This Faraday Discussion focuses on the scientific questions, challenges and areas for future development to advance polymer science. It comprises the following interrelated themes:utilisation of novel feedstocks and reduction in greenhouse gas emissions in making polymersmethods to control monomer sequence and polymer architectures for function and applicationpolymerisation processes, including data-driven design and manufacturing processesrecycling and depolymerisation methods, including biodegradation, to improve circularityNovel feedstocks This section focuses on the chemistry and processes to make monomers and to functionalise natural biopolymers. It includes papers on the use and benefits for biomass derived monomers, such as those from carbohydrates, triglycerides, lignin and terpenes, with a particular focus on use of co-products and wastes in polymer production. Catalysis This section investigates how catalysis can be used to make polymerisation processes more efficient and more sustainable, and to control polymer sequences, stereo- and regiochemistry, so as to enable innovative material and properties. Discussion topics include organocatalysis, metal-based catalysis and heterogeneous catalysis, the synthesis of novel catalytic systems, the elucidation of catalytic reactions using experimental and computational methods (including in situ reaction monitoring), and the impact of residual catalytic species on polymer properties. Polymerisation processes and computational methods to control structure This section discusses how to regulate, control and effect control over polymer sequences, structures, architectures and molar mass distributions by using external stimuli and process control. The section also covers how data and machine learning-driven approaches can help to improve polymerisation processes.  The types of chemistry discussed include ‘triggers/switches and stimuli’, methods to control molar mass distributions, polymer syntheses in flow, and computational approaches to optimise structures and performances. Closing the loop – the chemistry of  depolymerisation, polymer recycling and environmental degradation This section examines the chemistry and fundamental science challenges associated with the different end-life options for polymers. Discussion topics include chemical recycling, designing polymer structures for efficient mechanical recycling, polymer upcycling and re-purposing, depolymerisation kinetics/thermodynamics and mechanisms, depolymerisation catalysis, polymer composting and biodegradation. The environmental chemistry of polymers is also discussed. Future opportunities to combine effective polymerisation and depolymerisation strategies into the design of polymer structures are at the heart of this section and the associated discussions.