Poly(beta-hydroxythioether)s as shape memory polymer foams for oil sorption in aquatic environments

Oil spills in aquatic environments represent a significant ongoing threat to aquatic life due to the persistence of oil films or slick. While many methods are available for open ocean waterways, interior waterways represent a different set of challenges. To that end, we propose the use of poly(beta-hydroxythioether) (PBHTE) shape memory polymer foams as a highly porous, low density solid for environmental remediation through oil collection. PBHTE foams are produced through thiol-epoxy "click " reactions in the presence of an organobase, with gas blown foaming producing the highly porous scaffold with tunable pore sizes and salt-leaching yielding smaller pore sizes (similar to 400 mu m). The different porosities are used here for studying the oil sorption as functions of time and environmental temperature for different pore sizes and compositions. The PBHTE material demonstrated two different T(g)s when dry versus wet to compare against environmental differences. While dry the foam showed a T-g of 51.5 degrees C and conversely when wet the T-g was at 25 degrees C. The foams were compared to see how the pore size will affect the oil sorption of the material and how it can be optimized for oil spills in interior water ways. The pore sizes analyzed were 400 mu m, 800 mu m, and 1100 mu m. The relationship of pore size, temperature of the oil system during sorption, and time in the oil system seemed to have the largest impact on the sorption of oil during this study. The peak conditions for maximum oil sorption yielded the best performer being the 800 mu m foam at 10 degrees C after 15 h of sorption yielding a 2250% sorption, comparable with graphene and other low density sorption materials. Ultimately, the role of density in scavenging, along with a literature review, is used to assemble a density vs sorption Ashby chart to provide insight into the different materials available for such environmental remediation. In this context, PBHTE foams represent a new, promising class of material capable of absorbing oil in aquatic environments.