Read Mark’s Thermoplastic Starch Science fair – Characterization of Composite Plastics: Thermoplastic Starch vs. Added Toothpaste Solution for Film Packaging. He lives in the Philippines and is in the 9th Grade.
Thermoplastic Starch (TPS) is a highly biodegradable plastic but is functionally limited by its mechanical properties. This study aims to use toothpaste as filler for thermoplastic starch to improve these properties and to make a substitute to non-degradable plastics such as Low-density polyethylene (LDPE).
Toothpaste was taken from toothpaste tubes from different persons. Four (4) treatments were made, namely: treatment 1 – 1tsp toothpaste and 20ml water, treatment 2 – 3tsp toothpaste and 25ml water, treatment 3- 5tsp toothpaste and 30ml water, and treatment 4 – 7tsp toothpaste and 35ml water. Each was added to a stable amount of thermoplastic mixture and produced, replicated to 3 replicates.
There were 4 tests done, namely: tensile strength, elongation percentage, water absorption, and biodegradability rate. For the tensile strength, treatment 3 had the highest mean of 9 followed by treatment 2, treatment 1, and treatment 4, this also shows that treatment 3 has the ultimate tensile strength among all the treatments. For the elongation percentage, treatment 4 had the highest mean of 49 which means that this product is the most elastic among all the products followed by treatment 3, treatment 2, and treatment 1.
For the water absorption test, the treatment that has the least average of water absorbed is treatment 3 followed by treatment 2, treatment 4, and treatment 1. For the biodegradability test, the product which got the highest mean of biodegradability is treatment 1, followed by treatment 2, treatment 3, and treatment 4.
After results were recorded, the treatments were ranked. First is treatment 3, followed by treatment 2, then treatments 1 and 4. As treatment 3 has the ultimate properties, the product was subjected to thermal setting. The product was then compared to TPS and LDPE by their mechanical properties. For the thermal setting, LDPE had the highest initial softening temp. followed by the composite (treatment 3) then by TPS, the composite and the TPS has no melting point, followed by the LDPE with a melting point of 110-120 deg. Celsius. For the mechanical properties of each product, for the tensile strength, the LDPE was the strongest followed by the composite then the TPS. For the elongation percentage, the LDPE was the most elastic followed by the composite then the TPS. For the water absorption, the LDPE had the least average of water absorbed followed by the composite then TPS. And for the biodegradability, the composite was the most biodegradable followed by TPS then the LDPE. This concludes that the LDPE is the strongest among the treatments in terms of tensile strength, elongation percentage, and water absorption, but however is not biodegradable. This study also aimed to improve the properties of a TPS, which results that using toothpaste as filler for TPS is very acceptable because there really is a significant difference in terms of all the properties which was tested.