Poly Methyl Methacrylate Matrix Research Articles

Highly conductive polymethly(methacrylate)/multi-wall carbon nanotube composites by modeling a three-dimensional percolated microstructure

Multi-wall carbon nanotubes (MWCNTs) were incorporated into a poly-methylmethacrylate (PMMA) matrix by using MWCNT coated PMMA particles. The MWCNTs were well incorporated to PMMA particles by a simple solution mixing and drying method with dimethylformamide (DMF) and MeOH as mixing mediums; no additional processing was necessary to achieve this level of dispersibility. The PMMA/MWCNTs prepared from MWCNT-incorporated PMMA particles showed a high electrical conductivity of 1.23S/cm at an MWCNT loading of 3wt%. The critical exponent fitting by scaling law demonstrated that the electrical conduction is generated through 3-dimensionally in polymer matrices.The percolation threshold of the PMMA/MWCNT composite, which has a segregated structure in DMF, was noticeably lower than that of the PMMA/MWCNT resin, which had a randomly distributed structure. The lowest values of the percolation threshold were achieved at 0.0095wt% of MWCNT loading.

Near-infrared luminescent PMMA films containing Yb3+-complexes: preparation and characterization

Lanthanide luminescent soft materials have attracted broad attention due to their unique optical properties and functional versatility. Particularly, due to their characteristic sharp bands, near-infrared luminescent thin films employing lanthanide ion (Ln3+) complexes as the emitting sources have shown great potential applications in biological imaging, telecommunications, lasers, organic light-emitting diode devices, and solar cells. In this work, by loading Yb3+ complexes into polymethylmethacrylate (PMMA) matrix, we report a series of luminescent thin films which can tailor UV and visible light to near-infrared (NIR) range through the energy transfer from organic antenna molecule to Yb3+ ion. Benefiting from the negligible absorption of PMMA in the range of 300 to 2500 nm, our thin films show high transparency, good thermal stability, and extraordinary processability. This strategy can be easily applied to other lanthanide precursors, and the desired tailoring bands can be easily controlled by an appropriate choice of different organic ligands. These properties make them competitive candidates in down-conversion materials.

Transparent light-guided plates based on TiO2/Rhodamine6G composite thin films

Abstract Transparent light-guided plates for solar cell application from nano-titanium dioxide (TiO2), rhodamine 6G (R6G) and poly methyl methacrylate (PMMA) composite films were prepared by spin coating technique on glass substrates. Effects of the annealing temperatures and times on the formation of the TiO2 crystalline film that acted as an initial model for the light-scattered layer in solar concentrators were investigated. Physical and morphological properties of the TiO2 film were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and atomic force microscope (AFM). After the annealing process, TiO2 films obviously formed in the anatase phase with the enlarged crystallite size and the high rough surface by the increase of the annealing temperature and the treating time. Meanwhile, the optical properties of the TiO2 thin films were analyzed via a UV–Vis spectrophotometer. The transparency of the film was significantly affected by the annealing temperature and the aging time. Moreover, the light scattering performance of the TiO2 layer cooperated with Rhodamine6G in the PMMA matrix as the preliminary model of light-guide plate was investigated by fluorescence spectra. Strong light emission from the light-guide plate could be significantly enhanced by the existence of the TiO2 crystalline layer acting as the scattering film. Optimized performance of the planar light-guide plate incorporated with Rhodamine6G dye and the light-scattered TiO2 layer was obtained from the film annealed at 500 °C for 5 h.

Synthesize and Characterization Zr-Al-Si Post through Eggshell Membrane Strengthening with PMMA Matrix

Zr-Al-Si posts were successfully synthesized using biotemplate of eggshell membrane by sol-gel method and strengthening with matrix of polymethyl methacrylate (PMMA). The dental posts made were analyzed with the scanning electron microscope (SEM), three point bending and microvickers hardness tester. There are two methods used to synthesized Zr-Al-Si posts, with calcination and without calcination. The synthesized mechanism is discussed here.

Synthesis of PBMA-<i>b</i>-PGMA Block Copolymers via ICAR ATRP and their Application in Polymer/Titanium Dioxide Hybrid Materials

Well-defined functional block copolymers, polybutyl methacrylate-b-polyglycidyl methacrylate (PBMA-b-PGMA), were successfully synthesized via initiators for continuous activator regeneration atom transfer radical polymerization ( ICAR ATRP) with pentamethyldiethylene-triamine (PMDETA) as a ligand and copper bromide (CuBr2 ) as a catalyst with concentration of 500 ppm. The PBMA-b-PGMA grafted with titanium dioxide (TiO2 ) nanoparticles was obtained through the reaction between the epoxide on the PGMA segment and amine group on the surface of modified TiO2 nanoparticles. Results showed that the PBMA-b-PGMA block copolymer with about same length of PBMA and PGMA segment could get highest graft ratio and about 17%wt TiO2 nanoparticles were successfully grafted onto the PBMA-b-PGMA block copolymer. The sizes of the PBMA-b-PGMA grafted nanoparticles were about 74 nm in ethyl acetate. The PBMA-b-PGMA grafted TiO2 nanoparticles showed very good dispensability in organic solvent (e.g. ethyl acetate) and polymer matrix. Polymethyl methacrylate (PMMA) containing 0.5%wt PBMA-b-PGMA grafted TiO2 nanoparticles showed strong absorption at about 300 nm and good transparency in visible region, which was attributed to good dispensability of PBMA-b-PGMA grafted TiO2 nanoparticles in PMMA matrix.

Polymethylmethacrylate Composite Bone Cement Adding with Tetracalcium Phosphate

Polymethylmethacrylate (PMMA) cement has been used in orthopedics for more than 70 years. The advantages of PMMA bone cement include high compressive strength, stickiness, deformable ability and rapid self-setting. But the heat produced during polymerization would hinder the recovery. In order to improve the properties, in this research we added tetracalcium phosphate (TTCP) into polymethylmethacrylate cement as TP cement. A serious of characterizations including thermal property study, compression strength and micor-CT evaluation were carried out. According to the results, the polymerization heat was significantly reduced for the TP cement. The compressive strength was also enhanced with TTCP addition. TP-10 had better properties. As to thermal tests, TP-40 showed better results. Micro CT was used to monitor the composition inside the materials, and the results showed that TTCP was well dispersed in the PMMA matrix. The composite PMMA bone cement adding with tetracalcium phosphate seemed to be a potential candidate as low temperature product.

“Dimensional” effect due to the matrix isolation of luminescent composites of polyphenylquinolines

The dimensional effect previously observed in various matrices for 2,6-polyphenylquinoline containing oxygen bridge and carbazolediyl groups is confirmed for phenylamine-containing 2,6-polyphenylquinolines with carbazole- and indolocarbazolediyl moieties in a polymethyl methacrylate matrix. The effect is observed from the dependence of the luminescence parameters (intensity and peak position) on the film thickness and poly-4-phenylquinoline concentration in the matrix. It is shown that the luminescence intensity decreases as the film thickness decreases to less than 50 micrometers and at distances 〈D〉 between molecules in the composite of less than 9 nm, with the peak position shifted to shorter wavelengths. The dependence of the luminescence intensity on 〈D〉 has a clearly pronounced maximum at 6–9 nm.

Photophysical Parameters of Functional Transparent Polymethyl-Methacrylate/Double-Walled Carbon Nanotubes Nanocomposite Sheet Under UV-Irradiation

Polymethyl-methacrylate (PMMA)/double-walled carbon nanotubes DWCNTs was prepared by using casting technique and studying with different spectroscopic techniques. UV/Vis spectral analysis shows that, the transmittance reaches to 92 % for blank PMMA and decreases to 87 % for PMMA doped with 0.01 DWCNTs composite. The calculated refractive index and absorption coefficient increase, while the estimated values of Urbach energy decreased after embedding CNT into PMMA matrix. The optical band gap values were observed to vary slightly with doping amount. Photoluminescence (PL) spectra show that there is no shift in the emission peak position upon doping with CNTs, but PL intensity is enhanced.

Research on the tunability of point defect modes in a two-dimensional magneto-elastic phononic crystal

Point defect modes in a 2D phononic crystal with giant magnetostrictive material tuned by a magnetic field and compressive stress are investigated theoretically in this study. The 3D magnetostrictive constitutive model proposed by Liu and Zheng (2005 Acta Mech. Sin. 21 278–85) is adopted to develop effective elastic, piezomagnetic, and magnetic permeability constants. The finite element method, in combination with a supercell technique, is then applied to obtain the band structures and transmission spectra of the point defect modes in a 2D phononic crystal composed of Terfenol-D rods of circular cross section embedded in a polymethyl methacrylate matrix with a square lattice. The magnetic field not only enlarges the first band gap (FBG) but also opens up a new band gap of XY modes. New point defect modes are simultaneously trapped in the band gaps. The width of the FBG and the frequencies of the point defects of the Z mode decrease as the magnetic field increases.

Composite film polarizer based on the oriented assembly of electrospun nanofibers

Polarizers are widely applied in antiglare glasses, planner displays, photography filters and optical communications, etc. In this investigation, we propose a new strategy for the preparation of a flexible film polarizer based on the electrospinning technique. An aligned assembly of polyvinyl acetate (PVA) nanofibers was electrospun and collected by a fast-rotating drum, then soaked in polymethyl methacrylate (PMMA) solution and dried thoroughly to obtain a transparent PVA-PMMA composite film polarizer. The morphology, structure and optical performance of the PVA nanofibers and the film polarizers were characterized with a scanning electron microscope, UV–vis-IR spectrometer and polarized Raman spectra, etc. The PVA-PMMA film polarizer demonstrated efficient polarizing activity toward visible and near-infrared light, while keeping fair transparency in the range of 400–1400 nm. Due to the protection from the hydrophobic PMMA matrix, the PVA-PMMA film polarizers show high moisture resistance, making it applicable in a humid environment. Considering the scalability and versatility of the strategy employed here, the PVA-PMMA film polarizer prepared could replace the conventional film polarizers in a wide range of applications.

Controlled release of a microencapsulated arduous semi-hydrophobic active from coatings: Superhydrophilic polyelectrolyte shells as globally rate-determining barriers

Polymethylmethacrylate-based microcapsules containing the antimicrobial agent 2-n-octyl-4-isothiazolin-3-one (OIT) decorated by an anchored polyelectrolyte brush consisting of an amphiphilic diblock copolymer of polymethylmethacrylate-block-poly(sodium methacrylate) type have been formulated via a coacervation technique. The polyelectrolyte brush surface provided the microcapsule with a high and stable surface charge density. This enabled further surface modification of the colloidal particle with a thin and dense polyelectrolyte multilayer using the layer-by-layer technique. The addition of the highly charged and hydrophilic polyelectrolyte multilayer assembled on the microcapsule surface resulted in a considerable decrease of the release rate of the encapsulated OIT in aqueous suspension, corresponding to a 40 times reduction of the effective OIT diffusion coefficient in the polymethylmethacrylate matrix. Moreover, the release of encapsulated or freely dispersed OIT from coatings as a function of the matrix density was evaluated and analyzed within the framework of applied diffusion models. Encapsulation of OIT in polyelectrolyte multilayer composite microcapsules was found to significantly prolong the release and render the release rate more or less independent of the matrix density. In addition, the long-term antimicrobial properties of the coatings were evaluated in terms of their susceptibility for biofouling using the fungus and common biofouler Aspergillus niger as model organism. The results clearly demonstrated that the use of encapsulated OIT gave a significantly prolonged surface protection and allowed for the determination of the critical surface flux. The polyelectrolyte multilayer has therefore been recognized as the rate-determining barrier for OIT. The matrix density has a minor influence on the release rate of encapsulated OIT from these microcapsules and this concept may very well be expanded to cover a broad range of hydrophobic and semi-hydrophobic biocides.

Modification of cellulose nanocrystal via SI-ATRP of styrene and the mechanism of its reinforcement of polymethylmethacrylate

Cellulose nanocrystal (CNC) is a promising strengthener but is used limitedly since its poor compatibility with organic materials. The graft polymerization of styrene via surface-initiated atom transfer radical polymerization (SI-ATRP) of cellulose nanocrystal is adopted to modify its thermo-stability and compatibility. The modified crystals have been dosed into polymethylmethacrylate (PMMA) nanocomposites by the solution casting. The polymeric layer on the surface of CNCs should improve the thermal stability of CNCs, and provide significant dispersibility and compatibilization for the nanocomposites. Thermogravimetry analysis proved that the initial degrade temperature of CNC was increased 50°C with the modification. The scanning electronic microscope showed that the modified CNCs homogeneously dispersed in PMMA matrix. Breaking strength and elongation at break of the composites were improved, which was attributed to the reinforcement of CNCs modified with styrene. Transmittance of nanocomposite films measurement showed that the transmittance of PMMA/1%CNC was almost close to that of pure PMMA.

A nonlinear optical active polymer film based on Pd(ii) dithione/dithiolate second-order NLO chromophores

A film of [Pd(R2pipdt)(dmit)] (1), where R2pipdt = 1,4-didodecyl-piperazine-2,3-dithione (acceptor) and dmit = 2-thioxo-1,3-dithiole-4,5-dithiolate (donor) incorporated into a polymethylmethacrylate (PMMA) matrix, showing a good second-harmonic generation, has been prepared for the first time in the class of dithione-dithiolate 2nd order NLO-chromophores. Moreover full characterization of 1, including molecular second-order NLO properties in solution, is reported.

A Review on Organic Materials for Optical Phase Conjugation & All-optical Switches

Nonlinear optical materials with optimum properties are essential in continuous development of photonic and electro-optical devices, used in optical communications, networking, optical computation for signal processing, and data storage equipments. The changing trend is to use organic materials/dyes that exhibit exceptional nonlinear optical properties instead of conventional materials which have comparatively low nonlinear properties. These organic materials/dyes are easy to prepare in solution or solid form. The resulting organic material has a low dielectric constant, eliminating the need for poling while maintaining the refractive index. However, these organic materials have few of the drawbacks inherent in the processing of comparable inorganic materials like of intense light induced degradation or bleaching and aggregation at higher dye concentration. In order to overcome these drawbacks and for effective use of highly nonlinear dyes, the dye molecules are doped in polymer matrix. This idea of dye-doped polymer material matrix may increase the concentration of absorptive or fluorescence centers as well as the opto-chemical and opto-physical stability. In this paper, we have discussed the strategic advantages of dye-doped polymer nonlinear materials in comparison with organic and inorganic nonlinear materials for optical phase conjugation and all optical switches in future photonics technology. This was done by studying the linear optical properties and nonlinear optical Phase Conjugation properties of two azo dye-doped polymer films by considering organic dyes disperse orange (DO-25) and disperse yellow (DY-7) doped in a polymer matrix Polymethyl methacrylate methacrylic acid (PMMA-MA). The nonlinear optical phase conjugation properties are studied using Degenerate Four Wave Mixing set-up using 532 nm wavelength CW laser beam. The effect of dye concentration, intensity of backward, forward pump, and inter beam angle between IJMIE Volume 6, Issue 1 ISSN: 2249‐0558 ________________________________________________________ A Monthly Double‐Blind Peer Reviewed Refereed Open Access International e‐Journal ‐ Included in the International Serial Directories Indexed & Listed at: Ulrich's Periodicals Directory ©, U.S.A., Open J-Gage as well as in Cabell’s Directories of Publishing Opportunities, U.S.A. International Journal of Management, IT and Engineering http://www.ijmra.us

LED induced green luminescence in visually transparent PMMA films with CdS precursor

We demonstrate that [Cd(N(SCNEt2)2)2] is a CdS-containing compound that is well dissolved in a PMMA (polymethylmethacrylate) matrix. The PMMA films possessing up to 10% of these molecules are visually transparent and have no evidence of light scattering. Irradiation of these films by Light Emitting Diodes (LED) operated at a wavelength of 365 nm provides a permanent material alteration with the optical properties of the modified domains (absorption band, luminescent spectra) that are typical for the solid solution of CdS nanoclusters. We show that here the LED radiation is a more effective tool than both the forth and the third harmonics of a Nd:YAG laser and that both photochemical and light heating effects are significant for the above material processing.

Morphological and mechanical characterization of composite bone cement containing polymethylmethacrylate matrix functionalized with trimethoxysilyl and bioactive glass

Medical polymers of biostable nature (e.g. polymethylmetacrylate, PMMA) are widely used in various clinical applications. In this study, novel PMMA-based composite bone cement was prepared. Bioactive glass (BAG) particulate filler (30wt%) was added to enhance potentially the integration of bone to the cement. The polymer matrix was functionalized with trimethoxysilyl to achieve an interfacial bond between the matrix and the fillers of BAG. The amount of trimethoxysilyl in the monomer system varied from 0 to 75wt%. The effects of dry and wet (simulated body fluid, SBF at +37°C for 5 weeks) conditions were investigated. In total, 20 groups of specimens were prepared. The specimens were subjected to a destructive mechanical test in compression. Scanning electron microscopy (SEM) and micro-computed tomography (micro-CT) were used to study the surface and the three-dimensional morphology of the specimens. The results of the study indicated that the addition of trimethoxysilyl groups led to the formation of a hybrid polymer matrix which, in lower amounts (<10wt% of total weight), did not significantly affect the compression properties. However, when the specimens stored in dry and wet conditions were compared, the water sorption increased the compression strength (~5–10MPa per test group). At the same time, the water sorption also caused an evident porous structure formation for the specimens containing BAG and siloxane formation in the hybrid polymer matrix.

Release of zirconia nanoparticles at the metal stem–bone cement interface in implant loosening of total hip replacements

In a previous failure analysis performed on femoral components of cemented total hip replacements, we determined high volumes of abraded bone cement. Here, we describe the topography of the polished surface of polymethyl methacrylate (PMMA) bone cement containing zirconia radiopacifier, analyzed by scanning electron microscopy and vertical scanning interferometry. Zirconia spikes protruded about 300nm from the PMMA matrix, with pits of former crystal deposition measuring about 400nm in depth. We deduced that the characteristically mulberry-shaped agglomerates of zirconia crystals are ground and truncated into flat surfaces and finally torn out of the PMMA matrix. Additionally, evaluation of in vitro PMMA-on-PMMA articulation confirmed that crystal agglomerations of zirconia were exposed to grain pullout, fatigue, and abrasion. In great quantities, micron-sized PMMA wear and zirconia nanoparticles accumulate in the cement–bone interface and capsular tissues, thereby contributing to osteolysis. Dissemination of nanoparticles to distant lymph nodes and organs of storage has been reported. As sufficient information is lacking, foreign body reactions to accumulated nanosized zirconia in places of long-term storage should be investigated. Statement of SignificanceThe production of wear particles of PMMA bone cement in the interface to joint replacement devices, presents a local challenge. The presence of zirconia particles results in frustrated digestion attempts by macrophages, liberation of inflammatory mediators, and necrosis leading to aseptic inflammation and osteolyses. Attempts to minimize wear of articulating joints reduced the attention to the deterioration of cement cuffs. We therefore investigated polished surfaces of retrieved cuffs to demonstrate their morphology and to measure surface roughness. Industrially admixed agglomerates of the radiopacifier are abraded to micron and nano-meter sized particles. The dissemination of zirconia particles in the reticulo-endothelial system to storage organs is a possible burden. Research to replace the actual contrast media by non-particulate material deserves more attention.

Spectroflourimetric assessment of UO22+ by the quenching of the fluorescence intensity of Clopidogrel embedded in PMMA matrix

A new fluorescent optical sensor for highly sensitive and selective assessment of UO22+ in aqueous samples was introduced. The response of the sensor is based on the fluorescence quenching of [(+)-(S)-methyl 2-(2-chlorophenyl)-2-(6,7-dihydrothieno[3,2-c]pyridin-5(4H)-yl)acetate] (Clopidogrel) embedded in polymethylmethacrylate (PMMA) polymer by UO22+. The sensor displays; wide concentration range from 1.0×10−9 to 4.0×10−6molL−1, limit of detection (LOD) and limit of quantification (LOQ) are 2.6×10−10 and 7.8×10−10molL−1, respectively with a relatively fast response time of less than 60s. The present sensor was revealed good response characteristics with respect to stability, reproducibility, sensitive and selectivity. Also, the response and quenching mechanisms for the present sensor were discussed.

Vibration analysis of axially moving carbon nanotube–reinforced composite plate under initial tension

In the present research, vibration and instability of axially moving carbon nanotube–reinforced composite (CNTRC) plate under initial tension is investigated. Single‐walled carbon nanotubes (SWCNTs) are selected as a reinforcement inside polymethyl methacrylate (PMMA) matrix. Higher order shear deformation theory (HSDT) is used because of its accuracy of polynomial functions than other plate theories. Based on extended rule of mixture, the structural properties of composite plate are taken into consideration. The equations of motion are obtained using Hamilton's principle and solved by hybrid analytical–numerical solution in different boundary conditions. Influences of various parameters such as axially moving speed, volume fraction of CNTs, pre‐tension, thickness, and aspect ratio on the vibration characteristics of moving composite plate are discussed in detail. The results indicated that the critical speed of moving composite plate is strongly dependent on the volume fraction of CNTs. Therefore, the critical speed of moving plate can be improved by adding appropriate values of CNTs. The results of this investigation can be used in design and manufacturing of marine vessels and aircrafts. POLYM. COMPOS., 38:814–822, 2017. © 2015 Society of Plastics Engineers

Preparation and multicolored fluorescent properties of CdTe quantum dots/polymethylmethacrylate composite films

A new simple route was presented for the preparation of stable fluorescent CdTe/polymethylmethacrylate (CdTe/PMMA) composite films by using hydrophilic thioglycolic acid capped CdTe quantum dots (TGA-CdTe QDs) and polymethylmethacrylate (PMMA) as raw materials. The TGA-CdTe QDs were firstly exchanged with n-dodecanethiol (DDT) to become hydrophobic DDT-CdTe QDs via a ligand exchange strategy, and then incorporated into PMMA matrix to obtain fluorescent CdTe/PMMA composite films. The structure and optical properties of DDT-CdTe QDs and CdTe/PMMA composite films were investigated by XRD, IR, UV and PL techniques. The results indicated that the obtained DDT-CdTe QDs well preserved the intrinsic structure and the maximum emission wavelength of the initial water-soluble QDs and the resulting 6.10 wt% CdTe/PMMA composite film exhibited significantly enhanced PL intensity. Furthermore, the multicolored composite films with green, yellow-green, yellow and orange light emissions were well tuned by incorporating the CdTe QDs of various maximum emission wavelengths. The TEM image demonstrated that the CdTe QDs were well-dispersed in the PMMA matrix without aggregation. Superior photostability of QDs in the composite film was confirmed by fluorescence lifetime measurement. Thermo-gravimetric analysis of CdTe/PMMA composite films showed no obvious enhancement of thermal stability compared with pure PMMA.