Plastic has been an amazing resource for humans, but it has also generated a considerable amount of waste that poses a serious threat to wildlife. There are biodegradable plant-based plastics available, but there are some significant drawbacks. However, Ilker Bayer from the Italian Institute of Technology led a team that explored an alternative method of producing bioplastics that utilizes unwanted food scraps. The paper has been published in the journal Macromolecules.
Currently available bioplastics are typically based on starches, cellulose, and biopolymers. Many, but not all, are biodegradable and are better for wildlife than typical plastic products, though there are some drawbacks. Plant starches are derived from peas, corn, and potatoes, which utilizes crops that could be used for food. Additionally, it takes several steps to modify the plant products into a usable plastic, which takes longer and uses more energy than conventional plastic.
For this study, Bayer’s team focused on modifying the process of manufacturing cellophane from cellulose, which is found in plant cell walls. The cellulose is passed through a series of acidic and alkali baths to change its properties, bleached, and has glycerine added to keep the product flexible.
Rather than use cellulose from wood or hemp, the researchers utilized food scraps including cocoa pod husks, parsley waste, rice hulls, and spinach stems. The chemical treatment process of the plant material was also completely overhauled. Instead of a long series of baths, Bayer’s team soaked the plant material in trifluoroacetic acid (TFA) and found that it was ready to be shaped without any additional chemical treatments.
As an added bonus, the resultant plastic also kept certain properties of the plant from which it was derived. In addition to coloring, the plant type also influenced the integrity of the plastic making it suitable for different uses. Spinach-based bioplastic was rubbery and flexible, while the rice-derived plastic was more rigid. The researchers also speculate that bioplastic created from cinnamon could be naturally antibacterial.
While it is incredible that Bayer’s lab could make a product from agricultural waste scraps that rivals the quality of traditional plastics, there might be some difficulty in scaling it up to make it an economically-viable option. Though traditional bioplastics might require a great deal more energy and resources, it looks like it will still be the cheaper route for the foreseeable future. Until a more environmentally-friendly plastic alternative exists, please cut down on the amount of plastic generated and recycle whenever possible.
[Hat tip: New Scientist]