Poly Methyl Methacrylate Blends Research Articles

Synthesis, structural, optical, and thermal properties of LaFeO3/Poly(methyl methacrylate)/Poly(vinyl acetate) nanocomposites for radiation shielding

This work is an attempt to develop flexible radiation shielding based on a blend of polymethyl methacrylate (PMMA)/polyvinyl acetate (PVAc) and LaFeO3 nanoparticles (NPs). LaFeO3 and LaFeO3/PMMA/PVAc were made using simple chemical techniques. A high-resolution transmission electron microscope (HR-TEM) and X-ray diffraction (XRD) showed that well-crystallized LaFeO3 NPs with particles 79 nm in size and an orthorhombic shape were obtained. In addition, XRD confirmed the existence of PMMA, PVAc, and LaFeO3 in the nanocomposite films. Fourier transform infrared (FTIR) confirmed that the LaFeO3 NPs and the reactive functional groups in the blend interacted with each other. Field emission-scan electron microscope (FE-SEM) analysis showed that PMMA and PVAc form a homogenous blend and that the LaFeO3 NPs were spread out inside and on the blend surface. The samples showed transmittance in the range of 30–74% and a small extinction coefficient (≤ 0.08). The samples exhibited a dual-band gap structure, and the direct (indirect) band gap shrank from 5.1 to 4.7 eV (4.9 to 4.4 eV). The thermal analyses showed that the samples are thermally stable up to 260 °C. The Phy-X/PSD software was used to figure out the theoretical gamma-ray attenuation parameters, such as the mass attenuation coefficient, the mean free path, and the half-value layer, for different PMMA/PVAc + x% LaFeO3 composites. It is demonstrated that the PMMA/PVAc + 10 wt% LaFeO3 sample exhibits much better shielding effectiveness than PMMA/PVAc, and hence it is suitable for protecting against radiation.

Study the effect of nano NiCo2O4 doping on the optical and dielectric properties of PMMA/PEO/MWCNTs

In this study, NiCo2O4 nanoparticles were prepared using a hydrothermal process and examined by x-ray diffraction. After that, using the casting technique, blends of polymethyl methacrylate (PMMA)/poly(ethylene oxide) (PEO) were loaded with multi-walled carbon nanotubes (MWCNTs) and different amounts (x) of NiCo2O4 nanoparticles. The obtained blends were characterized using X-ray diffraction and scanning electron microscopy techniques. Utilizing diffuse reflectance measurements, various optical parameters, including energy gap, refractive index, extinction coefficient, optical dielectric constant, optical conductivity, and nonlinear optical parameters, were investigated. Following incorporation of MWCNTs/NiCo2O4 in the blend, the transmittance of the PMMA/PEO blend (90 %) displayed a drop reaching 21 %, the reflectivity and refractive index increased. The direct/indirect optical band gap values of PMMA/PEO (5.07/4.8 eV) decreased attaining 4.96/4.54 eV for the blend with 2.5 wt% NiCo2O4. The optical conductivity greatly enhanced, and the linear and nonlinear optical parameters increased as the amount of NiCo2O4 doping increased. The dispersion parameters for all blends were also calculated. Fluorescence spectra (FL) measurements revealed a reduction in the FL intensity with increasing the NiCo2O4 content (x). Through the dielectric measurements, the impact of increasing NiCo2O4 content on the ac conductivity, dielectric properties, energy density, and electric modulus was analyzed for all blends. Remarkably, a significant increase in AC conductivity was obtained upon loading with 1.5 wt% NiCo2O4. Overall, variation in the dielectric and optical features of the PMMA/PEO/MWCNTs/x wt.% NiCo2O4 blends makes them appropriate for optoelectronic and energy storage applications.

Synthesis of polymethyl methacrylate/depolymerized polyethylene terephthalate blend reinforced by titanium dioxide nanoparticles for dental fillings applications

The aim of this study is to use recycled waste materials to modify the performance of composites used as dental fillings. For this purpose, depolymerized polyethylene terephthalate (DPET) polymers were prepared by recycling waste polyethylene terephthalate (PET) using the glycolysis process. DPET was then blended with polymethyl methacrylate (PMMA) at different weight percentages. Polymer blends were subjected to mechanical, physical, and biological tests. It is evident that PMMA blended with a 5 wt% of DPET exhibits the highest compressive strength which is approximately two times that obtained from neat PMMA, highlighting the suitability of these resins to replace amalgam and to be considered for dental restorations. It was also found that the water absorption of the blends investigated is relatively stable at 5 wt% DPET. The SEM images showed no distinguishable phases, highlighting the high compatibility between DPET and PMMA. The biological tests, including in vitro cytotoxicity, showed that the cell viability mean values of PMMA containing 5 wt% DPET is higher than that of control group. Interestingly, in dental practice, the reliable in vitro cytotoxic approach is considered as an important aid in clinical procedures in the use of dental filling systems. The microbiology study has shown that the inhibition zones against Streptococcus mutans of PMMA: 5 wt% DPET is higher than the control group. According to the obtained results, the blend of PMMA: 5 wt% DPET was selected as an optimum blend, which was then reinforced with various weight percentages of nano-sized titanium dioxide (TiO2). The composites were then tested under compression, microhardness, and impact tests. The results demonstrated the significant impact of TiO2 on enhancing the properties of the composites investigated. This can provide a new protocol for synthesizing nanocomposite materials for dentistry.

Nanoscale friction force on thin films of polymer blends and silane layers matrix

In this paper, nanoscale friction measurements are obtained from the Atomic Force Microscope (AFM) cantilever tip interaction with the layer of polymer blends of Polymethyl Methacrylate (PMMA)/ Polystyrene (PS) (2:1 and 1:2 ratios), and silane (C8, C12 and C18) layers at different proportion. The contrast of these polymer blends is investigated from the simultaneous recording of the topographic and lateral forces imaging. The resonance frequency excitation method and the wedge calibrations are used to quantify the normal and the lateral force constant respectively. Then, the quantitative frictional forces are calculated from the obtained normal and lateral force constants. The nanonewton (nN) frictions are found to be dependent on the nano-dynamic properties of the tip-sample interaction, the proportion of the polymer matrix and silane layers, and the scan speed.

Thermal degradation study of polymethylmethacrylate with AlI3 nanoadditive.

Organic polymers in the process of thermal degradation produce a lot of toxic fragments. In this work, we designed a new method of degradation of polymethylmethacrylate (PMMA) materials with aluminum triiodide nanoadditives (AlI3 NAs). In the present research work, a thermal degradation study of PMMA blends with AlI3 NAs was carried out by using a specially designed pyrolytic assembly. Different blends of PMMA with AlI3 (P0, P3, P6, P9, P12, and P15) were prepared by changing the concentration of AlI3 NAs from 0% to 15%. FTIR and TGA studies show the stability of polymers with AlI3 NAs. Scanning electron microscopy analysis shows All3 spread uniformly at nanoscale throughout the polymer matrix. Horizontal burning test (HBT) test confirms that polymer burning is retarded with AlI3 NAs.

Poly(vinylidenefluoride) polymers and copolymers as versatile hosts for luminescent solar concentrators: compositional tuning for enhanced performance.

Novel host matrices based on fluoropolymers blended with poly(methyl methacrylate) (PMMA) are presented in this work for application in efficient and photochemically stable thin-film luminescent solar concentrators (LSCs). These systems consist of blends of PMMA with three different partially fluorinated polymers in different proportions: polyvinylidenefluoride homopolymer, a copolymer of vinylidenefluoride and chloro-trifluoro-ethylene, and a terpolymer of vinylidenefluoride, hexafluoropropylene and hydroxyl-ethyl acetate. A detailed chemical, physical and structural characterization of the obtained materials allowed us to shed light on the structure–property relationships underlying the response of such blends as a LSC component, revealing the effect of the degree of crystallinity of the polymers on their functional characteristics. An optimization study of the optical and photovoltaic (PV) performance of these fluoropolymer-based LSC systems was carried out by investigating the effect of blend chemical composition, luminophore concentration and film thickness on LSC device output. LSCs featuring copolymer/PMMA blends as the host matrix were found to outperform their homopolymer- and terpolymer-based blend counterparts, attaining efficiencies comparable to those of reference PMMA-based LSC/PV assemblies. All optimized LSC systems were subjected to weathering tests for over 1000 h of continuous light exposure to evaluate the effect of the host matrix system on LSC performance decline and to correlate chemical composition with photochemical durability. It was found that all fluoropolymer/PMMA-based LSCs outperformed reference PMMA-based LSCs in terms of long-term operational lifetime. This work provides the first demonstration of thermoplastic fluoropolymer/PMMA blends for application as host matrices in efficient and stable LSCs and widens the scope of high-performance thermoplastic materials for the PV field.

Power characteristics of a 70/30 wt.% PVDF/PMMA film in roadway electricity generation

Energy harvesting based on roadway electricity generation is investigated using synthetic polymers with piezoelectricity properties. In addition to the properties of polymers, such as high flexibility and resistance to compressible deformation, some polymers can also be piezoelectric. This work focuses on a new low-cost polymer blend, obtained by combining an inexpensive material such as polymethylmethacrylate (PMMA) with another proven piezoelectric polymer, called polyvinylidene-fluoride (PVDF). Several films with different PMMA contents in PVDF were analyzed to determine their output performance in car-tire roadway energy harvesting. The films were excited by normal stress in a range of 0.1–1.4 MPa modeling the mechanical stress that occur in tires. Electrical resistance between 10 and 30 MΩ was shown to induce an electric charge. The voltage measurements generated show that the voltage increases as a function of the applied stress for a 70 wt.% of PVDF in PMMA blend film. PVDF concentrations greater than 70 wt.% were observed to led to supersaturation, while lower concentration does not show an increase in the response. An output power of 2.7 mW m−2 is achieved with the best film blend, 70PVDF, below 1.4 MPa applied in slow motion. The paper highlights some advantages of the 70PVDF polymer to provide a new design of high-performance piezoelectric performance for roadway energy harvesting.

Highly anisotropic nanocellular polymers based on tri-phasic blends of PMMA with two nucleating agents

Abstract One strategy to produce nanocellular polymers is the use of nucleating species to promote nucleation. Whereas two-phase systems are widely studied, tri-phasic blends with two nucleating agents are uncommonly investigated. In this work, nanocellular polymers are obtained using tri-phasic blends of polymethylmethacrylate (PMMA) with two nucleating agents: needle-like sepiolites and a polymethylmethacrylate-polybutylacrylate-polymethylmethacrylate (MAM) block copolymer. Blends of PMMA with different concentrations of MAM and a fixed amount of sepiolites are produced by extrusion. Results show that at low MAM contents (1 wt%), the nucleation is a combination of the action of the two additives, but the addition of sepiolites induces the appearance of anisotropic structures. Meanwhile, at high MAM concentrations (10 wt%), MAM nanostructuration controls the nucleation and sepiolites increase the anisotropy. The alignment of the MAM micelles and the sepiolites in the extrusion direction promotes coalescence in this direction, leading to highly anisotropic nanocellular structures. Mean cell sizes of 100–300 nm and an average anisotropy ratio of 2.77 are obtained thanks to the combined effect of MAM and sepiolites.

Solid State Room Temperature Dual Phosphorescence from 3-(2-Fluoropyridin-4-yl)triimidazo[1,2-a:1',2'-c:1″,2″-e][1,3,5]triazine.

Organic room temperature persistent luminescence is a fascinating but still largely unexplored phenomenon. Cyclic-triimidazole and its halogenated (Br, I) derivatives have recently revealed as intriguing phosphors characterized by multifaceted emissive behavior including room temperature ultralong phosphorescence (RTUP) associated with the presence of H-aggregates in their crystal structure. Here, we move towards a multicomponent system by incorporating a fluoropyridinic fragment on the cyclic-triimidazole scaffold. Such chromophore enhances the molecular properties resulting in a high photoluminescence quantum yield (PL QY) in solution but preserves the solid-state RTUP. By means of X-ray diffraction (XRD) analysis, theoretical calculations, steady-state and time-resolved spectroscopy on solutions, polymethylmethacrylate (PMMA) blends and crystals, the nature of the different radiative deactivation channels of the compound has been disclosed. In particular, the molecular fluorescence and phosphorescence, this latter observed in frozen solution and in PMMA blends, are associated to deactivation from S1 and T1 respectively, while the low energy RTUP, observed only for crystals, is interpreted as originated from H aggregates.

Investigation of the dielectric properties of Sn – doped PMMA/PVA blends

Blends of Polymethyl methacrylate (PMMA)/polyvinyl alcohol (PVA) doped with 2% weight percentage of Sn were prepared with different blend ratios using casting technique. The measurements of A.C conductivity σa.c within the frequency range (25kHz – 5MHz) of undoped and Sn doped PMMA/PVA blends obeyed the relationship σ= Aws were the value of s within the range 0 > s > 1. The results showed that σa.c increases with the increase of frequency. The exponent s showed preceding increase with the increase of PVA content for PMMA/PVA blends doped with Sn. The dielectric constant, dielectric loss, A.C electrical conductivity are varied with the concentration of PVA in the blend and frequency of applied electrical field.

Fabrication of Ceramic/Polymer Hybrid Solid Electrolytes for All-Solid-State Lithium Batteries

The demand for solid-state lithium ion electrolytes has increased owing to the safety concerns regarding the use of lithium ion batteries, which contain flammable organic solvent electrolytes. The liquid electrolyte can give rise to serious problems such as leakage and gas explosions when the operating temperature rises. All solid-state batteries using organic or inorganic solid electrolytes have a higher energy density than lithium-ion batteries and can reduce the number of parts and packaging space, thereby saving weight and volume while using the same amount of power. To increase the size and, thus, the energy density of the lithium secondary battery while maintaining stability, the use of a solid electrolyte is required in place of the conventional flammable organic liquid electrolyte. NASICON-type Li1.3Al0.3Ti1.7(PO4)3 (LATP) ceramics are typical lithium ion conducting materials, with ion conductivities as high as 10-4 S·cm-1 at room temperature. In addition, LATP is chemically stable in humidified air or carbon dioxide and is expected to exhibit a high oxidative potential (4.21 V). In this regard, LATP has attracted significant attention as a promising solid electrolyte for all-solid-state lithium batteries. In addition to high ionic conductivity and chemical stability, the solid electrolyte needs to possess high strength and toughness to allow production of large area thin electrolyte sheets. The poor mechanical properties of ceramic-based solid electrolytes such as LATP or Li7La3Zr2O12 limit their practical application. Incorporating organic fillers with lithium ion conductivity in a ceramic-based electrolyte is an effective way to give not only flexibility but also enhanced mechanical properties. Dry polymer-based solid electrolytes present various advantages, such as excellent interfacial stability with lithium, the formation of complexes with lithium salts, and flexibility. Various types of polymer-based solid electrolytes exist, such as polyethylene oxide (PEO), polyacrylonitrile (PAN), polymethyl methacrylate (PMMA), polyvinyl chloride (PVC), and polyvinylidene fluoride (PVDF). Among them, the PEO-based polymer has attracted considerable attention, owing to its flexible skeleton and good interfacial stability with lithium electrodes. However, the commercialization of PEO is difficult because its room-temperature ionic conductivity is as low as 10−7–10−6 S·cm−1. Recently, we found that the solid polymer electrolyte with PEO:PMMA=8:1 and 8 wt% silica aerogel exhibited the high lithium-ion conductivity (1.35 × 10−4 S∙cm−1 at 30 °C) and good mechanical stability. In this study, a polymer blend of PEO and PMMA containing silica aerogel particles was incorporated to the LATP matrix. The PEO/PMMA solid polymer which was dispersed in the LATP skeleton permit flexibility and good bonding between the LATP. The LATP powder was synthesized by the sol-gel technique from lithium nitrate, aluminum phosphate, and titanium iso-propoxide to induce a rapid gelation reaction without further dissolution. The lithium ion conductivity of LATP/polymer composite electrolytes was measured from a symmetrical cell consisting of the LATP electrolyte and Pt blocking electrodes. The effects of the LATP:polymer ratio and the structure of the LATP skeleton such as porosity and grain size on the conductivity were investigated.

Enhancement of the Tensile and the Compression Properties for Heat- Cured Acrylic Resin Denture Base Materials

This work aims to investigate the tensile and compression strengths of heat- cured acrylic resin denture base material by adding styrene-butadiene (S- B) to polymethyl methacrylate (PMMA). The most well- known issue in prosthodontic practice is fracture of a denture base. All samples were a blend of (90%, 80%) PMMA and (10%, 20%) S- B powder melted in Oxolane (Tetra hydro furan). These samples were chopped down into specimens of dimensions 100x10x2.5mm to carry out the requirements of tensile tests. The compression strength test specimens were shaped into a cylinder with dimensions of 12.7mm in diameter and 20mm in length. The experimental results show a significant increase in both tensile and compression strengths when compared to control (standard) results for the preparation material.

Evaluation of the effects of acetyl tributyl citrate as bio‐based plasticizer on the physical, thermal, and dynamical mechanical properties of poly(vinyl chloride)/polymethyl methacrylate blends

This article details our work in studying the plasticization of Poly(vinyl chloride) (PVC)/Polymethyl methacrylate (PMMA) blends with bio‐based acetyl tributyl citrate (ATBC) in place of conventional plasticizers such as di(2‐ethylhexyl) phthalate. PMMA was blended with PVC in various ratios from 0 to 100 wt% by melt compounding with or without the plasticizer ATBC. Both the glass transition temperatures of the blends (differential scanning calorimetry) and Tα (dynamic mechanical thermal analysis) are consistent with a miscibility of the components, and Fourier transforms infrared spectroscopy studies show that there are specific interactions in the PVC/PMMA blends favoring the miscibility. The thermal degradation of the blends was studied by thermogravimetric analysis that shows the thermal degradation of rigid and plasticized PVC/PMMA is a process composed of two‐steps and that PMMA exercises a stabilizing effect on the thermal degradation of PVC during the first step by decreasing the rate of dehydrochlorination. J. VINYL ADDIT. TECHNOL., 25:E73–E82, 2019. © 2018 Society of Plastics Engineers

Enhancement of the Tensile and the Compression Properties for Heat- Cured Acrylic Resin Denture Base Materials

This work aims to investigate the tensile and compression strengths of heat- cured acrylic resin denture base material by adding styrene-butadiene (S- B) to polymethyl methacrylate (PMMA). The most well- known issue in prosthodontic practice is fracture of a denture base. All samples were a blend of (90%, 80%) PMMA and (10%, 20%) S- B powder melted in Oxolane (Tetra hydro furan). These samples were chopped down into specimens of dimensions 100x10x2.5mm to carry out the requirements of tensile tests. The compression strength test specimens were shaped into a cylinder with dimensions of 12.7mm in diameter and 20mm in length. The experimental results show a significant increase in both tensile and compression strengths when compared to control (standard) results for the preparation material.

Rheo-optical near-infrared (NIR) spectroscopy study of partially miscible polymer blend of polymethyl methacrylate (PMMA) and polyethylene glycol (PEG)

Tensile deformations of a partially miscible blend of polymethyl methacrylate (PMMA) and polyethylene glycol (PEG) is studied by a rheo-optical characterization near-infrared (NIR) technique to probe deformation behavior during tensile deformation. Sets of NIR spectra of the polymer samples were collected by using an acousto-optic tunable filter (AOTF) NIR spectrometer coupled with a tensile testing machine as an excitation device. While deformations of the samples were readily captured as strain-dependent NIR spectra, the entire feature of the spectra was overwhelmed with the baseline fluctuation induced by the decrease in the sample thickness and subsequent change in the light scattering. Several pretreatment techniques, including multiplicative scatter collection (MSC) and null-space projection, are subjected to the NIR spectra prior to the determination of the sequential order of the spectral intensity changes by two-dimensional (2D) correlation analysis. The comparison of the MSC and null-space projection provided an interesting insight into the system, especially deformation-induced variation of light scattering observed during the tensile testing of the polymer sample. In addition, the sequential order determined with the 2D correlation spectra revealed that orientation of a specific part of PMMA chain occurs before that of the others because of the interaction between CO group of PMMA and terminal OH group of PEG.

Resorcinol Formaldehyde Based Electrospun Carbon Fibers As High Capacity Anode Material for Lithium Ion Batteries

Introduction Resorcinol formaldehyde (RF) polymer derived carbon gels have been widely used as active electrode material in energy storage devices such as supercapacitors and lithium ion batteries due to their tunable surface area by varying drying conditions.1 In addition to the easily tunable surface area, morphology can also be modified by changing the synthesis parameters and methods.2,3 However, RF xerogel derived carbon nanofibers were not studied as anode material for Li-ion battery due to its non-electrospinnability. Recently, RF-based electrospun carbon nanofibers were prepared by blending it with stretchable Polymethyl methacrylate (PMMA).4 In this work, we have synthesized RF xerogel and PMMA blend based carbon nanofibers and used them as potential anode material for lithium ion battery. These RF xerogel derived electrospun carbon nanofibers show larger lithium ion intercalation capacity not only as compared to RF xerogel derived other carbon morphologies such as powder, interconnected carbon nanoparticles but also other carbon nanofibers based electrodes.5 , 6 Experimental RF sol was prepared by mixing resorcinol and formaldehyde (4:1 molar ratio) in acetone and HCl. Thus prepared RF sol was blended with templating PMMA polymer (1:2 Vol. ratio). A blend of this solution was used as precursor material for electrospinning. Electrospinning process parameters were tuned to yield long, continuous fibers. Controlled two step pyrolysis of these RF xerogel/PMMA electrospun fibers yielded carbon nanofibers. Results and discussions: RF-PMMA blend polymer fibers were electrospun directly on stainless steel wafer used as a substrate cum current collector. Average diameter of RF-PMMA electrospun RF-PMMA nanofibers as shown in Figure 1a was found to be 2.3 µm. These fibers were then pyrolyzed at 900 ⁰C to obtain carbon fibers with average diameter 1.4 µm. X-ray diffraction and Raman spectroscopy studies were done in order to confirm the glassy nature of as-derived carbon nanofibers. These RF-PMMA derived carbon nanofibers based electrode was then used as working electrode in Li (reference electrode) based half-cell. Galvanostatic charge discharge experiments were carried out at 37.2 mA/g current density. An initial reversible capacity of 620 mAh/g (Figure 1b) was observed for these carbon nanofibers which was significantly higher than reported values in literature for RF based powder, RF based graphitic powder and carbon nanoparticles. Further, cyclic stability and coulombic efficiency were found to be excellent. A detailed characterization of these carbon nanofibers and their electrochemical performance at different current densities will be presented during the conference.

The Influence of Blending Methods in Epoxy/PMMA Polymer Blend

Polymer blend consist of epoxy and polymethylmethacrylate (PMMA) was prepared via two different blending methods. Conventional blending method which required solvent to obtain polymer blend of PMMA and epoxy. However, due to the high consumption of solvent and environmental issue, a new approaching method: direct mixing method was used to prepare the polymer blend without the usage of solvent. The PMMA pellets are grinded and sieved into fine powders and incorporated into epoxy. Comparison between the conventional and new method was done through the investigation based on the morphology and mechanical behaviour, with different PMMA content (0, 10, 20, 30, 40 and 50 vol.%) between two blending methods. In overall, the polymer blend system prepared via direct mixing methods exhibited better mechanical properties as compared to conventional solvent dissolution method. Improvement on fracture toughness was observed in direct mixing method.

The interlaminar shear strength and impact performance of polytetrafluoroethylene fiber-reinforced polymethyl methacrylate composites filled with silicon dioxide

The interlaminar shear strength (ILSS) of polytetrafluoroethylene (PTFE) fiber-reinforced polymethyl methacrylate (PMMA) composites enhanced by filled silicon dioxide (SiO2) is studied. The PMMA blends were prepared by combining the techniques of high-speed mechanical stirring. Experimental results showed that ILSS and impact properties of PMMA composites were improved. The largest improvement in ILSS and impact strength were obtained with 7 vol % loading of SiO2. ILSS and impact strength were improved by 15 and 50%, respectively, compared with the composite without SiO2. The fracture and surface morphologies of the composite specimens were characterized using scanning electron microscopy. This PTFE fiber-reinforced composite can be applied to bioengineering and fabrics.

Preparation, characterization and performance of a novel PVDF/PMMA/TPU blend hollow fiber membrane for wastewater treatment

Polyvinylidene fluoride (PVDF)/polymethylmethacrylate (PMMA)/thermoplastic polyurethane (TPU) blend hollow fiber membranes were successfully prepared by the wet-spinning method with the loading of PMMA and TPU in a range of polymer concentrations varying from 0 to 20 wt% and at a total polymer concentration of 16 wt%. The influence of the addition of PMMA and TPU on the morphologies and the properties of such prepared membranes was investigated through FTIR-ATR, SEM, viscosity measurements, UF experiments and mechanical strength tests. Based on the experimental results, the compatibility of the PVDF, PMMA and TPU blend was best under the conditions of the PVDF-rich phase. The elongation at break of the membrane increased to a maximum of 146% with increase in the TPU concentration to 20 wt% in dope solution. The addition of PMMA increased the water permeation flux from 120 to 195 L/(m(2) h) initially. The flux then decreased when PMMA concentration was increased to over 10 wt%. The membranes obtained at optimized blending ratio were applied to the dyeing process wastewater filtration. During continuous filtration for 8 h, the flux was stabilized at about 20 L/(m(2) h) at 0.1 MPa. The reduction in COD(Cr), turbidity and color were about 63, 84 and 63% respectively.

Random lasing from granular surface of waveguide with blends of PS and PMMA

Lasing from a planar waveguide with the blend of Polystyrene(PS): Poly-methylmethacrylate(PMMA) doped with tris(8-hydroxyquinolinato)aluminum(Alq(3)) and 4-(dicyanomethylene)-2-tert-butyl-6(1,1,7,7-tetramethyljulolidyl-9-enyl)-4H-pyran(DCJTB) was investigated. Due to phase separation of the blend of PS:PMMA during the solvent evaporation process, a waveguide with granular surface was obtained, which has 2D island-like nanostructures with diameters ranging between 200 and 400 nm and heights at about 25 nm. Pumped by a YAG laser with wavelength of 355 nm, a significant random lasing was observed. Compared to the amplified spontaneous radiation (ASE) of planar waveguides with only PMMA or PS doped with Alq3:DCJTB prepared under the same conditions, the lasing threshold of the former is decreased by about 5 times, and the full width at half maximum (FWHM) is reduced to 1.7 nm from 12~15 nm. Our experiments show a promising method to achieve lower threshold for organic lasers.