Minimizing the Use of Polyethene inside Paper Coffee Cups

Although made of paper, most coffee cups are not recycled because of the polyethene covering their internal surface area (1, 2). Instead, they are sent to landfills where they break down into microplastics and negatively impact organisms after entering the food chain (2, 3). This is an especially alarming issue due to the extensive usage of paper coffee cups around the world. As a result, many global companies have been searching for an eco-friendly cup that eliminates the use of polyethene, a challenge that remains unresolved to this day (9). While the search continues, many businesses have relied on temporary strategies to reduce polyethene production until a design that eliminates its use is developed (9, 10, 11, 12). Two major methods include public awareness and promotion of reusable cups (2). However, these approaches have only resulted in minor changes due to their reliance on customer cooperation (2). To guarantee polyethene reduction, this report proposes a strategy that is independent of customer cooperation. This method determines the dimensions (i.e., height and bottom radius) that minimize the amount of polyethene needed to coat the internal surface area of a cup, while keeping the cup’s volume and lid size (i.e., top radius) the same. The resulting equation gives the surface area of the cup while the root to the first derivate of this equation corresponds to the optimal bottom radius. Using a derived equation for height, the optimal cup height is determined as well. To highlight its proper implementation, this strategy is applied to a Starbucks Grande coffee cup as a model for other companies to follow.