Methyl Methacrylate Vapor Research Articles

The effect of Eucalyptol on SOD and IL-10 expression in mice exposed to Methyl methacrylate vapor

Methyl methacrylate (MMA) is still widely used in medical, dental and industry. Inhalation is the important MMA occupational exposure route. Previous studies have shown that MMA may cause a wide range of adverse health effects such as hypersensitivity pneumonitis and increase the risk of asthma, nasal symptoms and phlegm. Eucalyptol, an active ingredient containing antioxidants has been shown to be able to inhibit the production of ROS and increase IL-10 anti-inflammatory cytokines. This study was done to determine the effect of eucalyptol on superoxide dismutase (SOD) and interleukin (IL)-10 expression in the airways of mice exposed to methyl methacrylate (MMA). This true experimental laboratory study involved the use of 30 mice as research subjects which were divided into five groups: a normal control group (K0), a positive control group (K1) and three treatment groups that were administered with 5mg, 10mg and 15mg doses of eucalyptol (P1, P2 and P3). The subjects were placed in a glass cage containing 150ppm MMA vapor nebulized with eucalyptol vapor for 120 minutes. The subjects were subsequently terminated and their lung tissue removed. Observation of the expression of SOD and IL-10 was carried out by immunohistochemical examination. MMA exposure significantly increased SOD (p <0.05). Administration of eucalyptol 5mg, 10mg and 15mg can reduce SOD, so that it was not different from K0 group. Only at a dose of 10mg and 15mg, eucalyptol was able to increase the expression of IL-10. It is concluded that Eucalyptol can reduce the expression of SOD and increase IL-10 expression in airway of mice exposed to MMA vapor.

Site‐selective atmospheric pressure plasma‐enhanced chemical vapor deposition process for micrometric deposition of plasma‐polymerized methyl methacrylate

AbstractAn atmospheric pressure plasma chemical vapor deposition process designed for the site‐selective deposition of organic functional materials with a sub‐millimetric lateral resolution is presented in this study. Injecting methyl methacrylate vapor in plasma post‐discharge allowed to synthesize plasma‐polymerized methyl methacrylate (ppMMA) coatings on metallic, dielectric, and polymer substrates at close to room temperature (40°C). A circular dot, as small as 400 µm in diameter, of ppMMA is deposited and characterized by Fourier‐transform infrared spectroscopy, X‐ray photoelectron spectroscopy, and high‐resolution mass spectrometry. Oligomeric species of poly‐MMA up to n = 18 have been detected, evidencing the particularly “soft” polymerization offered by the presented process.

Effect of acute methyl methacrylate vapor inhalation on smokers' and non-smokers' respiratory function in a sample of male dentistry students.

Methyl methacrylate (MMA) is one of the widely used organic monomers in dentistry. It may cause multiple adverse reactions, ranging from allergic reaction to systemic toxicity. Dentistry students are exposed to MMA in an acute manner; however, the concentration of its vapor cannot be estimated well. The aim of this study was to evaluate the effect of acute MMA vapor inhalation on the pulmonary function of dental students, both smokers and non-smokers. Thirty-eight male dental students were divided into 2 groups (group 1 - smokers and group 2 - non-smokers). The lung function parameters of the students were tested with a spirometer during their ordinary training work in a prosthodontics laboratory, before contact with MMA and immediately after it. The lung function test was performed using a standard protocol. The students were asked not to use any perfume or aromatic overlaps for a period of 24 h before starting the tests. The researchers noted a statistically significant decrease (p ≤ 0.05) in forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), peak expiratory flow (PEF), forced expiratory flow at 25-75% of the pulmonary volume (FEF25-75), and forced expiratory flow at 25% (FEF25) and 50% (FEF50) of the pulmonary volume in smokers and non-smokers by comparing the preand post-work tests. Acute inhalation of MMA vapor induced a moderate restriction of pulmonary function in dental students, both smokers and non-smokers, during their routine prosthodontics laboratory training work. No differences in the results of the pulmonary function tests between smokers and non-smokers were observed.

The Composition of Emissions from Sawing Corian®, a Solid Surface Composite Material.

We conducted detailed analyses of the composition of emissions from sawing Corian®, a solid surface composite material, in a laboratory testing system. The analyses included the aluminum content of size-selective dust samples, semivolatile organic compounds (SVOCs) in respirable dust samples, and volatile organic compounds (VOCs). The normalized respirable dust generation rate found using a Micro-Orifice Uniform Deposit Impactor was 5.9 milligrams per gram (mg g-1) suggesting that 0.59% of the mass removed from sawing Corian® becomes respirable dust. The alumina trihydrate content of the dust was consistently above 85% in most parts of the respirable size range, verifying an earlier finding that it is the dominant composition of the airborne particles of all sizes, including ultrafine particles. VOC analyses revealed that methyl methacrylate (MMA) was the most abundant compound, with a generation rate of 6.9 mg g-1 (0.69% of the mass removed from sawing Corian® became MMA vapor). The SVOC analysis only found a small amount of MMA (0.55%) in the bulk dust.

Methyl Methacrylate Levels in Orthopedic Surgery: Comparison of Two Conventional Vacuum Mixing Systems

Poly-methyl methacrylate bone cements contain methyl methacrylate (MMA), which is known for its sensitizing and toxic properties. Therefore, in most European countries and in the USA, guidelines or regulations exist for occupational exposures. The use of vacuum mixing systems can significantly reduce airborne MMA concentrations during bone setting. Our goal was to test two commonly used vacuum mixing systems (Palamix(®) and Optivac(®)) using Palacos(®) R bone cement for their effectiveness at preventing MMA vapor release in a series of standardized trials in a laboratory as well as in an operating theatre. MMA was quantified every second over a period of 3 min using a photoionization detector (MiniRAE(®) 3000) device positioned in the breathing area of the user. Significant differences in MMA mean vapor concentrations over 180 s were observed in the two experimental spaces, with the highest mean concentrations (7.61 and 7.98 ppm for Palamix(®) and Optivac(®), respectively) observed in a laboratory with nine air changes per hour and the lowest average concentrations (1.06 and 1.12 ppm for Palamix(®) and Optivac(®), respectively) in an operating theatre with laminar flow ventilation and 22 air changes per hour. No significant differences in overall MMA concentrations were found between the two vacuum mixing systems in either location. Though, differences were found between both systems during single mixing phases. Thus, typical handling of MMA in orthopedic procedures must be seen as not harmful as concentrations do not reach the short-term exposure limit of 100 ppm. Additionally, laminar airflow seems to have an influence on lowering MMA concentrations in operation theatres.

Assessment of methyl methacrylate genotoxicity by the micronucleus test

The aim of this study was to evaluate the genotoxic potential of methyl methacrylate (MMA) vapor by simulating standard occupational exposure of 8 hours per day and using the micronucleus test. We used 32 adult male Wistar rats divided into three groups: A - 16 rats exposed to MMA for 8 hours a day, B - Eight rats receiving single subcutaneous doses of cyclophosphamide on the first day of the experiment (positive control), C - Eight rats receiving only water and food ad libitum (negative control). Eight rats from group A and all of the rats from groups B and C were sacrificed 24 hours after beginning the experiment (acute exposure in group A). The remaining animals in group A were sacrificed 5 days after the experiment began (repeated exposure assessment in group A, simulating occupational exposure 40 hours/week). Femoral bone marrow was collected from each rat at the time of sacrifice for use in the micronucleus test. Two slides were completed per animal and were stained with Giemsa staining. Two thousand polychromatic erythrocytes were counted per animal. The Kruskal-Wallis test followed by a multiple comparisons test (Dunn test) was used for statistical analysis. The median number of micronuclei was 7.00 in the group exposed to MMA for 1 day, 2.00 in the group exposed to MMA for 5 days, 9.00 in the group exposed to cyclophosphamide (positive control) and 0.756 in the negative control group (p < 0.0001). MMA was genotoxic when measured after 1 day of exposure but was not evidently genotoxic after 5 days.

Inhalation study of polymethyl methacrylate following radiologist exposure during percutaneous vertebroplasty

To assess the atmospheric concentrations of methyl methacrylate (MMA) vapors during percutaneous vertebroplasty for the interventional radiologist and the other operating room staff. During percutaneous vertebroplasty, a polymethyl methacrylate (PMMA) mixture (about 20 mL) was prepared with a mixing system in a normally ventilated room. Atmospheric concentrations of MMA vapors were measured by a gas absorbent badge for individual exposure (GABIE) passive sampler attached to the surgical gowns of the interventional radiologist and the other operating room staff over a period of 460 min. Active sampling was performed over 15 min with an individual pump placed near the breathing zone of the radiologist. MMA vapor concentrations were then measured using gas chromatography and activated charcoal tubes. Mean MMA vapor concentrations measured by the GABIEs over the period of 460 min were 0.51 parts per million (ppm) for the radiologist and 0.22 ppm for the other operating room staff. The emission peaks measured by using charcoal tubes over 15 min were 3.7 ppm. MMA vapor concentrations during percutaneous vertebroplasty were well below the recommended maximum exposure of 100 ppm over the course of an 8-h workday.

Electron-induced interaction of selected hydrocarbons withTiO2 surfaces: the relevance to extreme ultraviolet lithography

The aim of this work is to characterize desorption inducedby electronic transition processes that affect the reflectivity ofTiO2-capped multilayer mirrors used in extreme ultraviolet (EUV) lithography. A low energyelectron beam is employed to mimic excitations initiated by EUV radiation. Temperatureprogrammed desorption, x-ray photoelectron spectroscopy, and low energy ionscattering are used to analyze the surface reactions. Carbon film growth on theTiO2(011) crystalline surface is measured during 10–100 eV electron bombardment inbenzene or methyl methacrylate vapor over a wide range of pressures andtemperatures near 300 K. Low energy secondary electrons excited by EUVphotons contribute substantially to the carbon accumulation on cleanTiO2 cap layers. Forbenzene on clean TiO2, secondary electron effects dominate in the initial stages of carbon accumulation, whereas for C-coveredTiO2, direct excitations appear to dominate. We report on the adsorption energy, thesteady-state coverage of the molecules on the surface and the cross sections forelectron-stimulated dissociation: all key parameters for understanding and modeling theprocesses relating to the EUV lithography mirrors.

DIET processes on ruthenium surfaces related to extreme ultraviolet lithography (EUVL)

The aim of this work is to provide insights into desorption induced by electronic transitions (DIET) processes that affect the reflectivity of ruthenium-capped Mo/Si multilayer mirrors working under EUVL (extreme ultraviolet lithography) operating conditions [high vacuum, and 13.5 nm (92 eV) photons]. Critical issues are associated with possible oxidation of the 2 nm thick Ru capping layer due to the inevitable background pressure of H 2O, and carbon build up due to background hydrocarbons. In the present work, we discuss aspects of the radiation-induced surface chemistry of Ru irradiated by 100 eV electrons and 92 eV photons. The cross section for electron-stimulated desorption of oxygen from O-covered Ru is ∼6 × 10 −19 cm 2. Carbon accumulation several nm thick occurs on the Ru surface during electron irradiation in methyl methacrylate (MMA) vapor, a model background impurity hydrocarbon. Radiation damage by low-energy secondary electrons is believed to dominate over direct photoexcitation of adsorbates under EUVL conditions. The secondary electron yield from Ru varies strongly with photon energy, and is ∼0.02 electrons/photon at 92 eV.

Assessment of methyl methacrylate vapor toxicity on the rat tracheal epithelium

Methyl methacrylate (MMA) is a monomer that is polymerized into resin by light and heat, producing a clear, resistant, durable and relatively inert plastic material. Because of these characteristics, MMA is largely used in Medicine as bone cement and in Dentistry, in dental braces and prostheses, thus generating continuous interest in its toxicity. Experimental and clinical studies have documented that monomers may cause a wide range of adverse health effects. The most important occupational exposure route of MMA is by inhalation. This study aims to evaluate the toxicity of MMA to the tracheal epithelium, according to the time of exposure. For this purpose, two experimental groups of rats were exposed to MMA by inhalation under poor ventilation: one group (n = 36) was exposed permanently, and the other (n = 36) was exposed during 8 hours per day, without water and food supply during the exposure period. A control group (n = 8) received normal air supply. Twelve animals of each study group were sacrificed after 5, 8 and 10 days of exposure together with two or four control animals. Twenty-nine (80.5%) of the rats continuously exposed to MMA developed inflammation on the tracheal epithelium, as well as 58.33% (n = 21) of those exposed 8 h/day and 87.5% (n = 7) of the control rats. No association was observed between the inflammatory process and MMA exposure; no significant alterations in the tracheal epithelium thickness were observed. Further studies on longer exposure times and analysis of other parameters will have to be conducted to exclude the possibility of tracheal damage by vapors of MMA.

Use of a pulsed electron beam for air cleaning from methyl methacrylate vapor

The results of experiments on methyl methacrylate (MMA) vapor decomposition in nitrogen-oxygen mixtures under the action of a pulsed electron beam are reported. It is established that there are two competitive mechanisms of MMA removal, with and without participation of active oxygen species.

Evaluation of exposure to methyl methacrylate among dental laboratory technicians.

Following the diagnosis of two cases of occupational asthma among dental technicians, an industrial hygiene survey was conducted in two dental laboratories to determine time-weighted average and peak concentrations of methyl methacrylate vapor and time-weighted average concentration of acrylic dust. The time-weighted average concentrations of methyl methacrylate vapor were 0.7 ppm and 1.6 ppm and average peak concentrations were 9.3 ppm and 9.7 ppm for the first and second laboratory, respectively. The use of a local exhaust ventilation system was significant in reducing the peak concentration of methyl methacrylate vapor in the breathing zone of dental technicians. However, the local exhaust ventilation was not efficient in reducing the concentration of airborne acrylic dusts. Occupational exposure of dental technicians to dental materials, in particular to methyl methacrylate, requires further investigation. Local exhaust ventilation systems can reduce the concentration of methyl methacrylate in the dental laboratories to a significant extent if installed and used properly.

Photoinitiated grafting of methyl methacrylate on highly oriented polyethylene: Effect of draw ratio on grafting

Modification of highly oriented polyethylene was performed using a photoinitiated grafting technique. The samples were first coated with photoinitiator and then exposed to methyl methacrylate vapor under UV light (λ > 290 nm) at 60°C. The extent of grafting was studied as a function of draw ratio. It was found that the extent of grafting decreased significantly as the draw ratio was increased. Control samples of undrawn samples with different thermal histories suggested that there was another factor in addition to crystallinity that influences the extent of grafting. It is proposed that amorphous orientation or taut-tie molecules reduce the photoinitiation process. Gravimetric and attenuated total reflectance-IR measurements indicated that the grafting reaction can occur below the sample surface (or internal grafting) and that the proportion of surface grafting increases with increasing draw ratio. © 1998 John Wiley & Sons, Inc. J. Appl. Polym. Sci. 70: 465–470, 1998

Photoinitiated grafting of methyl methacrylate on highly oriented polyethylene: Effect of draw ratio on grafting

Modification of highly oriented polyethylene was performed using a photoinitiated grafting technique. The samples were first coated with photoinitiator and then exposed to methyl methacrylate vapor under UV light (λ > 290 nm) at 60°C. The extent of grafting was studied as a function of draw ratio. It was found that the extent of grafting decreased significantly as the draw ratio was increased. Control samples of undrawn samples with different thermal histories suggested that there was another factor in addition to crystallinity that influences the extent of grafting. It is proposed that amorphous orientation or taut-tie molecules reduce the photoinitiation process. Gravimetric and attenuated total reflectance-IR measurements indicated that the grafting reaction can occur below the sample surface (or internal grafting) and that the proportion of surface grafting increases with increasing draw ratio. © 1998 John Wiley & Sons, Inc. J. Appl. Polym. Sci. 70: 465–470, 1998

Deposition conditions influence the postdeposition oxidation of methyl methacrylate plasma polymer films

Plasma polymer films were deposited from methyl methacrylate (MMA) vapor under various plasma conditions and XPS and FTIR used to study the changes to the compositions of the films as they were stored in air for longer than 1 year. The plasma power input per monomer mass unit (W/FM) markedly affected the composition of the freshly deposited MMA plasma polymers. A low value of W/FM led to a high degree of retention of the original monomer structure, whereas a high value of W/FM resulted in substantial monomer fragmentation and the formation of a partially unsaturated material considerably different to conventional PMMA. As the MMA plasma coatings were stored in ambient air after fabrication, all showed spontaneous oxidative changes to their composition, but the extents and reaction products differed substantially. Deposition at low W/FM led to moderate oxidative changes, whereas high power led to a pronounced increase in the oxygen content over time and resulted in a wide range of carbon–oxygen functionalities in the aged material. As the initial compositions/plasma deposition conditions thus influenced the oxidative postdeposition reactions, MMA plasma polymers deposited under different conditions not only varied in their initial composition but then became even more diverse as they aged. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 985–1000, 1998

A computational study of flame radiation in PMMA diffusion flames including fuel vapor participation

A numerical model of a polymethylmethacrylate (PMMA) diffusion flame in a stagnation-point geometry is solved with flame radiation. A narrow-band radiation model is used with carbon dioxide, water vapor (combustion products), and methylmethacrylate (fuel) vapor as the gaseous participating species. A detailed account of the emission and absorption from these species as well as the net radiative heat flux are given as a function of the flame stretch rate. Flame radiation is more important at low stretch rates. The contributions from carbon dioxide and water vapor to emission increase with decreasing stretch rate, because the thicker flames at low stretch rate produce a longer optical path. Because of the differnet concentrations at the fuel surface, the optical path length of the MMA vapor stays approximately the same with varying stretch rate, therefore contributing to a smaller fraction of the total emission at low stretch as compared with that at high stretch. Radiative absorption by these gaseous species is substantial and dominated by self-absorption. Consequently, the radiative contributin by MMA vapor is mainly as an emitter.

Biological monitoring and possible health effects in workers occupationally exposed to methyl methacrylate.

Monitoring by means of blood and urine analysis for methanol was successfully applied in 32 male workers who were exposed to methyl methacrylate (MMA) monomer at 6 ppm as a geometric mean and at 112 ppm as the maximum. Measurement of time-weighted average (TWA) intensity of the vapor exposure was successfully conducted with a diffusive sampler with activated carbon cloth as an adsorbent. Methanol concentrations in whole blood, serum, and urine samples were measured by headspace gas chromatography. The methanol concentrations in the three biological samples collected at the end of 8-h workshifts related linearly with the TWA MMA vapor concentrations, with correlation coefficients of 0.8-0.9. Quantitative evaluation of MMA in vapor and of methanol in urine suggests that only 1.5% of MMA inhaled will be excreted in urine as methanol. There were no significant clinical symptoms or abnormal hematological or serum biochemical findings at this exposure level, except that some workers complained throat irritation and frequent cough and sputa. The results indicate that biological monitoring by analysis for methanol is sensitive enough to detect MMA exposure at levels at which no serious health effects are to be expected.

Infrared Radiation Properties of Methyl Methacrylate Vapor

Abstract The present work reports measurements of the spectral absorptivities of the eight significant infrared bands for methyl methacrylate vapor. The experimental data were taken at low resolution for temperatures between 400 and 680 K and at a total pressure of 1 atm. Analysis of these data by the statistical narrow-band model yields the spectral-mean parameters for each band, while the wideband parameters have been correlated using both the exponential wide-band model and the Tien-Lowder continuous correlation. These correlated parameters allow convenient determination of the total emissivity, the Planck mean absorption coefficient and super-band parameters.

Thermocatalytic oxidation of organic compounds in gaseous discharges

This article examines results obtained in a kinetic study of the oxidation of a model mixture of air with methyl methacrylate vapor, or iron-chromium catalyst at 100-450 C under steady-state conditions. Indicates that the thermocatalytic oxidation of methyl methacrylate vapor in mixture with air at 100-400 C proceeds in the kinetic region with a high degree of oxidation, ensuring that the maximum permissible concentration will not be exceeded. Points out that because of the relatively low oxidation temperature that is required, the treatment of the discharge can be made more economical in terms of energy costs. Notes that at 400-500 C, the process goes forward in the transition region, since external diffusion factors begin to be imposed at temperatures above 400 C. Concludes that the proposed mathematical model offers a means for scientifically based selection of the most economical region for realization of commercial processes in treatment of discharges.

A dual mechanism for intestinal motor effects of methyl methacrylate vapor.

The influence of methyl methacrylate (MMA) vapor on the motor activity of the isolated guinea pig ileum is summarized in this report. MMA vapor was delivered to innervated and denervated strips via the tissue bath air supply at a concentration of 755 +/- 38 ppm. Innervated strips usually showed spontaneous motor activities (sma) which developed shortly after the muscle was mounted. None of the denervated strips exhibited sma. Upon exposure to MMA vapor, there was a rapid and significant decrease in sma and in the contractile responses to electric field stimulation and 0.01 mg acetylcholine administration. Denervated strips demonstrated a similar reduction in response magnitude to electric field and drug stimulation but required a longer time period. The persistence of the MMA-induced inhibitory response of the denervated strips indicates that the inhibitory effect is partly due to a direct action of the agent upon the contractile mechanism of the small intestine.