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Highlights The characterization of S. persica (Salvadora persica) extract, which involved evaluating its antibacterial activity, demonstrated the extract's strong efficacy. Additionally, incorporating it into PMMA/HA showcased the composite's good antibacterial activity. The objective of this work is to evaluate how the incorporation of S. persica extract affects the wear resistance of the dental composite PMMA/HA, considering the critical importance of wear resistance in dental applications. The wear response of this biocomposite was tested against an Alumina ball using a pin‐on‐disc tribometer. Initially, the hydroxyapatite (HA) micro particles demonstrate a remarkable influence on wear behavior when incorporated at an optimal percentage (10%wt). This optimal inclusion rate not only significantly increases the wear rate but also instigates a shift in the wear mechanism, favoring abrasive wear while minimizing adhesive wear comparing to PMMA. The addition of the extract nanoparticles to the composite PMMA/HA decreases the wear rate except the composite containing 10 wt% of each filler. Additionally, it introduces adhesive wear, in addition to the existing fatigue and abrasion wear. Thus, the composite PMMA/HA could accommodate up to 10 wt% of the S. persica extract as the optimal percentage that provides antibacterial activity to this biocomposite without exhibiting a deterioration in wear performance. The evaluation of the effect of incorporating S. persica extract, which provides antibacterial activity, on the wear resistance of the PMMA/HA dental composite generally demonstrates a reduction in this property. The addition of S. persica extract introduces adhesive wear in addition to the fatigue and abrasion wear already present in the PMMA/HA composite. The composite PMMA/HA can accommodate up to 10 wt% of S. persica extract without compromising its wear performance. [ABSTRACT FROM AUTHOR]

Artificial sub‐microfluidic and nanofluidic devices allow for studying mass or ion transport effects under spatial confinement. It remains challenging to fabricate large‐scale, nanofluidic channels of well‐defined thickness for fundamental studies and practical applications, especially for extreme confinement conditions (e.g., with sub‐10 nm channel height). Here, a strategy is reported to fabricate large‐scale nano‐channels with the channel height down to 5.0 nm. The fabrication is enabled by developing ultra‐flat and ultra‐thin polymethylmethaacrylate (PMMA) layers as the spacer. The ease of scaling up the channel length to a millimeter in the lateral dimensions with high mechanical stability is demonstrated. Furthermore, experimental evidence is provided of the role of the mechanical coupling between the spacer and capping materials in determining the device's mechanical properties, and how controlling the channel width and the top graphite thickness can be employed to tailor the device's mechanical properties. Finally, employing near‐field IR experiments, the decay constant is established for the near‐field absorption intensity of PMMA molecules inside the channel by increasing the top layer thickness. This work develops a novel method for fabricating large‐area, mechanically stable nano‐channels for nanofluidic devices and lays the foundation for further in situ spectroscopic studies of electrochemistry within sub‐10 nm confinement. [ABSTRACT FROM AUTHOR]

Insects attach to various surfaces that differ, among others, in roughness and wettability. Identifying surface characteristics that allow or prevent insects from attaching are an important research avenue of pest control. Here we take an experimental approach to analyse the attachment of common bed bugs, Cimex lectularius Linnaeus (1758), to Perspex (PMMA) substrates. We construct a reliable centrifuge device that allows the measurement of attachment forces at substrate roughnesses, Ra, between 0.02 and 1.3 μm and at two wettabilities. Our results suggest that bed bug attachment to surfaces is minimal at a substrate roughness of 0.2 and 0.4 μm on normal PMMA, where the lowest attachment force was 0.8 mN and the safety factor 15. At lower and higher roughness, attachment forces were higher and the safety factor increased to a maximum of 133. On PMMA that was made superhydrophobic by spray‐coating, attachment was lowest (0.2 mN) at the lowest roughness and continuously increased with increasing roughness, reaching 2.5 mN and a safety factor of 46. For every roughness, attachment forces were lower on superhydrophobic than on normal PMMA. This knowledge may inspire the development of repelling substrates for bed bug control. [ABSTRACT FROM AUTHOR]

Highlights Recently, thermosetting epoxy resin is expected to be substituted by thermoplastic featured from green circular economy. Poly(methyl methacrylate) (PMMA) has been well known as one promising thermoplastic resin, although its mechanical property needs to be further investigated. In this paper, the free radical polymerization of methyl methacrylate (MMA) was initiated by lauroyl peroxide/N,N‐dimethylaniline (LPO/DMA) and lauroyl peroxide/N,N‐dimethyl‐p‐toluidine (LPO/DMT) redox system at room temperature, respectively. The PMMA (n(MMA:LPO:DMA) = 200:1.2:1) exhibited excellent mechanical properties, and the tensile strength was 66.5 MPa, the bending strength was 118.0 MPa. The tensile strength increased to 78.9 MPa at −40°C, which suggested a promising application at low temperature. The resin was applied to fabricate continuous glass fiber reinforced PMMA (GF/PMMA) composites by vacuum‐assisted resin infusion. The 0° tensile strength and modulus were 1.17 and 43.7 GPa and 90° tensile strength and modulus were 48.3 MPa and 13.2 GPa, respectively. The mechanical properties of GF/PMMA composites are higher than GF/epoxy. Moreover, PMMA resin and glass fiber can be recycled from GF/PMMA composites by MMA as solvent, which is more energy‐efficient and environment‐friendly. This work is of great significance for preparing sustainable resin and composites. GF/PMMA composites were fabricated by vacuum perfusion. GF/PMMA composites showed higher mechanical properties than GF/epoxy. GF/PMMA composite was recycled with MMA and closed‐loop recovery was achieved. [ABSTRACT FROM AUTHOR]

Inorganic fillers like hexagonal boron nitride (h‐BN) have the potential to enhance the thermal conductivity of polymer mixtures. However, it has been restricted due to poor dispersion of particles in polymer matrices by melt mixing process. The addition of inorganic powders into sticky prepolymer is expected to alleviate the aggregation of powders. In this paper, h‐BN/polymethyl methacrylate (PMMA) composites were prepared by in situ polymerization of methyl methacrylate (MMA) with 5 and 20 μm of h‐BN particle as fillers respectively, for even distribution of fillers with in composites. The structures and properties of composites were characterized by FT‐IR, DSC, TGA, SEM, laser thermal conductivity meter and universal electronic tester. By SEM, it can be seen that a highly uniform dispersion of h‐BN in PMMA. When the mass fraction of h‐BN is 20 wt%, the thermal conductivity of the composites is increased by 107% for 5 μm h‐BN and 189% for 20 μm h‐BN, respectively. With the mass constituting of 5 wt% h‐BN, majority of mechanical characteristics of the composite, such as tensile strength, tensile modulus, along with impact strength, are enhanced, alongside a decrease in bending strength. This work would provide a filling strategy of h‐BN into the polymer matrices to achieve uniform dispersion, and enhance both the thermoconductivity and mechanical strength of thermoplastic composites. Highlights: A technique for creating h‐BN/PMMA composites using in suit redox polymerization.Ehancing the thermal conductivity of these composites is achievable through the even distribution of h‐BN flakes within the PMMA matrix.It provides a reference for the design of future h‐BN/PMMA composites with favorable the thermal conductivity which achieves a good balance between performance and cost. [ABSTRACT FROM AUTHOR]

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 (Ud ~ 38 J/cm3 at 825 MV/m) compared to the pristine PMMA (Ud ~ 9.5 J/cm3 at 522 MV/m) and PMP capacitors (Ud ~ 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. [ABSTRACT FROM AUTHOR]

Fractional differential viscoelastic models can describe complex material behaviours and fit experimental data well; however, the physical significance of model parameters is difficult to express. In this study, the fractional differential Maxwell, Kelvin, and Zener models were used to fit the short-term creep compliance curves of polymethyl methacrylate at different ageing times. The model fits were in good agreement with the experimental data. As the ageing time increased, the fractional differential Zener model showed a relative increase in the modulus parameter of the spring and a relative decrease in the modulus parameter reflecting the viscosity of the spring-pot, which indicated that physical ageing made the material more elastic. The relaxation time of the material increased, which indicated that the physical ageing reduced the free volume of the material, hindered the movement of molecules/segments, and increased the time required for the material to reach equilibrium. The fractional order of the model decreased, which reflected the phenomenon that physical ageing reduced the creep compliance of the material. Using the relaxation time as the time scale, the creep curves at different ageing times under the same stress level could be superimposed, naturally presenting the time–ageing time equivalence principle. [ABSTRACT FROM AUTHOR]

Polymer specifications' optimization for tailored applications is desirable for enhanced applicability. In this research, we have successfully prepared the PMMA/metal oxide (0.1 wt% CeO2, and TiO2) through a feasible casting method. The implications of the metal oxides incorporation were explored. XRD reveals the successful formation of the composites, with 20 nm crystallite size of both composites. FTIR reinforces the intended composite formation with significant bands allocation. Optical bandgaps for PMMA/CeO2 and PMMA/TiO2 are 2.91 and 3.15 eV for direct transitions, respectively. For indirect transitions, the bandgap is around 3.33 eV for both. Other optical parameters were calculated as real and imaginary dielectric constants. THz displays a linear manner with a somewhat more PMMA fixed band due to the inharmony of intermolecular vibration mode. Dielectric studies manifest polymer loss spectra with multiple non-Debye relaxation progressions β, and γ relaxations alongside MVS polarization for films containing CeO2 or TiO2. The synthesized nanocomposites indicated antibacterial influence against (S. aureus, and B. subtilis) as Gram-positive bacteria, and (E. coli, and K. pneumoniae) as Gram-negative bacteria, (C. albicans) (A. niger) as yeast and Fungi strains. The PC samples show a high impact against Gram-positive bacteria, yeast, and Fungi strains, while PT samples show a high impact against Gram-negative bacteria. [ABSTRACT FROM AUTHOR]

In this study, PMMA/Bentonite and PMMA/HNT nanocomposites were synthesized by in-situ and solution blending methods by using polymethyl methacrylate (PMMA) obtained from methyl methacrylate by emulsion polymerization method and bentonite and halloysite (HNT) at different ratios (5 wt.% and 10 wt.%). Biodegradable PMMA/PLA, PMMA/PLA/Bentonite, and PMMA/PLA/HNT were obtained by mixing the synthesized PMMA and PMMA/clay nanocomposites with a polylactic acid (PLA) with PMMA:PLA weight ratio of 50:50. Characterization studies of synthesized nanocomposites; Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA) and Scanning Electron Microscope (SEM) analyzes, and Shore-D hardness test was performed. In addition, to observe the effects of clay additives and production methods on biodegradability, the synthesized samples were buried in two different soils, humus soil and cactus soil, and monitored for six months. When the obtained nanocomposites were compared with the pure polymer, it was determined that the hardness values of the nanocomposites were much higher than the pure polymer, and their thermal stability increased with HNT and bentonite additives. When nanocomposites synthesized by the in-situ production method and solution blending production method are compared, it was determined that nanocomposites produced by the solution blending method degrade faster in the soil and show better distribution in the structure. In addition, it was observed that cactus soil created a better degradation environment than humus soil, and bentonite accelerated degradation more than HNT. [ABSTRACT FROM AUTHOR]

Nerve injuries and neurodegenerative disorders remain serious challenges due to the poor results of nerve cell regeneration. The most promising treatment for such injuries is treatments based on stimulating cells to grow and differentiate stem cells in that area into nerve cells, but there are obstacles in controlling the growth and differentiation into fully functional nerve cells and research is ongoing to overcome these obstacles. In this study, polymethyl methacrylate (PMMA) and its laser modified surfaces were used for cell culture and differentiation into neuron-like cells. In order to show the differentiation of PC12 cells into neuron-like cells, the expression levels of the neuronal markers Map2 and Synapsin-1 were examined. The results showed the growth of PC12 on raw PMMA was increased significantly compared to the control group and micrometric parallel grooves lead to a significant difference in cell growth compared to raw PMMA. Also, the simultaneous irradiation of laser to the cell cultured on PMMA caused more cell adhesion on the surface, faster growth and differentiation of PC12 into neuron-like cells. [ABSTRACT FROM AUTHOR]

The aim of the present in vitro comparative study is to validate a novel composite polymer, named "ONLY", developed to overcome the mechanical drawbacks of conventional, metal-reinforced poly(methyl methacrylate) (PMMA) interim restoration. Ten interim restorations were designed and fabricated (five in the composite "ONLY" group, and five in the metal-reinforced PMMA group). All the samples were screwed into the prototype models, simulating a complete edentulous mandible rehabilitated with six straight implants. Outcome measures were break point (load, N) and displacement (mm) through a static compression test, and material behavior through a dynamic cyclic test method (fatigue test). A total of 20 samples were tested (10 for static and 10 for dynamic). In each group, five samples (test and control) were used. All the specimens completed the mechanical tests, as planned. There was no statistically significant difference between groups for any test. In the test group, the break point was 1953.19 ± 543.73 N, while it was 2031.10 ± 716.68 N in the control group (p = 0.775). The displacement was 1.89 ± 0.34 mm in the test group and 1.98 ± 0.75 mm in the control group (p = 0.763). Using the dynamic cyclic test method, in the control group the mean load was 2504.60 ± 972.15 N, while in the test group the mean load was 3382.00 ± 578.50 N. The difference between groups was 877.40 ± 579.30 N (p value = 0.121). Within the limitations of this in vitro study, the novel composite polymer can be used to immediately load dental implants. Further clinical research is needed to confirm these preliminary results. [ABSTRACT FROM AUTHOR]

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Polymeric nanocell foam is a promising material that faces manufacturing challenges. Producing sizable and thick foams for properties testing has been challenging. This study aims to scale up and understand the foaming mechanism of nanocellular foams by controlling the saturation temperature, pressure, and molecular weight distribution of the matrix to fine‐tune the glass transition temperature of the polymer/gas mixture. The hot‐press foamed samples possess a 100 × 70 × 6 ~ 8 mm3 dimension and a cell size of less than 200 nm. Bimodal structures can also be created by controlling the critical processing parameters. Introducing 37% microcells into unimodal nanocellular foam reduced the relative density from 0.29 to 0.19. The thermal conductivity of the foams was tuned by controlling the cell size distribution. Unimodal nanofoams have the lowest thermal conductivity for foams of the same density due to the Knudsen effect and tortuosity. The measured thermal conductivity is in agreement with theoretical models. Highlights: PMMA nanofoam with a dimension of 100 × 70 × 6–8 mm3 and cell size below 200 nm.The morphology of nanofoams was tuned to be unimodal and bimodal.The foam density of the bimodal nanofoams was lowered below 0.238 g/cm3.The thermal conductivity of foams was tuned by controlling the cell structure. [ABSTRACT FROM AUTHOR]

The authors studied Poly (methyl methacrylate) also called PMMA films with different concentrations of Poly (9, 9′-di-n-octylfuorenyl-2, 7-diyl) also called PFO and concluded that 1% PFO blended with PMMA is the best choice for opto-electronic applications. In the present study, the authors prepared nanocomposite films of PMMA + 1% PFO + different concentrations of TiO2 nanoparticles. The resulting films were subjected to FTIR, XRD, UV–visible, fluorescence and electrical conductivity studies. The polymer matrix undergoes modifications in its molecular and microstructural characteristics as evidenced by FTIR and XRD results. The addition of TiO2 nanoparticles leads to a uniform dispersion and good interaction with the blend matrix resulting in homogeneous films. The additional peaks were found at a wavenumber of 3620 cm−1 in FTIR can be attributed to stretching vibration of TiO2. The presence of TiO2 nanoparticles is confirmed by the distinctive diffraction peaks observed at 25.4°, 37.8°, 48.3°, 54.3°, 55.2°, and 62.8°. With a shift in the absorption peak towards higher wavelengths, the nanocomposites show greater absorption in the UV and visible regions. As the concentration of TiO2 increases, the optical parameters such as absorption coefficient, extinction coefficient, Urbach energy, refractive index and optical conductivity also increase. The direct optical band gap of the PNC films decreases from 5.03 to 3.06 eV and indirect band gap decreases from 4.52 to 1.92 eV at 10 wt% of TiO2 concentration. The addition of TiO2 nanoparticles to the PFO/PMMA matrix resulted in an increase in fluorescence emission intensity. The AC electrical conductivity exhibits increasing trend with frequency in Audio-Frequency range. Thus TiO2 nanoparticles improve the overall optical, electrical, and structural properties of PFO-PMMA nanocomposites. This means that they can be used in a variety of optoelectronic and advanced optical devices. [ABSTRACT FROM AUTHOR]

Energy storage devices play a crucial role in all kinds of electronic devices. Rechargeable lithium-ion batteries have run across problems such as energy density, toughness, and safety. In order to conquer these hindrances, in this work, a novel solid-state polymer electrolyte for lithium-ion batteries was synthesized by blending polymethyl methacrylate (PMMA) in poly (vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP) with constant weight percent of ethylene carbonate (EC) and lithium bis (trifluoro methane sulfonyl) imide (LiTFSI), and different concentrations of calcium oxide (CaO). The composite polymer electrolytes (CPEs) (PVdF-HFP:PMMA:LiTFSI:EC:CaO) were fabricated using the solution casting technique. Powder XRD reveals enhancement in intensity with increasing CaO content. FTIR shows the interaction between the polymer-salt matrix. Among the analyzed films, PVdF-HFP:PMMA:LiTFSI:EC:CaO (10 wt.%) exhibits high ionic conductivity (10–4 S/cm) and good electrochemical (4 V) and thermal stability (350℃) which makes it suitable for solid-state electrolyte as a separator in energy storage applications. [ABSTRACT FROM AUTHOR]

Photonic Crystal Fiber (PCF) constructions, controlled light propagation for measuring amplitude, phase, polarization and wavelength of the spectrum, and PCF-incorporated interferometry techniques are the foundations upon which sensors operate. But the existing PCF techniques have very large stretching that tends to be difficult to align due to the cross-polarization mode of the optical fiber structure. Hence, the novel Polymer graphene-based Hexagonal cladding is designed by using a hexagonal hollowed core and a cladding material of Polymethyl methacrylate reinforced with gyroidal graphene which increases confinement strength. Once the crystal structure is designed, normally the presence of substrate the Q-factors is degraded. On substrates, Q-factors are enhanced by fine-tuning the position of the neighboring holes. Hence, the novel Bilayer Grating Stratum solves the degrading issues in Q-factors, which utilizes a Silicon polyamide-coated FBG in the crystal that is incorporated using the Femto-laser technique thereby increasing the wavelength tenability. To identify the electric field pattern, the designed structure is simulated in COMSOL software. Thus, the proposed system has a high sensitivity of 22 with a low material loss of 0.1% and a low response time of 0.2 s. [ABSTRACT FROM AUTHOR]

Ultrasonic Hot Embossing of polymers is one of the most attractive manufacturing methods of high-quality and complex microparts needed for biological and chemical processes. A little simulation work has been done to study the deformation mechanism and the required load in the Ultrasonic Hot Embossing of polymethyl methacrylate (PMMA). This paper developed a 2D coupled thermo-mechanical finite element model to simulate the forming behavior of the ultrasonic embossing process of PMMA, optimize the mold microfeature corner, and predict the embossing load as well. VDISP ABAQUS subroutine has been used to describe the downward motion of the mold assisted with ultrasonic vibration. The Arbitrary Eulerian-Lagrangian re-meshing technique has been implemented to refine the deformation zone during simulation to avoid divergence due to localized excessive deformation. Embossing load, temperature, stresses, strains, and energy dissipation have been recorded and analyzed. Simulation results revealed that the coupled thermo-mechanical FE Model efficiently captures the deformation behavior and Embossing load. It also proved that a Mold microfeature corner of 20 μm filet radius is recommended to adequately fill out the area around the mold and maintain uniform temperature and strain distributions. [ABSTRACT FROM AUTHOR]

Highlights This study intends to investigate the mechanical, thermal, and aging behaviors of 3D‐printed PLA (polylactic acid)‐blend with 10% polymethyl methacrylate (PMMA) and 10% alumina polymer composites for biomedical applications using compressive, DSC, and DMA analysis. The experimental results revealed that aged PLA blend with alumina samples increased compressive strength by 60.1% and 37.8% during hydrolytic and enzymatic degradation, respectively, compared to aged PLA samples. Also, it was reported that the PLA blend with PMMA samples increased compressive strength by 51.1% and 24% after hydrolytic and enzymatic degradation, respectively, as compared to aged PLA samples. Furthermore, DSC analysis revealed that alumina blended samples had a higher Tg than pure PLA and PMMA blended samples. In addition, DMA investigation revealed that the Tg of aged neat PLA, PLA/PMMA, and PLA/alumina increased by 4.38%, 4.8%, and 4.6%, respectively, compared to unaged polymer composites. Additionally, PLA/alumina‐aged samples exhibited stronger aging properties than neat PLA and PLA/PMMA blended‐aged samples. It was reported that the weight loss of PLA/Alumina was lowered by 10.7% and 15.6% compared to aged PLA/PMMA samples, for hydrolytic and enzymatic aging respectively. It was found that PLA alumina has better mechanical, thermal, and degradation resistance than PLA materials. Alumina and PMMA materials were blended with PLA. Examined the aging and mechanical properties of PLA blended composites. Utilized hydrolytic and enzymatic aging for biomedical applications. Evaluated mechanical strength performance of aged and unaged samples. DSC and DMA were utlised for this research. [ABSTRACT FROM AUTHOR]

The fast advancements in technology have generated significant interest in optoelectronic materials. Nevertheless, the difficulty of creating affordable materials with exceptional optical characteristics is an ongoing challenge. Therefore, the objective of this work was to tune the optical properties of poly(methyl methacrylate) (PMMA) by embedding silver vanadate (SV) in the polymer matrix. Moreover, the wettability test of the fabricated composite membranes showed a hydrophobic behavior, with the PMMA film containing 0.6 wt.% SV showed a contact angle of 86.75 ± 0.7°. Furthermore, SV showed high thermal stability with a maximum weight loss of 0.74% at 830°C, which is very high thermal stability at high temperatures. In addition, the 0.6 wt.% SV@PMMA film exhibited a maximum weight loss of 96.7% at 785°C. Moreover, the 0.6 wt.% SV@PMMA film showed the lowest indirect band gap energy (2.02 eV) compared to the other films and pure SV NPs. The findings demonstrate the potential of the synthesized films for optoelectronic applications. [ABSTRACT FROM AUTHOR]

Several studies have confirmed the antimicrobial effect of a mixture solution composed of hydrogen peroxide 3% and vinegar 4% (HPV) as a disinfectant solution used for Polymethylmethacrylate (PMMA) denture base. Immersing dentures in this solution may result in alterations to the physical characteristics of PMMA. This in vitro study was conducted to examine the effect of different immersion times of HPV on surface roughness of heat cure and computer-aided design/computer- aided manufacturing (CAD/CAM) PMMA. Material and methods: 60 PMMA samples were prepared and divided equally according to two different types of PMMA materials: a) heat cure (H) and b) computer-aided design/computer-aided manufacturing (CAD/CAM) (A) PMMA. Each type was subdivided into three groups (10 samples for each) according to immersion time in the HPV mixture prepared with a ratio of (1:1); the control group was not immersed (H0 and A0), the second group was immersed for 90 days (H1 and A1) and the last group for 180 days (H2 and A2). Each group was examined before and after two immersion times with surface roughness measured by a portable roughness tester. The collected data were analyzed using Shapiro-Wilk for normality test and statistically analyzed with Two-way ANOVA. The data were considered statistically significant when P≤ 0.05. Results: statical analysis shows the highest surface roughness mean value was observed for the heat cure PMMA group (0.141). Statistical analysis showed no significant changes in the two immersion times (90, and 180 days) for both materials. Conclusions: The study concluded that HPV could be used as an alternative disinfectant solution for heat and CAD/CAM PMMA without promoting deleterious effects on surface roughness. [ABSTRACT FROM AUTHOR]

Polymeric sheets of poly(methyl methacrylate) loaded with organic dye with various amounts of metal oxide nanopowder are promising alternatives to traditional inorganic materials, as they have similar mechanical properties to flexible substrates with relatively high refractive index that can be used in flexible optical/optoelectronic devices. Polymeric sheets of poly(methyl methacrylate) loaded with boron subphthalocyanine chloride with various amounts of cerium(IV)-zirconium(IV) oxide nanopowder were fabricated. Fourier transform infrared spectroscopy and X-ray diffraction techniques were used to examine and analyse the structure of the fabricated polymer sheets. Introducing organic dye and nanofiller in the polymer molecular chains matrix does not change the infrared characteristic transmission peaks. The X-ray diffraction spectra of the polymeric sheets have an amorphous nature. Characterized by spectroscopic measurements (fluorescence, transmittance, and reflectance), the optical properties such as the optical energy gap, emission bands, and refractive index of the fabricated polymer sheets were explored. By controlling the concentration of boron subphthalocyanine chloride and cerium(IV)-zirconium(IV) oxide nanopowder, energy gaps and the refractive indexes of the fabricated polymer sheets can be controlled. The poly(methyl methacrylate) loaded with boron subphthalocyanine chloride with 20 mg cerium(IV)-zirconium(IV) oxide nanopowder showed optical energy gap transitions at 4.79, 2.66 eV, and 2.08 eV, it has the highest PL intensity with a strong emission band at 413 nm, and also it has the highest refractive index. Finally, the obtained experimental results showed that the prepared polymer systems can be considered promising flexible polymer sheets for optics, and photonics devices. [ABSTRACT FROM AUTHOR]

In this work, we study the combinational effects of UV irradiation, functionalized graphene (FG) sheets, and organic solvents on the crack evolution in PMMA/FG composites. The UV irradiation leads to the scission of polymer chains in the PMMA/FG composites with the FG sheets hindering the scission of polymer chains. The evolutions of surface cracks and the pre-formed crack in the PMMA/FG composites depend on the diffusion of organic solvents. The increase of Hansen solubility distance (HSD) with the solvent follows the order of cyclohexanol, 2EA, and 1-butanol sequence. The solvent with a smaller HSD diffuses faster in polymer, producing larger tensile stress to cause the nucleation and growth of cracks. The density of surface cracks and the length of the pre-formed crack decrease with increasing the FG fraction and HSD and increase with increasing the UV dose. The activation energy and heat of mixing for the growth of surface cracks increase with the FG fraction and HSD and decrease with increasing the UV dose. The activation energy for the growth of the pre-formed crack increases with increasing the FG fraction and HSD and decreases with increasing the UV dose. The activation energy for the inculcation period of the growth of the pre-formed crack has an opposite trend to the activation energy for the growth of the pre-formed crack versus the FG fraction, HSD, and UV dose. The experimental results show that the evolutions of surface cracks and the pre-formed crack follow the scaling law describing the diffusion of organic solvents in solids. [ABSTRACT FROM AUTHOR]

A macromolecule viz; poly (p-phenylene azomethine) (PPAM) has been synthesized by a novel methodology for utilization in opto-electronic devices. The developed PPAM has been comprehensively characterized by using UV-Visible and FTIR techniques. X-ray studies affirmed the crystalline nature of PPAM, while UV-visible absorption spectroscopy, in DMSO, confirmed the extensive conjugation; with promising optical properties. Thermal stability was evaluated through thermogravimetric analysis. The computational analysis of PPAM was also implemented to complement the experimental observations. To explore practical applications, a homogenous film was successfully developed from PPAM with a minor quantity (0.25wt%) of poly(methyl methacrylate) PMMA. The resulting film was characterized for thermal stability, morphological features, and optical behaviour. The findings underscore the potential of PPAM as a versatile material with tunable properties, opening avenues for innovative applications in the realm of optical science. [ABSTRACT FROM AUTHOR]

In this study, the uncertainty of equivalent Young's modulus (EN) estimation from nanoindentation experiments by following the conventional method for poly (methyl methacrylate) (PMMA) is discussed in detail. A constant strain rate load function is followed to perform nanoindentation experiments in a wide range of applied loads. It is well known that the stiffness (S) value is the primitive requirement for EN estimation which is affected by viscous deformation. Thus, a load function with prolonged holding time (150 s) and fast unloading rate (4500 µN/sec) is followed to minimize viscous effects on unloading data. Thereafter, S values are estimated by fitting with various equations reported in the literature for different ranges of unloading data. In addition, the contact area (Ac) is estimated from the tip area calibration data and the actual tip geometry relationship. The EN values are calculated from estimated S and Ac, and it is found that the selection of the fitting range for S estimation is not universal to obtain EN ~ tensile/compression modulus (E). Finally, it is concluded that the selection of the fitting range relies on the applied load, choice of contact area estimation method, and fitting equation. [ABSTRACT FROM AUTHOR]

This study fixates on determining the optimum laser input parameters that simultaneously meet the desired kerf width and depth during CO2 laser cutting of various polymethylmethacrylate (PMMA) sheets. It has three contributions. The first is to model the cutting process of PMMA by polynomial curve fitting as a function of laser power, laser speed, and standoff distance. R-squared (R2), adjusted R2 and root-mean-square error (RMSE) criteria were taken into account to measure the performance of the proposed model. The effect of laser parameters on the process is investigated by analysis of variance (ANOVA) and sensitivity analysis. The second is to optimize the derived nonlinear regression models using genetic algorithm (GA), particle swarm optimization (PSO), whale optimization algorithm (WOA) and ant lion optimization (ALO) metaheuristic methods and compare the performances of the algorithms. The third is to compare the adequacy of the optimization process with the artificial neural network (ANN). The investigations exhibited that the best-fitting polynomials are obtained with the R2 and adjusted R2 values of over 99% and 97%, respectively. ANOVA and sensitivity test revealed that the sensitivity of the laser power, which is the most effective parameter, was 150 at low powers and decreased to 0 as the power value increased. When the nozzle distance is 4.1, the proposed metaheuristics gave effective and sufficiently accurate results. PSO stood out in terms of both best cost value (3.49 × 10–8) and relative error value (0.19%). The relative error of the ANN was found as 3% in terms of kerf depth. [ABSTRACT FROM AUTHOR]

This work aims to evaluate the effect of acquisition parameters of the abdominal computed tomography protocol on image quality and dose, including the contrast-to-noise ratio (CNR), noise, spatial resolution (SR) as well as volumetric computed tomography dose index (CTDIvol). The measurements have been performed on a 16-slice HITACHI scanner using the polymethylmethacrylate phantom for CTDIvol and Catphan 500 for image quality. Two tube voltages of 120 kVp and 100 kVp have been analyzed while varying the tube current settings from 100 to 300 (mA) to measure image quality quantities and dose (CTDIvol). The scanning with 100 kVp compared to 120 kVp has led to a dose reduction up to 38% at mAs ranging from 100 to 300, a decrease in CNR by 28%, with a slight decrease in spatial resolution accompanied by an increase in noise. This work has shown that despite the increase in noise at 100 kVp, it is possible to reduce the dose without affecting the quantities of spatial resolution and the contrast/noise ratio by lowering the tube voltage from 120 kVp to 100 kVp. [ABSTRACT FROM AUTHOR]

Melamine polyphosphate (MP), a halogen-free flame retardant was utilized to prepare flame retardant enhanced montmorillonite (MP-MMT), which was introduced into polymethyl methacrylate (PMMA) by emulsion polymerization to improve its heat resistance and flame retardancy. The decorated PMMA were characterized by SEM, FTIR, XRD, and XPS, indicating that MP-MMT/PMMA composites were successfully prepared. The resulting composites exhibited excellent heat resistance, the temperature at maximum weight loss rate was increased from 360 °C to 377 °C, and the char residue at 500 °C was increased to 1.93%. In addition, the LOI value of PMMA composite system was increased from 17.2% to 22.4%, and MP-MMT/PMMA-3 achieved UL-94 V-1 rating. Compared with pure PMMA, the total heat release and peak heat release rate of MP-MMT/PMMA were reduced by 23.0% and 32.4%, respectively. The total smoke release of the optimal flame-retardant PMMA resin decreased by 22.1%, the CO production increased slightly, and the CO2 production decreased significantly. This indicates that the incorporation of MP-MMT has a good effect on flame retardancy. Finally, the flame retardant mechanism of MP-MMT to inhibit PMMA combustion was analyzed. The intercalation modification of MMT is potentially valuable for flame retardant studies of PMMA. [ABSTRACT FROM AUTHOR]

Choosing polymers as antenna substrates has become a significant challenge, as it involves addressing the escalating demands of emerging 5G applications for bandwidth and data transfer, while simultaneously prioritizing environmental adaptability. Furthermore, various applications such as IoT and smart wearables utilize specific frequency bands, such as sub-6 GHz, millimeter waves (MMwaves), and terahertz, which are characterized by unfavorable conditions of propagation. The current in-depth study focuses on the exploration of two specific polymers, Polymethyl methacrylate (PMMA) and Polydimethylsiloxane (PDMS), as potential substrates for designing flexible microstrip antenna operating at 5.8 Ghz. The proposed antenna showcases a compact design, measuring 25.6 × 45.6 × 2.2 mm3 for PMMA and 20.2 × 40.2 × 2.2 mm3 for PDMS. Notably, with a consistent substrate thickness of 2.2 mm, the PMMA polymer outperforms PDMS, achieving a higher gain of 4.4dBi compared to PDMS's gain of 3.75dBi. Furthermore, both substrates exhibit improved performance under bending conditions and excellent impedance matching, it is worth that in both cases, the return loss remains under 22 dB. This comprehensive analysis firmly establishes the viability of PMMA and PDMS in delivering efficient flexible microstrip antenna performance, thereby contributing significantly to the advancement of IoT devices technology and design within the Sub-6 GHz frequency band. [ABSTRACT FROM AUTHOR]

In this study, PMMA/SiO2 composites were fabricated with monodispersed SiO2 and PMMA using four distinct methods—physical blending, in situ polymerization, random copolymerization, and block copolymerization—to investigate the composites' thermal, mechanical, and optical properties. In the physical blending approach, SiO2 nanoparticles were dispersed in a PMMA solution, while during in situ polymerization, silica nanoparticles were incorporated during the synthesis of PMMA/SiO2 composites. 3-methacryloxypropyltrimethoxysilane (MPS) was modified on the SiO2 surface to introduce the reactive double bonds. The MPS@SiO2 was either random- or block-copolymerized with PMMA through RAFT polymerization. The PMMA/SiO2 composites prepared via these different methods were characterized using FTIR, TGA, and DSC to determine their chemical structures, thermal degradation temperatures, and glass transition temperatures, respectively. Scanning electron microscopy (SEM) was employed to observe the microstructures and dispersion of the composites. This comprehensive analysis revealed that the PMMA/SiO2 composites prepared via block copolymerization exhibited thermal stability at temperatures between 200 and 300 °C. Additionally, they demonstrated excellent transparency (86%) and scratch resistance (≥6H) while maintaining mechanical strength, suggesting their potential application in thermal insulation materials. [ABSTRACT FROM AUTHOR]

This study applies the Morris method for a sensitivity analysis to evaluate the input parameters' influence on the heat release rate in a pyrolysis model, focusing on two materials, poly(methyl methacrylate) (non-charring) and poly(vinyl chloride) (charring), examined under a cone calorimeter. A key aspect of our exploration was the role of input parameter variation intervals on the sensitivity outcomes. We analyzed three interval-setting methods: 1. A standard ±10% deviation from the nominal value, commonly used in the literature. 2. A range determined by the experimental uncertainties for individual parameters. 3. A span from minimum to maximum values found in existing literature for each parameter. Our intensive literature review supported the framing of intervals for the latter two methods. Our findings underscore the critical role of the selected variation interval. Specifically, while a uniform ±10% variation identified activation energies as the primary influencers—consistent with prior literature—the introduction of experimental uncertainties shifted this prominence toward heats of reaction. Thus, the selected interval can drastically reshape the perceived importance of certain parameters. This original work challenges the traditionally employed variation ranges in sensitivity studies, emphasizing the need for a nuanced approach. [ABSTRACT FROM AUTHOR]

Acrylic substrates made from polymethylmethacrylate (PMMA) are anticipated to develop craze and scratches owing to their continual wear. In this study, novel silane modified acrylic resin based organic-inorganic hybrid coating materials have been formulated to provide protection to PMMA substrates against wear. Varied amounts (5, 10 and 15 % wt./wt.) of tetraethoxysilane (TEOS) were added to the acrylic resin solution (containing xylene and 10% ammonia) and the resultant hybrid coating materials were then coated on PMMA substrates through the dip coating method. The hybrid coating materials were transformed into hard coats upon hydrolysis, condensation and cross-linking. The coated samples were characterized to assess the effect of TEOS addition on optical and mechanical properties as well as abrasion resistance of the hybrid coatings. Hardness, stiffness and reduced elastic modulus of the dry coatings obtained through the instrumented indentation technique were observed to increase (up to ca. 56%, 28% and 65% respectively) whereas their viscous nature and plasticity decreased with the addition of TEOS. The hybrid coatings also demonstrated improved wet abrasion resistance which augurs well with their physico-mechanical properties. These observations can be ascribed to the combined contributions of organic-inorganic phase interactions in the coating materials via hydrogen bonding and the formation of cross-linked silica structures as observed through infrared spectroscopy and microscopy. [ABSTRACT FROM AUTHOR]

This research article focused on the blending of poly(lactic acid)/poly(methyl methacrylate) (PLA/PMMA) polymer materials to overcome PLA's inherent weaknesses, such as low glass transition temperature, brittleness, and lack of melt strength. Consolidated feasible characteristic investigations, such as mechanical, thermal, and aging behavior, were carried out for PLA/PMMA blended polymer materials. Initially, the miscibility of PLA/PMMA blend filaments was prepared at various blend ratios (91/9, 82/18, and 73/27) and samples were printed by fused deposition modeling (FDM). Differential scanning calorimetry (DSC) and Fourier infrared spectroscopy (FTIR) analysis have been utilized to evaluate the glass transition temperature (Tg) and intermolecular interaction, respectively, on blended polymer materials. Experimental tensile, compression, and flexural strength testing were performed on neat polymers and blended polymer composites. Compared to neat PLA materials, blended composites had 13.24% and 19.07% higher flexural and compression strengths. Besides, the interfacial interaction of neat and blended polymers has been done using dynamic mechanical analysis (DMA). Furthermore, Tg, storage modulus, and aging behavior of blended polymer materials have significantly improved over neat PLA materials. Altogether, the development of PMMA/PLA blends as sustainable biomaterials for dental applications aligns with environmental concerns and the need for biocompatible materials in dentistry. Highlights: Blending of PLA and PMMA helps mitigate the inherent constraints of PLA.Blended composites exhibited greater compressive and flexural strengths.Better glass transition temperature and intermolecular interaction.Excellent thermal stability and water aging imply viable dental biomaterials. [ABSTRACT FROM AUTHOR]

A simple solution casting technique was used to formulate films of polyvinylidenefluoride‐co‐hexafluoropropylene, polymethylmethacrylate, and Ti3AlC2 MAX phase polymer nanocomposites (PPT) with different filler content. The functional groups present in the PPT films were studied using the Fourier transform infrared spectroscopy and the nature of crystallinity was observed using X‐ray diffraction technique. The morphology of the films was studied by scanning electron microscopy. The thermal analysis was done using the thermogravimetric analysis and differential thermogravimetry analysis. The tensile behavior of the prepared films was studied from the stress‐strain graphs. The ultraviolet–visible spectra revealed their optical characteristics. The dielectric parameters of the polymer blend and nanocomposite films like dielectric constant, loss tangent, AC conductivity, and complex impedance spectroscopy with corresponding equivalent circuits were studied. A comparative study of the above parameters was done for both the polymer blend and nanocomposites to find out the advancement in the properties of the prepared nanocomposite compared with the polymer blend. The nanocomposite film having 3 wt% of Ti3AlC2 MAX phase filler loading exhibited the best properties among all the nanocomposites. The enhanced dielectric properties of the nanocomposites with mechanical and thermal resistance can be used for real‐time efficient energy storage applications. [ABSTRACT FROM AUTHOR]

In order to contribute to the demanded sustainability transparent poly(methyl methacrylate) (PMMA) composites with cellulose nanocrystals (CNC) up to high shares of 50 wt% were prepared by in situ radical polymerization in green solvent Cyrene. The weight average molecular weights of PMMA were in the range from 144,000 to 160,000 g mol−1 and the dispersity was in the range of 1.49 to 1.89 with high conversion of monomer to polymer. The DSC thermal analysis showed that the glass transition temperature of pure PMMA was at 99°C while in composites increased from 103°C up to 129°C with the increase of CNC from 1 wt% to 50 wt%. TGA shows that the addition of CNC does not have a significant effect on the thermal stability of PMMA. In composites Young's modulus increases with the increasing CNC ratio and composites with 50 wt% of CNC showed more than twice the modulus of the PMMA matrix. The SEM images indicate uniform distribution of CNC in polymer matrix. The transparent and semitransparent PMMA/cellulose composites of improved sustainability with higher modulus of elasticity and glass transition temperature can be used as lightweight materials for a wide range of technical and everyday applications as well as optical lenses or acoustic lenses for ultrasound transducers and other devices. Highlights: Cellulose nanocrystals/PMMA composites fabricated by a green in situ process.Synthesized PMMA matrices have high molecular weights.Improved elastic modulus and glass transition temperature were achieved.Prioritizing eco‐friendly chemicals for a greener production approach. [ABSTRACT FROM AUTHOR]

The control of Candida albicans biofilm formation on dentures made of poly(methyl methacrylate) (PMMA) is an important challenge due to the high resistance to antifungal drugs. Interestingly, the natural compounds undecylenic acid (UDA) and farnesol (FAR) both prevent C. albicans biofilm formation and could have a synergetic effect. We therefore modified PMMA with a combination of UDA and FAR (UDA+FAR), aiming to obtain the antifungal PMMA_UDA+FAR composites. Equal concentrations of FAR and UDA were added to PMMA to reach 3%, 6%, and 9% in total of both compounds in composites. The physico-chemical properties of the composites were characterized by Fourier-transform infrared spectroscopy and water contact angle measurement. The antifungal activity of the composites was tested on both biofilm and planktonic cells with an XTT test 0 and 6 days after the composites' preparation. The effect of the UDA+FAR combination on C. albicans filamentation was studied in agar containing 0.0125% and 0.4% UDA+FAR after 24 h and 48 h of incubation. The results showed the presence of UDA and FAR on the composite and decreases in the water contact angle and metabolic activity of both the biofilm and planktonic cells at both time points at non-toxic UDA+FAR concentrations. Thus, the modification of PMMA with a combination of UDA+FAR reduces C. albicans biofilm formation on dentures and could be a promising anti-Candida strategy. [ABSTRACT FROM AUTHOR]

CO2 laser machining is a cost effective and time saving solution for fabricating microchannels on polymethylmethacrylate (PMMA). Due to the lack of research on the incubation effect and ablation behavior of PMMA under high-power laser irradiation, predictions of the microchannel profile are limited. In this study, the ablation process and mechanism of a continuous CO2 laser machining process on microchannel production in PMMA in single-pass and multi-pass laser scan modes are investigated. It is found that a higher laser energy density of a single pass causes a lower ablation threshold. The ablated surface can be divided into three regions: the ablation zone, the incubation zone, and the virgin zone. The PMMA ablation process is mainly attributed to the thermal decomposition reactions and the splashing of molten polymer. The depth, width, aspect ratio, volume ablation rate, and mass ablation rate of the channel increase as the laser scanning speed decreases and the number of laser scans increases. The differences in ablation results obtained under the same total laser energy density using different scan modes are attributed to the incubation effect, which is caused by the thermal deposition of laser energy in the polymer. Finally, an optimized simulation model that is used to solve the problem of a channel width greater than spot diameter is proposed. The error percentage between the experimental and simulation results varies from 0.44% to 5.9%. [ABSTRACT FROM AUTHOR]

Polymethyl methacrylate (PMMA) is an important thermoplastic polymer and a versatile lithographic resist. However, the low heat resistance and low dry-etch resistance seriously restricts the application of PMMA in high-end devices and advanced nanolithography. Herein, methyl methacrylate (MMA) was copolymerized with two comonomers 1-adamantyl methacrylate (AdMA) and 1-acryloyloxy-3-hydroxyadamantane (HAdMA), and a series of copolymers P(AdMA-co-MMA) and P(HAdMA-co-MMA) with different contents of HAdMA were prepared. The UV–Vis, ellipsometer, DSC, TG, and TG–MS techniques were employed to investigate the effects of adamantyl and hydroxyadamantyl substituents on the optical and thermal properties of PMMA. The introduced hydroxyadamantyl not only significantly enhanced the refractive index, but also maintained the high transparency and low dispersion of PMMA. The glass transition temperature and thermal stability of PMMA were also greatly improved by the hydroxyadamantyl. The initial decomposition temperature of PMMA increased from 160 to about 260 ℃ after introducing 5% HAdMA. HAdMA was more effective than AdMA in improving the optical and thermal properties of PMMA. The novel P(HAdMA-co-MMA) copolymer has overcome the shortcomings of traditional PMMA and is anticipated to significantly broaden its range of applications. [ABSTRACT FROM AUTHOR]

The utilization of polymethyl methacrylate (PMMA) bone cement is employed for the purpose of stabilizing fractured vertebral bodies. The existence of a mechanical imbalance in hard polymethylmethacrylate (PMMA) bone cement has the potential to increase the likelihood of a fracture occurring in the neighbouring vertebral body. In order to reduce potential difficulties, the primary goal of this study is to investigate the potential benefits of increasing PMMA bone cement's bioactivity and lowering its elastic modulus. The incorporation of a 10% volume fraction of hyaluronic acid (HyA) and polyethylene glycol (PEG) into the bone cement led to an improvement in the bioactivity and decreasing of elastic modulus of polymethylmethacrylate (PMMA). The integration of HyPE gel phase presents several advantages over pure PMMA bone cement, including enhanced setting parameters, improved degradability, and increased biocompatibility. The gel phase is additionally accountable for a reduction in the elastic modulus of polymethylmethacrylate (PMMA) bone cement. In addition, the existence of a porous structure that arises from the degradation of the HyPE gel phase delivers a significant amount of room, thereby enhancing the process of bone regeneration when implanted in the femur of rabbits. The utilization of HyPE in PMMA has been shown through comprehensive µ-CT analysis to enhance bone formation, thereby promoting osteointegration at the implantation site. Furthermore, the histological analysis demonstrated the existence of osteogenic activity in the PMMA polyethylene glycol supplemented with 10% HyA and 10% PEG after a 2-month period subsequent to implantation. [ABSTRACT FROM AUTHOR]

In the current study, films of promising nanocomposites were fabricated from poly-methyl methacrylate(PMMA) filled with chromium oxide (Cr2O3) and silicon carbide(SiC) nanostrucures to employ in several advanced nanoelectronics and optical fields. The PMMA/Cr2O3/SiC nanocomposites have remarkable characteristics compared with other types of nanocomposites included inexpensive, excellent optical properties, good physical and chemical behaviours. The structural and optical properties of PMMA/Cr2O3/SiC nanocomposites films were tested. Results confirmed that the PMMA absorbance increased of 26.3% and 27.6% at λ = 380 nm (UV/spectra) and λ = 580 nm (VIS/spectra) when the Cr2O3/SiC NPs ratio reached of 5.7 wt.%. The PMMA transmittance decreased of 14.8% and 13.4% at λ = 380 nm and λ = 580 nm, these results make the PMMA/Cr2O3/SiC nanocomposites films are promising nanostructures for nanoelectronics and optics applications. The indirect allowed energy gap reduced from 3.82 eV to 3.47 eV with rising concentration of SiC/Cr2O3 NPs to 5.7 wt.%. The optical factors of PMMA improved with rising SiC/Cr2O3 NPs concentration. Finally, the attained results showed the PMMA/Cr2O3/SiC nanocomposites are promising nanocomposites and major key for potential nanoelectronics and optics applications. [ABSTRACT FROM AUTHOR]

The human head can sometimes experience impact loads that result in skull fractures or other injuries, leading to the need for a craniectomy. Cranioplasty is a procedure that involves replacing the removed portion with either autologous bone or alloplastic material. While titanium has traditionally been the preferred material for cranial implants due to its excellent properties and biocompatibility, its limitations have prompted the search for alternative materials. This research aimed to explore alternative materials to titanium for cranial implants in order to address the limitations of titanium implants and improve the performance of the cranioplasty process. A 3D model of a defective skull was reconstructed with a cranial implant, and the implant was simulated using various stiff and soft materials (such as alumina, zirconia, hydroxyapatite, zirconia-reinforced PMMA, and PMMA) as alternatives to titanium under 2000N impact forces. Alumina and zirconia implants were found to reduce stresses and strains on the skull and brain compared to titanium implants. However, PMMA implants showed potential for causing skull damage under current loading conditions. Additionally, PMMA and hydroxyapatite implants were prone to fracture. Despite these findings, none of the implants exceeded the limits for tensile and compressive stresses and strains on the brain. Zirconia-reinforced PMMA implants were also shown to reduce stresses and strains on the skull and brain compared to PMMA implants. Alumina and zirconia show promise as alternatives to titanium for the production of cranial implants. The use of alternative implant materials to titanium has the potential to enhance the success of cranial reconstruction by overcoming the limitations associated with titanium implants. [ABSTRACT FROM AUTHOR]

Background: Polymethylmethacrylate (PMMA) bone cement is used in orthopedics and dentistry to get primary fixation to bone but doesn't provide a mechanically and biologically stable bone interface. Therefore, there was a great demand to improve the properties of the PMMA bone cement to reduce its clinical usage limitations and enhance its success rate. Recent studies demonstrated that the addition of halloysite nanotubes (HNTs) to a polymeric-based material can improve its mechanical and thermal characteristics. Objectives: The purpose of the study is to assess the compressive strength, flexural strength, maximum temperature, and setting time of traditional PMMA bone cements that have been manually blended with 7 wt% HNT fillers. Methods: PMMA powder and monomer liquid were combined to create the control group, the reinforced group was made by mixing the PMMA powder with 7 wt% HNT fillers before liquid mixing. Chemical characterization of the HNT fillers was employed by X-ray fluorescence (XRF). The morphological examination of the cements was done using a scanning electron microscope (SEM). Analytical measurements were made for the compressive strength, flexural strength, maximum temperature, and setting time. Utilizing independent sample t-tests, the data was statistically assessed to compare mean values (p < 0.05). Results: The findings demonstrated that the novel reinforced PMMA-based bone cement with 7 wt% HNT fillers showed higher mean compressive strength values (93 MPa) and higher flexural strength (72 MPa). and lower maximum temperature values (34.8 °C) than the conventional PMMA bone cement control group, which was (76 MPa), (51 MPa), and (40 °C), respectively (P < 0.05). While there was no significant difference in the setting time between the control and the modified groups. Conclusion: The novel PMMA-based bone cement with the addition of 7 wt% HNTs can effectively be used in orthopedic and dental applications, as they have the potential to enhance the compressive and flexural strength and reduce the maximum temperatures. [ABSTRACT FROM AUTHOR]

In order to study the influence of open joint on blasting damage and crack propagation, plexiglass (PMMA) specimens with open joints were designed to carry out a study using a digital laser dynamic caustic experimental system. The results showed that the crack could not pass through the opening joint. The joint could promote the destruction of the medium between the borehole and the joint. Affected by the reflected stress wave at the joint, the crack was no longer simply subjected to tensile stress. Instead, it was influenced by the combined action of tensile stress and shear stress. The fracture type of crack changed from Type I to mixed Types I and II. During the reflected stress wave stage, the crack growth rate and intensity factor of dynamic stress increased. [ABSTRACT FROM AUTHOR]

This work aims to demonstrate the effect of ZrO 2 and MgO inclusion into the Poly(methyl methacrylate) (PMMA). To fabricate novel hybrid composites via heat cure method, various composites (PZM2, PZM4 and PZM6) were synthesized in the system [(95-x) PMMA + 5 ZrO 2 + x MgO] (x = 2, 4, and 6) respectively. Density of the prepared composites were determined and varying between 1.035–1.152 g/cm3. X-ray Diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) followed by EDAX and mechanical testing were performed to evaluate the fabricated composite properties. Moreover, to explore the structure of the fabricated composites the 13 C CP-MAS SSNMR and 1 H-13 C Phase-Modulated Lee Goldberg (PMLG) HETCOR Spectrum were recorded which clarify chemical shifting and motional dynamics of the composites. Mechanical tests were performed by UTM and the obtained parameters such as compressive strength, Young's modulus, fracture toughness, brittleness coefficient, flexural strength and flexural modulus are found to be in the range of 91–100 MPa, 0.48–0.51 GPa, 9.122–9.705 MPa.m1/2 , 0.66–0.815, 51.03–42.78 MPa and 499–663 MPa respectively. Some more mechanical parameters such as proportional limit, elastic limit, failure strength, modulus of resilience and modulus of toughness were also calculated. Furthermore, tribological properties were also determined and the coefficient of friction (COF) was decreased by 17.4 % and 38 % for composite PZM6 at 20 N and 40 N as compared to the composite PZM2 and the lowest wear volume of 1.55 mm3 was observed for PZM2, whereas the maximum volume loss of 5.64 mm3 is observed for composite PZM6. To check out the biocompatibility, cytotoxicity and genotoxicity of the fabricated composites the Trypan-blue assay was also performed for PZM2 and PZM6 composites. Dissection on the gut of larvae was also performed on the both composites followed by DAPI and DCFH-DA staining. Therefore, these synthesized samples can be used for the fabrication of denture materials. [Display omitted] • Synthesis of ZrO 2 and MgO reinforced denture-based resin composites via heat cure method. • Density of the composites were determined and varying between 1.035-1.152 g/cm3. • The structure of the fabricated composites was studied using the 13 C CP-MAS SSNMR and 1 H-13 C Phase-Modulated Lee Goldberg (PMLG) HETCOR spectrum. • The PZM6 composite shows the maximum compressive strength, 100 MPa. • To check out the biocompatibility, cytotoxicity and genotoxicity, the Trypan-blue assay was performed. [ABSTRACT FROM AUTHOR]

This work aims to enhance the optical and structure characteristics of silicon nitride (Si3N4)/silica (SiO2)/poly-methyl methacrylate (PMMA). The films of (PMMA–SiO2–Si3N4) were fabricated using casting method. The structure and optical characteristics of Si3N4/SiO2/PMMA nanostructures were studied, the structure characteristics of PMMA/SiO2/Si3N4 nanostructures included: FTIR and optical microscope. The optical properties were investigated at wavelength (λ = 240–740 nm). The results confirmed the absorption increased of 61.5% and transmission reduced of 42.2% when the Si3N4 and SiO2 NPs content reached 6.9 wt%, these results make them as a superior materials for many optical fields. The energy gap of PMMA reduced from 4.25 to 3.09 eV when the Si3N4 and SiO2 NPs content reached 6.9 wt%, this behavior made the Si3N4/SiO2/PMMA nanostructures suitable for optoelectronics nanodevices. The optical constants, the absorption coefficient, refractive index, extinction coefficient, real and imaginary dielectric constants, as well as optical conductivity increases with increasing in the concentrations of Si3N4 and SiO2 NPs. The results confirmed that the PMMA/SiO2/Si3N4 nanomaterials can be considered as future nanosystems to exploit in a variety of promising nanoelectronics and optics applications. [ABSTRACT FROM AUTHOR]

Cranioplasty is the procedure that is frequently used to treat deficiencies in the skull bone brought on by skull abnormalities in bone, traumatic skull fractures, bone malignancy, and infections. In surgery, biocompatible materials with unique properties have been utilized. Given the functionality and aesthetic standpoint, the human skull approach for repairing and restoring the abnormalities is hugely challenging. Polymethylmethacrylate (PMMA) cement, based on a dough-like material formed by combining two powdered polymer and liquid monomer components, is considered one of the earliest materials to treat cranial defects. Regarding the development of the latest additive manufacturing technologies, 3D printing has become a promising method for creating cranial implants customized to each patient. This study uses a solid basic medical grade PMMA material as a basis filament for the fused filament fabrication (FFF) process. This paper presents a high-quality model and manufacturing of a left parietal-temporal implant in the human skull based on computed tomography CT images. It evaluates the fitting accuracy and topographical roughness of the PMMA cranial implant. The results proved that the root means square error values for the deviation between the cranial implant's physical model and its planned model are (0.628, 0.833, and 0.650 mm) and implant roughness measurements are (2.5, 2.81, and 3.23 μm). The implemented framework outlined in the present study indicates that the contour continuity between implant-skull overlap, fitting accuracy, implant roughness topography, and the cosmetic outcome achieved entirely satisfactory results. Highlights: Reconstructed the skull defect by using mouldless 3D printing PMMA to manufacture high-quality patient-specific cranial implants directly. A qualitative and quantitative evaluation of implant dimensional accuracy is given and ensure the contour continuity between implant-skull overlap is ensured. Evaluate the cranial implant surface topography. [ABSTRACT FROM AUTHOR]

(1) Background: The addition of antibiotics to bone cements is a common practice in the treatment of periprosthetic joint infections. In revision cases, the amount and type of antibiotic is often insufficient and additional antibiotics must be added. The addition, however, changes the product itself, and the surgeon becomes the "manufacturer" of the bone cement. PMMAe wished to clarify whether the admixture of antibiotics changes the mechanical stability of the bone cements used and if the added antibiotics were still functional and released in sufficient quantities. (2) Methods: We compared two industrially manufactured vancomycin-containing PMMA cements; the low-viscous VancogenX® (TECRES, Sommacampagna, Italy) and the high-viscous Copal® G+V (Heraeus Medical GmbH, Wehrheim, Germany), with two PMMA cements loaded with aminoglycosides, to which 2.0 g of vancomycin (Hexal CT1631) were manually added—the high-viscous Smartset® GHV and the medium-viscous Antibiotic Simplex with Tobramycin (antibiotic Simplex® T). Test specimens of the bone cements were used to determine mechanical stability (bending strength and bending module), and the release of the antibiotics was determined by HLPC and modified Kirby–Bauer assays. (3) Results: All tested bone cements showed an initial high release within the first hours. Repeated testing after 24 h showed a reduced efficacy of VancogenX® and Smartset® GHV in Kirby–Bauer assays. Long-time release over days showed a release of functional antimicrobial active ingredients over this period of time in anti-microbial assays, but no activity of VancogenX® from day 21 onward. No significant differences in the ISO bending modules could be detected, but in contrast to the bending module, the ISO bending strength was substantially reduced by 10–15 mPal in comparison to both cements of the reference group. The Simplex®T met just the ISO 5833; the Smartset® GHV did not after adding vancomycin. (4) Conclusions: In conclusion, the manual addition of 2 g of vancomycin to 40 g of PMMA powder is recommended for the treatment of methicillin-resistant staphylococci. Vancomycin is released over a period of 42 days with concentrations above the MIC for typical staphylococci. The mechanical properties of the PMMA just met, or did not fulfill, ISO mechanical specification. Copal® G+V showed a better elution than VancogenX® over time. [ABSTRACT FROM AUTHOR]

A thermogravimetric analysis of the thermal decomposition of polymethylmethacrylate (PMMA) in a carbon dioxide flow is carried out. The kinetic constants of the process are determined. The heating rate of the sample varies over in wide range and amounts to 2, 5, 8, 20, 35, and 50 K/min. The values of the kinetic constants of PMMA decomposition are determined using the isoconversional method. For the degree of conversion of the substance ranging from 10 to 90%, the values of activation energy for the thermal decomposition of PMMA vary in the range from 213.5 to 194.3 kJ/mol, and the values of the preexponential coefficient change in the range from 1.62 × 1016 to 6.85 × 1012 1/s. The average activation energy for the thermal decomposition of PMMA in a carbon dioxide flow is 206 kJ/mol. [ABSTRACT FROM AUTHOR]

Abstract The authors studied Poly (methyl methacrylate) also called PMMA films with different concentrations of Poly (9, 9′-di-n-octylfuorenyl-2, 7-diyl) also called PFO and concluded that 1% PFO blended with PMMA is the best choice for opto-electronic applications. In the present study, the authors prepared nanocomposite films of PMMA + 1% PFO + different concentrations of TiO2 nanoparticles. The resulting films were subjected to FTIR, XRD, UV–visible, fluorescence and electrical conductivity studies. The polymer matrix undergoes modifications in its molecular and microstructural characteristics as evidenced by FTIR and XRD results. The addition of TiO2 nanoparticles leads to a uniform dispersion and good interaction with the blend matrix resulting in homogeneous films. The additional peaks were found at a wavenumber of 3620 cm−1 in FTIR can be attributed to stretching vibration of TiO2. The presence of TiO2 nanoparticles is confirmed by the distinctive diffraction peaks observed at 25.4°, 37.8°, 48.3°, 54.3°, 55.2°, and 62.8°. With a shift in the absorption peak towards higher wavelengths, the nanocomposites show greater absorption in the UV and visible regions. As the concentration of TiO2 increases, the optical parameters such as absorption coefficient, extinction coefficient, Urbach energy, refractive index and optical conductivity also increase. The direct optical band gap of the PNC films decreases from 5.03 to 3.06 eV and indirect band gap decreases from 4.52 to 1.92 eV at 10 wt% of TiO2 concentration. The addition of TiO2 nanoparticles to the PFO/PMMA matrix resulted in an increase in fluorescence emission intensity. The AC electrical conductivity exhibits increasing trend with frequency in Audio-Frequency range. Thus TiO2 nanoparticles improve the overall optical, electrical, and structural properties of PFO-PMMA nanocomposites. This means that they can be used in a variety of optoelectronic and advanced optical devices.

The current study aimed to evaluate the suitability of polyester resin as an alternative material to polymethyl methacrylate (PMMA) for computed tomography (CT) dosimetry phantoms using the GEANT4/GATE Monte Carlo simulation platform. Cylindrical phantoms (32 cm diameter) constructed of polyester resin and PMMA were simulated and compared in terms of atomic composition, effective atomic number, electron density, mass density, and photon interaction mechanisms. Weighted CT dose index (CTDIw) values were calculated for each phantom at 80, 110, and 130 kVp tube voltages based on measurements of CTDI100,c and CTDI100,p. Results demonstrated that the physical properties of polyester closely matched those of PMMA, and the polyester phantom displayed equivalent dosimetric behavior to the PMMA phantom at all tube voltages tested. CTDIw values from the polyester phantom were within 1.4 % of the PMMA phantom across all tube voltages. Conversion coefficients were derived to equate polyester CTDIw values to PMMA dose equivalents. This study found that a polyester resin phantom exhibited radiation dosimetry commensurate with the standard PMMA phantom for CT dose assessment. Consequently, polyester resin represents a viable substitute material when PMMA is unavailable for construction of CT dosimetry phantoms.

Abstract PMMA/PEG and PMMA/PEG doped with SiO2, TiO2, and Al2O3 were fabricated using the solution-casting technique. The composites were characterized by X-ray diffraction and scanning electron microscopy (FE-SEM), which revealed that the amorphous nature of PMMA/PEG blend doped with Al2O3 was hindered by the crystalline nature of those doped with SiO2 and TiO2. The absorption of PMMA/PEG blend doped with Al2O3 is higher, band gap energies were decreased from 4.90 eV for PMMA/PEG blend to 4.03 eV, 3.09 eV, and 2.09 eV for SiO2, TiO2, and Al2O3 doped PMMA/PEG blend, respectively. The dielectric constant, ε′ has a high value (2 × 104) for samples PMMA/PEG and SiO2/PMMA/PEG. While dielectric loss $$\left( {\varepsilon ^{{\prime \prime }} } \right)$$ ε ″ -values decreased to