Pure Poly Methyl Methacrylate Research Articles

Effect of graphene on the key electrical, optical, and magnetic properties of polymethylmethacrylate: a study based on molecular modeling.

In this work, a new polymeric structure was designed consisting of a nanometric sheet of graphene (G) and a polymethylmethacrylate (PMMA) repeat unit, which was designated as PMMA-G. Three degrees of polymerization of PMMA-G were considered: monomer (PMMA-G1), dimer (PMMA-G2), and trimer (PMMA-G3). The effect of incorporating a nanometric sheet of graphene into the molecular structure of PMMA on the modification of some of its main optical, magnetic, and electrical properties was investigated. Currently, the study presented here is of great relevance since various areas of technology require new materials with specific properties for the development of new devices. The results of our study reveal that the dielectric constant of PMMA is reduced when graphene is incorporated. However, a percentage increase of 14.48% in the refractive index of PMMA when graphene is inserted to form the nanocomposite is observed. It is found that the absolute value of molar magnetic susceptibility of PMMA increases considerably when reinforced with graphene. Finally, when reinforcing PMMA with graphene to obtain the PMMA-G nanocomposite, the electrical resistivity increases by almost an order of magnitude. We used computational tools under Materials Studio (MS) software. We built a PMMA molecule with three degrees of polymerization, graphene sheet, and polymethylmethacrylate-graphene composite (PMMA-G) was built also with three degrees of polymerization using a concentration of 50% graphene over the PMMA polymer. For each structure, we used computational code DMol3 of MS, which is based on the Density Functional Theory, and the geometry optimization process was carried out to obtain the most stable structures. Finally, using the connectivity indices method together with topological properties of the molecular structures, implemented in Synthia computational code of MS software, we calculated the dielectric constant, magnetic susceptibility, refractive index, and electrical resistivity, for pure PMMA and PMMA-G structures for their three degrees of polymerization. The results were analyzed, and the changes in these properties were discussed in terms of the effect of an electric and magnetic field on the molecular structures of PMMA-G with respect to PMMA.

Study of structural and various optical properties of pure poly-methyl-methacrylate (PMMA) with doped ferric chloride (FeCl3)

Study of structural and various optical properties of pure poly-methyl-methacrylate (PMMA) with doped ferric chloride (FeCl3)

Influence of alumina and PMMA on mechanical properties and aging behavior of 3D printed PLA composites: A comparative study

AbstractThis 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.Highlights 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.

Enhancement of thermal and mechanical properties of PMMA nanocomposites by adding spark plug ceramic waste

In this research, poly methyl methacrylate (PMMA) resin was used as a base material and spark plug ceramic waste (CW) particles as a support material with different weight ratios (0%, 1%, 2%, 4%, 6%, 10%, 14%, and 20%) to study the thermal and mechanical properties through diffraction examination. FE-SEM surface structure images showed that the fracture surface of the (94% PMMA +6%CW) nanocomposite sample manifests a good distribution of particles at low and high levels. The result showed that the thermal conductivity (K) slightly increased until it reached the maximum value (0.6 watt/m.ºC) at the ratio (86%PMMA +14%CW). For the impact strength, it was noticed that the impact strength of PMMA increases with the increased weight ratios (1, 2, 4, 6, 10, 14, and 20%) of fine powder of ceramic waste compared with pure PMMA to reach the maximum value (6.02 kJ/mm2) at the sample (94% PMMA +6%CW) under L.C. Moreover, after 30 days of submersion in water, the PMMA reinforced with ceramic waste particles had enhanced impact strength. The shore D-number readings for all of the samples showed an increase as a result of the findings of nanocomposite compared with PMMA pure, where the sample (94% PMMA+6%CM) attained the greatest shore D numbers (87 H.NO). The compressive strength at the weight percentage (99% PMMA + 1% CW) was somewhat reduced. Then the compressive strength increased till it reached its maximum value (29.94 MPa) at the weight percentage (94% PMMA + 6% CW).

Enhanced PMMA Denture Bases Using Functionalized MWCNT Fused g-C3N4 Nanocomposites

This study presents the development and analysis of a new metal-free nanocomposite that incorporates functionalized multi-walled carbon nanotubes (f-MWCNTs) with graphitic carbon nitride (g-C3N4) for reinforcing polymethyl methacrylate (PMMA) denture bases. The f-MWCNTs were integrated with g-C3N4 nanoparticles, and their structural and morphological features were examined using various techniques, including X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), high-resolution transmission electron microscopy (HR-TEM), Fourier-transform infrared spectroscopy (FT-IR), and Raman spectroscopy. A mechanical blending process was employed to synthesize the nanocomposite by mixing 2 wt% of the f-MWCNT/g-C3N4 with PMMA polymer powder, followed by heat curing to form the composite material. Specimens for mechanical testing were crafted to measure flexural strength, impact resistance, compressive performance, and hardness. The findings revealed that the f-MWCNT/g-C3N4-reinforced PMMA composites outperformed standard PMMA in mechanical robustness. Surface examination of the tested samples through SEM showed distinctive dimpling and roughness, indicating a toughened fracture surface in comparison to pure PMMA and g-C3N4 samples. The study concludes that this innovative f-MWCNT/g-C3N4 composite is a promising reinforcement for PMMA denture bases, enhancing both their mechanical and physical attributes.Keywords: PMMA, functionalization, MWCNTs, Graphitic Carbide Nitride, Mechanical Properties and Denture Base

Compatibilizing and foaming of PC/PMMA composites with nano‐cellular structures in the presence of transesterification catalyst

AbstractCompatibility of polycarbonate (PC) and polymethyl methacrylate (PMMA) alloys was improved by using a transesterification catalyst (SnCl2·2H2O). Modified PC/PMMA alloys exhibit single Tg, and their initial island phase existing in the SEM were transformed into uniform surface. Besides, the transmittance of the modified alloys was increased from original 40% to 85%. Moreover, PC/PMMA alloys and PC foams with micro‐cellular and nano‐cellular structures were prepared by solid‐state CO2 foaming in the presence of transesterification catalyst. Distinctively, there are obvious nano‐cellular structures existing in the PC samples, but no related nanostructures were found in PMMA samples, after treated by same amount of catalyst and foaming process for pure PC and PMMA matrix. Furthermore, the effects of foaming temperature and segment structure on their foaming behavior were also studied. Additionally, a uniaxial stress experiment was conducted at a specific temperature to simulate the biaxial stress during the foaming process for discovering the mechanism of nanopore formation. Therefore, the concept of nano‐cellular structures will point out a direction for the development of high‐performance, heat insulation PC materials of the next generation.Highlights Transesterification catalysts enhanced compatibility between PC and PMMA. Nanopore structures were successfully constructed in PC foams. Segment stretching was the main reason for the formation of nanopores.

In vivo evaluation of hyaluronic acid–polyethylene glycol amended PMMA bone cement for orthopaedic application

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.

Experimental Study of the Flame Retardancy of PMMA-Graphene Composite Materials

In this paper, Polymethyl methacrylate (PMMA)-graphene nano-composites were prepared and tested with the use of a cone calorimeter. Graphene was added to PMMA in limited weight percentages to improve the flame retardancy of PMMA. Two samples of PMMA-graphene, namely 1 and 3 wt%, were investigated. The combustion properties of the tested samples of PMMA-graphene composites, mass loss rate, heat release rate, and time to ignition were measured and calculated. It was found that the peak heat release rate of PMMA-graphene composites reduced by 17% when 3 wt% graphene was added to pure PMMA. Adding graphene to PMMA improves the thermal stability of PMMA by reducing the time of ignition. Also, the presence of graphene enhanced the formation of a continuous carbonized layer at the surface of the burned PMMA.

Mechanical properties and wear performance of denture base polymethyl methacrylate reinforced with nano Al2O3

Polymethyl methacrylate (PMMA) has been widely used as a material in dentistry. The deterioration of pure PMMA denture teeth is a significant issue that can alter the vertical dimensions of dentures. This study investigates the effect of aluminum oxide (Al2O3) nano-ceramic addition as reinforcements into the heat-cure acrylic resin denture teeth. The PMMA was reinforced with Al2O3 concentrations of 1, 3, 5, and 10 wt.%. The PMMA without ceramic addition is produced for comparison purposes. The color change, densification, microhardness, and compressive properties of the produced PMMA resin and its composites were investigated to detect the effect of Al2O3 nano ceramic addition on the physical and mechanical properties. Furthermore, the microstructure was also performed using scanning electron microscopy (SEM) analysis. A chewing simulator was utilized to conduct two-body wear testing, employing a human enamel antagonist. The wear behavior of the PMMA and their composites were assessed by measuring the weight loss after submitting them to 37,500 cycles. The SEM microstructure analysis revealed sound specimens of PMMA reinforced with 0, 1, 3, and 5 wt.% Al2O3 without any porosity and micro defects using the applied production procedures. In contrast, the aggregated sites and propagation of cracks were detected for the PMMA/10 wt.% Al2O3 specimen. The densification and hardness properties of the produced PMMA composites improved with increasing the Al2O3 additions. The microhardness of PMMA/10 wt.% Al2O3 improved by around 233% compared to the PMMA matrix. The higher compressive properties were detected for the PMMA/5 wt.% Al2O3 composite specimen with ultimate compressive strength (UCS) of 54.75 MPa and yield strength (YS) of 45.6 MPa and improved than the PMMA matrix by around 98 % and 117 %, respectively. In addition, incorporating Al2O3 nano-ceramic particles into a PMMA matrix revealed a significant improvement in the wear resistance of the produced composites compared to the PMMA matrix.

Influence of Congored on the Optical, Dielectric and Thermal Behavior of Polymethyl Methacrylate and Polyvinyl Chloride

Polymethyl methacrylate (PMMA)/Congo Red (CR) and polyvinyl chloride (PVC)/CR composite films were prepared on optical glass by the drop method for optical measurements and also prepared as tablets under pressure for dielectrical measurements. The optical transmission spectra measurements for PMMA and PVC film doped with CR showed a highly absorption in the ultraviolet-visible (UV-Vis) optical range (at 353 nm and 518 nm) and considerably blocking in broad visible range (190 nm–640 nm). PMMA/CR and PVC/CR composite films containing congo red at a concentration of 1 wt% showed maximum absorption bands at 290 nm and 416 nm, but their transmittance percentages were reasonably reduced compared to those of pure PMMA and PVC. Both of composites indicated high transmittances between 640 nm and 800 nm. The optical constants of the PMMA/CR and PVC/CR composite films such as optical band energy gaps (Eg) estimated using Tauc’s model, refractive index and reflectance (%) were calculated. UV–Vis, Fourier transform infrared spectroscopy (FTIR) and Thermogravimetry Analysis (TGA) measurements were used to confirm the breakdown of the -N = N- azo group bonds attached to the aromatic ring as a result of thermal decomposition of CR at 500 °C, and it was suggested that N2 gas was eliminated from the CR above 360 °C. The dielectric plots showed that the dielectric constant increased when the CR is doped up to 70 wt% in the polymer matrices. A further increase in the doping concentration of CR resulted in an increase of the dielectric constant. The dielectric constant decreased with an increase in the frequency for all of the samples. The ac (alternating current) conductivity values of PMMA and PVC showed an increase with increasing CR dopant in the polymer composites, while the ac conductivity values were found to be values between those of the pure polymers and CR.

Influence of Novel SrTiO3/MnO2 Hybrid Nanoparticles on Poly(methyl methacrylate) Thermal and Mechanical Behavior.

While dental poly methyl methacrylate(PMMA) possesses distinctive qualities such as ease of fabrication, cost-effectiveness, and favorable physical and mechanical properties, these attributes alone are inadequate to impart the necessary impact strength and hardness. Consequently, pure PMMA is less suitable for dental applications. This research focused on the incorporation of Strontium titanate (SrTiO3-STO) and hybrid filler STO/Manganese oxide (MnO2) to improve impact resistance and hardness. The potential of STO in reinforcing PMMA is poorly investigated, while hybrid filler STO/MnO2 has not been presented yet. Differential scanning calorimetry is conducted in order to investigate the agglomeration influence on the PMMA glass transition temperature (Tg), as well as the leaching of residual monomer and volatile additives that could pose a threat to human health. It has been determined that agglomeration with 1 wt% loading had no influence on Tg, while the first scan revealed differences in evaporation of small molecules, in favor of composite PMMA-STO/MnO2, which showed the trapping potential of volatiles. Investigations of mechanical properties have revealed the significant influence of hybrid STO/MnO2 filler on microhardness and total absorbed impact energy, which were increased by 89.9% and 145.4%, respectively. Results presented in this study revealed the reinforcing potential of hybrid nanoparticles that could find application in other polymers as well.

High Refractive Index Carbonized Polymer Dots Acting as Light Scattering Units in Nanocomposites for Full‐Screen Light Guide Plate

AbstractThe full‐screen mobile phone can be fabricated by integrating the camera beneath the screen, which needs the nanocomposite light guide plate (nano‐LGP) with exceptional transparency and light‐guiding properties simultaneously. Choosing an appropriate nanoparticle with a high refractive index and exceptional compatibility within the polymer matrix is crucial for producing the nano‐LGP. In this study, the high refractive index carbonized polymer dots (HRI‐CPDs) are synthesized through the solvothermal treatment, achieving a refractive index value of 1.7220 at 450 nm. Subsequently, the modified HRI‐CPDs (mHRI‐CPDs)/polymethyl methacrylate (PMMA) nanocomposites are fabricated by copolymerizing the mHRI‐CPDs with methyl methacrylate . Due to the high visible light transmittance and Rayleigh scattering characteristics when light passes through the nanocomposites, this kind of nanocomposites is suitable for serving as nano‐LGPs. The potential of carbonized polymer dots as light‐scattering unit is originally explored to improve surface illuminance and uniformity of nano‐LGPs. The best‐performing 4.3‐inch LGP with 1.0 wt.% doping content shows 15.8 times higher surface illuminance and 2.1 times higher uniformity than pure PMMA. This new type of LGP based on mHRI‐CPDs/PMMA nanocomposite holds tremendous promise in conjunction with advanced liquid crystal display technology.

Effect of denture base acrylic resin containing silver nanoparticles on Candida Albicans adhesion and its release in artificial saliva

Background Candida albicans was considered a main reason of precipitate formations and decomposition of acrylic denture base; so many trials were objected to resist this microbial action and prolong the shelf life of the formulated fitting base. Aim of the work The present study aimed to adopt a new mixture of the silver nanoparticles with the PMMA denture base to get a prolonged antimicrobial protection for the formed base against Candida albicans. Statement of problem Accumulation of Candida Albicans on fitting surface of poly methyl meth-acrylate (PMMA) denture base. Purpose To evaluate the effect of denture base acrylic resin containing silver Nanoparticles (Ag NP) on Candida Albicans adhesion and its release in artificial saliva. Materials and methods Sixty round disks with dimensions of 15 mm diameter and 3 mm thickness specimens were prepared for this research. Control group A: 10 specimens were prepared from pure PMMA. Experimental group B: 50 specimens were prepared from PMMA containing 5% of Ag NP. Isolation and identification of Candida Albicans were taken from oral cavity of 10 patients by swabbing. The Specimens were immersed in artificial saliva for 3, 6, and 9 months. Microbiological test was done for specimens of each group to detect Candida Albicans accumulation at the same interval period by measuring the inhibition zone created around the disks. Specimens were taken from the artificial saliva to evaluate silver release in it by using UV-Vis Spectrophotometer Instrument ‘SHIMADZO UV-310 PC. For Spectrophotometer 1.0 cm and/or 0.2 cm matched silica cells. The amount of accumulated silver released was calculated to detect its cytotoxic effect1. Results For control group A there was no inhibition zone for Candida growth around the specimens. While for group B with Ag NP the greatest antimicrobial effect was found at zero time then was decreased gradually with increasing the time till reaching zero effect after 9 months resembling the control group. The amount of Nano silver in artificial saliva after 3 months was found to be little then it was increased gradually with increasing time. Conclusion Adding Ag NP to PMMA denture base has antimicrobial effect against Candida Albicans for only 9 months; then there was no effect as silver was released in saliva. The amount of released silver was found to be with no cytotoxic effect.

Mechanical and tribological properties of nano clay/PMMA composites extruded with a twin-screw extruder

An analysis has been done on the strength and wear of the nanocomposites. The synthesis of nano clay or poly-methyl methacrylate (PMMA) nanocomposites by using a twin-screw extruder is discussed here. During the synthesis of nanocomposites, a compatibilizer was added to improve the bonding between the clay and matrix between the five different types of composites. The samples obtained are then used for tensile testing after being molded into dog-bone-shaped samples. The tensile test is done by using a UTM (Universal Testing Machine) and tensile strength and tensile modulus were recorded. Then flexural strength and modulus were recorded by conducting a flexural test. The rectangular part of the dog-bone samples is sliced for this test. Similarly, testing of wear was done using a pin-on-disc apparatus. After the flexural test and wear test analysis, scanning electron microscope imaging of the failed and worn-out surfaces is recorded. It was concluded that the pure PMMA sample has lesser strength than the 2.5 wt% sample. But the pre PMMA sample exhibits higher tensile strength and flexural modulus. And on boosting the filler content in the composite material, the strength reduces but the wear resistance of the composite improves.

Experimental study on flame spread over PMMA composites with addition of carbon nanotubes

Experiments on flame spread over cantilevered polymethyl methacrylate (PMMA) composites with addition carbon nanotubes (CNTs) were conducted and flame spread behaviors was analyzed. Results show that the two flame regions, surface flame and dripping flame, are distinguished because of the enhanced viscosity of the molten materials with the addition of CNTs. The combustion-supporting effect from the dripping flame promotes flame spread, the flame height and the flame spread rate are increased with CNTs. There is a power-law relationship between the whole flame height and the dripping flame height, H∝H20.682. The heat transfer analysis is also conducted based on the divisions of flame region. As the content of CNTs increases, the heat flux from surface flame is almost constant, but for dripping flame, it is twice as much as pure PMMA at 2.5% CNTs and the contribution in heat flux of dripping flame reaches 40%. The heat flux from dripping flame has important effects on sustaining flame spread and the increasing flame spread rate is mainly attributed to the enhancement of the heat feedback of dripping flame. These results are contrary to the effects of the flame retardancy by CNTs, which means the application of CNTs as flame retardants in polymers needs to consider the fire scenarios.

Analysis of X-ray and gamma ray shielding performance of prepared polymer micro-composites

Polymethyl-methacrylate (PMMA) was used as the matrix to prepare micro composites for radiation shielding, with 10%, 20%, 30%, and 40% Bi2O3 filler loadings, by melt mixing method. The mass attenuation coefficients (MAC) of prepared micro composites along with pure PMMA were measured with a NaI (Tl) scintillator detector spanning a wide range of energies (59–1332 keV). Several radioactive point sources, which are commonly used in many industrial and medical applications, namely Co-60 (1173 and 1332 keV), Co-57 (122 keV), Cs-137 (662 keV), Am-241 (59.6 keV), Ba-133 (81 and 356 keV) and Ra-226 (242 keV), were used in the experimental work. The shielding performance increased substantially with increasing Bi2O3 filler loading especially in the low energy range and decreased with increasing energy except at 122 keV due to bismuth K-absorption edge. At higher energies 1173 and 1332 keV, Compton effect is the most dominant effect leading to minor variations as observed. XCOM software was used for comparison, by computing the mass attenuation coefficient for prepared micro composites at all used Bi2O3 loadings including pristine PMMA. In addition, the effective atomic number Zeff, electron density Neff as well as the photoelectric absorption and incoherent scattering contributions to MAC, were evaluated for further analysis. The prepared PMMA-Bi2O3 micro composites shielding materials performed very well in the whole energy range 59–1332 keV of interest to medical and industrial applications, and are excellent at lower energies and higher Bi2O3 loadings. In particular, at 40% loading, the experimental MAC for the Cs-137 gamma line (662 keV) reached 93.4% of that of lead element. Therefore, these composites are much recommended cost effective, light and safe shielding material for x and gamma rays.

Preparation and characterization of novel MP-MMT/PMMA composite microspheres

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.

Molecular dynamics simulation and experiment on analyzing mechanical properties of PMMA/SiO2 composites based on interfacial interaction

In this paper, we investigate the impact of modified SiO2 nanoparticles on the mechanical properties of Polymethyl methacrylate (PMMA) composites through a combination of molecular dynamics simulation and experimentation. Our investigation focuses on analyzing the elastic modulus, bulk modulus, shear modulus, and Cauchy ratio of pure PMMA, PMMA/SiO2 composites, and PMMA/modified SiO2 composites over a temperature range of 200–400 K. Our results indicate that, as the temperature increases, the elastic modulus, bulk modulus, and Cauchy ratio of all materials decrease, while the shear modulus initially increases and then decreases. Notably, at room temperature, the elastic modulus, bulk modulus, and shear modulus of the composites increase with an increase in the degree of nanoparticle modification, while the Cauchy ratio exhibits the opposite trend. Our findings suggest that modified SiO2 nanoparticles have the potential to enhance the mechanical properties of composite materials. To validate our simulation results, we also conducted experiments that demonstrated the rationality of our approach.

Preparation and characterization of PMMA/ZnO nanocomposites for antistatic and biomedical applications

Polymethyl methacrylate (PMMA)/Palm oil/ZnO nanocomposite films of concentrations 0, 0.5, 1, 2, 5, 10, and 15 wt% were prepared by solution casting technique. Tween 80 was used as a surfactant. The prepared films were characterised by different techniques in addition to antimicrobial and cytotoxicity tests. The scanning electron microscope (SEM) micrographs of fractured surfaces of the films showed that palm oil (PO) and Tween 80 enhanced ZnO NPs dispersion. An excess ZnO loading led to polymer saturation with ZnO NPs which accumulate on PMMA surface. X-ray diffraction (XRD) measurements confirmed SEM results as the crystallinity increased by ZnO NPs loading and decreased by excess loading. In addition, the presence of PO and Tween 80 enhanced thermal stability of pure PMMA and the optimum concentration is 0.5 wt% ZnO NPs. Further, the permittivity (ε′), dielectric loss (ε′′), and electrical conductivity (σ) were investigated. It was found that PO addition increased the values of ε′, ε′′, and σ of PMMA. Upon ZnO loading, these values increased up to 10 wt% ZnO NPs then decreased upon reaching 15 wt% ZnO NPs. The conductivity values revealed that the prepared nanocomposites can perform as antistatic materials for lower ZnO content and electrostatic dissipation application at 10 wt% ZnO. The antimicrobial and cytotoxicity studies revealed that the prepared films are nontoxic and the antimicrobial properties of the films against Staphylococcus aureus, Enterococcus faecalis and Candida albicans were enhanced by PO and ZnO NPs addition.

Antifungal Effect of Polymethyl Methacrylate Resin Base with Embedded Au Nanoparticles.

Full and partial restorations in dentistry must replicate the characteristics of the patient's natural teeth. Materials must have good mechanical properties and be non-toxic and biocompatible. Microbes, which can form biofilms, are constantly in contact with restorations. In this study, we investigate how well Candida albicans adheres to a polymethyl methacrylate (PMMA) resin base with gold (Au) nanoparticles. We synthesized Au nanoparticles and characterized them. The average size of Au nanoparticles embedded in PMMA was 11 nm. The color difference ΔE between PMMA and PMMA/Au composites was 2.7 and was still esthetically acceptable to patients. PMMA/Au surfaces are smoother and more hydrophilic than pure PMMA surfaces, and the isoelectric point of both types of surfaces was 4.3. Above the isoelectric point, PMMA/Au surfaces are more negatively charged than PMMA surfaces. The added Au nanoparticles decreased the tensile strength, while the hardness did not change significantly. Adhesion measurements showed that PMMA surfaces modified with Au nanoparticles reduced the extent of microbial adhesion of Candida albicans.