Polymers, Plastics, and Bioplastics
Making the gelatin-based bioplasticCopyright Christena Graves, iPhone camera
Students learn about polymers, plastics, and bioplastics by exploring both natural polymers (e.g., hair, DNA, and cotton) and synthetic polymers found in everyday items (e.g., clothing, toothbrushes, and carpets). They begin by modeling polymer chains from paper clips, starting with simple chains and then modifying their structures to observe how changes affect flexibility, rigidity, and strength. Students also consider the environmental impacts of synthetic plastics, including their persistence in the environment for hundreds of years, and the challenges of recycling, such as high energy costs. They explore how bioplastics (i.e., materials with plastic-like properties that are biodegradable) could offer a more sustainable alternative. Using a guided recipe, students design their first bioplastic piece and then modify the recipe to achieve a different outcome, applying the engineering design process and analyzing how changes in ingredients influence material properties.
This activity connects engineers who work with materials, chemicals, and the environment. Materials engineers design and test materials to make them stronger, more flexible, or more durable. Chemical engineers figure out how to turn natural or synthetic substances into useful products such as plastics or bioplastics. Environmental engineers focus on making materials safer for the planet, reducing pollution, and finding sustainable alternatives.
After this activity, students should be able to:
- Model polymer structures using everyday materials to understand how polymers form plastics.
- Design and create a bioplastic using specific materials and constraints.
- Test and evaluate bioplastic performance by measuring shrinkage and observing flexibility and rigidity.