Poly Methyl Methacrylate Matrix Research Articles

Study of Prepared Lead-Free Polymer Nanocomposites for X- and Gamma-ray Shielding in Healthcare Applications.

Polymer composites were synthesized via melt mixing for radiation shielding in the healthcare sector. A polymethyl-methacrylate (PMMA) matrix was filled with Bi2O3 nanoparticles at 10%, 20%, 30%, and 40% weight percentages. The characterization of nanocomposites included their morphological, structural, and thermal properties, achieved using SEM, XRD, and TGA, respectively. The shielding properties for all synthesized samples including pristine PMMA were measured with gamma spectrometry using a NaI (Tl) scintillator detector spanning a wide range of energies and using different radioisotopes, namely Am-241 (59.6 keV), Co-57 (122.2 keV), Ra-226 (242.0), Ba-133 (80.99 and 356.02 keV), Cs-137 (661.6 keV), and Co-60 (1173.2 and 1332.5 keV). A substantial increase in the mass attenuation coefficients was obtained at low and medium energies as the filler weight percentage increased, with minor variations at higher gamma energies (1173 and 1332 keV). The mass attenuation coefficient decreased with increasing energy except under 122 keV gamma rays due to the K-absorption edge of bismuth (90.5 keV). At 40% loading of Bi2O3, the mass attenuation coefficient for the cesium 137Cs gamma line at 662 keV reached the corresponding value for the toxic heavy element lead. The synthesized PMMA-Bi2O3 nanocomposites proved to be highly effective, lead-free, safe, and lightweight shielding materials for X- and gamma rays within a wide energy range (<59 keV to 1332 keV), making them of interest for healthcare applications.

Synergistic effects of zinc borate and graphene on enhanced thermal stability and antimicrobial properties of poly(methyl methacrylate)

AbstractThe use of graphene nanoplatelets (GnP) as reinforcing material for thermoplastic polymer matrices, polymethyl methacrylate (PMMA) and zinc borate (ZnB), as an antimicrobial and fire‐retardant agent was studied. PMMA‐ZnB and PMMA‐GnP‐ZnB (ZG) composite films were fabricated with different ZnB concentrations (2.5, 5, 10 wt%) by solvent casting method using acetone. The effect of additives on the antimicrobial activity, thermal and mechanical properties, and surface morphologies of the composites were investigated. Antimicrobial surface activity tests were conducted against seven microorganisms, including bacterial and fungal species. An improvement in antimicrobial activity by up to 99.99% with increasing ZnB content was observed. Thermal stability was increased with increasing concentration of ZnB and a combination of ZnB and GnP additions. 10% ZG‐based composites increased the % char residue value of PMMA from 0.5% to 9.3%. The incorporation of the ZnB and GnP into the PMMA matrix resulted in an increase in the calculated limiting oxygen index (LOI). 10% and 50% weight loss temperature increased by 11.7°C and 3.7°C, respectively, for 10% ZG composites. The Young's modulus of the composites increased with increasing ZnB and a combination of ZnB and GnP loading (increasing by 16% to 2033 MPa with the addition of 10 wt% ZG). The commercial application for this study would be in high touch and piano black automotive interior, construction, and medical applications.

Photoluminescence of Metal−Polymer Complexes Based on Functional Triazole−Carbazole Copolymers with Terbium Ions

Functional copolymers of 1-vinyl-1,2,4-triazole (VT) and N-vinylcarbazole (VK) were synthesized using a free-radical polymerization. The content of hole-conducting N-vinylcarbazole units was found to be 9, 16, and 37 mol. %. Fourier transform infrared spectroscopy, 1H-NMR spectroscopy, gel permeation chromatography, thermogravimetric analysis, and differential scanning were applied to characterize the poly(VT–co–VK). Based on a polymer ligand, metal−polymer complexes with Tb³⁺ ions were obtained in a polymethyl methacrylate matrix, and their luminescent properties were studied. The maximum photoluminescence of the complex can be achieved when using 16 mol. % of N-vinylcarbazole units. This is because two photoprocesses (excimer formation and excitation energy transfer) occur simultaneously and competitively.

Photo‐Activated Circularly Polarized Luminescence Film Based on Aggregation‐Induced Emission Copper(I) Cluster‐Assembled Materials

AbstractIn this study, a pair of chiral copper(I) cluster‐assembled materials (R/S‐2) was prepared, exhibiting unique photo‐response characteristics with a concentration‐wavelength correlation property in DMSO solution. By the combination of R/S‐2 with a polymethyl methacrylate (PMMA) matrix, the first photo‐activated circularly polarized luminescence (CPL) film was developed, the CPL signal (glum=9×10−3) of which could be induced by UV light irradiation. Moreover, the film exhibited a reversible photo‐response and extremely good fatigue resistance. Mechanism study revealed that the photo‐response properties of the R/S‐2 solution and film are attributed to the aggregation‐induced emission (AIE) characteristics of R/S‐2 and a photo‐induced deoxygenation process. This study enriches the types of luminescent cluster‐assembled molecules and provides a new strategy for the construction of metal cluster‐based stimuli‐responsive composite materials.

Photo-Activated Circularly Polarized Luminescence Film Based on Aggregation-Induced Emission Copper(I) Cluster-Assembled Materials.

In this study, a pair of chiral copper(I) cluster-assembled materials (R/S-2) was prepared, exhibiting unique photo-response characteristics with a concentration-wavelength correlation property in DMSO solution. By the combination of R/S-2 with a polymethyl methacrylate (PMMA) matrix, the first photo-activated circularly polarized luminescence (CPL) film was developed, the CPL signal (glum =9×10-3 ) of which could be induced by UV light irradiation. Moreover, the film exhibited a reversible photo-response and extremely good fatigue resistance. Mechanism study revealed that the photo-response properties of the R/S-2 solution and film are attributed to the aggregation-induced emission (AIE) characteristics of R/S-2 and a photo-induced deoxygenation process. This study enriches the types of luminescent cluster-assembled molecules and provides a new strategy for the construction of metal cluster-based stimuli-responsive composite materials.

Thermoacoustic response of polymethyl methacrylate composite shells reinforced by carbon nanotube resting on Winkler–Pasternak elastic foundation

This paper presented an analytical method for investigating the vibroacoustic response of polymethyl methacrylate composite shells reinforced by CNTs resting on an elastic foundation under thermal loading. This structure is submerged in a moving fluid and excited by an acoustics plane wave. The CNTs are assumed to have a graded distribution in the polymethyl methacrylate matrix. The properties of the CNTs are assumed to be temperature-dependent. Different types of CNTs distributions such as UD, X, V, and O are considered. The Winkler–Pasternak model is applied to describe the vibrational behavior of the elastic foundation. The equations of motion of the structure are based on Hamilton’s principle using the TSDT, considering the effects of shear and rotation. To validate the present analytical method, the obtained results are compared with those of other researchers. Next, the effects of various significant parameters such as elastic foundation, temperature gradient, CNTs distributions, and Mach number on the TL are studied. The results show increasing the temperature reduces the TL because the stiffness bending of the structure decreases. It can be seen that the addition of CNTs to the matrix, with an appropriate volume fraction, improves the sound transmission loss due to the enhancement of stiffness.

Enhanced energy density at low operating field strength of laminated multicomponent polymer-based composites via regulation of electrical displacement

Dielectric polymer-based composites have demonstrated enormous promise in the applications of electrostatic film capacitors due to their exceptional insulating characteristics. However, the achievement of great energy-storage density (U e) is always difficult in linear dielectric polymer-based composites for operation at weak field strength due to the low permittivity (ϵ r) and electric displacement difference (D max − D rem) values. Here, a tri-layered configuration of multicomponent polymeric films is proposed. The outer layers of the tri-layered composite are linear dielectric polymethyl methacrylate (PMMA), and the inner layer is a nonlinear polymer incorporating a low number of polydopamine-modified barium titanate particles (BT@PDA). An increased ϵ r of 8.9@1 kHz is achieved in the designed composite featuring only 2 wt% BT@PDA fillers, equivalent to 234% of the PMMA (∼3.8@1 kHz) matrix. An improved U e of 9.3 J cm−3 at 340 MV m−1 is endowed in the designed film, implying an enormous ∼343% increment of the energy storage compared to the benchmark biaxially oriented polypropylene (∼2.1 J cm−3 at 300 MV m−1). All these advantages present a practical strategy for supplying linear dielectric polymer-based composites with anticipative capacitive energy-storage properties for operation at weak field strengths.

Preparation of Bio-Composite Coatings on Titanium Substrate by Electrostatic Spray Deposition

In this research, the most modern deposition technique used will be utilized for biomedical applications is Electrostatic Spray Deposition (ESD), which focused on enhancing the corrosion resistance as well as biocompatibility of commercially pure titanium substrate by constructing bio composite coating, various percentages (2, 6, and 10) wt.% of Hydroxyapatite (HAP) powder were combined with (98, 94, and 90) wt.% of polymethyl methacrylate (PMMA) powder, and the same percentages (2, 6, and 10) wt.% of Nickel Oxide (NiO) powder also combined with (98, 94, and 90) wt.% of PMMA. The effects of HAP and NiO percentages in the PMMA matrix on the surface characteristics of titanium were analyzed. The FESEM, XRD, contact angle, and anti-bacterial test demonstrated that the coating layer was successfully made consistent throughout and devoid of cracks. the samples exhibited favorable wetting qualities and inhibited bacterial growth.

Influence of chitosan and chitosan oligosaccharide on dual antibiotic-loaded bone cement: In vitro evaluations.

The purpose of this study was to investigate the effect of incorporating chitosan (Ch) and chitosan oligosaccharides (ChO) into the commercially premixed antibiotic-loaded bone cement (ALBC). We compare antibiotic release profiles, antibacterial activity, and mechanical properties among different ALBC formulations. The hypothesis was that increasing the amount of Ch and ChO in the cement mixture would increase the antibiotics released and bacterial control. ALBC mixed with Ch or ChO may create a greater effect due to its superior dissolving property. The bone cement samples used in this project were made from Copal® G+V composed of vancomycin and gentamicin. To prepare the Ch and the ChO mixed bone cement samples, different amounts of Ch and ChO were added to the polymethylmethacrylate matrix with three concentrations (1%, 5%, and 10%). Drug elution assay, antimicrobial assay, in vitro cytotoxicity, and mechanical properties were conducted. Bone cement samples made from Copal® G+V alone or combined with Ch or ChO can release vancomycin and gentamicin into the phosphate-buffered saline. Mixing ChO into the bone cements can increase the amount of drug released more than Ch. ChO 10% gave the highest amount of antibiotics released. All samples showed good antibacterial properties with good biocompatibility in vitro. The microhardness values of the Ch and ChO groups increased significantly compared to the control group. In all groups tested, the microhardness of bone cements was reduced after the drug eluted out. However, this reduction of the Ch and ChO groups was in line with the control. Various attempts have been made to improve the ALBC efficacy. In our study, the best bone cement formulation was bone cement mixed with ChO (10%), which had the highest drug release profiles, was biocompatible, and contained antibacterial properties with acceptable mechanical properties. This phenomenon could result from the superior water solubility of the ChO. When ChO leaves the bone cement specimens, it generates pores that could act as a path that exposes the bone cement matrix to the surrounding medium, increasing antibiotic elution. From all above, ChO is a promising substance that could be added to ALBC in order to increase the drug elution rate. However, more in vitro and in vivo experiments are needed before being used in the clinic.

Ionic Liquid Encapsulated Poly (Methyl Methacrylate) Electrolyte Film in Electrical Double Layer Capacitor

One of the main components of electrical double layer capacitor (EDLC) is the electrolyte. Gel-type electrolyte has shown good performance in EDLC. However, not much information is available on film-type electrolytes, which are known to provide better mechanical stability than the gel-type electrolyte. In present study, we have reported the performance of film-type poly(methyl methacrylate (PMMA) as electrolyte in electrical double layer capacitor (EDLC) systems and compared with the gel-type PMMA electrolytes. This film-type PMMA electrolyte is modified by encapsulating 1-methyl-3-pentamethyldisiloxymethylimidazolium bis (trifluoromethylsulfonyl)imide, [(SiOSi)C1C1 im][NTf2 ], an ionic liquid (IL), into the PMMA matrix, PMMAIL. Doping this PMMAIL film with 30% lithium triflate salt (LiTf), LiTfPMMAIL, provides an EDLC cell with higher breakdown voltage (3.2 V) and higher specific discharge capacity (Csp) (6.59 Fg-1 ) and energy density (0.92 Whkg-1 ) than the selected PMMA-based gel electrolyte systems. These values exceed the minimum requirements for a working supercapacitor. However, this LiTF-PMMAIL cell exhibited lower power density (23.04 Wkg-1 ) than the selected EDLC cells due to the more congested system of LiTF-PMMAIL. Thus, the performance of this LiTF-PMMAIL cell could be improved by adjusting the amount of doping salt and using different types of carbon electrodes. Keywords—capacitors, charging/discharging, polymer electrolyte films, poly (methyl methacrylate) electrolytes, solid electrolytes.

Recent Advances in Organic Room-Temperature Phosphorescence of Heteroatom (B/S/P)-Containing Chromophores

Recent Advances in Organic Room-Temperature Phosphorescence of Heteroatom (B/S/P)-Containing Chromophores

Microfibrillation and properties of poly (styrene acrylate) microspheres reinforced polymethyl methacrylate composite fibers

The composite fibers were prepared by blending the poly(styrene-acrylate) microspheres prepared by suspension polymerization with the polymethyl methacrylate matrix by melt blending. The morphological changes of the dispersed phase microspheres during the shear-extrusion-drawing process were observed, the microfibrillation mechanism of the composite microspheres was revealed, and the mechanical properties were tested. The experimental results show that the poly(styrene-acrylate) microspheres correspond to morphological changes during the shearing-extrusion-drawing process. The microspheres were deformed in the shear flow field, to be microfibers end-to-end in the extrusion flow field continuously, and extended to form nano-microfibers under the action of the drafting flow field. Compared with pure PMMA, the composite fibers prepared by poly(styrene-methyl methacrylate) (PSM) presented better mechanical properties, with an increase of 10.85% and 152.81% for the tensile strength and elongation at break, respectively.

Highly Emissive Luminogens in Both Solution and Aggregate States

Highly Emissive Luminogens in Both Solution and Aggregate States

Synthesis of semiconductors nanocomposites of polymethyl methacrylate and reduced graphene oxide by ultraviolet radiation

Polymeric nanocomposites of polymethylmethacrylate (PMMA) added with up to 20wt.% of graphene oxide (GO) were synthesized by the solvent evaporation technique and, for the first time, irradiated with ultraviolet radiation (UV-B) to reduce GO and obtain novel films of electrically semiconductive nanocomposites (PMMA-rGO). The exposition times to reduce the GO in these nanocomposites were 48 and 96 h. Chemical, physical, and electrical conductivity analyses were performed, and both GO and rGO added PMMA nanocomposites results were compared before and after UV-B radiation. Plain PMMA results were also compared as control. These results showed that the addition of GO flakes and its reduction (rGO) by UV-B radiation promoted better thermal stability and stiffness to the nanocomposites than to plain PMMA, as demonstrated by the thermogravimetric and differential scanning calorimetry analyses. High resolution scanning electron microscopy demonstrated well distributed rGO particles in the PMMA matrix. FTIR and Raman confirm the reduction process of GO after being UV-B rays irradiated. The colorimetric analyses showed that the GO and rGO flakes and the PMMA matrix presented an excellent superficial interaction. The results of electrical conductivity for the PMMA matrix (4.50 × 10−9 S/m) and the nanocomposites with 2 wt. % GO (1.21 × 10−9 S/m) revealed an insulating behavior, whcich decreases for an addition of 20 wt.% GO. The electrical conductivity displayed a significant improvement with UV-B radiation, such that with 20 wt.% rGO exposed to 48 and 96 h of UV-B radiation, the PMMA-rGO nanocomposites became semiconductor.

Feasibility Study of a Novel Magnetic Bone Cement for the Treatment of Bone Metastases.

Bone cement is a crucial material to treat bone metastases defects, and can fill the bone defect and provide mechanical support simultaneously, but the antitumor effect is very limited. Magnetic bone cement not only supports bone metastasis defects but can also achieve magnetic hyperthermia to eliminate tumor cells around the bone defect. However, the physicochemical properties of the bone cement matrix will change if the weight ratio of the magnetic nanoparticles in the cement is too high. We mixed 1 weight percent Zn0.3Fe2.7O4 with good biocompatibility and high heating efficiency into a polymethyl methacrylate matrix to prepare magnetic bone cement, which minimized the affection for physicochemical properties and satisfied the hyperthermia requirement of the alternating magnetic field.

Investigation of TiO2 and Ce3+-activated TiO2 particles on optical properties of the PMMA embedded YAG: Ce3+ and LuAG: Ce3+

Ce3+ activated garnets; LuAG and YAG are extensively used in lighting applications, electronics, and display technologies. Both of the phosphors have been studied many times to increase their brightness and provide a red-shift in their emission maximum towards warmer colors for potential white light emitting diode (WLED) applications. In this work, binary blends of the LuAG: Ce3+ with the micro-scale TiO2 and Ce3+-equipped TiO2 particles were prepared and tested in terms of photoluminescence characteristics in a polymethyl methacrylate (PMMA) matrix. Similar work was also performed for the YAG: Ce3+and its TiO2-based composites. Blue-wavelength excitation and emission performances as well as decay characteristics of the phosphors were investigated in detail. When excited by blue wavelengths, the TiO2 blends of the LuAG: Ce3+ and YAG: Ce3+ exhibited strong enhancement in emission intensities extending to 2.80 and 2.20 fold in comparison to their additive-free forms. Additionally, 32 and 66 nm of red shifts were measured in the emission maximum of the TiO2-based blends, respectively. The decay time measurements performed in the microsecond time scale revealed parallel variations to the increases observed in the intensities. The distinguishable enhancement observed in the quantum efficiency of the phosphors by using cost-effective TiO2 particles can be concluded as a remarkable development. Additionally, the ability of the phosphor blends to be excited with simple blue LEDs looks very promising for future lighting applications.

Highly efficient indoor/outdoor light harvesting luminescent solar concentrator employing aggregation-induced emissive fluorophore

The rapid development of luminescent solar concentrators (LSCs) is largely attributable to their advantageous features including colorful aesthetics, design flexibility, and their ability to harvest both outdoor (solar) and indoor (light emitting diodes (LD)) light. In this study, we fabricated and characterized a highly efficient LSC containing a newly synthesized pyrrolopyrazine-based aggregation-induced emissive fluorophore (PP1). PP1 comprises a central pyrrolopyrazine stator surrounded by three phenyl rotors proportionally end-capped with electron-donating dimethylamines and electron-accepting cyano moieties. Due to the high photoluminescence quantum yield (75%) of PP1 in polymethyl methacrylate matrix and a large Stokes shift, the fabricated LSCs showed the external photon efficiency (ηext) as high as 5.3% under 1 sun and 8.3% under LED illumination. Additionally, a theoretical model was employed to estimate the ηext of large-area (up to 100 cm length) PP1 LSCs. Photovoltaic measurements under 1 sun revealed that the champion device displayed a power conversion efficiency (ηPCE) of 1.68% with scattering background and 0.95% without scattering background, the highest recorded ηPCE among the aggregation-induced emission based LSCs. While the ηPCE of the same LSC under LED illumination was 1.05% and 0.67% with and without scattering background, respectively. Collectively, this work demonstrates a substantial step forward toward the realization of highly efficient aggregation-induced emissive fluorophores based LSCs, that can be utilized not only as power producing building windows but also as the aesthetically appealing “wireless power suppliers” for uninterrupted functioning of various indoor electronic devices such as Internet-of-Things (IoT) and network sensors.

Antibacterial Properties of PMMA Functionalized with CuFe2O4/Cu2O/CuO Nanoparticles

We have prepared a composite thin coating by incorporation of CuFe2O4/Cu2O/CuO nanoparticles in polymethyl methacrylate (PMMA) matrix by using the solution casting method. The electrical explosion of two twisted wires (EETW) was used to obtain multicomponent CuFe2O4/Cu2O/CuO nanoparticles with an average particle size of 20–70 nm. The microscopic studies showed that the nanoparticles in the composite coatings are evenly distributed. However, nanoparticles are strongly agglomerated as the powder concentration in the coating increases to 5 wt.% and 10 wt.%, as the size of particle agglomerates increases to 50 and 100 μm, respectively. Therefore, nanoparticles were pre-treated with ultrasound when introduced into the PMMA matrix. The thermal stability of the composite coating does not change with the introduction of CuFe2O4/Cu2O/CuO nanoparticles in the amount of 5 wt.%. The inclusion of nanoparticles in the PMMA matrix significantly enhances its antibacterial activity. The addition of 5 wt.% nanoparticles inhibited the growth of E. coli by 100% and the growth of MRSA by 99.94% compared to pure PMMA already after 3 h of exposure of bacteria on the surface of the composites. This research provides an easy-to-manufacture and cost-efficient method for producing a CuFe2O4/Cu2O/CuO/PMMA composite coating with a broad application as an antibacterial material.

A novel strategy to improve the flame retardancy and electrical conductivity of polymethyl methacrylate by controlling the configuration of phosphorus-containing polyaniline@needle coke with magnetic field

Currently, it is still a challenge to endow polymethyl methacrylate (PMMA) with excellent electroconductivity and fire safety. In this work, we have designed a novel hybrid aiming to achieve the flame resistance and electrical conductive of PMMA by fabricating an ordered structure of the FR-PANI@Fe3O4@NC. Employing a magnetic field, the FR-PANI@Fe3O4@NC hybrid shows a beneficial configuration structure to reduce the electrical resistivity of 8.9 kΩ·cm−1 for the PMMA composite by controlling the added volume at 20 wt%. Moreover, the PMMA composite exhibits conspicuous fire resistance with an LOI of 27.4% and a V-0 rating in the UL-94 tests. Simultaneously, combined with the regular configuration structure of FR-PANI@Fe3O4@NC hybrid, the thermal stability and fire behaviour of the PMMA composite has been improved by the plentiful char residue formation. The flame-retardant mechanism of FR-PANI@Fe3O4@NC hybrid in PMMA material has been deduced by TG-IR, FTIR, and SEM, and the results implied that the FR-PANI@Fe3O4@NC hybrid containing abundant P-N functional groups generates phosphorus-containing compounds to promote the dehydration reaction of the PMMA matrix in a condensed phase. This is beneficial to improve the flame retardancy of PMMA by the formation of a char layer, providing the shielding effect to prevent the heat transfer and flammable micro-molecules volatilisation process. Hence, the as-exploited FR-PANI@Fe3O4@NC hybrid herein is believed to expand the range of applications of PMMA materials in the advanced material field.

Influence of fumed silica and PMMA on optical properties of blue-emitting CH3NH3PbBr3 perovskite nanocrystals

Fabricating highly efficient and great optical properties of blue organic-inorganic halide perovskite (OIHP) has proven difficult and continues to be a source of significant interest. Herein, we successfully synthesized blue-emitting CH3NH3PbBr3 perovskite using a ligand assisted reprecipitation process, followed by embedding in fumed silica and poly-methylmethacrylate (PMMA) matrix. By adding fumed silica, the photoluminescence (PL) peak spectrum of CH3NH3PbBr3 was blue-shifted from 481 to 477 nm. Furthermore, OIHP also exhibited a blue shift from 477 nm to 471 nm after being embedded in the PMMA matrix. On the other hand, the OIHP absorbance spectrum shifted from 451 nm to 426 nm, which correlates to the blueshift in the PL peak spectrum. The emergence of two peaks in the absorbance spectrum indicates that nanoparticles with small size distribution have grown on the OIHP. This phenomenon demonstrates that the OIHP has a strong quantum confinement effect. Therefore, the results demonstrated that CH3NH3PbBr3/SiO2/PMMA composite films have great optical properties, which is promising for their uses in potential optoelectronic applications.