Styrene is called a colorless liquid substance with a specific odor that can harm human health. At the moment, phenylethylene, ethylene and vinyl benzene are widely used in industry mainly in the production of polymers and synthetic rubbers. Of course, at the enterprises during the work with these chemicals it is necessary to strictly observe safety measures.
Styrene production
This substance is obtained in special installations (the productivity of modern ones can reach 150-300 thousand tons of product per year) by the dehydrogenation method. The reaction that synthesizes styrene is classified as endothermic and proceeds at a temperature of about 600-700 degrees. In this case, an iron oxide catalyst with the addition of chromium and potassium is used. The generated waste is recycled in a multi-stage system. If the use or production technologies are violated, styrene may be released into the environment. We will talk about what this usually has consequences a little lower. First, let's figure out what this substance is and what characteristics it differs.
The properties
So what is this styrene chemical? Its properties are diverse. Consider them:
- very poor solubility in water;
- light oxidation;
- fast solubility in organic compounds;
- ability to easily dissolve polymers;
- polymerization with the formation of a solid glassy mass;
- copolymerization with monomers;
- halogen addition.
Styrene, whose smell is very unpleasant, can enter the human body both through the upper respiratory tract and through the digestive tract. In direct contact with liquids containing it, it can be absorbed through the skin.
Styrene and the environment
This substance is quite harmful and can have a negative effect on living organisms. However, styrene in the air decomposes very quickly. Therefore, even with accidental releases, it cannot cause special harm to nature. In the soil and groundwater, styrene breaks down into its constituent substances. The same thing happens in the air under the influence of sunlight.
However, in most states, the maximum allowable amount of this substance released into the environment by enterprises is regulated by law.
Rules for working with styrene
In the manufacture of this substance and its use for the manufacture of polymers, of course, safety precautions should be followed. In most countries of the world, the maximum permissible concentration of styrene is established in the premises in which the employees of the enterprise are located. According to the rules, it is recommended that such workshops be equipped with effective ventilation systems. Of course, employees of these enterprises should try not to inhale vapors of styrene and use personal protective equipment if necessary.
Safety precautions should be observed when mixing styrene with other substances (catalysts, peroxides, additives). Reactions conducted in violation of the manufacturer's instructions can proceed very violently or in an undesirable mode. Transfusion and mixing of styrenes should be carried out in separate rooms, designed specifically for this purpose and well ventilated.
Styrene polymerization occurs even at room temperature. The danger of this process is that it can be accompanied by an explosion. Therefore, this substance should be stored in accordance with the instructions.
The harm of styrene to the human body
Contact with this chemical can cause both acute poisoning reactions and chronic diseases in humans. Almost all organs - kidneys, liver, urinary, blood systems - can be affected by vapors of a substance such as styrene. What is the danger of this carcinogen for humans specifically in each of these cases, in all details, and we will consider below. Styrene is considered a poison of general toxic effect and belongs to hazard class 2 . Inhalation of air containing 10,000 mg / m 3 styrene can result in death for humans.
What are the acute effects of styrene?
When the concentration of vapor in the air in an amount of 420 mg / m 3 , people begin to show signs of irritation of the mucous membranes of the respiratory tract and eyes. When the content is exceeded in 840 mg / m 3 nausea and drowsiness develop. In this case, the victim has various kinds of problems with the vestibular apparatus.
Genetic changes
The mutagenic effect is another nuisance that can lie in wait for a person who has been inhaling styrene for a long time. What is he dangerous in this regard? Judging by the research of scientists, it is quite possible that prolonged inhalation of styrene vapors can lead to an increase in the frequency of chromosomal structural aberrations in blood lymphocytes. Research was conducted on workers employed in the manufacturing process of polystyrene and reinforced plastics.
Effect on Playback Function
Tests conducted on rodents also allow us to conclude that inhaled styrene can have an embryotoxic effect on living organisms . However, a survey of women workers in styrene manufacturing enterprises did not reveal any particular violations.
Carcinogenic effect
Some studies have confirmed that inhaling styrenes increases the risk of developing cancer in the hematopoietic and lymphatic systems of people. However, such an effect can only occur with a very long (for many years) exposure to the vapors of such substances.
Permissible Concentrations
So, we have examined what harm styrene can cause to the human body. The danger of this chemical product, you now understand. Of course, in those rooms where people have been staying for a long time, the vapor concentration of this substance should not exceed the maximum permissible norms. At enterprises for its manufacture or for the production of polymers and rubbers it should be contained in air in an amount of not more than:
- in the working area - 30 g / m 3 ;
- in water bodies - 0.02 g / l.
The average maximum permissible concentration of a substance such as styrene in the air is 10 mg / m 3 , the average daily concentration is 0.002 mg / m 3 , and the one-time concentration is 0.04 mg / m 3 .
Styrene in food packaging
Unfortunately, this substance can enter the human body not only from the environment during emissions from enterprises. Polystyrene and acrylonitrile-butadiene-styrene are actively used in the production of packaging materials for transportation and storage of food products. It would seem that they should be completely harmless. However, as a result of studies, it was found that styrene monomer is able to migrate to food from both soft and hard packs. In some cases, this substance even gives an unpleasant aftertaste to food, milk or juice.
Styrene is used, the smell of which is very unpleasant, and in the production of household items, building materials, etc.
Harm of expanded polystyrene
This material is currently one of the most popular types of insulation. You can buy it at any hardware store, and it is used very widely, including in the construction of residential buildings. Meanwhile, polystyrene foam is very easily degraded, decomposing over the entire period of service by 10-15%. Moreover, the monomer content in the decay products is not less than 65%.
In addition, in the production of this insulation, the polymerization of styrene is very rarely complete and uniform. This means that there is always a residual amount in the granules. Therefore, styrene copolymers in any case emit harmful fumes. The fact that the use of this insulator for warming residential premises from the inside is prohibited by standards, unfortunately, not everyone knows. In this case, it is better to use other materials. However, you should be aware that styrene is also found in polystyrene. Since this substance is considered more harmful than formaldehyde, it is better to warm the houses from the inside using mineral wool.
Vinyl wallpapers
Sometimes apartment owners do not even suspect that styrene is contained in the finishing materials used for repairs. What is the danger of this chemical product to humans, we have already found out. Therefore, about what materials and household items he may be present, to know, of course, worth it. For example, a small amount of this substance is found in vinyl wallpaper. However, unlike polystyrene foam, this type of finishing for walls in residential premises can be used. Under normal conditions, styrene does not stand out from the wallpaper. In order for its fumes to appear in a room covered with vinyl, it is necessary to increase the ambient temperature not less than 50 degrees Celsius.
ABS plastics
Acrylonitrile butadiene styrene is an impact-resistant resin used for the manufacture of automobile parts (manual controls, instrument panels, etc.), housings for household appliances (vacuum cleaners, control panels, coffee makers) and electronics (processors, monitors), furniture, plumbing, medical supplies , suitcases and even children's toys.
In the usual state, all these things do not represent a special danger to human health. Styrene in its pure form begins to stand out from them only under the following conditions:
- Very strong heat.
- In medicine, when used in conjunction with biomaterial.
- When using such plastics for storing food. Particularly unacceptable is the pouring of alcohol from such material into containers. In this case, an effect similar to heating occurs.
At present, the share of styrene polymers, including ABS, from all marketable and structural plastics is 50%.
What to do with styrene poisoning
In the event that a person has been exposed to a high concentration of styrene vapor for a long time and he has signs of poisoning, the following actions should be performed:
- Remove victim from clean room to clean air.
- In case of loss of consciousness or very poor condition, use an oxygen mask.
- If necessary, do artificial respiration.
- Monitor the body temperature of the victim. It should not be raised or lowered.
If styrene gets on the skin or mucous membranes, plenty of washing with water is necessary. The procedure should be at least 15 minutes. After its implementation, the victim must be taken to the hospital. If styrene suddenly enters the body, you must first drink a very large amount of milk or water. After this patient must be hospitalized immediately.
As you can see, getting styrene is a procedure that, if the safety rules are not followed for workers, is far from harmless. Therefore, when performing production tasks at enterprises, one should be as attentive and careful as possible. It is worthwhile to be vigilant when purchasing modern building materials, as well as food products in polystyrene packaging.