(178f) Current Trends and Future Plastics

There is a need to reshape the design and synthesis of plastics with superior end-of-life considerations over petroleum derived materials to address environmental issues and support circular carbon economy. Existing data in the literature and databases that best explain plastics synthesis, structure and behavior needs to be re-analyzed to drive the synthesis and production of new hierarchical plastics with the desired properties by inverse design approaches. To overcome limitations of conventional mechanical recycling (including sorting), chemical recycling has gained attention in the last years to turn a plastic’s polymers into individual monomers which can be re-polymerized and remade into new plastics. This process has been used for nylons and can be applied to other types of plastics by pushing the boundaries to determine how and where recycled materials can be used. New methods for delamination, depolymerization (e.g. selective dissolution and reprecipitation), and compatibilization of mixed plastics have trended to increase recycling efficiency. However, no systematic schemes are in place to ensure that these considerations are embedded in a new product’s design.

Biopolymers that possess an intrinsically negative carbon footprint are mainly derived from plant-based resources that must be first transformed into polymerizable forms (monomers). The question arises: can monomers/polymers still be considered renewable after many conversion steps away from the renewable resource to produce bioplastics similar to fossil-driven plastics, also referred to as drop‐in plastics? Also, even if originally made from renewable resources, these plastic products are usually non‐biodegradable as they have the same technical properties as their fossil fuel-based counterparts. Thus, t, future plastics from renewable sources should minimize the number of transformation steps, maximize the conversion and atom efficiencies of each step, and apply ‘greener’ conditions and catalytic reactions. In addition, future research should emphasize the design of performance-advantaged, degradable and environmentally benign or recyclable-upcyclable plant-based polymers.