PMMA Content Research Articles

Pyroelectric performance of porous Ba0.85Sr0.15TiO3 ceramics

AbstractPorous Ba0.85Sr0.15TiO3 (BST) ferroelectric ceramics were synthesized by sintering compacts consisting of BST and Poly(methyl methacrylate) (PMMA) (2%, 4%, 6%, 8%, and 10% by wt.) as pore‐forming agent. Systematic investigation of role of porosity on microstructural, dielectric, and pyroelectric performance is carried out. It is observed that as PMMA increased from 0% to 10%, the porosity increased from 7.5% to 29.5%. Dielectric constant decreases and dielectric loss increases with increasing PMMA content at fixed frequency. When porosity reached 29.5%, the relative dielectric constant of the BST composition decreased by more than 78% (from 3500 to 750) at 10 kHz and 300 K. Porosity leads to a significant reduction in dielectric constant and volume‐specific heat capacity, which are of great interest for improving pyroelectric figure of merits (FOMs). Further, the pyroelectric figure of merits for current responsivity (Fi), voltage responsivity (Fv), detectivity (Fd), and energy harvesting (Fe and Fe*) are calculated for all investigated compositions. Compared with dense ceramic, porous BST (10% PMMA) showed an improvement of Fd by 19%, Fe by 61%, and Fe* by 98%. Fv increased by 210% at 300 K/10 kHz. All of these advancements are favorable for the development of pyroelectric devices.

PLLA/PMMA blend in polymer nanoparticles: influence of processing methods

The preparation and synthesis of PLLA/PMMA blend nanoparticles by miniemulsion/solvent evaporation, miniemulsion polymerization, and seeded emulsion polymerization strategies is herein presented. We evaluate the effect of nanoparticle preparation technique and blend ratio over nanoparticle morphology and blend miscibility, and our results indicate that the nanoparticle processing method can greatly influence the final morphology characteristics of blend nanoparticles. By miniemulsion/solvent evaporation, miscible blend and homogeneous nanoparticles were obtained, and an increase in PMMA content led to a concomitant increase of nanoparticle size. Miniemulsion polymerization, on the other hand, resulted in an immiscible blend with a core-shell-like morphology nanoparticles. Under the conditions used, seeded emulsion polymerization led to the formation of secondary smaller particles of pure PMMA in addition to miscible PLLA/PMMA blend nanoparticles. PLLA/PMMA nanoparticles were further used to encapsulate a hydrophobic drug with high entrapment efficiency, showing to be a promising hydrophobic compound carrier.

Enhanced pyroelectric figure of merits of porous BaSn0.05Ti0.95O3 ceramics

Porous BaSn0.05Ti0.95O3 (BTS) ceramics were prepared by sintering compacts consisting of BTS and Poly (methyl methacrylate)(PMMA)as pore former. Porous BTS ceramics were systematically characterized for microstructural, ferroelectric, dielectric and pyroelectric properties. Porosity increased from 4% to 22.5% with increasing PMMA content. Dielectric constant decreases and loss increases with porosity. At 22.5% porosity, relative dielectric constant of BTS decreased by 47% (from 2525 to 1335) at 1MHz/303K. Porosity leads to significant reduction in dielectric constant and volume specific heat capacity, which are of great interest for improving pyroelectric figure of merits (FOMs). Further, FOMs for current responsivity (Fi), voltage responsivity (Fv), detectivity (Fd) and energy harvesting (Fe and Fe*) are calculated. Compared with dense ceramic, 2% PMMA specimen showed an improvement of Fe by 166% and Fe*by 177%. Fv increased by 77%, Fd by 73% and Fi by 56% at 303K. All of these advancements are favorable for pyroelectric device applications.

Facile fabrication and property of biocompatible and biodegradable cellulose-coated PMMA composite microspheres by Pickering emulsion system

ABSTRACTSCNWs-coated poly[methyl methacrylate] (PMMA) composite microspheres (PMMA@SCNW CMs) were fabricated by the Pickering emulsion stabilized by cellulose nanowhiskers (SCNW) combined with the solvent evaporation method. The structure and morphology of the CMs affected by the concentration of PMMA in dichloromethane solution and the volume ratio of water-to-oil were investigated and further characterized by polarized optical microscopy, confocal laser scanning microscopy, scanning electron microscopy, and Fourier transform infrared spectroscopy. Finally, methyl red as model drug was loaded into CMs and exhibited fine drug–controlled release performance. This method will also be available to other polymers for preparing composite microspheres.

PMMA contents dependent ion transports in ruthenium complex based electrochemiluminescence devices

PMMA contents dependent ion transports in ruthenium complex based electrochemiluminescence devices

Transport behaviour of aromatic solvents through styrene butadiene rubber/poly [methyl methacrylate] (SBR/PMMMA) interpenetrating polymer network (IPN) membranes

Sequential polymerization technique has been adopted for the synthesis of a series of full and semi interpenetrating polymer network (IPN) membranes based on styrene butadiene rubber (SBR) and poly [methyl methacrylate] (PMMA). IPN morphology has been tuned by varying the blend composition and extent of cross-linking of both the phases. The dispersed and co-continuous morphologies of IPNs were characterised by AFM, SEM and TEM analysis. The transport behaviour of aromatic hydrocarbons through the membranes has been studied in detail by tracing the solvent uptake up to equilibrium. As the PMMA content in the IPN increases to 60 wt %, the solvent uptake value decreases by about 50% which is in tune with the morphological changes of the system where PMMA phase forms a well interconnected network structure with the SBR phase. The network structure has been compared with the Phantom and the Affine models and also with the theoretical predictions.

Critical Insights into the Effect of Shear, Shear History, and the Concentration of a Diluent on the Polymorphism in Poly(vinylidene fluoride)

The effect of shear, shear history, and addition of poly(methyl methacrylate) (PMMA) in inducing the β-polymorph in poly(vinylidene fluoride) (PVDF) was investigated systematically for melt-mixed PVDF/PMMA blends. Various techniques such as polarized optical microscopy (POM) coupled to a hot stage and a shear cell, Fourier transform infrared spectroscopy (FTIR), differential thermal analysis, melt-rheology, and dielectric relaxation spectroscopy were used to gain a mechanistic insight for the observed polymorphism in PVDF. Different PVDF rich blends were prepared by melt-mixing and were subjected to different shear histories on a rheometer, and the induction time was monitored with respect to PMMA content and the applied shear flow in the blends. The rheological measurements revealed that the induction time was significantly lower for blends with a higher PVDF content (≥80 wt %), which was ascribed to the diluent effect of PMMA that restricts the chain mobility of PVDF and a longer time is required to start the crystallization process. The crystalline morphology observed from POM demonstrates that the growth rate of spherulites was greatly reduced with increasing PMMA content in the blends. FTIR results were used to determine the amount of β phase in the blends before and after the shear history. The blends that were sheared at high temperature (220 °C) showed more β phase than the blends that were sheared around the crystallization temperature. This study clearly demonstrates the fact that shear, shear history, and the content of PMMA significantly influence the conformational change that results in phase transformation in PVDF. Further, this study will help guide researchers working on various aspects of polymer processing where the effect of blending and shear on polymorphism is very important.

Crystallization Induced Phase Separation: Unique Tool to Design Microfiltration Membranes with High Flux and Sustainable Antibacterial Surface

In the present study, a strategy has been used to fabricate microfiltration membranes through phase separation induced by crystallization in PVDF/PMMA [polyvinylidene fluoride/poly(methyl methacrylate)] blends. Nanoporous channels in the membranes were designed by selective etching of PMMA and tuned by varying the PMMA concentration in the blend. The interconnectivity of the designed membranes was tuned by changing the concentration of PMMA in the blend. Scanning electron microscopy (SEM) studies showed that the spherulites appeared more compact in the 90/10 blend as compared to 70/30 and 60/40 PVDF/PMMA blends. The obtained flux was higher compared to membranes that are commercially available. Biofouling of membranes is a major concern, and in order to address this concern, silver was sputtered on the token membranes and leaching of Ag+ was monitored using inductively coupled plasma atomic emission spectroscopy (ICP). This strategy is “scalable” and is an industrially viable route to design antibiofoulin...

Improving dielectric properties of BaTiO3/poly(vinylidene fluoride) composites by employing core-shell structured BaTiO3@Poly(methylmethacrylate) and BaTiO3@Poly(trifluoroethyl methacrylate) nanoparticles

Polymer based dielectric composites were fabricated through incorporation of core-shell structured BaTiO3 (BT) nanoparticles into PVDF matrix by means of solution blending. Core-shell structured BT nanoparticles with different shell composition and shell thickness were prepared by grafting methacrylate monomer (MMA or TFEMA) onto the surface of BT nanoparticles via surface initiated atom transfer radical polymerization (SI-ATRP). The content of the grafted polymer and the micro-morphology of the core-shell structured BT nanoparticles were investigated by thermo gravimetric analyses (TGA) and transmission electron microscopy (TEM), respectively. The dielectric properties were measured by broadband dielectric spectroscopy. The results showed that high dielectric constant and low dielectric loss are successfully realized in the polymer based composites. Moreover, the type of the grafted polymer and its content had different effect on the dielectric constant. In detail, the attenuation of dielectric constant was 16.6% for BT@PMMA1/PVDF and 10.7% for BT@PMMA2/PVDF composite in the range of 10Hz to 100kHz, in which the grafted content of PMMA was 5.5% and 8.0%, respectively. However, the attenuation of dielectric constant was 5.5% for BT@PTFEMA1/PVDF and 4.0% for BT@PTFEMA2/PVDF composite, in which the grafted content of PTFEMA was 1.5% and 2.0%, respectively. These attractive features of BT@PTFEMA/PVDF composites suggested that dielectric ceramic fillers modified with fluorinated polymer can be used to prepare high performance composites, especially those with low dielectric loss and high dielectric constant.

Fabrication of PMMA Membranes with Nano-Pillars Array Using Template/Spin-Coating Method

Template/spin-coating method was presented for fabricating single-layer nano-pillar array polymethylmethacrylate (SL-PMMA) and double-layer nano-pillar array polymethylmethacrylate (DL-PMMA) membranes. The different mass ratio of PMMA/DiMethyl Formamide (DMF) solution was dripped on single-layer porous anodic alumina (SL-PAA) or double-layer porous anodic alumina (DL-PAA) membrane and spun at 4000rpm speed for 30 seconds. The SL-PAA and DL-PAA membranes had been put into vacuum oven at 150°C for 2 hours, before SL-PMMA and DL-PMMA were removed. Experimental results show that the regularity degree of PAA fabricated in OAS/PAS is higher than that of PAA fabricated in PAS by two-step anodization method. The ordered pores and clear double-layer outline can be observed from the surface and cross-section FESEM images of DL-PAA membranes. When the content of PMMA in mixture solution is 20 wt%, the top shape of nano-pillars is convex, because the solution was completely filled in the pore of SL-PAA, and the length of nano-pillars is equal to the height of pore of PAA. However, the top pore amount on nano-pillars at ascending speed 20°C per minute is more than that of at ascending speed 10°C per minute. The PMMA membranes with ordered mid-hollow and porous nano-pillars will have wide application prospect in biosensors, chemical sensors, microcapsules fabrication fields due to many advantages such as simple operation, low cost, high specific surface area, etc.

Nanostructure and morphology of poly(vinylidene fluoride)/polymethyl (methacrylate)/clay nanocomposites: correlation to micromechanical properties

Nanocomposites based on poly(vinylidene fluoride) (PVDF)/poly(methyl methacrylate) (PMMA) with untreated clay were prepared in one step by reactive melt extrusion. Chemical reactions took place between the polymer matrices, the inorganic clay particles, and three reactive agents, leading to the PVDF/PMMA/clay nanocomposites. The microstructure characterizations were carried out by differential scanning calorimetry and wide-angle X-ray scattering (WAXS). The mechanical behavior was investigated by tensile experiments, impact tests, and microhardness measurements. The morphological characterization was carried out by optical and atomic force microscopy (AFM). The decrease of the melting and crystallization temperatures of the PVDF with the increasing PMMA content is attributed to the interactions between the oxygen of the PMMA carbonyl group and the PVDF’s hydrogen atom. WAXS analysis shows that there is neither an intercalation step nor total exfoliation in any composition. As the PMMA content increases, WAXS diagrams show either the PVDF α-crystallographic form, both, α- and β-forms, or only the β-form. For PMMA contents higher than 40 wt%, the materials became amorphous. The microhardness of the samples decrease for a PMMA content up to 20 wt%. The study by optical microscopy and AFM illustrates the significant effect in the presence of clay on the film’s surface morphology.

A Parametric Study on the Influence of Synthesis and Transfer Conditions on the Quality of Graphene.

In this paper, a systematic and comprehensive study has been carried out to observe the effect of synthesis and transfer conditions on the quality and uniformity of graphene deposition in an atmospheric pressure chemical vapour deposition set up. It was observed that the quality of graphene was highly affected by the synthesis conditions, such as, synthesis temperature, synthesis duration, methane and hydrogen flow rate ratio and total flow rate during deposition and cooling cycles. The quality of graphene was observed to be significantly improved upon increasing the synthesis temperature while increase in methane and hydrogen flow rates beyond a particular limit resulted into degradation in the quality of graphene. From the comparison of scanning electron microscopy images of graphene grown at different times, it was found that the nucleation and growth of graphene domains strongly depend on the growth time. The process of transfer of monolayer graphene was significantly improved by controlling the PMMA concentration using a modified three step technique. Raman spectroscopy and the high mobility (˜8153 cm2V−1s−1) of graphene after transferred onto a SiO2/Si substrate confirm the high quality of monolayer graphene obtained by the optimizations of synthesis and transfer conditions in this study.

Utilization of poly(methyl methacrylate) rejection blended with acrylonitrile butadiene styrene resins and the effect on product properties

PMMA is one of the main raw materials for the injection molding process in the lens industries. Since this process requires extremely careful techniques to obtain lens with the best quality, it leads to a high rate of product rejection. These rejected products do not only pose an issue for the industrial environment and require storage space, their price also falls significantly. Among the solutions to this problem is to reuse the rejected products as substitute materials for the manufacture of another product’s part such as lamp holders. This process reuses rejected PMMA-containing products in the ABS base polymer industries so as to generate PMMA-containing products with better physical properties. In this experiment, 10 to 40 % (w/w) of rejected PMMA was blended with ABS resins. The monomer content in the ABS resins was analyzed by NMR. Moreover, the mechanical, thermal, and morphological properties of the blended products were also examined. The NMR analysis showed that the resin contained 21.6 % butadiene monomer, in which its value was higher than the value required for materials with high-impact class application. The blend of resins and rejected PMMA (10-30% w/w) could increase the tensile strength value and decrease Izod impact strength and elongation percentage. The morphological analysis showed that this increased PMMA content may also result in widespread brittle areas. Since the blend was designed without compatibilizers, the DSC analysis indicated that the resulting blend in any ratios was not completely miscible. It was revealed that ABS resins containing 10% PMMA was the best blend for the polymer engineering application and this blend still had adequate properties and elastomer content required. Keywords: ABS, blending, properties, PMMA regrind.

Experimental investigation of the effect of electrospinning parameters on properties of superhydrophobic PDMS/PMMA membrane and its application in membrane distillation

Considerable efforts have been devoted to finding economic and simple preparation methods for polydimethylsiloxane (PDMS) superhydrophobic membrane in past decades. This study provides a simple method to electrospin PDMS membrane using poly (methyl methacrylate) (PMMA) as carrier polymer. Effects of PMMA concentration, PDMS/PMMA mass ratio and main parameters of electrospinning process (voltage and injection rate) were investigated to obtain superhydrophobic membrane with high water contact angle (WCA). A highest WCA of 163° could be obtained on the membrane surface fabricated by electrospinning solution containing PDMS: PMMA: tetrahydrofuran (THF): N,N-dimethylformamide (DMF) (mass ratio 1: 1: 8.88: 9.48) under applied voltage of 11kV and injection rate of 0.1mm/min. The superhydrophobic PDMS/PMMA membrane was further applied in membrane distillation process for desalination, and a high permeation flux of 39.61L/m2h and an excellent salt rejection of 99.96% were achieved during long-term MD process (24h).

Fabrication of PMMA/zeolite nanofibrous membrane through electrospinning and its adsorption behavior

ABSTRACTThe present work investigates the effect of various solution parameters and electrospinning parameters on the characteristics of electrospun nanofibrous membranes. Scanning electron microscopy was used to analyze the surface morphology of the nanofibrous membrane. Adsorption test on methyl orange was also carried out and analyzed using the UV–vis. Results showed that increasing voltage decreased mean nanofiber diameter. Meanwhile, increasing PMMA concentration, feed rate, distance between collector‐and‐needle tip increased mean nanofiber diameter. Zeolite concentration and needle size did not affect the surface morphology significantly. The UV–vis spectra of the adsorption test showed that ∼93%, 85.5%, and 78% of methyl orange were adsorbed for 30, 50, and 100 mg L−1 initial dye concentration, respectively, within 11 min. The maximum adsorption capacity was found to be 95.33 mg g−1. Therefore, PMMA/zeolite nanofibrous membranes possess the adsorption capability toward effective dye removal. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44450.

Tuning Surface Properties of Poly(methyl methacrylate) Film Using Poly(perfluoromethyl methacrylate)s with Short Perfluorinated Side Chains.

To control the surface properties of a commonly used polymer, poly(methyl methacrylate) (PMMA), poly(perfluoromethyl methacrylate)s (PFMMAs) with short perfluorinated side groups (i.e., -CF3, -CF2CF3, -(CF3)2, -CF2CF2CF3) were used as blend components because of their good solubility in organic solvents, low surface energies, and high optical transmittance. The surface energies of the blend films of PFMMA with the -CF3 group and PMMA increased continuously with increasing PMMA contents from 17.6 to 26.0 mN/m, whereas those of the other polymer blend films remained at very low levels (10.2-12.6 mN/m), similar to those of pure PFMMAs, even when the blends contained 90 wt %PMMA. Surface morphology and composition measurements revealed that this result originated from the different blend structures, such as lateral and vertical phase separations. We expect that these PFMMAs will be useful in widening the applicable window of PMMA.

Exploring the relationship of dielectric relaxation behavior and discharge efficiency of P(VDF-HFP)/PMMA blends by dielectric spectroscopy

The dielectric relaxations in P(VDF-HFP)/PMMA blends were investigated by dielectric relaxation spectroscopy. Various dielectric relaxation and their molecular mechanisms of P(VDF-HFP), PMMA, and P(VDF-HFP)/PMMA composite films were analyzed. According to the fitted data of the Havriliak–Negami (HN) function, all relaxation processes belong to non-debye relaxation, the activation energy (Ea), relaxation time (τHN) and dielectric relaxation strength (Δϵ) of P(VDF-HFP)/PMMA blends significantly decreased around and below room temperature with increasing PMMA content. But, the results of αc relaxation are opposite. In addition, the conductivities (σ) of P(VDF-HFP)/PMMA composite films also sharply decreased with the addition of PMMA. Thus, the high discharge energy density and efficiency of dielectric materials closely related with the lower Ea, τHN, Δϵ and σ.

Capacitive properties of hierarchically structured carbon nanofiber/graphene/MnO2 hybrid electrode with nitrogen and oxygen heteroatoms

Hierarchically structured carbon nanofiber/graphene/MnO2(CGMn) hybrid with oxygen and nitrogen functionalities was fabricated in the form of a web via electrospinning as an electrode material for supercapacitors. The CGMn electrode exhibited a high capacitance (225 Fg−1 at 1 mAcm−2), enhanced energy and power efficiency (15.8–13.6 Whkg−1 in the power density range of 197–4000 Wkg−1), and excellent capacitance retention (13% of the initial value at a discharge current of 20 mAcm−2) in a 6 M KOH aqueous electrolyte, because of the combination of the double-layer capacitance and the pseudocapacitive character associated with the surface redox-type reactions. The porosity and the number of heteroatoms of the CGMn composite were adjusted by changing the PMMA concentration and carbonization temperature. Therefore, the oxygen- and nitrogen-containing hierarchical porous CGMn hybrid prepared by a simple method is a promising candidate as an electrode material for supercapacitors.

Investigation of the dielectric relaxation, conductivity and energy storage properties for biaxially oriented poly(vinylidene fluoride-hexafluoropropylene)/poly(methyl methacrylate) composite films by dielectric relaxation spectroscopy

The dielectric relaxations in biaxially oriented P(VDF-HFP)/PMMA composite films with less than 40 % PMMA were investigated using dielectric relaxation spectroscopy. Various relaxation processes and their locations of P(VDF-HFP), PMMA, and P(VDF-HFP)/PMMA composite films were analyzed. According to the fitted data of the Havriliak–Negami (HN) function, different relaxation processes belong to non-debye relaxation, the activation energy (Ea) and dielectric relaxation strength (∆e) of P(VDF-HFP)/PMMA composite films significantly decreased around and above glass transition temperature (Tg) with increasing PMMA content. In addition, the conductivities (σ) of P(VDF-HFP)/PMMA composite films also sharply decreased with the addition of PMMA. The decrease of dielectric relaxation strength (∆e) benefits the drop of Pr, lower the activation energy (Ea) makes coercive field decrease and the lower conductivity (σ) could enhances the breakdown strength. Thus, dielectric film of high energy storage density and low loss was closely related with the lower Ea, ∆e and σ.

Effect of electrospinning on the ionic conductivity of polyacrylonitrile/polymethyl methacrylate nanofibrous membranes: optimization based on the response surface method

A novel fibrous polymer electrolyte membrane was produced based on polymethyl methacrylate/polyacrylonitrile (PMMA/PAN) blend. This was achieved through optimization in the loadings of the two polymers and electrospinning method. Consequently, the effect of PMMA on the ionic conductivity was assessed. A quantitative relationship between ionic conductivity and the important parameters including voltage, solution concentration, and PMMA content was determined. The response surface method (RSM) was employed to obtain the quantitative relationship and to determine the ion conductivity of PAN/PMMA electrospun membrane. Analysis of variance technique was used to study the importance of parameters and their interactions. A regression model was applied to determine the most influential factors on the ionic conductivity and to find the maximum ionic conductivity of the electrolyte membrane as an optimal result. The average fiber diameter was in the range of 206–367 nm, and the membranes were associated with high porosities between 50 and 91 %, and the electrolyte uptakes were in the range of 285–460 %. For all samples, the ionic conductivity of gel polymer electrolytes at 25 °C was above the 1 mS/cm. The ionic conductivity changed with the voltage directly and with the solution concentration inversely. According to the results, the ionic conductivity showed its dependency with the PMMA content, increasing with the PMMA content up to 50 % and smoothly decreasing with PMMA further increases. Some important interactions between the parameters were also detected.