Poly Methyl Methacrylate Matrix Research Articles

Application of Cyrene solvent for the fabrication of polymethyl methacrylate, polyethyl methacrylate and composite films containing hydroxyapatite and diamonds

AbstractCyrene is a new biodegradable solvent, which represents a green alternative to many traditional toxic solvents for advanced polymers. Therefore, this investigation is motivated by interest in applications of Cyrene for polymer processing. The feasibility of solubilization of polymethyl methacrylate (PMMA) and polyethyl methacrylate (PEMA) in Cyrene is demonstrated. The ability to form relatively concentrated solutions of the high molecular mass polymers is an important factor for the formation of PMMA and PEMA films by a dip coating method. It was found that the polymer coatings provide corrosion protection of stainless steel in 30 g L−1 NaCl solutions. Another important finding is that the use of Cyrene facilitates the fabrication of stable suspensions of hydroxyapatite (HAp), microdiamond, and nanodiamond particles. Therefore, the problems of the dispersant selection for dispersion of chemically inert diamond and development of biocompatible dispersants are avoided using Cyrene. For the fabrication of composite films, HAp nanorods with reduced particle size are obtained using rutin as a chelating capping agent. Composite films containing HAp, microdiamond and nanodiamond in the PMMA or PEMA matrix are obtained. The composite films are promising for biomedical applications. It was found that the film morphology, composition and microstructure are influenced by the solvent–particle–polymer interactions and processing conditions.

Exciton Delocalization and Polarizability in Perylenetetracarboxylic Diimide Probed Using Electroabsorption and Fluorescence Spectroscopies.

Perylenetetracarboxylic diimide (PTCDI) is an n-type organic semiconductor molecule that has been widely utilized in numerous applications such as photocatalysis and field-effect transistors. Polarizability and dipole moment, which are inherent properties of molecules, are important parameters that determine their responses to external electric and optical fields, physical properties, and reactivity. These parameters are fundamentally important for the design of innovative materials. In this study, the effects of external electric fields on absorption and fluorescence spectra were investigated to obtain the PTCDI parameters. The PTCDI substituted by an octyl group (N,N'-Dioctyl-3,4,9,10-perylenedicarboximide) dispersed in a polymethyl methacrylate (PMMA) matrix was studied in this work. The features of vibronic progression in the absorption spectrum were analogous to those observed in solution. The red shift of the absorption band caused by the Stark effect was mainly observed in the presence of an external electric field. Changes in parameters such as the dipole moment and polarizability between the ground and the Franck-Condon excited states of the PTCDI monomer were determined. The fluorescence spectrum shows a contribution from a broad fluorescence band at wavelengths longer than the monomer fluorescence band. This broad fluorescence is ascribed to the excimer-like fluorescence of PTCDI. The effects of the electric field on the fluorescence spectrum, known as the Stark fluorescence or electrofluorescence spectrum, were measured. Fluorescence quenching is observed in the presence of an external electric field. The change in the polarizability of the monomer fluorescence band is in good agreement with that of the electroabsorption spectrum. A larger change in the polarizability was observed for the excimer-like fluorescence band than that for the monomer band. This result is consistent with exciton delocalization between PTCDI molecules in the excimer-like state.

Enhancing the O2 sensitivity of [Ru(bpy)3]2+ dye by incorporating SnO2 and Ni:SnO2

Oxygen (O2)-sensitive probes encapsulated in a polymeric matrix have gas sensitivity improved by adding different metal oxide semiconductors (MOSs) to the composition. In this research, O2-sensitive tris(2,2′-bipyridyl) ruthenium(II) chloride ([Ru(bpy)3]Cl2) was chosen as a fluorophore, and SnO2 and Ni:SnO2 additives were used to enhance the oxygen sensitivity of the dye. While preparing sensing agents as a form of thin film and nanofiber, dye and MOSs powders were immobilized into the polymethylmethacrylate (PMMA) matrix in close proximity to each other. The oxygen-induced intensity measurements, decay time kinetics, and kinetic response were investigated for each of the sensing slides in the concentration range of 0–100% [O2]. Signal decreases in the emission-based intensity values of all MOSs-doped [Ru(bpy)3]2+-based complexes were monitored. Compared with free form, Ni:SnO2-doped [Ru(bpy)3]2+-based nanofiber agents exhibited a 4.03-fold increase in signal change (I0/I) ratio. The nanofiber structure, which allows the sensor slide to have a higher surface/volume ratio, allows O2 gas to penetrate more effectively. This can lead to greater interaction of the gas within the sensor matrix, resulting in more sensitive detection. Higher Stern Volmer (Ksv) values, greater O2 -induced sensing capabilities, more linear spectral measurements over larger concentration ranges, and faster response and recovery times show that MOSs-doped [Ru(bpy)3]2+-based sensing agents make promising candidates as oxygen probes.

Structural Characterization and Bioactivity of a Titanium(IV)-Oxo Complex Stabilized by Mandelate Ligands.

Research on titanium-oxo complexes (TOCs) is usually focused on their structure and photocatalytic properties. Findings from these investigations further sparked our interest in exploring their potential biological activities. In this study, we focused on the synthesis and structure of a compound with the general formula [Ti8O2(OiPr)20(man)4] (1), which was isolated from the reaction mixture of titanium(IV) isopropoxide with mandelic acid (Hman) in a molar ratio of 4:1. The structure (1) was determined using single-crystal X-ray diffraction, while spectroscopic studies provided insights into its physicochemical properties. To assess the potential practical applications of (1), its microcrystals were incorporated into a polymethyl methacrylate (PMMA) matrix, yielding composite materials of the type PMMA + (1) (2 wt.%, 5 wt.%, 10 wt.%, and 20 wt.%). The next stage of our research involved the evaluation of the antimicrobial activity of the obtained materials. The investigations performed demonstrated the antimicrobial activity of pure (1) and its composites (PMMA + (1)) against both Gram-positive and Gram-negative strains. Furthermore, MTT tests conducted on the L929 murine fibroblast cell line confirmed the lack of cytotoxicity of these composites. Our study identified (1) as a promising antimicrobial agent, which is also may be use for producing composite coatings.

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.

Microwave-Assisted Grafting of Coal onto Nitrogen-Doped Carbon Dots with a High Quantum Yield and Enhanced Photoluminescence Properties.

The fluorescent nitrogen-doped carbon dots (N-CDs) were synthesized via a facile one-pot solvothermal process using coal (Jin 15 Anthracite and Shaerhu lignite) as raw materials and dimethyl formamide (DMF) as the solvent, employing a microwave pyrolysis method. This approach demonstrates remarkable efficacy in the development of nitrogen-doped carbon dots (N-CDs) with a high quantum yield (QY). The N-CDs prepared have strong photoluminescence properties. Moreover, the obtained N-CDs emit blue PL and are easily dispersed in polymethyl methacrylate (PMMA), preserving the inherent advantages of N-CDs and the PMMA matrix. The JN-CDs exhibit a high quantum yield (QY) of 49.5% and a production yield of 25.7%, respectively. In contrast, the SN-CDs demonstrate a quantum yield of 40% and a production yield of 35.1%. It is worth noting that the production yield and quantum yield of coal-based carbon dots are inversely related indices. The lower metamorphic degree of subbituminous coal favors an enhanced product yield, while the higher metamorphic degree of anthracite promotes an improved quantum yield in the product, which may be attributed to the presence of amorphous carbon within it. Consequently, we propose and discuss potential mechanisms underlying N-CD formation.

Incorporation of an Anion-Coordinated Triple Helicate into a Thin Film for Choline Recognition in an Aqueous System.

Functional thin films, being fabricated by incorporating discrete supramolecular architectures, have potential applications in research areas such as sensing, energy storage, catalysis, and optoelectronics. Here, we have determined that an anion-coordinated triple helicate can be solution-processed into a functional thin film by incorporation into a polymethyl methacrylate (PMMA) matrix. The thin films fabricated by the incorporation of the anion-coordinated triple helicate show multiple optical properties, such as fluorescence, CD, and CPL. In addition, the film has the ability to recognize choline and choline derivatives in a water system. The successful recognition of Ch+ by the film represents the first example of utilizing 'aniono'-supramolecular architectures for biomolecule detection in aqueous solution and opens up a new route for designing biocompatible functional materials.

Attenuation properties of poly methyl methacrylate reinforced with micro/nano ZrO2 as gamma-ray shields

This research aimed to examine the radiation shielding properties of unique polymer composites for medical and non-medical applications. For this purpose, polymer composites, based on poly methyl methacrylate (PMMA) as a matrix, were prepared and reinforced with micro- and nanoparticles of ZrO2 fillers at a loading of 15%, 30%, and 45% by weight. Using the high purity germanium (HPGe) detector, the suggested polymer composites’ shielding characteristics were assessed for various radioactive sources. The experimental values of the mass attenuation coefficients (MAC) of the produced composites agreed closely with those obtained theoretically from the XCOM database. Different shielding parameters were estimated at a broad range of photon energies, including the linear attenuation coefficient (μ), tenth value layer (TVL), half value layer (HVL), mean free path (MFP), effective electron density (Neff), effective atomic number (Zeff), and equivalent atomic number (Zeq), as well as exposure buildup factor (EBF) and energy absorption buildup factor (EABF) to provide more shielding information about the penetration of γ-rays into the chosen composites. The results showed that increasing the content of micro and nano ZrO2 particles in the PMMA matrix increases μ values and decreases HVL, TVL, and MFP values. P-45nZ sample with 45 wt% of ZrO2 nanoparticles had the highest μ values, which varied between 2.6546 and 0.0991 cm−1 as γ-ray photon energy increased from 0.0595 to 1.408 MeV, respectively. Furthermore, the highest relative increase rate in μ values between nano and micro composites was 17.84%, achieved for the P-45nZ sample at 59.53 keV. These findings demonstrated that ZrO2 nanoparticles shield radiation more effectively than micro ZrO2 even at the same photon energy and filler wt%. Thus, the proposed nano ZrO2/PMMA composites can be used as effective shielding materials to lessen the transmitted radiation dose in radiation facilities.

Enhanced TNT vapor sensing through a PMMA-mediated AIPE-active monocyclometalated iridium(III) complex: a leap towards real-time monitoring.

Based on the explosive nature and harmful effects of nitro-based explosive materials on living beings and the environment, it is extremely important to develop luminescence-based probe molecules for their detection with excellent selectivity and sensitivity. Two AIPE (aggregation-induced phosphorescence emission)-active iridium(III) complexes (M1 and M2) were developed for the sensitive detection of TNT in both contact and non-contact modes. The aggregate solutions of both complexes (M1 and M2 in THF/H2O, 1/9 by volume) detected TNT at the pico-molar (pM) level. These complexes showed greatly enhanced emission intensity while embedded in a PMMA(polymethyl methacrylate) matrix film. The amplified quantum efficiency, improved phosphorescence lifetime, and enhanced porous network of M2-PMMA composite helps to improve the sesitivity of TNT vapor detection. Interestingly, the sensitivity of the detection of TNT by the M2 complex was significantly improved (5-fold) in a PMMA-incorporated complex (CP) with an observed limit of detection (LOD) of 12.8 ppb. From the BET analysis of CP, it was observed that the mesoporous network of CP has an average pore diameter of 8.52 nm and a surface area of 2.03 m2 g-1. The porous network of CP assists in trapping TNT vapor in a polymeric network containing an electron-rich probe (iridium(III) complex, M2), which helps to effectively trap TNT, thus enhancing electronic communication. As a result, significant emission quenching was observed.

Enhanced luminescence of a silica‐nitride phosphor; La3Si6N11:Ce3+by using Cr3+‐activated TiO2 nanoparticles

AbstractCe3+‐activated silica nitride phosphors (lanthanum silicate‐nitride [LSN]) are promising thermostable conversion components for white‐light‐emitting diodes, screen technologies, and other optoelectronic applications. Cr3+‐activated TiO2, on the other hand, is a strongly absorbing material depending on its size and optical microenvironment. In this work, we gathered Cr3+‐doped TiO2 and La3Si6N11:Ce3+ in an optically transparent polymethylmethacrylate matrix. Photoluminescence of the binary blends of La3Si6N11:Ce3+/TiO2 and La3Si6N11:Ce3+/TiO2:Cr3+ has been investigated under two different excitation energies by steady‐state and lifetime‐based measurements, respectively. When the microscale La3Si6N11:Ce3+ phosphor and nanoscale TiO2:Cr3+ particles were gathered at a critical concentration, the resulting composite exhibited 3.14‐fold enhancement in the emission signal intensity with respect to the additive‐free phosphor. Upon excitation, the La3Si6N11:Ce3+–TiO2:Cr3+ blend exhibited different excited‐state lifetimes for the nano‐ and microsecond time‐scales compared to the LSN. The microsecond time‐scale measurements performed under 378 nm excitation supported the existence of a potential energy transfer from the TiO2:Cr3+ to the La3Si6N11:Ce3+.

Coal Pitch Derived Yellow‐Emissive Carbon Dots and Their Application in Luminescent Solar Concentrators

AbstractUsing coal pitch as the carbon source to synthesize carbon dots (CDs), one of the most promising photoluminescence (PL) materials, can play an important role in the global demand for carbon neutralization. However, the reported CDs derived from coal pitch are mainly limited blue emission. Here, a new route to synthesize yellow‐emissive CDs from coal pitch is developed by extracting the lightweight aromatic compounds from coal pitch and solvothermally treating the extracts in dichloromethane in the presence of a small amount of nitric acid and sulfuric acid. Notably, the obtained CDs exhibit excitation independent yellow emission, large Stokes shift and good photostability. The application of the CDs for luminescent solar concentrators (LSCs) is evaluated. It is found that the CDs can be well dispersed in polymethyl methacrylate (PMMA) matrix and fabricated transparent LSCs. The synthesized LSC (4 × 4 × 0.2 cm3) with the optimal CDs concentration exhibits an optical conversion efficiency (ηopt) of 3.31% and power conversion efficiency (ηPCE) of 1.95% under simulated sun light illumination (100 mW cm−2). This research offers a new strategy to synthesize new kind of CDs with desired performance by exploiting the native chemistries of coal pitch.

Controlling dendrite growth and side reactions in anode-free Zn-ion aqueous batteries with PMMA:Zn coated electrode

In this study, we propose the implementation of a protective layer consisting of a dense polymethylmethacrylate matrix containing Zn ions (PMMA:Zn) on the Cu electrode in Zn-ion aqueous batteries (ZABs). By introducing Zn2+ ions into the PMMA matrix, the PMMA:Zn coating layer exhibited significantly improved ion conductivity, enabling uniform Zn deposition between the PMMA layer and the current collector. This innovative coating effectively mitigated dendrite growth, hydrogen evolution reactions, and ZnO film formation, leading to enhanced electrochemical performance. The half-cell with PMMA:Zn-coated Cu foil exhibited remarkable stability, achieving near 100 % Coulombic efficiency and enhanced rate capability even under high current densities of 10 mA cm−2. Moreover, in an anode-free configuration, the PMMA:Zn coating layer enabled extended cycling life and consistent operation. Furthermore, employing ZnMnO2 cathodes in the full cell configuration demonstrated elevated specific capacity of 257 mAh g−1 at a current density of 1 A g−1 and outstanding capacity retention over 80 % at the 300th cycle. These findings underscore the immense potential of the PMMA:Zn coating layer as a promising strategy for enhancing the performance and reliability of ZABs, thereby opening up possibilities for their practical integration in diverse energy storage systems.

Buckling analysis of stiffened functionally graded multilayer graphene platelet reinforced composite plate with circular cutout embedded on elastic support subjected to in-plane normal and shear loads

Buckling analyses of orthogonally stiffened functionally graded graphene platelet reinforced composite plate with circular cutout supporting on Winkler elastic foundation is conducted according to the third order shear deformation plate theory and the finite element method to achieve the desired solutions. Material properties of the composite plate are evaluated using Rule of mixture and Halpin-Tsai approach. Graphene platelet reinforcements and Poly methyl methacrylate matrix are considered as the two components of the composite media. The material of the stiffeners is selected the same as that of the polymer matrix. In one efficient case, adding a set of stiffeners increased the critical buckling load by 41.8 % with only a 10.3 % increase in weight of the structure. Influence of broad range of factors such as GPLs nanofillers distribution pattern and weight fraction, Winkler-type elastic foundation, uniaxial and biaxial normal and shear loads, plate thickness and aspect ratio, width, height and number of longitudinal and transverse stiffeners are reported in several tabular and graphical data in detail.

Promoting organic room temperature phosphorescence through in situ polymerization

AbstractOrganic room temperature phosphorescence materials (RTP) have attracted much attention for their wide application in organic light‐emitting diodes, anti‐counterfeiting, and sensors. In this work, a series of organic luminogens containing carbonyl and aromatics were fixed in a three‐dimensional polymethyl methacrylate (PMMA) network by in situ polymerization. All organic luminogens‐doped in situ PMMA (s‐PMMA) columns achieved longer RTP lifetimes than those of doped commercial PMMA (c‐PMMA) films, especially, the RTP lifetime of NMP2O in these PMMA matrixes increased from 1.82 ms to 156.34 ms by about 86 times. It is mainly due to the restriction of molecular motions by highly entangled polymer chains and rigid environments to efficiently inhibit the non‐radiative transitions. Also, the excellent shielding effect toward oxygen by the in situ polymerization process can avoid possible quenching effects on triplet excited states, beneficial to RTP emission. Thus, it affords an efficient approach to achieving persistent RTP for three‐dimensional displaying applications.

Novel nanocomposites based on Tetrazine liquid crystals for energy storage application

Polymethyl methacrylate (PMMA) /Tetrazine liquid crystal (LCTZ12) nanocomposites with different CNTs loadings have been prepared. The prepared nanocomposites were characterized using polarizing light microscope (POM), differential scanning calorimetry (DSC), Fourier transform Infrared Spectroscopy (FTIR) and broadband dielectric spectroscopy (BDS) in the range 10-1-106 Hz respectively. The most commonly observed texture of soft crystal phases was that of a mosaic pattern, as revealed by the POM technique. PMMA alone does not change the polarization states and appeared as isotropic material, but once LCTZ12 is added, crystal growth could be clearly noticed in the needle pattern inside the polymer matrix to compose an amazing structure of soft crystal G texture. The increase of LCTZ12 to about 20 wt% in the PMMA matrix led to more heterogeneous aggregation of liquid crystalline molecules. This ratio addition is enhancing of network connections inside the PMMA. Moreover, the dispersion of carbon nanotubes mounted on catalysts is found to accumulate in segregations in PMMA/ LCTZ12 nanocomposites. However, the location of CNTs is concentrated at bottom of polymer network due to the large difference in densities of LCs, PMMA, and CNTs. DSC is in agreement with the POM result of LCTZ12, which has multi soft crystals or highly self-assembled ordered liquid crystal phases near to room temperature. The FTIR proved that blend PMMA/ LCTZ12 (80/20) has a dramatic increase in the 1387 cm−1 peak of C = C as a response of the rise in the concentration or number of aromatic rings. Additionally, the vibrational scissoring peak located at 1477 cm−1 of methylene CH2 groups is increased significantly and C–H stretching in aliphatic regions at 2850 cm−1 and 2990 cm−1 as well. However, there is no significant change observed after CNTs addition to the PMMA/ 20 wt% LCTZ12 matrix. Regarding dielectric results, it was found that, the polymer dispersed liquid crystals PDLC system composed of (PMMA/20 wt% LCTZ12) possesses the most promising dielectric properties, that is; high dielectric permittivity with low losses compared to the other ratios. The addition of CNTs results in more localization of charge carriers along with mobile ions, causing higher ionic conductivity. The conductivity ranges altered from 3.2 × 10-10 S/cm in pure PDLC system to become 1.7 × 10-3 S/cm for PDLC doped with 10 wt% CNTs nanocomposite. The electrical energy density measurements for 3,6-bis(5-(Dodecyloxy) pyridin-2-yl)-1,2,4,5-tetrazine (LCTZ12) liquid crystals with 6 cationic centers in polymeric matrices proved to be suitable for flexible and efficient electrolytes for energy storage devices.

Modulation of intramolecular charge transfer in D-A functionalized pyrrolopyrazine and their application in luminescent solar concentrators

In this study, we fabricated LSCs using pyrrolopyrazine-based organic fluorophore (PP2) with an intramolecular charge transfer (ICT) function and aggregation-induced emission. PP2 incorporates unique features, including an intramolecular charge transfer (ICT) function and aggregation-induced emission. The pyrrolopyrazine core of PP2 is decorated with an electron-rich dimethylamine group and two electron-poor cyano groups, enhancing its potential for light harvesting in LSC applications. In the polymethylmethacrylate (PMMA) matrix, PP2 showed strong absorption near ultraviolet (395 nm–406 nm), emitted green-colored visible light (474 nm–478 nm), and exhibited a photoluminescence quantum efficiency (PLQY) of 67%. The external photon efficiency (ηext) and internal photon efficiency (ηint) of the fabricated LSC under AM 1.5G illumination (1 sun) were 3.36% and 39.1%, respectively. Subsequently, we conducted an analytical simulation to estimate the ηext and the ηint as the dimensions of the LSC were scaled up. In addition, the photovoltaic performance measurement under 1 sun showed a power conversion efficiency (ηPCE) of 1.074% with a scattering background and 0.633% without a scattering background. Thus, this research introduces PP2 as a novel fluorophore with promising prospects for advancing the field of LSC technology.

Experimental and Numerical Study of Healing Effect on Delamination Defect in Infusible Thermoplastic Composite Laminates.

The integrity of delaminated composite structures can be restored by introducing a thermally-based healing effect on continuous fiber-reinforced thermoplastic composites (CFRTPC). The phenomenon of thermoplastics retaining their properties after melting and consolidation has been applied by heating the delaminated composite plates above their glass transition temperature under pressure. In the current investigation, the composite is comprised of Methyl methacrylate (MMA)-based infusible lamination resin combined with benzoyl peroxide initiator, which polymerizes into a Polymethyl methacrylate (PMMA) matrix. For the reinforcement, unidirectional 220 gr/m2 glass filament fabric was used. Delamination damage is artificially induced during the fabrication of laminate plates. The distributed delamination region before and after thermally activated healing was determined by using non-destructive testing with active thermography. An experimental approach is employed to characterize the thermal healing effect on mechanical properties. Experimentally determined technological parameters for thermal healing have been successfully applied to repair delamination defects on composite plates. Based on the compression-after-impact (CAI) test methodology, the intact, damaged, and healed composite laminates were loaded cyclically to evaluate the healing effect on stiffness and strength. During the CAI test, the 3D digital image correlation (DIC) technique was used to measure the displacement and deformation fields. Experimental results reveal the difference between the behavior of healed and damaged specimens. Additionally, the numerical models of intact, damaged, and healed composite laminates were developed using the finite element code LS-Dyna. Numerical models with calibrated material properties and tie-break contact constants provide good correlation with experimental results and allow for the prediction of the mechanical behavior of intact, damaged, and healed laminated plates. The comparison analysis based on CAI test results and modal characteristics obtained by the 3D Laser Doppler Vibrometer (Polytec GmbH, Karlsbad, Germany) proved that thermal healing partially restores the mechanical properties of damaged laminate plates. In contrast, active thermography does not necessarily indicate a healing effect.

Facile preparation of novel type polymethyl methacrylate/CoFe2O4/BNNS composite cements and their caloric performance in alternating magnetic fields

AbstractMagnetic hyperthermia generated by functionalized bone cement is a promising approach to treat postosteocarcinoma cancer regeneration. However, it is crucial to minimize the magnetic field intensity using localized high‐caloric‐generating nanoparticles to avoid the potential hazards of electromagnetic field exposure to living organisms. Herein, in situ hydrothermally synthesized CoFe2O4 (CoFe) nanoparticles and boron nitride nanosheet (BNNS)–supported CoFe complexes (BNCoFe) are incorporated into polymethyl methacrylate (PMMA) cement to prepare a composite implant with high‐intensity magnetic–thermal performance and safety. The results show that the CoFe nanoparticles (size = ~70 nm) anchored on BNNS surfaces exhibit a maximum magnetic–thermal ablation temperature of ~42°C within 50 s under an alternating magnetic field of 400 KHz (field frequency) and 30 Oe (field intensity) in vitro. Furthermore, the incorporation of BNNSs into the PMMA matrix notably increases the thermal conductivity of PMMA from 0.07 to 0.25 W mK−1 and improves its mechanical properties (compressive strength increases from 74.0 ± 1.6 to 81.0 ± 1.0 MPa), which is attributed to the crystalline structure of BNNSs in the PMMA matrix. Inductively coupled plasma analysis shows a considerably reduced Co2+ ion release from PMMA/BNCoFe, indicating its potential as a safe implantation material for hyperthermia treatment.

Hybrid Organic–Inorganic PMMA Optical Fibers Functionalized with Photochromic Active WO3 Nanoparticles: From Materials Design to Photochromic Fabrics

AbstractHere, the direct incorporation of photochromic WO3 nanoparticles is investigated in a matrix of polymethyl methacrylate (PMMA) by bulk radical polymerization for the fabrication of plastic optical fibers (POFs). All the prepared composites, from preforms to 1D single fibers and 2D fabrics, are thoroughly investigated, leading to insight into their thermal, morphological, and photochromic properties (coloring/bleaching amplitudes and kinetics). It is found that the preforms exhibit partially irreversible photochromic behavior, whereas the single fibers proved to be effectively reversibly photochromic through a degradation of transmission signal upon UV irradiation and a full recovery under dark conditions. The as‐prepared PMMA plastic fibers, both undoped and doped, show good homogeneity without any imperfections or contamination. The WO3 nanoparticles play a dual role as intrinsic and extrinsic absorption centres leading to higher transmission losses. Finally, a hand‐made textile woven with a bundle of doped fibers is presented. The proposed 1D single fibers and 2D fabrics demonstrate their great potential as novel hybrid inorganic–organic materials in the domain of flexible UV‐sensors and photochromic smart textile with improved color stability and lifetime.

Understanding significantly reinforced polymethyl methacrylate composites induced by two‐dimensional Tin+1Cn from an atomistic perspective

AbstractMXenes, which have good reinforcing and toughening effects, can serve as excellent polymer additives. However, the mechanism whereby MXenes act has not been revealed. In this study, to understand the reinforcement effect of Tin+1Cn on polymethyl methacrylate (PMMA) from an atomistic perspective, we used molecular dynamics to conduct unidirectional tensile simulations of PMMA composites reinforced with monolayer Ti2C and Ti3C2 sheets. The results showed that Ti3C2 can more significantly improve the mechanical properties of the PMMA polymer than Ti2C, and the yield stress and Young's modulus of the Ti3C2/PMMA complexes were respectively 54.39% and 73.46% higher than the Ti2C/PMMA complexes. To further reveal the interaction mechanism between Tin+1Cn and PMMA, different separation speeds were used to simulate the pull‐out of Tin+1Cn from the PMMA matrix. The results showed that, in addition to the enhancement of interfacial strength by non‐bonding van der Waals forces, there were TiO and CTi bonds between Tin+1Cn and PMMA, which further increased the interfacial strength. Ti3C2 formed a denser interfacial region with PMMA, it could more effectively resist the formation and expansion of cracks. These findings may provide an important theoretical basis to design new type of MXene/polymer composites with excellent mechanical properties.Highlights MXene greatly improved the mechanical properties of the PMMA matrix. Formation of chemical bonds improved connection between the MXene and PMMA. The addition of MXene slows down the rate of crack propagation in PMMA.