Methyl Methacrylate

Methyl methacrylate is an organic compound with the formula CH2=C(CH3)COOCH3. It is the methyl ester of methacrylic acid (MAA) and is a monomer produced on a large scale for the production of poly(methyl methacrylate) (PMMA). [fusion_builder_container hundred_percent=”yes” overflow=”visible”][fusion_builder_row][fusion_builder_column type=”1_1″ background_position=”left top” background_color=”” border_size=”” border_color=”” border_style=”solid” spacing=”yes” background_image=”” background_repeat=”no-repeat” padding=”” margin_top=”0px” margin_bottom=”0px” class=”” id=”” animation_type=”” animation_speed=”0.3″ animation_direction=”left” hide_on_mobile=”no” center_content=”no” min_height=”none”][1] Methyl methacrylate is a colourless liquid with an acrid fruity odour. It is a flammable liquid and is slightly soluble in water and is soluble in some organic solvents. [2]

 

Uses [3]

 

Methyl methacrylate is used in the manufacture of methacrylate resins and plastics e.g., Plexiglas. The principal uses of methyl methacrylate are: cast sheet and other grades (advertising signs and displays, lighting fixtures, glazing and skylights, building panels and sidings, and plumbing and bathroom fixtures), moulding/extrusion powder, and coatings (latex paints, lacquer, and enamel resins). It is also used in the impregnation of concrete to make it water-repellent, and also has uses in the fields of medicine and dentistry to make prosthetic devices and as a ceramic filler or cement.

 

In the Environment [4]

 

Methyl methacrylate evaporates when exposed to air. It dissolves when mixed with water. Most releases of methyl methacrylate to the environment are to air. Methyl methacrylate can also evaporate from water or soil exposed to air. Once in air, it breaks down to other chemicals. Microorganisms that live in water and in soil can also break down methyl methacrylate. Because it is a liquid that does not bind well to soil, methyl methacrylate that makes its way into the ground can move through the ground and enter groundwater. Plants and animals are not likely to store methyl methacrylate.

 

Sources & Routes of Exposure [3,4]

 

Sources of Exposure

 

Potential for exposure exists for employees of manufacturers of methyl methacrylate and its polymers, as well as doctors, nurses, dentists, and dental technicians. Individuals may also be exposed to methyl methacrylate via consumption of contaminated water. Exposure to methyl methacrylate can occur in the workplace or in the environment following releases to air, water, land, or groundwater. In addition, exposure can occur when people use certain exterior latex house paints, adhesives, inks, and floor polishes.

 

Routes of exposure

 

Exposure to methyl methacrylate is primarily occupational, through dermal and inhalation routes. Methyl methacrylate enters the body when people breathe air or consume water or food contaminated with methyl methacrylate. It can also be absorbed through skin contact. Methyl methacrylate does not remain in the body due to its breakdown and removal.

 

Health Effects [3]

 

Acute Effects

 

Methyl methacrylate is irritating to the skin, eyes, and mucous membranes in humans. An allergic response to dermal exposure may develop. Respiratory symptoms reported in humans include chest tightness, dyspnea, coughing, wheezing, and reduced peak flow. Neurological symptoms, including headache, lethargy, lightheadedness, and sensation of heaviness in arms and legs, have occurred in humans following acute exposure to methyl methacrylate. In mice and rats acutely exposed to high concentrations of methyl methacrylate by inhalation, degenerative olfactory changes in the nasal passages and lung damage have been observed. High doses of methyl methacrylate may cause pulmonary oedema. Acute oral exposure of animals to methyl methacrylate has caused damage to the liver. Tests involving acute exposure of rats, mice, rabbits, and guinea pigs have demonstrated methyl methacrylate to have low to moderate acute toxicity by inhalation or oral exposure.

 

Chronic Effects

 

Respiratory and nasal symptoms and reduced lung function have been reported in chronically exposed workers. In one study, occupational exposure to high doses of methyl methacrylate was associated with cardiovascular disorders in humans. Chronic inhalation of methyl methacrylate by rats has resulted in respiratory effects (e.g., inflammation of the nasal cavity, degeneration/loss of olfactory epithelium in nasal turbinates, and lung congestion). Chronic inhalation of high levels of methyl methacrylate has resulted in degenerative and necrotic changes in the liver, kidney, brain, spleen, and bone marrow, decreased body weight gain, listlessness, prostration, and ocular and nasal discharge in animals. EPA has calculated a Reference Concentration (RfC) for methyl methacrylate of 0.7 milligrams per cubic metre (mg/m3) based on respiratory effects in rats. EPA has calculated a Reference Dose (RfD) of 1.4 milligrams per kilogram body weight per day (mg/kg/d) based on no adverse effects in rats.

 

Reproductive/Developmental Effects

No adequate reproductive or developmental studies in humans are available. Inhalation exposure of rats to maternally toxic levels of methyl methacrylate resulted in foetal abnormalities (haematomas and skeletal anomalies) and decreased foetal weight and crown-rump length.

 

Cancer Risk

 

From a retrospective epidemiology study, a causal relationship between occupational exposure and increased incidences of colon and rectal cancers has been suggested; however, the causal relationship could not be established when relative accumulated total exposures and latency were considered. No carcinogenic effects were observed in several inhalation and oral animal studies. EPA considers methyl methacrylate not likely to be carcinogenic to humans.

 

Safety [5]

 

First Aid Measures

 

  • Eye Contact: Check for and remove any contact lenses. Immediately flush eyes with running water for at least 15 minutes, keeping eyelids open. Cold water may be used. Do not use an eye ointment. Seek medical attention.
  • Skin Contact: After contact with skin, wash immediately with plenty of water. Gently and thoroughly wash the contaminated skin with running water and non-abrasive soap. Be particularly careful to clean folds, crevices, creases and groin. Cold water may be used. Cover the irritated skin with an emollient. If irritation persists, seek medical attention. Wash contaminated clothing before reusing.
  • Serious Skin Contact: Wash with a disinfectant soap and cover the contaminated skin with an anti-bacterial cream. Seek medical attention.
  • Inhalation: Allow the victim to rest in a well ventilated area. Seek immediate medical attention.
  • Serious Inhalation: Evacuate the victim to a safe area as soon as possible. Loosen tight clothing such as a collar, tie, belt or waistband. If breathing is difficult, administer oxygen. If the victim is not breathing, perform mouth-to-mouth resuscitation. Seek medical attention.
  • Ingestion: Do not induce vomiting. Loosen tight clothing such as a collar, tie, belt or waistband. If the victim is not breathing, perform mouth-to-mouth resuscitation. Seek immediate medical attention.

 

Fire & Explosion Data

 

  • Methyl methacrylate is flammable in presence of open flames and sparks.
  • It is explosive in presence of heat.
  • To extinguish small fires use dry chemical powder. For large fires use alcohol foam, water spray or fog.

 

Engineering Controls & Personal Protection

 

Engineering Controls

 

Provide exhaust ventilation or other engineering controls to keep the airborne concentrations of vapours below their respective threshold limit value. Ensure that eyewash stations and safety showers are proximal to the workstation location.

 

Personal Protective Equipment

 

The following personal protective equipment is recommended when handling methyl methacrylate:

  • Splash goggles;
  • Lab coat;
  • Vapour respirator (be sure to use an approved/certified respirator or equivalent);
  • Gloves

 

Personal Protection in Case of a Large Spill:

  • Splash goggles;
  • Full suit;
  • Vapour respirator;
  • Boots;
  • Gloves
  • A self contained breathing apparatus should be used to avoid inhalation of the product.
  • Note: Suggested protective clothing might not be sufficient; consult a specialist BEFORE handling this product.

 

Regulation [2,3]

 

United States

 

  • American Conference of Governmental and Industrial Hygienists’ threshold limit value is 410mg/m3.
  • National Institute of Occupational Safety and Health’s recommended exposure limit is 410mg/m3.
  • NIOSH’s immediately dangerous to life or health concentration is 4100mg/m3
  • Occupational Safety and Health Administration’s permissible exposure limit expressed as a time-weighted average is 410mg/m3.

 

Australia

 

  • Safe Work Australia has set a limit for methyl methacrylate, of 100 parts per million over an eight hour workshift.

 

References

 

  1. http://en.wikipedia.org/wiki/Methyl_methacrylate
  2. http://www.npi.gov.au/substances/methyl-methacrylate/index.html
  3. http://www.epa.gov/ttn/atw/hlthef/methylme.html
  4. http://www.epa.gov/chemfact/methy-fs.txt
  5. http://www.sciencelab.com/msds.php?msdsId=9927360

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