Considering that PVC is one of the most widely used polymers, it is necessary to pay attention to the Environmental effects of PVC of products of this material on health and the environment. The consumption of the products of this polymer, which has wide applications in fields such as construction and medicine, is growing rapidly. The reason for this is that compared to other traditional materials, these products have lower weight, higher durability and good relative resistance against corrosion and moisture. They have corruption.
Concentration of VCM in the air near the PVC factory
The release of VCM into the atmosphere has decreased by more than 99% since 1976. According to the American environmental standard, in 1976, the amount of VCM and ADC vapors in the atmosphere, at a distance of about five miles from the manufacturing plants, should be less than 1 ppb.
The permissible amount of VCM and ADC vapors in the work environment
In the 1970s, the relationship between excessive exposure of workers to VCM vapors and a type of liver cancer, called angiosarcoma, was found. Then in 1997, the American Center for Disease Control re-examined its reports from the seventies and, considering the use of closed reactor technology in new production units, announced that the amount of workers’ contact with VCM vapors in this The unit has almost reached zero and therefore there is no danger to the workers’ health.
Dioxins
Harmful gases
Polychlorinated dibenzo-para-dioxins and polychlorinated dibenzofurans are the main polluting compounds that are produced from the burning of chlorinated organic compounds. These materials have unique toxicity and are produced when burning, recycling and producing PVC products. For this reason, many laws have been formulated regarding the release of these substances into the environment. Of course, PVC industries are not one of the most important production sources of dioxins, but nevertheless, they are always required to comply with the rules of release of these substances by environmental organizations. In 1995, the United States Environmental Protection Agency presented a report on the release of these compounds, in which the release amounts of these compounds were predicted and met during the years 2002 and 2004.
Mixing processes
As stated in the previous chapters, the three main types of PVC resins are suspension resin, emulsion resin, and mass resin. Suspension PVC resin is the most widely used type, the reason for this is the high cost and environmental problems of bulk PVC resin. It is worth mentioning that suspension and bulk PVC resins can be easily replaced with each other in many applications due to having similar properties. If the emulsion PVC resin has smaller particles and more stabilizers than the other two types.
One of the most important uses of emulsion PVC resin is in liquid polymer mixtures and plastisols. Of course, sometimes this type of resin is used as an additive for other PVC mixtures. Due to the fact that PVC resins have low flammability, they can be easily stored in warehouses and silos equipped with conventional firefighting systems, such as water sprinklers, dry powder or foam. In case of fire, by removing the source of fire from the PVC resin, this polymer will extinguish itself and slowly. For each type of PVC resin, you should refer to its certificate prepared by the resin manufacturers in order to be informed of the existence of various additives that may require special considerations. The most common equipment used during fire are PVC resin, oxygen capsule and mask. Because by burning this polymer, dangerous gases such as HCL are also produced.
Environmental effects of PVC
Environmental effects of PVC When processing and shaping PVC resin, due to the production of dangerous gases such as HCL, a mask must be used. Meanwhile, in places where there is PVC dust fog in the environment, dust masks and goggles should be used. Because PVC dust may come into contact with the eyes, causing irritation and burning sensation. In this case, you should quickly wash the eye with water and see a doctor. Of course, there has been no report of the adverse effect of PVC on the skin.
In this section, a summary of the safety points related to chlorine PVC is given. The method of transporting and storing chlorine PVC is similar to PVC. Of course, the presence of additional chlorine in chlorinated PVC improves the anti-flammability properties of this polymer.
Many studies have been done regarding the effect of HCL on health. In an experiment, it was found that 5 minutes of contact with 30,000 ppm of HCL and 15 minutes of contact with 5,000 ppm of HCL did not have any adverse effects on the health of monkeys. Therefore, the toxicity of gases resulting from burning PVC and chlorinated PVC is considered similar to burning other common materials such as wood.
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