The current lack of sustainability of and the limited portfolio of recycling processes for synthetic polymers have posed serious threats to the environment. Using reaction pathway analysis, we are pursuing a portfolio of strategies for redesign and recycling of polymers for sustainability. Pyrolysis is a promising method for resource recovery from plastic waste that is compatible with current petrochemical infrastructure that thermally converts polymers in the absence of oxygen into valuable chemical feedstocks and monomer. To provide further insight into polymer pyrolysis, a greater understanding of the mechanistic and kinetic details of the underlying reaction network is needed. To handle the complexity of mechanistic modeling of polymer degradation, we have developed both continuum and kinetic Monte Carlo (kMC) models. Alternatively, redesign efforts focusing on polymers that can be reused and recycled to monomers can lead to sustainable solutions for the plastics waste problem. One pathway to success is to identify bioprivileged molecules, biology-derived chemical intermediates that can be efficiently converted to a diversity of chemical products, including both novel molecules and drop-in replacements, and molecules emanating from them that can be used as monomers leading to recyclable polymers. We have developed a framework for molecule discovery and reaction pathway design that is automated and flexible and can be used to screen for bioprivileged candidates and target molecules. The application to discovery of known and novel monomers for poly(hydroxyurethanes) that are derived from biobased molecules and lead to recyclable materials will be discussed, and computational methods to evaluate the recyclability of different polymers will be outlined.