Efficient Computational\nand Experimental Probes for\nKinetic Scavenging in Rubber Antiozonants

Since the discovery of 6PPD quinone and its severe toxicity\nto\naquatic organisms, the development of safer rubber antiozonants (AO3s)\nhas become imperative. Rubber AO3s must, by definition, protect rubber\ncompounds against degradation due to ozone (O<sub>3</sub>), a function\nthat is critical to long-term performance of commercial rubber products,\nmost notably in the tire industry. Identification of candidate AO3s\nis a challenging problem owing to both the susceptibility of virgin\nrubber compounds to ozonolysis and the stringent performance requirements\nfor tires. While AO3s are known to protect rubber compounds through\ncombined mechanisms of kinetic scavenging and film formation, aspects\nof each of these are underexplored. Herein, we develop the use of\nvarious experimental and computational metricsgel permeation\nchromatography and solution viscometry as well as ground-state density\nfunctional theoryfor the quantitative determination of kinetic\nscavenging ability across a benchmark data set of 35 rubber antidegradants.\nWe demonstrate an efficient screening protocol for kinetic scavengers\nand discuss the implications for design of 6PPD alternatives, particularly\nthose that have been proposed in recent literature.