Poly Methyl Methacrylate Polymer Matrix Research Articles

Features of charge transport in polymer composites polymethylmethacrylate - polyaniline

The influence of polymer matrix of polymethyl methacrylate (PMMA) on the specific conductivity, percolation threshold, energy of activation of charge transport in polymer composites PMMA − polyaniline (PAN) was studied.
 Concentration dependence of the electrical conductivity of composites reveals percolation behavior with the low value of percolation threshold within 2 % content of polyaniline. It is found that in the polymer composites PMMA - PAN the specific conductivity increases by more than 8−9 orders of magnitude compared to the original matrix.
 On the base of temperature dependence of the specific conductivity of the obtained composites, it is concluded that PMMA polymer matrix does not change the semiconductor nature of PAN conductivity in the composite but effects on the activation parameters of the charge transport.
 From ESR spectra, it found that the presence of a polymeric matrix causes significant delocalization of the charge along the macrochains of the dielectric polymeric matrix.

Exploring the direct effect of intermediate band semiconductor materials on the structural, thermal and optical properties of PMMA nanocomposite

In this work, polymethylmethacrylate (PMMA) doped with SnS2, Sn0.75Fe0.25S2, and Sn0.75Cr0.25S2 nanoparticles films were prepared using both thermolysis and casting procedures. The purity, structural and shape of the nanofillers were confirmed by Rietveld refinement method. The compositional changes for nanocomposite films were studied by energy dispersive spectrometry technique. Nanoparticles morphology and particle size were examined by transmission electron microscopy (TEM) technique. Proper interactions between added nanofillers and the polymer matrix were discussed in detail by Fourier transform infrared spectroscopy technique (FTIR). The variations in the FTIR absorption bands position and their shape proved the effect of doping on the composite films. The effect of dopant elements on the thermal properties of PMMA polymer matrix has been investigated by thermogravimetric analysis (TGA). Results showed an improvement in the degradation temperature of doped polymers compared to undoped ones. Clear regular arrangements of images for nanoparticles and composite films have been represented by scanning electron microscopy (SEM). Different optical parameters have been examined using UV–vis spectroscopy technique. Due to the high transmittance values in the wavelength range of 320–800 nm, the formed composite films could be used as protective window layers for solar cells. The energy gap values decreased from 4.3 eV for undoped PMMA polymer to 4, 3.85, and 3.16 eV depending on the doping element.

Flexural strength of hydrogen plasma-treated polypropylene fiber-reinforced polymethyl methacrylate denture base material.

Objectives:The present study aimed to evaluate flexural strength of hydrogen plasma-treated polypropylene fibers-reinforced polymethyl methacrylate (PMMA) polymer composite.Materials and Methods:One control group with no fiber reinforcement and 9 polymer composite test groups with varying fiber weight percentage (2.5, 5, and 10 Wt%) and aspect ratio (3/220, 6/220, and 12 mm/220 μm) were prepared. Flexural strength was measured using Instron.Results:All hydrogen plasma-treated polypropylene fiber-reinforced test groups obtained significantly higher flexural strength characteristics. Among the test groups, 6 mm long fibers reinforced in 10 Wt% showed superior flexural strength.Conclusion:Hydrogen plasma treatment on polypropylene fiber has a significant role in enhancing the adhesion between PMMA polymer matrix and the polypropylene fibers and thereby the flexural strength.

A highly stable and efficient quasi solid state dye sensitized solar cell based on Polymethyl methacrylate (PMMA)/Carbon black (CB) polymer gel electrolyte with improved open circuit voltage

Dye sensitized solar cells (DSSCs) have received significant attention due to their low production cost and easy fabrication process. However, the leakage and volatilization of the liquid organic solvent in the liquid electrolyte affect the long term stability of DSSCs. Therefore, in this present work, to improve the durability of DSSCs, polymethyl methaacrylate (PMMA) based polymer gel electrolyte (PGE) with different weight percent of carbon black (CB) was studied to replace the conventional liquid electrolyte. CB was used to improve the ionic conductivity of the PGE. DSSCs fabricated with the prepared PGEs exhibit very good long term stability in comparison to liquid electrolyte. The optimized DSSC with 0.57 weight percentage of CB in PMMA polymer matrix exhibits the highest photo-conversion efficiency of 5.52±0.03% with short circuit current density (Jsc) value of 12.43±0.04mAcm−2, open circuit voltage (Voc) value of 766.02±0.52mV and fill factor (FF) value of 58.01±0.02%. A significant enhancement of Voc is observed with the employment of the PGE. The impact of the PGE in the enhancement of Voc was studied by analyzing the charge transfer kinetics data at the interface of the photoanode and the PGE. Furthermore, the study of long term stability shows that after 1000h of testing the optimized DSSC (PGE(0.57)) retains the Jsc value at 83% of the initial performance exhibiting very significant long term stability in comparison to the DSSC fabricated with liquid electrolyte.

Effect of polymer matrix on the photophysical behaviors of pressure sensitive films

Based on the oxygen quenching of the luminescent intensity of the excited chromophoric probes in polymer matrix, pressure sensitivity paint film was particularly of interest to oxygen concentration or partial pressure measurement. The photophysical behaviors, especially the oxygen pressure sensitivity of pressure sensitive film are not only affected by the luminescence probes, but also by the polymer matrix.The photophysical behaviors of the pressure sensitive films composed of platinum tetra(pentafluorophyenyl)porphine (PtTFPP) in the polymer matrix of polymethylmethacrylate (PMMA), polybutylmethacrylate (PBMA), ethyl cellulose (EC) or ethylene-vinyl acetate copolymer (EVA) were investigated in this article. The results confirmed that all of the oxygen permeability of the polymer matrix, the molecular interaction between the probes and polymer and the depth distribution of the probes in the polymer matrix showed significant influence on the photophysical properties, oxygen quenching and pressure sensitivity of the pressure sensitive films.

Optically induced anisotropy and electrooptics in ferroic organic nanocomposites

The occurrence of linear electrooptics and optical anisotropy is observed in the ferroic crystals \([\hbox {NH}_{2}(\hbox {C}_{2}\hbox {H}_{5})_{2}]_{2} \hbox {CuCl}_{4 }\) embedded into polymethylmethacrylate polymer matrix. The studies were performed for the optically treated bulk crystals and the large-size nanocrystals (with sizes higher than 50 nm) embedded into the polymer matrix. The specimens were both in a form of bulk as well as in the form of the composite films. To understand the mechanisms giving the principal role to the effect we have performed polarized absorption measurements for the samples treated in the external dc-electric field and bicolour 532 nm/1,064 nm laser treatments. The behaviour of the birefringence and of the linear electrooptics coefficients were studied within a temperature range covering the incommensurate phase existence.

GaN/PMMA nanocomposite: synthesis and optical properties

High crystalline quality wurtzite-GaN nanoparticles, with diameters of about 11 nm, well dispersed in a poly-methyl methacrylate polymer matrix, were synthesized using a routine two-step route and were structurally and optically characterized. The as-prepared composite showed three broad overloading photoluminescence emission peaks with centers at 3.45, 3.29, and 3.10 eV. The 3.45 eV emission band is assigned to the recombination of the free exciton of GaN particles. The other two emission peaks possibly originate from the interfacial structure between the nanoparticles and polymer matrix or aggregation. The Fourier transform infrared (FTIR) spectrum further confirms the interfacial interaction that can be described as R-(C=O)-O-(GaN particle).

Interactions in organic rectorite composite gel polymer electrolyte

AbstractRectorite (REC) was modified with dodecyl benzyl dimethyl ammonium chloride (1227) to form an organic-modified rectorite, termed OREC. The OREC was used as a filler additive to modify gel polymer electrolytes (GPEs) which consisted of polymethyl methacrylate (PMMA), propylene carbonate (PC) and LiClO4. Studies of ionic conductivity and viscosity of liquid electrolytes and pure PC, respectively, clearly showed that these properties are greatly influenced by temperature and the amount of OREC added; a consequence of the interactions between the components of CPEs. The Fourier transform infrared (FTIR) spectroscopy results indicated that there were two kinds of interaction: namely (1) a strong hydrogen bond between Si–OH and C=O of PC and (2) a weak interaction between Li+ and C=O. Inverse gas chromatography (IGC) research supported the FTIR interpretation, indicating that the two interactions exist and that the H bond is the stronger of the two. In CPEs, the polymer matrix of PMMA merely supports the active components and does not influence the interactions between them. The OREC greatly increased the crucial plasticizer maintenance property when the amount of clay added was optimum.

Effect of complexation with lanthanide metal ions on the photochromism of (1,3,3‐trimethyl‐5′‐hydroxy‐6′‐formyl‐ indoline‐spiro2,2′‐[2h]chromene) in different media

Complexation of lanthanide ions {Ln(III) ions [Tb(III), Eu(III), or Sm(III)]} with the spiropyran‐derived merocyanine obtained in dark and under steady irradiation of indoline spiropyran (1,3,3‐trimethyl‐5′‐hydroxy‐6′‐formyl‐indoline‐spiro‐2,2′‐[2H]chromene) induces a noticeable hypsochromic shift of about 10–110 nm of its visible absorption band concomitant with hypochromic effect and influences its thermal bleaching in the dark. The effect of lanthanide ions and medium on photochromic, spectral‐and‐kinetic, and luminescence properties of the spiropyran and its complexes in solution and polymer matrix of polymethylmethacrylate (PMMA) is studied. Efficient energy transfer from the spiropyran moiety results in efficient typical luminescence from the Ln(III) ion that becomes more pronounced in polar nonalcoholic solvents and PMMA solid matrix. Moreover, luminescence mappings for pattern recognition analysis have been obtained from which the nature of the solvent and/or the ligand is clearly identified.

Origin of photoinduced third harmonic generation anisotropy for quinoline derivatives molecules embedded into polymethylmethacrylate polymer matrix

Substantial anisotropy of photoinduced change of third harmonic generation (THG) was observed during investigation of the 3-(4-nitrophenyl)-6- N, N-diphenylamin-1-phenyl-1 H-pyrazolo [3,4- b]quinoline chromophores embedded into polymethylmethacrylate polymer matrix. Large THG decay was observed for the co-polarized pump–probe configuration, and small increase (weak pump intensity) or decrease (strong pump intensity) of THG signal for the cross-polarized pump–probe configuration. The performed molecular geometry optimization and quantum chemical evaluations have shown that the observed effect is originated from photoinduced anisotropy of electronic charge density distribution within the separate molecule contrary to the generally adopted model of the hole burning typical for the cis– trans isomerization.

Excimer laser-induced modification in PMMA/Ni-acetylacetonate films for selective metallization

We describe the selective production of thin metal layers on the surface of flexible polymeric substrate. The method consists in KrF-excimer laser irradiation of an organometallic compound (Ni-acetylacetonate) embedded in a polymer matrix of polymethylmethacrylate (PMMA). By this laser processing, photodecomposition of the organic compound is observed, which liberates metallic atoms in the polymeric medium. This presence is further demonstrated by immersing the irradiated substrate in an electroless bath for selective metal deposition.

Interfacial interactions and mechanical properties of mineral filled polymer composites: wollastonite in PMMA polymer matrix

The nature of stearic acid and polymethylmethacrylate (PMMA) adsorption onto wollastonite has been studied from basic, neutral and acidic organic solvents by infrared (IR) spectroscopy. The roles of acid-base interactions on adsorption and wollastonite dispersion in polymer matrix have been discussed with the determined mechanical properties of surface-treated (stearic acid) and untreated wollastonite-filled PMMA polymer composites. Maximum adsorption of either stearic acid or PMMA occurs from a nonpolar solvent, and the adsorption is found to decrease with increasing acidity or basicity of the solvents. The adsorption corresponds to two geometrical layers either from nonpolar (carbon tetrachloride) or from slightly basic (benzene) and acidic (methylene dichloride) solvents. Increased acidity (chloroform) or basicity (tetrahydrofuran) of solvents led to a monolayer or a fraction of the monolayer coverage. The primary adsorption of stearic acid is thought to be the formation of hydrogen bonds between surface hydroxyl groups and carboxylic acid groups. The tensile and impact strength properties of the composites that are filled with stearic acid-treated wollastonite are improved when compared to the untreated filled composite. The results suggest a stronger interfacial bonding between stearic acid and filler than that of polymer to the filler. Thus, the application of stearic acid for surface modification of acidic fillers such as wollastonite is emphasized.

Radiation-Induced Trapped Charge Carriers in Organic Polymers. A Model of Thermoelectric Current Generation

Trapping and detrapping of radiation-induced charge carriers in polymethylmethacrylate (PMMA), polyvinyl chloride (PVC), and several other polymers were investigated. Thermoelectric currents were generated in the polymers after irradiation by thermally stimulating the release of the trapped charges and subjecting them to a temperature gradient. Heating similarly irradiated samples in the absence of a temperature gradient produced a tenfold reduction in the observed current. The charge carriers were determined to be positive from the polarity of the colder electrode. To observe thermoelectric currents, electrons liberated during irradiation had to be trapped to prevent recombination with trapped positive charges. This trapping is not done by the polymer matrix of PMMA at 25°C but by added impurities. PVC contains a built-in trap in the polymer chain at the C-C1 group. The electron trap in commercial PMMA (Lucite) is benzoyl peroxide or another chemical initiator. Electron traps were also internally generat...