6. Pour the measured styrene monomer into each of the labeled glass jars that contain the benzoyl peroxide initiator prepared earlier, and for each beaker, follow the same steps (step 5 to 14).
7. Stir the mixture gently with a glass rod until all the benzoyl peroxide initiators have dissolved.
8. Place the beaker on a hot plate, which is heated to between 80C and 90C (consult your TA for a recommended hotplate setting to reach this temperature), which is the temperature at which benzoyl peroxide starts to form free radicals.
9. Stir the mixture continuously with a glass rod while heating. Take care to avoid sharp edges of the glass rod.
10. After about 10 minutes, bubbles begin to appear as white smoke is released from the solution. This indicates that carbon dioxide gas is being produced. In this case, carbon dioxide gas is the side product of the initiator decomposition.
11. Take note of the changes in viscosity and volume of the polymerization during the reaction.
12. To check if the reaction has come to completion, occasionally pull the glass rod out of the beaker. This would cause the solution mixture to be stretched to form a fiber. Allow the fiber to solidify for a few seconds, and then try to break the solidified fiber with your fingers (make sure you are wearing gloves!!!)
13. If the fiber breaks in a brittle manner, remove the beaker from the hot plate and cast the polymer solution gently, but quickly (solidification of the polymer takes place quickly at room temperature) onto a Petri dish to form a thin layer of film. If the fiber does not break appear brittle, keep stirring and checking.
14. Leave the casted polymer solution in the hood for a few minutes to solidify completely.