The relative mass loss data (Supplementary Tables ) was fit to Equation 3 using nonlinear least-squares regression. Data sets for the CDA films were fit after a robust regression and outlier (ROUT) removal step with a coefficient Q of 1% to clean the data of any outlying points (Supplementary Figure ). All fits had R 2 >0.90. Relative mass loss data for PP and PLA films, and PS foams were not fit because any mass loss was within the uncertainty of the mass loss measurements. Instead, mass loss trajectories were constrained for these materials using specified values of 𝑘 𝑑 and the sample's dimensions. All regressions were performed in GraphPad Prism 10.1.0 (264). Projected environmental lifetimes (𝑡 𝐿 ) were calculated using Equation 4.