My class is doing a poster on different subjects, I chose engineering. I'm glad to hear that you are interested in engineering. Let me try to help with your project. There are many different types of engineers. Polyester is used in many different types of clothing.
Polyester is also the plastic that is used to make plastic pepsi and coke bottles.
My job was to watch over the chemical reactions and make sure that the plastic was coming out of the process as is should be. Sometimes, the plastic would melt at a lower temperature, say around 390 degrees. This would cause serious problems for the people who buy the plastic. My job was to find out what was causing this and correct the problem. Chemical engineers also design or make the equipment in which these chemical reactions take place.