The polydispersity index of a polymer containing 10 molecules with molecular mass $1.0 \times 10^4$ and 10…
The polydispersity index of a polymer containing 10 molecules with molecular mass $1.0 \times 10^4$ and 10 molecules with molecular mass $1.0 \times 10^5$ is approximately.
1.67
0.59
1.55
0.83
Solution
The PDI (polydispersity index) $=\frac{M_w}{M_n}=1.67$
$M_w=$ Weight average molecular weight.
$M_n=$ Number average molecular weight.
$
\begin{aligned}
& M_n=\frac{N_1 M_1+N_2 M_2}{N_1+N_2}=55,000 \\
& M_w=\frac{N_1 M_1^2+N_2 M_2^2}{N_1 M_1+N_2 M_2}=91818
\end{aligned}
$