Polydispersity Index

Q. Polydispersity index for polymers represents?

1. A measure of the number of molecular chains in a polymer.
2. A measure of the variance in the molecular chain lengths and weights in a synthetic polymer.
3. It is a quantity to determine the average molecular mass of a natural polymer.
4. It gives us the number of molecules of the same size in a polymer.

Q. The number average molecular weight (${\stackrel{-}{M}}_n$) of Teflon polymer is $120,000g/mol$. Find the Degree of polymerization.

Q. The $P$(poly) Dispersity Index $\left(PDI\right)$ of a polymer is: $(\overline{M_w}=$ weight average molecular mass and $\overline{M_n}=$ number average molecular mass).

1. the sum of $\overline{M_n}$ and $\overline{M_w}$
2. the ratio between $\overline{M_w}$ and $\overline{M_n}$
3. the product of $\overline{M_n}$ and $\overline{M_w}$
4. the difference between $\overline{M_w}$ and $\overline{M_n}$

Q. The mass average molecular weight and number average molecular weight of a polymer are respectively 40000 and 30000. The poly-dispersity index of the polymer will be

1. <1
2. >1
3. 1
4. 0