Harmful Algal Blooms are large amounts of algae that overgrow in lakes and oceans, releasing deadly toxins into the ecosystem. To reduce amounts of red algae in oceans, my purpose is to produce a biodegradable and flexible polymer by combining Carrageenan, extracted from Chondrus crispus, with Grapefruit Seed Extract as my plasticizer. Carragee is an extremely thick gel extract produced from Rhodymenia but more specifically, Chondrus crispus seaweed. A plasticizer is a substance that can be combined with another material to increase the plasticity, strength, and elasticity of the material. I used Grapefruit Seed Extract (GSE) as my plasticizer because it can increase strength of a material and it is eco-friendly.

To produce my polymer, I purchased powdered Carrageenan and converted it into a gel by adding water. Once I obtained a smooth Carrageenan gel, I added around 20-30 drops of Grapefruit Seed Extract. Then, I poured the mixture onto a teflon pan to cast and dry. I produced a total of nine polymers from powdered Carrageenan, all varying in amounts of Grapefruit Seed Extract. To test the strength of my polymers, I used an instron Tensile Tester and a Gram Gauge tester to test the flexibility of my polymer. I also tested the strength of five regular plastic bags to compare to my polymers produced with powdered Carrageenan. After | perfected my polymer procedure in Phase 1, I did a second phase of my experiment where I extracted my own Carrageenan from dried Chondrus crispus, and used my homemade Carrageenan to produce a polymer from my original procedure. Furthermore, I soaked two samples from the same polymer in distilled water to test the biodegradability of my polymers.

I discovered that there was an increase in the maximum force that my polymers could bear while the amount of Grapefruit Seed Extract added increased. The more GSE added, the more pounds my polymers could hold. I also discovered that regular plastic bags had a larger tensile strength than my polymers, but I polymers could bear more weight that the majority of other plastic bags, but not extend as much. I also discovered that my polymers made from Carrageenan from scratch were quite sticky and more elastic than plastic bags and polymers produced from powdered Carrageenan. Next, through my biodegradability test, I observed that my first sample (which was thinner) dissolved in three days, but my second polymer (thicker) is still in the process of dissolving. My polymer is extremely biodegradable when thin, but durable when thicker. I also discovered that my polymer with more drops of GSE required less force to bend the polymer and I can conclude that more drops of Grapefruit Seed Extract can make my polymer more flexible.

To conclude, my polymer is extremely biodegradable and healthier for the environment than many other plastics. Furthermore, my polymer can bear more strength than plastic bags (up to 11 pounds). Through my experiment, I successfully produced a biodegradable, flexible, and strong polymer from Rhodymenia.