Currently, plastic waste is a prominent problem across the globe. Every day, 10 million metric tons of plastic are carried into the Pacific Ocean in the Los Angeles area alone. All of this plastic accumulates in the oceans and creates large “islands" of garbage and debris. An example is the Pacific Garbage Patch, which covers about 1.6 million square kilometers in the Pacific Ocean. This plastic is extremely harmful to the marine life since many animals eat the plastic, and since it is not readily biodegradable, it causes internal problems for these animals, sometimes leading to death. Biodegradable plastics have been made from organic resources, however, they prove to be expensive, and organic resources can be hard to attain in quantities that are needed for our world's demand for plastic.

Creating plastic from bamboo is an ideal option since bamboo is an extremely renewable source, as it can grow up to 3 feet a day. Since bamboo grows so rapidly and can be grown around the world, it provides a good solution for creating a biodegradable plastic. The goal of my project is to create a biodegradable and renewable plastic foam from the cellulose of Bambusa multiplex, a species of bamboo.

In order to make this plastic, I first practiced my techniques using commercial microcrystalline cellulose. I immersed the cellulose in a sodium hydroxide solution to make it amorphous, and I combined the amorphous cel lulose with different amounts of a plasticizer. The plasticizer was an equimolar mixture of glycerol and citric acid, and I made plastics with 10% cellulose and 90% plasticizer, 20% cellulose and 80% plasticizer, and 30% cellulose and 70% plasticizer. I then cured the plastics in the oven for one hour at 180°C. After I had successfully made plastic with the commercial cellulose, I moved on to make it with cellulose extracted from bamboo. To extract the cellulose from bamboo, I first cut stalks of Bambusa multiplex and used a grater to break them down into small pieces to dry. Then, I submerged the bamboo particles in ethanol to extract the cellulose and lignin, since other parts of the cell were soluble in ethanol, After that, I isolated the cellulose by submerging the bamboo particles in nitric acid, sodium hydroxide and sodium sulfite, and sodium hypochlorite solutions. With this cellulose, I re peated the procedure used with the commercial cellulose to make the plastics.

I tested the biodegradability, compression, and insulation properties of the plastics. I tested the biodegrad ability by putting the plastics in distilled water, observing the changes, and measuring the total loss of mass. My biodegradability tests suggested that the plastics made with bamboo cellulose degraded at a higher rate than those made with commercial cellulose, and plastic samples with a higher cellulose content degraded faster than those with a lower cellulose content. I also tested the compression properties by placing the plastics between 2 plates, slowly applying a force of 100 Newtons, and measuring the distance that the plastic compressed, and how much it rebounded after compression. The compression test suggested that the plastics made with bamboo cellulose had a compression rate which was similar to that of a polyethylene foam with the same open-cell characteristics. Finally, I tested the insulation properties by measuring the amount of time it took for a sample of water at -1.0°C to rise in temperature to 10.0°C while being insulated by the plastics, and this test suggested that the plastic foams made with 10% cellulose insulated better than those created with 20% cellulose.

Through my tests, I determined that the ideal percentage of cellulose in these plastic foams is between 10% and 20%, because the samples with 20% cellulose do biodegrade faster, but the samples with 10% cellulose have better insulation properties and have a higher rebound rate after they are compressed. My experiments and studies suggest that the plastic foam that I created could be a solution to our globe's problem of plastic waste; however, further testing is necessary to confirm this. Future studies include testing the biodegradability of the plastic foams in soil, testing the tensile strength of the plastics, and testing the ability of the plastics to insulate hot objects.