Methyl Methacrylate Content Research Articles

Effect of methyl methacrylate on the properties of transparent flame retardant unsaturated phosphate ester copolymer

The effect of methyl methacrylate (MMA) on the properties of transparent flame retardant unsaturated phosphate ester copolymer (poly[UPE‐co‐MMA]) prepared by bulk polymerization technique was investigated. Fourier transform infrared spectra, gel fraction (G) test, and dynamic mechanical analysis revealed the structure and crosslinking density of poly(UPE‐co‐MMA) copolymers. The thermal degradation and flame retardancy of copolymers were indicated by thermogravimetric analysis, limiting oxygen index (LOI), and microscale combustion calorimeter (MCC) test. Besides, the mechanical properties and transparency were tested with testing machines and solid ultraviolet absorption spectra. As the MMA content increased to 50%, the copolymer contained 50 wt% MMA showed the maximal G (88.93%) and transmittance was up to 91.72%. From the poly(UPE‐co‐MMA) copolymers, the tensile strength increased from 14.62 to 26.95 MPa, assigned to the increase of crosslinking density of copolymers. The char yield of poly(UPE‐co‐MMA) was up to 21.18 wt%, which was a result of decomposition of phosphate groups, producing a phosphorus‐rich layer that increased the thermal stability of the residues. LOI and MCC results confirm that the introduction of MMA can retain the flame retardancy of copolymer remarkably. POLYM. ENG. SCI., 59:2103–2109, 2019. © 2019 Society of Plastics Engineers

Characterizing Occupational Health Risks and Chemical Exposures Among Asian Nail Salon Workers on the East Coast of the United States.

The products used in nail care services contain toxic chemicals. This study aimed to characterize occupational health risk factors and chemical exposures among Asian nailsalon workers onthe East Coast of the U.S. for informing the development of more effective, culturally appropriate interventions. We conducted a community-based participatory research (CBPR) study to characterize occupational health risks. A face-to-face, self-reported survey was performed, and personal exposure to volatile organic compounds (VOCs) was evaluated. Three VOCs, acetone, methyl methacrylate (MMA), and toluene, were measured using 3M 3500 organic vapor monitors. We collected data on 112 workers with 100 personal chemical exposure measurements from 25 nail salons. Self-reported health problems that emerged or worsened after participants started working in the nail salon industry included headaches (8%); lightheadedness (9.8%); and irritation to the nose, eyes, throat, and skin (21.2%). Approximately 70% of participants reported that they had been pregnant, 11.7% of whom had at least one miscarriage. The mean concentrations of acetone, MMA, and toluene were 18.51parts per million(ppm), 39.45ppm, and 0.09ppm, respectively. Mean concentrations of acetone and MMA measured fromsalons in New York City were significantly lower than those measured in Philadelphia and southern New Jersey. CBPR proved to be as an efficient approach for recruiting hard-to-reach Asian immigrant nail salon workers. Adverse health symptoms and problems associated with providing nail salon services were identified in theseworkers. Further studies are needed to better understand the long-term health effects of chronic chemical exposures in nail salon environments.

Poly (2-hydroxyethylmethacrylate -co-methylmethacrylate)/Lignocaine Contact Lens Preparation, Characterization, and in vitro Release Dynamic.

2-hydroxyethyl methacrylate, methylmethacrylate, ethylene glycol dimethyl methacrylate, and lignocaine (drug) were mixed together and the monomers were copolymerized at 60 °C through a free radical polymerization in the presence of α,α′-Azoisobutyronitrile in tetrahydrofuran. A series of copolymer/drug composites with different monoacrylate monomer compositions were prepared by solvent evaporation and characterized by different methods such as nuclear magnetic resonance, differential scanning calorimetry, Fourier transform infrared, X-ray diffraction, and mechanical and optical testing. The water content in the copolymers and the cell viability test on the samples were also examined in this investigation. The results of the analyses of the properties of this drug-carrier system are promising, indicating that this material may be a potential candidate for contact lens applications. The release dynamic of this medication from the prepared drug-carrier systems was investigated in neutral pH media. The results obtained revealed that the diffusion of lignocaine through the copolymer matrix obeys the Fick model and the dynamic release can be easily controlled by the methyl methacrylate content in the copolymer.

Development of high‐modulus thermoset materials based on bioglycerol

AbstractA high‐value application of crude bioglycerol in polymers was developed. In this application, bioglycerol was first transformed into a highly polyunsaturated resin (MAGLYMA) through maleinization–methacrylation reactions, under mild conditions (80–90 °C, 1–2 h). The resin was copolymerized with methyl methacrylate (MMA) (20%–50%) at room temperature over 8 h, affording rigid materials. The effect of MMA content on the mechanical and thermal properties was evaluated. The flexural modulus, flexural strength and surface hardness of the materials were around 3800 MPa, 130–180 MPa and 77 (Shore D), respectively. Tg values were in the range 92–105 °C. It is remarkable that excellent mechanical and thermal properties were obtained using a low concentration of MMA (20%). In particular, the mechanical properties of this material were better than those obtained for a commercial unsaturated polyester thermoset. © 2019 Society of Chemical Industry

Pilot Studies of VOC Exposure Profiles during Surgical Operations.

Volatile organic chemical exposure resulting from surgical operations is common in operating room personnel. The potential risk of long-term exposure to these low-level chemicals is always a concern. This study was conducted in an area hospital located in northern Taiwan to investigate the internal exposure scenario for operating room personnel. Breath samples were collected before and after surgery, whereas area samples were collected during the surgeries in process. There were 18 volatile organic compounds identified in the samples with gas chromatography-mass spectrometry. The average concentrations of sevoflurane (P = 0.0082), dimethyl sulfide (P = 0.0550), and methyl methacrylate (P = 0.0606) in breath samples collected after surgical operations were significantly higher compared to those obtained before surgical operations, whereas only slight elevations were present for benzene and hexamethyldisiloxane (P < 0.100). In addition, electrosurgical smoke-related chemicals, such as benzene, toluene, ethylbenzene, and m/p-xylene, also presented higher levels in operating room samples compared to the control area. Specifically, the findings in this preliminary study suggested the associations of elevated exposure to sevoflurane across various surgeries to methyl methacrylate with orthopedic surgery and to hexamethyldisiloxane with conventional electrosurgical units. Future study is warranted to explore the short-term high-level chemical exposure in operating rooms and to propose effective preventive measures accordingly to keep any exposure to chemicals at the lowest practical level.

Label-free toxicology screening of primary human mesenchymal cells and iPS-derived neurons.

The high-throughput, label-free Corning Epic assay has applications in drug discovery, pharmacogenomics, cell receptor signaling, cell migration, and viral titration. The utility of Epic technology for biocompatibility testing has not been well established. In manufacturing of medical devices, in vitro and in vivo biocompatibility assessments are mandatory, according to ISO 10993. The new medical device regulation MDR 745/2017 specifies that ex vivo assays that can closely recapitulate in vivo scenarios are needed to better evaluate biomedical devices. We propose herein that Epic technology—which enables detection of variations in cell mass distribution—is suitable for biocompatibility screening of compounds. In this study, we challenged primary human osteoblasts, endothelial cells, and neurons derived from induced pluripotent stem cells with specific concentrations of methyl methacrylate (MMA). Polymeric MMA has long been applied in cranioplasty, where it makes contact with multiple cell types. Application of Epic technology yielded real-time cytotoxicity profiles for all considered cell types. The results were compared with those from microscopic observation of the same culture plate used in the Epic analyses. The Epic assay should be further examined for its utility for cell biology, genomics, and proteomics companion assays. Our results suggest that Epic technology can be applied to biocompatibility evaluation of human cells in medical device development.

Swelling and auramine-O adsorption of carboxymethyl cellulose grafted poly(methyl methacrylate)/Cloisite 30B nanocomposite hydrogels

Carboxymethyl cellulose (CMC) grafted poly(methyl methacrylate)/Cloisite 30B nanocomposite hydrogels were prepared for adsorptive removal of auramine-O (as a cationic dye model) from wastewater. For the synthesis of nanocomposite hydrogel by free radical polymerization method, potassium persulfate (KPS), methyl methacrylate (MMA), N,N′-methylene bisacrylamide (MBA) and Cloisite 30B were used as initiator, monomer, cross-linker and nano-filler, respectively. The nanocomposite hydrogels were characterized by FTIR, TGA, SEM and XRD techniques. The FTIR results showed that the monomer was grafted onto carboxymethyl cellulose chains successfully. Swelling behavior of nanocomposite hydrogel as a function of KPS, MBA, MMA concentration and CMC/Cloisite 30B weight ratio was studied by Taguchi method using Minitab 16 software. According to ANOVA results, the most effective factor of equilibrium swelling of nanocomposite hydrogel was CMC/Cloisite 30B weight ratio. Addition of Cloisite 30B to hydrogel up to a certain amount improved swelling, though its high amount decreased swelling. The effects of pH and ionic strength on swelling of optimum hydrogels were investigated. Maximum swelling of nanocomposite hydrogel occurred at pH 7.0. The kinetic data of adsorption fitted well to pseudo-second-order model. The best isotherm for investigation of adsorption mechanism was Langmuir model suggesting the formation of a monolayer on the adsorbent surface. FTIR results, before and after auramine-O adsorption, showed that complexation is the main mechanism of adsorption. High adsorption capacity of nanocomposite hydrogels made them more efficient in wastewater treatment application.

Strength Developments and Deformation Characteristics of MMA-Modified Vinyl Ester Polymer Concrete

This study investigated the strength developments and deformation characteristics of methyl methacrylate (MMA)-modified vinyl ester polymer concrete, with MMA contents and curing temperatures as test variables. To lower the viscosity of the vinyl ester resin applied as a binder, an MMA monomer was added. In this study, the developed 168-h compressive and flexural strengths were 43.8–77.2 and 18.2–21.8 MPa, respectively. Also, these values decreased as MMA contents increased and curing temperatures decreased. The coefficient of thermal expansion ranged from 10.82 × 10−6 to 14.23 × 10−6/°C, and it decreased as an MMA content increased. The ultimate compressive strain ranged from 0.00391 to 0.00494, which decreased with an increase in MMA contents and notably decreased with a decrease in curing temperatures. The modulus of elasticity tended to decrease as MMA contents increased and curing temperatures decreased.

Kinetics of methyl methacrylate combustion over a Pt/alumina catalyst

The combustion of methyl methacrylate (MMA) over a commercial Pt/?-alumina catalyst was investigated, in the lean air mixtures specific for the depollution applications. The experiments were performed at temperatures between 150 and 360?C, with MMA concentrations of 460 to 800 ppmv and the gas flow rates between 200 and 300 mL min-1. The results evidenced a negative influence of MMA concentration on the combustion kinetics. A kinetic model of the combustion process was developed, based on the Langmuir?Hinshelwood mechanism, assuming the surface reaction between adsorbed oxygen atoms and adsorbed MMA molecules as the controlling step. The rate expression included the inhibition effects of MMA and water adsorption on the process kinetics. The MMA combustion process simulations evidenced the significant influences of the bulk gas to catalyst particle mass transfer, on the overall kinetics.

Polymer Based Thin Film Screen Preparation Technique

Phosphor screens, mainly prepared by electrophoresis, demonstrate brightness equal to the standard sedimentation on glass or quartz substrate process and are capable of very high resolution. Nevertheless, they are very fragile, the shape of the screen is limited to the substrate shape and in order to achieve adequate surface density for application in medical imaging, a significant quantity of the phosphor will be lost. Fluorescent films prepared by the dispersion of phosphor particles into a polymer matrix could solve the above disadvantages. The aim of this study is to enhance the stability of phosphor screens via the incorporation of phosphor particles into a PMMA (PolyMethyl MethAcrylate) matrix. PMMA is widely used as a plastic optical fiber, it shows almost nearly no dispersion effects and it is transparent in the whole visible spectral range. Different concentrations of PMMA in MMA (Methyl Methacrylate) were examined and a 37.5 % w/w solution was used for the preparation of the thin polymer film, since optical quality characteristics were found to depend on PMMA in MMA concentration. Scanning Electron Microscopy (SEM) images of the polymer screens demonstrated high packing density and uniform distribution of the phosphor particles. This method could be potentially used for phosphor screen preparation of any size and shape.

Studies on Viscoelastic, Thermal and Morphological Properties of Vinyl Ester – Mixed Diluents System

Abstract Vinyl ester resin networks formed by using mixture of diluents were prepared. Methyl methacrylate (MMA) diluent was mixed in various proportions with vinyl ester resin which was already premixed with styrene diluent (45 wt. %). Weight ratios e.g. 80:20, 70:30 and 60:40 of VE resin: MMA diluents were studied. Viscoelastic properties of the cross-linked resin were studied by dynamic mechanical analyzer in terms of storage modulus and tanδ. Thermal analysis was performed using non-isothermal mode of Differential scanning calorimetry. The samples with mixed diluents, showed higher modulus, and glass transition temperature in comparison to that of the pure vinyl ester-styrene resin cross-linked in presence of styrene only. The difference in thermal stability between vinyl ester-styrene and vinyl ester-MMA-styrene was checked. Vinyl Ester - 20 wt. % MMA-Styrene samples have the best thermal property among all other prepared samples. Multiphase morphology was formed for the thermoset crosslinked with mixed diluents in contrast to that formed with single diluent. With increase in MMA content in the resin dispersed domain size increased.

Grafting and properties of a porous poly(methyl methacrylate) film on a silicon surface by a one‐step dipping method

ABSTRACTIn this study, we prepared a porous poly(methyl methacrylate) (PMMA) film on an Si surface with a novel dipping method. We conducted the process by directly dipping the Si substrate into acidic aqueous media in a simple flask at 10 °C. First, 4‐nitrobenzene diazonium tetrafluoroborate (NBD) was spontaneously reduced at the Si surface. Then, the aryl radicals during the reduction of NBD were directly grafted onto the Si surface. Meanwhile, the aryl radicals initiated the polymerization of methyl methacrylate (MMA) monomers, and the radical‐terminated PMMA chains formed in the solution were grafted onto the Si surface. Because water was a poor solvent for MMA, the grafted PMMA chains easily aggregated together, and this resulted in a porous polymer film. The porosity of the film depended on the grafting time and the MMA concentration. Furthermore, the permittivity of the porous PMMA film was relatively low, and its dielectric dissipation factor was extremely small. Therefore, its excellent dielectric properties should allow the porous film to have many applications in industry. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44930.

Effects of Curing Temperature and MMA Content on the Working Life of MMA-Modified Vinyl Ester Polymer Concrete

The main purpose of this study is to identify the effects of curing temperature and methyl methacrylate (MMA) content on the working life of vinyl ester polymer concreteusing MMA as a monomer, N,N-dimethyl-p-toluidine (DMP) and methyl ethyl ketone peroxide (MEKPO) as initiators and cobalt naphthenate as a promoter. The results have shown that the working life of vinyl ester polymer concrete was shortened with an increased curing temperature and a decreased MMA content. Also, it was found that the curing temperature had a greater influence on the working life of vinyl ester polymer concrete than MMA content. The working life of vinyl ester polymer concrete was found to be about 70 and 10 min longer than the setting time of vinyl ester polymeric binder at curing temperatures of -10 and 20°C respectively. The MMA content had a much smaller effect on the curing temperature. Lastly, a linear regression equation was drawn by analyzing the correlation between setting time of the binder and working life of polymer concrete, which could be used for the prediction of the working life of vinyl ester polymer concrete based on the setting time of the vinyl ester binder.

アルミナ粉砕によるMMAのメカノケミカル重合反応に及ぼす溶媒の影響

Mechanochemical polymerization of methyl methacrylate (MMA) monomer was carried out by grinding alumina powder that had high thermal conductivity. A planetary ball mill with high grinding ability was used because alumina has high hardness. The experiments were conducted using different monomer concentrations and different types of solvents. In addition, the effects of grinding conditions on the fineness of alumina particles and the amount of generated polymer were examined. It was found that the amount of polymer could be controlled by the MMA concentration and that the rate of mechanochemical polymerization was highest in aqueous solution. The polymerization occurred in alcohol solvents, but to a limited extent because of inhibition of radical initiation.

Pigment epithelium derived factor (PEDF) prevents methyl methacrylate monomer-induced cytotoxicity in H9c2 cells

Acrylic bone cements are currently the most frequently and extensively used materials in orthopedic implant treatment. However, adverse effects have been described of acrylic bone cement on the cardiovascular system. In the present study, we examined the cytotoxicity of bone cement ingredient methyl methacrylate (MMA) to cardiomyocytes and the potential detoxifying effect of pigment epithelium-derived factor (PEDF) in H9c2 cells. We found that high concentration of MMA (>120 mmol/L) led to necrotic cell death in H9c2 cells. However, MMA at low concentrations (30-90 mmol/L) caused apoptosis. Pretreatment of PEDF prevented MMA-induced cytotoxicity. In addition, PEDF enhanced total superoxide dismutase activities, and decreased MMA-induced production of malonaldehyde. Furthermore, MMA-induced downregulation of Akt activity was suppressed by PEDF. PEDF also increased the levels of peroxisome proliferator activated receptor gamma (PPAR g) and lysophosphatidic acids (LPA) through PEDF receptor. These results indicated that PEDF inhibited MMA-induced cytotoxicity through attenuating oxidative stress, activating the phosphatidylinositol 3-kinase (PI3K)/Akt pathway and/or PEDF receptor-LPA-PPAR g pathways in H9c2 cells. PEDF may be explored as a candidate therapeutic agent for alleviating bone cement implantation syndrome during orthopedic surgery.

Development of an Elongational‐Flow Microprocess for the Production of Size‐Controlled Nanoemulsions: Batch Operation

Performances of a newly developed microprocess in producing size‐controlled nanoemulsions in the lower nanometer range are assessed. The microprocess comprises an elongational‐flow micromixer with a bore size of either 150, 250, or 500 μm. By inducing a reciprocating flow through the restriction of the micromixer, methyl methacrylate (MMA)‐based nanoemulsions with controlled sizes in the range 50–300 nm are successfully prepared at low pressures (ca. 2.5 bars) in laminar to intermediate hydrodynamic flow regimes. Effect of process parameters (flow rate through the restriction, number of cycles), micromixer parameters (angle, bore size), and finally composition parameters (weight content of MMA and surfactant, dispersed to continuous phase viscosity ratio) on nanodroplet size and size distribution is thoroughly studied. A unique empirical correlation is extracted from the experimental results and is found to fairly well model the variations of the nanodroplet size with aforementioned parameters. image

Forward extrusion of bulk wood containing polymethylmethacrylate: Effect of polymer content and die angle on the flow characteristics

In this study, the forward extrusion of non-pulverized bulk wood containing polymethylmethacrylate (PMMA) was investigated to obtain new fundamental insights regarding the plastic forming of bulk wood. In particular, we studied the effect of the polymer content and die angle (20°–120°) on the extrusion forces and flow of various types of bulk wood during extrusion. Plastic-impregnated wood (composite) specimens with high (49%) and low (27%) polymer content were obtained by impregnating wood with solutions containing different concentrations of methyl methacrylate (MMA). Before the impregnation, the wood was hydrophobized by acetylation to allow the MMA to penetrate into the cell walls. The load during extrusion for the 49% composite was lower than that for the 27% composite at all die angles. For both composites, the extrusion force increased with decreasing die angle for small die angles (20°–40°) because of the increase in friction force at the die wall surface. For the 27% composite, the extrusion force increased with increasing die angle beyond 40° due to the formation of dead zones and shear zones in the wood. Therefore, the optimal die angle that minimized the extrusion force was near 40°. In contrast, the extrusion force for the 49% composite exhibited no significant difference for die angles larger than 40° in spite of the formation of dead zones and shear zones. Chevron cracking appeared in the 49% composites, whereas no cracks and voids were formed in the 27% composites.

Synthesis and fluorescence properties of a waterborne polyurethane–acrylic hybrid polymeric dye

A waterborne polyurethane–acrylic hybrid polymeric dye was prepared depending on soap-free emulsion polymerization method. The resulting polymeric dye composed of methyl methacrylate (MMA) monomer which was polymerized into polymethyl methacrylate (PMMA) as cores and waterborne polyurethane-based dye was synthesized by anchoring dye monomers (6-amino-2-cyclohexyl-benz[de]isoquinone-1,3-dione) to polyurethane chains as shells. The average particle sizes of the hybrid polymeric dye emulsions were found to be increased with the increase in MMA contents for MMA monomers. Compared with dye monomers, the absorption intensities and fluorescence intensities of the hybrid polymeric dye were enhanced with the increase of particle sizes. This study revealed that enhanced fluorescence intensity of the hybrid polymeric dye was mainly attributed to the hindered formation of exciplexes among dye monomers and an augmented light absorption area. It was found that the fluorescence intensity of the hybrid polymeric dye was increased with increasing temperature and the trend first increased and then decreased with increase in concentration. Furthermore, the fluorescence of the hybrid polymeric dye emulsions was found to be very stable and not sensitive to the fluorescence quencher.

The determination of n-pentane solubility and diffusivity in styrene–methyl methacrylate copolymers via designed apparatus

In this work, styrene–methyl methacrylate copolymer particles were synthesized by suspension polymerization process with different copolymer compositions. A system was designed to measure the solubility and diffusivity of n-pentane in the synthesized copolymers. The designed system consisted of the self-sealing cell equipped to the pressure and temperature controllers. The synthesized copolymer particles were impregnated by n-pentane and their expansion were recorded visually. Furthermore, the solubility and diffusivity of n-pentane in copolymer particles were measured by the same apparatus. The effect of different foaming conditions on the solubility and diffusivity of n-pentane in the samples were examined. It was concluded that the sorption pressure and temperature have contradictory effects on the solubility and diffusivity of n-pentane in styrene–methyl methacrylate copolymers at different sorption pressures. It was concluded that with methyl methacrylate content increment in copolymer, the diffusivity and dissolved n-pentane content in copolymer were reduced.

Setting Shrinkage Characteristics of Methyl Methacrylate-Modified Vinyl Ester Polymer Concrete

This study evaluated the setting shrinkage characteristics of Methyl Methacrylate (MMA)-modified vinyl ester polymer concrete with different curing ages, MMA contents and curing temperatures. Results have shown that most of the setting shrinkage developed within 24 h after curing initiation. It was also found that an increase in MMA content led to an almost linear decrease in setting shrinkage, indicating that adding an MMA monomer was an effective measure to reduce the setting shrinkage of MMA-modified vinyl ester polymer concrete. A higher curing temperature tended to result in greater setting shrinkage, indicating that low-temperature curing is beneficial for reducing the setting shrinkage. The magnitude of setting shrinkage observed in vinyl ester polymer concrete was much greater than the drying shrinkage typically observed in ordinary Portland cement concrete but was smaller than the setting shrinkage of polymer concrete incorporating other types of binder.