Multiple choice

Arrange the following polymers in increasing order of their glass transition temperature (Tg) -

  1. Polypropylene
  2. Polystyrene
  3. Poly(α-methylstyrene)
  4. Poly(o-methylstyrene)
  5. Poly(m-methylstyrene)

  1. 1 < 2 < 3 < 4 < 5

  2. 1 < 3 < 2 < 5 < 4

  3. 1 < 5 < 2 < 4 < 3

  4. 2 < 1 < 4 < 5 < 3

  5. 2 < 5 < 1 < 4 < 3
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Bulky side groups that are stiff and close to the backbone cause steric hindrance, decrease chain mobility and hence,  raise glass transition temperature (Tg).Polypropylene (Tg = –10 °C) < Poly(m-methylstyrene) (Tg = 72 °C) < Polystyrene (Tg = 100 °C) < Poly(o-methylstyrene) (Tg = 119 °C) < Poly(α-methylstyrene) (Tg = 192 °C). Hence, the correct answer is 1 < 5 < 2 < 4 < 3.

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