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1. Thermally-healable network solids of sulfur-crosslinked poly(4-allyloxystyrene)

   https://doi.org/10.1039/c8ra06847j  

   Thiounn, Timmy; Lauer, Moira K.; Bedford, Monte S.; Smith, Rhett C.; Tennyson, Andrew G. (November 2018, RSC Advances)

   Network polymers of sulfur and poly(4-allyloxystyrene), PAOSx ( x = percent by mass sulfur, where x is varied from 10–99), were prepared by reaction between poly(4-allyloxystyrene) with thermal homolytic ring-opened S 8 in a thiol-ene-type reaction. The extent to which sulfur content and crosslinking influence thermal/mechanical properties was assessed. Network materials having sulfur content below 50% were found to be thermosets, whereas those having >90% sulfur content are thermally healable and remeltable. DSC analysis revealed that low sulfur-content materials exhibited neither a T g nor a T m from −50 to 140 °C, whereas higher sulfur content materials featured T g or T m values that scale with the amount of sulfur. DSC data also revealed that sulfur-rich domains of PAOS90 are comprised of sulfur-crosslinked organic polymers and amorphous sulfur, whereas, sulfur-rich domains in PAOS99 are comprised largely of α-sulfur (orthorhombic sulfur). These conclusions are further corroborated by CS 2 -extraction and analysis of extractable/non-extractable fractions. Calculations based on TGA, FT-IR, H 2 S trapping experiments, CS 2 -extractable mass, and elemental combustion microanalysis data were used to assess the relative percentages of free and crosslinked sulfur and average number of S atoms per crosslink. Dynamic mechanical analyses indicate high storage moduli for PAOS90 and PAOS99 (on the order of 3 and 6 GPa at −37 °C, respectively), with a mechanical T g between −17 °C and 5 °C. A PAOS99 sample retains its full initial mechanical strength after at least 12 pulverization-thermal healing cycles, making it a candidate for facile repair and recyclability. 

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2. Exploring the Toba Eruption: Impacts on Biological Productivity and Global Climate Dynamics

   Gairhe, Romin; Abbott, Dallas; Bostick, Benjamin (December 2024, American Geophysical Union)

   Our study examines how volcanic ash layers affect Earth's environment and climate, focusing on carbon, cadmium, and sulfur changes in deep-sea sediment from the Toba super eruption 74,000 years ago. This eruption, the largest of the Quaternary period, released 2,800 cubic kilometers of material and sulfur dioxide, which formed sulfate aerosols, potentially causing a volcanic winter. In sediment core RC14-37, we found a 15 cm thick Toba ash layer at 100-115 cm depth, with the highest ash concentration at 102-104 cm, significantly diluting the sulfur signal from 102-106 cm and masking the sulfur peak. Elevated sulfur levels just below the top of the ash layer suggest rapid deposition after most ash settled, with levels decreasing towards the base, indicating additional atmospheric sulfur. We used X-ray fluorescence (XRF) to measure sulfur and cadmium content. High cadmium levels in the ash layers suggest increased marine productivity. The SiO2 content in the ash ranged from 66% to 78%. Given that Toba ash contains 12 ppm sulfur, our corrected sulfur content (1700-3100 ppm) suggests most sulfur came from atmospheric sulfate aerosols. These results indicate increased biological productivity and sulfur in the ash layers, providing insights into the eruption's ecological impacts. 

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3. Upcycling mixed-material waste with elemental sulfur: applications to plant oil, unseparated biomass, and raw post-consumer food waste

   https://doi.org/10.1039/D4SU00104D  

   Guinati, Bárbara_G S; Sauceda_Oloño, Perla Y; Kapuge_Dona, Nawoda L; Derr, Katelyn M; Wijeyatunga, Shalini K; Tennyson, Andrew G; Smith, Rhett C (June 2024, RSC Sustainability)

   Herein we report the preparation of high sulfur-content materials (HSMs) using food waste and elemental sulfur. 

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4. Polymerizations with Elemental Sulfur: From Petroleum Refining to Polymeric Materials

   https://doi.org/10.1021/jacs.1c09329  

   Lee, Taeheon; Dirlam, Philip T.; Njardarson, Jon T.; Glass, Richard S.; Pyun, Jeffrey (December 2021, Journal of the American Chemical Society)

   The production of elemental sulfur from petroleum refining has created a technological opportunity to increase the valorization of elemental sulfur by the synthesis of high-performance sulfur-based plastics with improved optical, electrochemical, and mechanical properties aimed at applications in thermal imaging, energy storage, self-healable materials, and separation science. In this Perspective, we discuss efforts in the past decade that have revived this area of organosulfur and polymer chemistry to afford a new class of high-sulfur-content polymers prepared from the polymerization of liquid sulfur with unsaturated monomers, termed inverse vulcanization. 

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5. Facile new approach to high sulfur-content materials and preparation of sulfur–lignin copolymers

   https://doi.org/10.1039/c9ta10742h  

   Karunarathna, Menisha S.; Tennyson, Andrew G.; Smith, Rhett C. (January 2020, Journal of Materials Chemistry A)

   null (Ed.)

   This report introduces a new approach to high sulfur-content materials. This route, RASP (radical-induced aryl halide/sulfur polymerization), expands the substrate scope beyond olefins required for the traditional inverse vulcanization route to such materials. RASP allows direct reaction of two unmodified industrial waste products to give lignin–sulfur composites. 

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