UPSC Prelims 2023 Question:

Consider the following statements

1. Carbon fibres are used in the manufacture of components used in automobiles and aircrafts.
2. Carbon fibres once used cannot be recycled.
   
   

Which of the statements given above is/are correct?

Explanation:

• Carbon fibres can be defined as fibres with a carbon content of 90% or above. They are produced by the thermal conversion of organic fibres with a lower carbon content such as polyacrylonitrile (PAN) containing several thousand filaments with diameters between 5 and 10 μm.
  
  

• Aerospace and automobiles were some of the first industries to adopt carbon fibre. The high modulus of carbon fibre makes it suitable structurally to replace alloys such as aluminium and titanium. The weight savings carbon fibre provides is the primary reason carbon fibre has been adopted by the aerospace industry. So, statement 1 is correct.
  
  

• Currently, the most common recycling process used to recover carbon fibre from composite waste is pyrolysis, where high heat basically burns off the resin. Solvolysis, which uses a solvent to dissolve the resin, has long been claimed to offer superior properties. However, one of the main challenges to date has been obtaining recycled carbon fibre keeping the same mechanical properties as virgin carbon fibre. So, statement 2 is not correct.
  
  

Therefore, option (1) is the correct answer. 

Subject: Science & Technology | Miscellaneous(s&t)