Ethenylbenzene (styren) --> Polyethenylbenzen (polystyrene)
......H2C=CH.............-(-H2C-CH)-n......
n×........ _|_.....--->............._|_..........
............/ .。.\....................../. 。.\.........
............\__ /......................\__ /.........
I dunno the catalysts, I don't think you're required to know them. Those horrible little dots are my pitiful attempt at drawing a benzene ring - I'm not good at ASCII
Also,
))<>((
Forever