Pvc

Polymerization: PVC (Polyvinyl Chloride)

PVC or Polyvinyl Chloride (Poly (chloroethene)) is a type of plastic used all over the world for a range of things such as pipes, clothing and electrical cables. PVC is considered a thermoplastic resin meaning it resoftens when heated. It’s molecular formula is (C2H3CL)n and is a white powder that’s resistant to oxidation and degradation. However, it can be harmful to the environment but since it’s economically beneficial to many countries this is often overlooked.

Scientific Communication:

PVC is made by polymerizing chloroethene (figure 3) CH2 = CHCl. To make PVC a process called suspension polymerization is used as shown in figure 1 and figure 2.

In suspension polymerization of PVC Vinyl Chloride (VCM) is pressurized and liquefied. The liquid is then fed into a polymerization reactor (40 – 60 °C) containing water and suspending agents and put through high-speed agitation inside the reactor where small amounts of VCM are obtained. Then, an initiator is fed into the reactor to become a source of free radicals so polymerization reaction can start. The PVC is then suspended in water in slurry form which is then discharged from polymerization reactor, stripped of residual monomer, dehydrated, dried and particles size is controlled by screening to yield PVC in white powder. Unreacted VCM is then recovered through stripping process and can be recycled back into the reactor. This reaction is exothermic so gives off heat and since temperature within reactor must be controlled this heat must be removed so a cooling jacket is used to maintain the temperature.

The polymerization process produces atactic polymers with chlorines orientated randomly along the chain as shown in figure 4.

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...th PVC prevent potentially fatal electrical accidents. In hospitals around the world PVC medical tubing – which does not break or kink – delivers fluids and medicines to the sick. Car components which use very strong PVC can reduce the risk of any injuries being caused in case of an accident. Most PVC products are long lasting – up to and over 60 years. These applications are reliable throughout their service lives and cut down vastly on maintenance or repair. Modern cars, for example, last many years longer simply because PVC protects the underside from water and corrosion.

Conclusion:

In conclusion, although PVC can have detrimental effects on the environment and on ourselves but if we use PVC carefully and responsibly then I think PVC should be used so we can feel the economic benefits and so it can be used in our everyday life. However, it must be controlled.