Seaweed as the New Plastic

At the beginning of February 2018, my scientific research project was started. This project looks into combining different types seaweed extracts with chemical plasticisers, in search for a perfect alternative to the plastic lining in coffee cups. The duration of this research and investigation totalled to roughly seven months, with many improvements along the way.

It is an honour to say that my project has led me to many prizes, such as the STANSW Young Scientist Award, as well as the BHP Science and Engineering Award. The poster below is made for display during the BHP Award Ceremony.

Abstract

The purpose of this investigation was to design a polysaccharide coating that would increase the water-resistance of paper when combined, and thus finding a substitution of the plastic lining that is commonly used in disposable coffee cups. This investigation arrives from the current challenge that the plastic lining is posing to the recycling industry, since paper cups cannot be recycled once combined with the plastic lining. To make the polysaccharide coating, agar, alginate, and carrageenan powder was respectively mixed with water, boiled in a glass dish, and then coated onto filter papers by dipping each filter paper single-sidedly into the coating solution. In addition, common plasticisers, namely glycerine and the combination of pectin with polyvinyl alcohol (PVA) powder, was also added separately into the glass dishes. Five out of eight filter papers made from each combination were then treated with glutaraldehyde to improve the water-impermeability of coatings.

The first hypothesis was that the filter papers coated with agar will have the best water resistance in comparison to filter papers coated with carrageenan or alginate. The second hypothesis was that pectin and PVA as plasticiser combination would best increase the water-resistance of polysaccharide filter papers. Finally, the third hypothesis was that the addition of a cross-linking step would improve the water resistivity of the bioplastic lining developed in the previous steps.

In order to test these hypotheses, multiple samples of filter papers were prepared and placed on a filtering funnel inside a conical flask. Thirty mL of hot water was then poured onto the filter paper, and the stopwatch was started at the same time. The stopwatch was stopped once the first drop of water dripped to the bottom of the conical flask from the filtering funnel. The controlled sample had no polysaccharide coating, plasticiser, or glutaraldehyde solution treatment (crosslinker).

This investigation found that filter papers coated with alginate powder, polyvinyl alcohol, and pectin were the most effective in their ability to contain water. Before the cross-linker was applied, the result varied greatly. However, as an overall trend, the best polysaccharide was alginate, followed by agar and carrageenan; whereas the best plasticiser to use was the combination of pectin and PVA, followed by glycerine. After the coatings were treated in GA cross-linker, the result showed significant improvement in filter papers’ water resistance. This investigation also confirmed that plasticiser does indeed improve the water resistance of polysaccharide coatings, as evident when comparing the filter papers with and without the addition of plasticisers.

For the entire report, visit the link below

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