Material efficiency quantifies the amount of material used to make a functional product . Optimizing the material efficiency of a plastic product has the added benefit of reducing many of its embodied environmental impacts (e.g., greenhouse gas emissions and freshwater usage) because these impacts are largely proportional to the amount of material used . Foams can be the most material-efficient form of a material . As a result, along with their other properties (e.g., low thermal conductivity, vibration and impact absorption), plastic foams have found many applications, particularly in food packaging . Despite these favorable properties for packaging and insulation, the end-of-life management of plastic foams poses challenges. Mechanical recycling facilities do not accept plastic foams because they lack the capability to sort these items, their material efficiency makes them less valuable items, and items used for food applications are often contaminated . As a result, most plastic foams follow a linear life cycle that ends with landfilling or incineration . Moreover, mismanaged foamed items routinely leak into the environment, greatly contributing to plastic pollution. In 2022, plastic foam takeaway containers were the seventh most collected item in beach surveys globally . For these reasons and others, legislation has been enacted in states and municipalities and proposed in the U.S. Congress to ban plastic foams, namely polystyrene (PS) foams . Yet, this legislation appears to overlook the many benefits that plastic foams provide because of their material efficiency . In numerous life-cycle assessments (LCA), PS foam was the best choice because of this property . Thus, there is a need to understand and quantify the tradeoffs underlying design decisions and environmental impacts and investigate alternative foamed materials with improved end-of-life scenarios.