2024 Author: Howard Calhoun | [email protected]. Last modified: 2023-12-17 10:16
It must be said that modern life would be quite uncomfortable without PVC. What is it for the modern economy? PVC parts today account for up to 15 kilograms of the total mass of an average European car, this material is used in the production of consumer goods (balls, clothing, shoes, furniture, flooring, credit cards, etc.)
Medicine has also been using PVC for more than half a century. What it is can be seen by referring to the numerous disposable equipment. Here you can find pill boxes, splints, surgical gloves, catheters, feeding equipment, blood containers. This material is cheap, successfully replaces rubber and glass, is easily sterilized, and can be used inside the human body.
If we look at the things that we have in our home, many of them are also made of PVC. What could it be? Polyvinyl chloride often forms the basis of electrical insulation, pipes, window profiles, children's toys, packaging materials, mobile phones, plastic bottles, toothpaste tubes and more.
What makes PVC so widespread? What is it from a chemical point of view? According to its formula (-CH2–CHCl-) in the degree of n (degree of polymerization), PVC is a synthetic polymer, which is among the basic ones and is produced from chlorine and oil (57 and 43 percent, respectively). Production processes are less than half dependent on the supply of petroleum products, which makes the production of this material profitable and its price low.
Polyvinyl chloride in its appearance is a white powdery substance with good dielectric properties. It is odorless and tasteless, insoluble in water, resistant to oxidation, burns poorly (due to chlorine in the composition), resistant to acids, mineral oils, alkalis, alcohols. When heated to 100 degrees C, the substance decomposes with the release of hydrogen chloride.
The production of PVC begins with the extraction of chlorine from a solution of sodium chloride (by exposure to an electric discharge). In parallel, ethylene is extracted from the oil (a procedure called "cracking"). The chlorine and ethylene are then combined to form ethylene dichloride. In turn, vinyl chloride (monomer) is created from the dichloride, which is then converted into the required substance during the polymerization process. Various components are added to it, allowing you to getfinished product with certain properties for the respective industry.
PVC manufacturers use three main methods for the polymerization of monomers: block, suspension and emulsion. In this case, suspensions are used to obtain soft, semi-rigid and rigid plastics, and emulsions are used for soft products obtained through plastisols. Depending on the absence or presence of plasticizers in the composition, unplasticized and plasticized material is produced, respectively. The first is less resistant to low temperatures (down to minus 15 degrees C), while the second can withstand cooling down to -60 degrees. Today, the most urgent problem associated with these substances is their collection and disposal.
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