Question

The mass average molecular mass & number average molecular mass of a polymer are respectively 40,000 and 30,000. The polydispersity index of polymer will be

• A. < 1
• B. > 1
• C. 1
• D. 0 (e) – 1

Answer 1

Answer: (B)

> 1

Answer 2

Average number molecular weight $\overline{M_{n}} = 30,000$

Average mass molecular weight $\overline{M_{w}} = 40,000$

Polydispersity index (PDI) $= \frac{\overline{M_{w}}}{\overline{M_{n}}} = \frac{40,000}{30,000} = 1.33$