Fiber Formation from Recyclable Polymers

MATERIALS NEEDED:

• Hot plate
• Wood splint or glass rod
• Aluminum dish or foil
• Sample of recyclable plastic (e.g. HDPE, LDPE, or PET)

PROCEDURE:

1. Cut polymer sample (HDPE, LDPE, PET from yogurt lids, plastic wash bottles, etc.) into @ one square centimeter pieces.
2. Place two or three pieces of the sample into an aluminum dish ( this may be fashioned from aluminum foil - try to keep the bottom as flat as possible for good heat transfer).
3. Place the aluminum dish on a hot plate and heat until the sample is molten. If the plastic starts to brown or discolor, decrease the temperature of the hot plate. It is best to remove samples that are discoloring from the heat source to avoid inhaling any decomposition products. If the sample is very discolored, it may be necessary to repeat with a new sample.
4. Insert the tip of a wooden splint or glass rod into the sample and hold it in the molten polymer for a few seconds.
5. Slowly pull the splint away at a constant speed. Try to produce the longest fiber possible. The withdrawal speed may need to be adjusted depending on the polymer being used.
6. Try to "cold-draw" the fibers you have formed by stretching them after they have cooled. How far can they be extended before they break? What happens to the tensile strength as the fibers are stretched? Why might the tensile strength change upon stretching?