More than 2,000 tonnes of plastic waste are produced in Hong Kong every day. Plastic is the by-product of petroleum and its production process gives rise to lots of greenhouse gas emissions. Plastic waste is difficult to decompose, hence putting enormous pressure to the landfills and polluting our oceans. In an effort to find an alternative, we organized the “Let’s Go Bananas! - Banana Peels Bioplastic Lab” workshop in MakerBay, a maker space, on 8 October. Together we discussed the possibilities of bioplastic development and tried our hands on making some of these renewable plastic alternatives.

Plastic is an invention of the last century. An American Leo Baekeland made plastic from fossil fuels for the first time in 1907. After the oil crisis in the 70’s, scientists began to realize that petroleum was non-renewable and actively searched for other renewable resources. In 1997, American oceanographer Charles Moore confirmed that the North Pacific oceanic circulation is full of plastic waste twice the size of Texas. This part of the ocean is known as the Great Pacific Garbage Patch, an alarming reminder to the world how serious plastic waste pollution is.

Other than plastic, there are actually lots of natural resources available. In MakerBay, the largest maker space in Hong Kong, there are various tools and equipment such as carpentry, 3D printers and laser cutting for crafts work design. MakerBay has also opened a Natural Factory in July this year. The Natural Factory stores a comprehensive collection of natural materials including loofah, coconut shells, mycelium foam, as well as bioplastics such as starch-based plastic bags. The information is also available from its website.

Bioplastic made of natural materials is invented to replace petroleum plastics. It can be classified into various types and polylactic acid is a common one. Starch is extracted from corn or glucose and turned into polymer polylactic acid particles to replace ordinary plastic. Many large corporations such as supermarkets and chain stores, as well as bottled water companies, use bioplastic products these days. Bio-based plastic is the fusion of bioplastic and petrochemical materials aiming to enhance heat resistance.

Starch-based biodegradable plastic is one of the easiest and simplest to make. The banana peels bioplastic made in this workshop belongs to this kind. Elif Bilgin, a Turkish student, has successfully invented a method to turn banana peels into bioplastic a few years ago. Her invention won large-scale science awards in 2013. The workshop participants followed Bilgin’s steps to test the production of bioplastics from banana peels. Banana peels were first blended and boiled with water. Other ingredients were then added to the banana mix which was boiled again until water has evaporated. To complete the production process, the mixture was put in the oven and baked for 45 minutes. 

Although the raw materials used to make bioplastic are renewable, its development is thought to be limited. For example, bioplastic can only be decomposed in a designated environment and its recycling is difficult. Apart from that, the inappropriate use of biological raw materials for the manufacturing of bioplastic may worsen the food crisis. During the discussion session, participants brainstormed for solutions and feasible applications of banana peels bioplastic. Some participants suggested using it to make coasters, flower pots or toys. Others wish to see more labeling and designated recycling plants for bioplastic products. After the event, participants took their DIY banana peel bioplastic products home or left them at the MakerBay Natural Factory for display purpose.