Eliminating light modulating additives in plastics by controlling the microstructure

Many consumer goods ranging from dairy products to pharmaceuticals are light sensitive. To protect these products, plastic packaging materials are designed using light modulating additives such as dyes and pigments or secondary materials like aluminum and paper. These additives limit polymer recovery and contaminate polymer waste streams. The continued use of these additives limits the quantity and quality of recycled polymers, creating a significant barrier to plastics circularity. We use a light scattering approach to give pure polymer materials light-filtering properties. We make these materials by modifying the microstructure of the plastic to selectively scatter high-energy light without additives. Such materials therefore remain optimally recyclable. We will discuss the physical principles underlying the fabrication of these materials and their light-filtering properties.