Answer:
In styrene, there is a phenyl group which is electron-withdrawing. So the electronic density in the double bonds increases, hence easy to associate as monomers. While in methoxystyrene, there is a carbonyl group which is not electron deficient. so no easy association with monomers.
Step-by-step explanation:
![{ \sf{styrene \: is \: phenylethene \: }} \\ { \sf{its \: polymer \: is \: polystyrene}}](https://img.qammunity.org/2022/formulas/chemistry/college/a9cidx0yjl13b9acp2b1bu5zd7h05vyot5.png)