Q. Bisphenol A (BPA), a cause of concern, is a structural/key component in the manufacture of which of the following kinds of plastics?
a) Low-density polyethylene
b) Polycarbonate
c) Polyethylene terephthalate
d) Polyvinyl chloride
Correct Answer: b) Polycarbonate
Question from UPSC Prelims 2021 GS Paper
Explanation :
Bisphenol A (BPA) in Polycarbonate Plastics and Epoxy Resins
Bisphenol A (BPA) is a chemical compound that is primarily used in the production of polycarbonate plastics and epoxy resins. Polycarbonate is a type of plastic known for its strength, durability, and transparency, which makes it suitable for a wide range of applications, including the manufacture of water bottles, sports equipment, medical devices, and the lining of metal food cans.
The reason BPA is a key component in the manufacture of polycarbonate plastics is due to its chemical structure. BPA has two phenol functional groups, which are reactive and can be used to form the backbone of the polycarbonate polymer chain through a process known as polymerization. When BPA molecules react with phosgene (COCl2) or with a carbonyl chloride-based compound in a condensation reaction, they form long chains of polycarbonate polymer.
Alternative Plastics and BPA Usage
The other plastics listed do not typically use BPA in their manufacturing processes:
1. Low-density polyethylene (LDPE) is made from the polymerization of ethylene and does not require BPA for its production.
2. Polyethylene terephthalate (PET) is made from the polymerization of ethylene glycol and terephthalic acid and does not include BPA in its structure.
3. Polyvinyl chloride (PVC) is made from the polymerization of vinyl chloride monomers and also does not contain BPA.
Health Concerns and BPA
BPA has become a cause for concern because it can leach out of plastics and into food and drinks, particularly when the plastic is heated or damaged. Studies have shown that BPA can mimic estrogen and other hormones in the body, potentially leading to health effects such as reproductive disorders, developmental problems, and other illnesses. As a result, many manufacturers and governments have taken steps to reduce the use of BPA in consumer products, especially those intended for food and drink storage.
