$PE:-(CH_2-CH_2)-_n$
$n=\frac{16800}{28}=600$
$PVC:-[CH_2-CH(Cl) ]-_n$
$n=\frac{25000}{62,5}=400$
$\text{Cao su tự nhiên}: -[CH_2-C(CH_3)=CH-CH_2]-_n$
$n=\frac{34000}{68}=500$
$\text{Cao su buna}: -(CH_2-CH=CH-CH_2)-_n$
$n=\frac{32400}{54}=600$
$\text{ Tơ olon}:-[CH_2-CH(CN)]-_n$
$n=\frac{42400}{53}=800$