. MIC results show antifungal activity of 1% Ag nanoparticles and the PMMA-2.5% (ZnO-1% Ag) nanocomposite. PMMA-1% (ZnO-1% Ag) nanocomposite and 1% ZnO-Ag nanoparticles are efficient in preventing biofilm formation. However, ZnO nanoparticles showed antibiofilm activity, and the PMMA-ZnO nanocomposite does not protect against biofilm deposition. Incorporating hybrid ZnO-Ag nanoparticles into PMMA is a promising antibiofilm method, especially with ZnO-1% Ag nanoparticles. Full article

The ubiquitous, rising demand for energy storage devices with ultra-high storage capacity and efficiency has drawn tremendous research interest in developing energy storage devices. Dielectric polymers are one of the most suitable materials used to fabricate electrostatic capacitive energy storage devices with thin-film geometry with high power density. In this work, we studied the dielectric properties, electric polarization, and energy density of PMMA/2D Mica nanocomposite capacitors where stratified 2D nanofillers are interfaced between the multiple layers of PMMA thin films using two heterostructure designs of the capacitors, PMMA/2D Mica/PMMA (PMP) and PMMA/2D Mica/PMMA/2D Mica/PMMA (PMPMP). The incorporation of a 2D Mica nanofiller in the low-dielectric-constant PMMA leads to an enhancement in the dielectric constant, with ∆ε ~ 15% and 53% for PMP and PMPMP heterostructures at room temperature. Additionally, a significant improvement in discharged energy density was measured for the PMPMP capacitor (U_d ~ 38 J/cm³ at 825 MV/m) compared to the pristine PMMA (U_d ~ 9.5 J/cm³ at 522 MV/m) and PMP capacitors (U_d ~ 19 J/cm³ at 740 MV/m). This excellent capacitive and energy storage performance of the PMMA/2D Mica heterostructure nanocomposite may inform the fabrication of thin-film, high-density energy storage capacitor devices for potential applications in various platforms. Full article

Background: Nanocomposite resins have been widely used in modern denture manufacturing. However, their long-term color stability is a concern for both dental professionals and patients. Purpose: to evaluate the effect of different beverages on the color stability of 3D-printed denture base resins modified with zirconium dioxide nanoparticles (ZrO₂NPs). Methods: A total of 440 specimens were fabricated and distributed into 11 groups (n = 40/group). The control group of heat polymerized (PMMA) and five groups of two different 3D-printed resins (NextDent and ASIGA) as experimental groups with various concentrations of ZrO₂NPs added to the 3D-printed resins (0.5 wt%, 1 wt%, 3 wt%, 5 wt%) in addition to one unmodified group per resin. Specimens per group are sorted into four subgroups (n = 10) according to tested beverages, as follows: coffee, tea, cola, and mineral water. Before immersion, all the specimens were exposed to 5000 thermal cycles. Color changes (ΔE₀₀) were assessed prior (T0) and following immersion for 6 days (T1) and 12 days (T2) using a spectrophotometer. Color difference values were calculated by using CIEDE2000 color difference. Data was analyzed by ANOVA and post hoc Tukey test with a significant level of less than 0.05. Results: Tea produced the highest color change for both NextDent and ASIGA materials, whereas water caused the least color change on PMMA at T2. Increasing the immersion time resulted in more color changes, with tea and coffee showing significant differences. PMMA had considerably less color change than 3D-printed resins. The color change of 3D-printed increased after adding ZrO₂NPs. Conclusions: Beverage type and immersion time have an impact on the color stability of unmodified and ZrO₂NP-modified denture base resins with significant change after immersion in tea and coffee. Full article

In this work, the effect of etching the surface of polymer matrix nanocomposites with atmospheric pressure plasma targeting to achieve enhanced dielectric properties was investigated. Polymer nanocomposites, with varying reinforcing phase content, were modified by atmospheric-pressure plasma resulting in an increase in the surface filler’s concentration. Polymethyl methacrylate (PMMA) matrix nanocomposites reinforced with zinc oxide (ZnO) nanoparticles were prepared and dielectrically studied as a function of the nanoparticle content and the plasma modified surfaces. The electrical response of the composite systems was studied by means of Broadband Dielectric Spectroscopy (BDS) over a wide range of temperatures and frequencies. The dielectric permittivity increased with the embedded phase content and with plasma surface treatment. Energy density followed the same trend as dielectric permittivity, and the plasma-treated nanocomposite with the higher ZnO content exhibited approximately 27% higher energy density compared to the unreinforced matrix. Full article

Closely packed nanoparticles in polymer films are interesting materials where collective as interactive optical properties could be tuned based on nanoparticle proximity, surface morphology, types of encapsulation and matrix parameters. Two types of polymers (polymethylmethacrylate (PMMA) and polyvinyl alcohol (PVA))-based nanocomposite films featuring dual-colored emission peaks (~578 nm and ~650 nm) were fabricated from CdSe quantum dots to study their viability in optoelectronic applications. Using a 405 nm excitation laser, the evolution of photoluminescence (PL) intensities and peak wavelengths were examined as a function of increasing excitation intensity. While PL intensities showed systematic saturation and quenching, the emission wavelengths were found to be linearly red shifting with increasing excitation intensities in the PMMA films. The 650 nm emitting QDs seem to tune the PL saturation behavior in these films, as opposed to the PVA-based materials, where no such impact was seen. The material system could be a low-cost, low-maintenance alternative for future mesoscale sensing and light-emitting device applications. Full article

Composite polymer materials have high strength and lightness, which makes them attractive for use in a variety of structures and products. The present article contains an overview of modern works devoted to the production of composite materials based on poly(methyl methacrylate) (PMMA) with improved characteristics. The possibility of obtaining such materials can be a key area for creating more efficient and durable products in various industries. Various methods were considered to improve the characteristics of PMMA by doping the polymer matrix with carbon nanotubes (CNTs), graphite, nanohydroxyapatite particles, micro-zirconia nanoparticles, titanium dioxide, etc. The possibilities of using the obtained composite materials in various industries such as aviation, automotive, construction, medical and others are discussed. This article also presents the results of our own research on the mechanisms of interaction of PMMA with single-layer CNTs, leading to the creation of a composite polymer system “PMMA+CNT”, achieved using the modern quantum chemical method DFT. This article presents a review of the recent research on the effect of CNTs on the mechanical and electrically conductive properties of nanocomposite materials. The outcomes of this study can be important for the development of science and technology in various fields, from fundamental chemistry to applied scientific research. Full article

An improvement of water supply and sanitation and better management of water resources, especially in terms of water reuse, is one of the priorities of the European Green Deal. In this context, it is crucial to find new strategies to recycle wastewater efficiently in a low-cost and eco-friendly manner. The immobilization of inorganic nanomaterials on polymeric matrices has been drawing a lot of attention in recent years due to the extraordinary properties characterizing the as-obtained nanocomposites. The hybrid materials, indeed, combine the properties of the polymers, such as flexibility, low cost, mechanical stability, high durability, and ease of availability, with the properties of the inorganic counterpart. In particular, if the inorganic fillers are nanostructured photocatalysts, the materials will be able to utilize the energy delivered by light to catalyze chemical reactions for efficient wastewater treatment. Additionally, with the anchoring of the nanomaterials to the polymers, the dispersion of the nanomaterials in the environment is prevented, thus overcoming one of the main limits that impede the application of nanostructured photocatalysts on a large scale. In this work, we will present nanocomposites made of polymers, i.e., polymethyl methacrylate (PMMA), and photocatalytic semiconductors, i.e., TiO₂ nanoparticles (Evonik). MoS₂ nanoflakes were also added as co-catalysts to improve the photocatalytic performance of the TiO₂. The hybrid materials were prepared using the sonication and solution casting method. The nanocomposites were deeply characterized, and their remarkable photocatalytic abilities were evaluated by the degradation of two common water pollutants: methyl orange and diclofenac. The relevance of the obtained results will be discussed, opening the route for the application of these materials in photocatalysis and especially for novel wastewater remediation. Full article