Effects of Polymer Morphology on Solvent and Catalyst Accessibility during Polyethylene and Polystyrene Autoxidation

Maurya, Anjani K. [SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States); BOTTLE Consortium, Golden, CO (United States)] (ORCID:0000000291346693); Asundi, Arun S. [SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States). Stanford Synchrotron Radiation Lightsource (SSRL); BOTTLE Consortium, Golden, CO (United States)] (ORCID:0000000303336784); Hesse, Sarah A. [SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States). Stanford Synchrotron Radiation Lightsource (SSRL); BOTTLE Consortium, Golden, CO (United States)] (ORCID:0000000223834476); Ebrahim, Amani M. [SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States). Stanford Synchrotron Radiation Lightsource (SSRL); BOTTLE Consortium, Golden, CO (United States)]; Sullivan, Kevin P. [BOTTLE Consortium, Golden, CO (United States); National Laboratory of the Rockies (NLR), Golden, CO (United States)]; Miscall, Joel [BOTTLE Consortium, Golden, CO (United States); National Laboratory of the Rockies (NLR), Golden, CO (United States)]; Richardson, Jocelyn A. [SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States). Stanford Synchrotron Radiation Lightsource (SSRL)]; Bare, Simon R. [SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States). Stanford Synchrotron Radiation Lightsource (SSRL); BOTTLE Consortium, Golden, CO (United States)] (ORCID:0000000249320342); Sarangi, Ritimukta [SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States). Stanford Synchrotron Radiation Lightsource (SSRL); BOTTLE Consortium, Golden, CO (United States)] (ORCID:0000000227642279); Beckham, Gregg T. [BOTTLE Consortium, Golden, CO (United States); National Laboratory of the Rockies (NLR), Golden, CO (United States)] (ORCID:000000023480212X); Tassone, Christopher J. [SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States); BOTTLE Consortium, Golden, CO (United States); Stanford Univ., CA (United States)]

doi:10.1021/jacsau.6c00230

DOE OSTI · 3029047

Effects of Polymer Morphology on Solvent and Catalyst Accessibility during Polyethylene and Polystyrene Autoxidation

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Abstract

Efficient catalytic deconstruction of plastics requires facile solvent and catalyst access to polymer substrates to minimize mass transfer effects. Autoxidation using Co(II) acetate, Mn(II) acetate, and a radical carrier in acetic acid is a promising strategy to deconstruct mixed plastic waste, yet the role of polymer morphology in governing solvent and catalyst accessibility remains poorly understood. Here, in situ simultaneous small- and wide-angle X-ray scattering (SAXS/WAXS), complemented by X-ray fluorescence (XRF) imaging and high-pressure differential scanning calorimetry (DSC), were used to elucidate interactions between acetic acid, a Co/Mn catalyst solution, and semicrystalline polyethylene (PE) and amorphous polystyrene (PS) from room temperature to 160 °C. In PE, acetic acid and catalyst access were confined to amorphous regions and cryomilled particle interfaces at room temperature, while crystalline lamellae remained intact after soaking for up to 34 h. Increasing temperature enabled solvent uptake into PE, followed by solvent-assisted softening above 100 °C, and a modest melting-point depression that removed lamellar transport barriers upon melting. Conversely for PS, acetic acid penetrated the glassy polymer without inducing chain mobility until the glass transition was reached, above which the observed structural changes were consistent with enhanced segmental mobility which enabled bulk penetration. These results suggest that polymer morphology and thermally activated physical transitions arising from diffusion and polymer–solvent interactions can influence whether autoxidation of plastics is transport-limited or kinetically controlled, providing a framework for aligning reaction conditions with reaction outcomes.

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09 BIOMASS FUELS 36 MATERIALS SCIENCE 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY X-ray fluorescence (XRF)chemical recycling high-pressure differential scanning calorimetry (DSC)plastics small- and wide-angle X-ray scattering (SAXS/WAXS)x-ray fluorescence (XRF)

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Maurya, Anjani K. [SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States); BOTTLE Consortium, Golden, CO (United States)] (ORCID:0000000291346693), Asundi, Arun S. [SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States). Stanford Synchrotron Radiation Lightsource (SSRL); BOTTLE Consortium, Golden, CO (United States)] (ORCID:0000000303336784), Hesse, Sarah A. [SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States). Stanford Synchrotron Radiation Lightsource (SSRL); BOTTLE Consortium, Golden, CO (United States)] (ORCID:0000000223834476), Ebrahim, Amani M. [SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States). Stanford Synchrotron Radiation Lightsource (SSRL); BOTTLE Consortium, Golden, CO (United States)], Sullivan, Kevin P. [BOTTLE Consortium, Golden, CO (United States); National Laboratory of the Rockies (NLR), Golden, CO (United States)], Miscall, Joel [BOTTLE Consortium, Golden, CO (United States); National Laboratory of the Rockies (NLR), Golden, CO (United States)], Richardson, Jocelyn A. [SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States). Stanford Synchrotron Radiation Lightsource (SSRL)], Bare, Simon R. [SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States). Stanford Synchrotron Radiation Lightsource (SSRL); BOTTLE Consortium, Golden, CO (United States)] (ORCID:0000000249320342), Sarangi, Ritimukta [SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States). Stanford Synchrotron Radiation Lightsource (SSRL); BOTTLE Consortium, Golden, CO (United States)] (ORCID:0000000227642279), Beckham, Gregg T. [BOTTLE Consortium, Golden, CO (United States); National Laboratory of the Rockies (NLR), Golden, CO (United States)] (ORCID:000000023480212X), Tassone, Christopher J. [SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States); BOTTLE Consortium, Golden, CO (United States); Stanford Univ., CA (United States)]. 2026-04-16. Effects of Polymer Morphology on Solvent and Catalyst Accessibility during Polyethylene and Polystyrene Autoxidation. https://doi.org/10.1021/jacsau.6c00230

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