Ordinary Portland Cement (OPC) production consumes tremendous amounts of fresh water and energy and releases vast quantities of CO₂ into the atmosphere. Not only would an alternative to OPC whose production requires no water, releases little CO₂, and consumes less energy represent a transformative advance in the pursuit of industrial decarbonization, but the greater availability of safe drinking water would lead to significantly improved public health, particularly among vulnerable populations most at risk from contaminated water supply. For any OPC alternative to be adopted on any meaningful scale, however, its structural capabilities must meet or exceed those of OPC. An inverse vulcanization of brown grease, sunflower oil, and elemental sulfur (5:5:90 weight ratio) was successfully modified to afford the high-sulfur-content material SunBG₉₀ in quantities > 1 kg, as was necessary for standardized ASTM and ISO testing. Water absorption (ASTM C140) and thermal conductivity (ISO 8302) values for SunBG₉₀ (<1 wt% and 0.126 W·m⁻¹·K⁻¹, respectively) were 84% and 94% lower than those for OPC, respectively, suggesting that SunBG₉₀ would be more resistant against freeze-thaw and thermal stress damage than OPC. Consequently, not only does SunBG₉₀ represent a more environmentally friendly material than OPC, but its superior thermomechanical properties suggest that it could be a more environmentally robust material on its own merits, particularly for outdoor structural applications involving significant exposure to water and seasonal or day/night temperature swings.

Over 80 MT of elemental sulfur, a byproduct of fossil fuel desulfurization, are generated annually. This has spurred the development of high sulfur content materials (HSMs) via inverse vulcanization as a productive pathway towards sulfur utilization. In this study, we evaluate the antimicrobial performance of SunBG₉₀, an HSM made from brown grease and sulfur, as tiles or infused into fabric squares. The static antimicrobial activity of SunBG₉₀ tiles was assessed, revealing excellent efficacy against Gram-positive bacteria, with reductions of 96.84% for Staphylococcus aureus and 91.52% for Listeria monocytogenes. The tiles also exhibited strong antifungal activity, reducing Candida auris by 96.20% and mold (fumigatus) by 83.77%. In contrast, efficacy against Gram-negative bacteria was more variable, with moderate reductions for Escherichia coli (61.10%) and Salmonella enteritidis (62.15%), lower activity against Campylobacter jejuni and Salmonella typhi, and no effect on Clostridium perfringens. Under dynamic conditions, SunBG₉₀-infused fabrics achieved a near-complete inhibition of L. monocytogenes (99.91%) and high reduction of E. coli (98.49%), along with a 96.24% inhibition of Candida auris. These results highlight the potential and limitations of SunBG₉₀ for antimicrobial applications, emphasizing the need for further optimization to achieve consistent broad-spectrum activity.

Plastics and composites for consumer goods often require flame retardants (FRs) to mitigate flammability risks. Finding FRs that are effective in new sustainable materials is important for bringing them to the market. This study evaluated various FRs in SunBG₉₀ (a composite made from triglycerides and sulfur)—a high sulfur-content material (HSM) promising for use in Li–S batteries, where flame resistance is critical. SunBG₉₀ was blended with FRs from several classes (inorganic, phosphorus-based, brominated, and nitrogen-containing) to assess compliance with UL94 Burning Test standards. Inorganic FRs showed poor flame retardancy and lower mechanical strength, while organic additives significantly improved fire resistance. The addition of 20 wt. % tetrabromobisphenol A enabled SunBG₉₀ to achieve the highest flame retardancy rating (94V-0), while also enhancing wear resistance (52 I_W, ASTM C1353) and bonding strength (26 psi, ASTM C482). Selected organic FRs also enhance compressive strength compared to the FR-free SunBG₉₀. This research highlights the potential of HSMs with traditional FRs to meet stringent fire safety standards while preserving or enhancing the mechanical integrity of HSM composites.

A series of six composites was prepared from the reaction of lignin-derived guaiacol, fatty acids, and sulfur. In this preparation, the organic comonomers undergo C–S bond-forming reactions to establish a highly crosslinked network material in which some non-covalently incorporated sulfur species are also entrapped. Both monounsaturated oleic acid and diunsaturated linoleic acid were used as fatty acid components to assess the influence of their unsaturation levels on composite properties. The ratio of organics and the proportion of sulfur (70 or 80 wt%) was also varied to assess the effect on thermal, morphological, and mechanical properties. Thermogravimetric analysis showed that composites exhibited good thermal stability up to ~220 °C. Differential scanning calorimetry revealed that the materials generally exhibit melting features for entrapped cyclo-S₈, cold crystallization features for some materials, and a composition-dependent glass transition temperature. The flexural and compressive strengths of the composites revealed that some of the composites exhibit strengths significantly higher than those required of Portland cements used in residential housing fabrication and may be more sustainable structural materials. The thermal and mechanical properties could be tailored by changing the degree of unsaturation of the fatty acid comonomer or by altering the percentage of fatty acid in the monomer feed. The highest mechanical strength was achieved with greater amounts of monounsaturated oleic acid comonomer.

Herein high-strength composites are prepared from elemental sulfur, sunflower oil, and wastewater sludge. Fats extracted from dissolved air flotation (DAF) solids were reacted with elemental sulfur to yield composite DAFS (10 wt% DAF fats and 90 wt% sulfur). Additional composites were prepared from DAF fat, sunflower oil and sulfur to give SunDAF _x (x = wt% sulfur, varied from 85–90%). The composites were characterized by spectroscopic, thermal, and mechanical methods. FT-IR spectra revealed a notable peak at 798 cm^–1 indicating a C–S stretch in DAFS, SunDAF ₉₀ , and SunDAF ₈₅ indicating successful crosslinking of polymeric sulfur with olefin units. SEM/EDX analysis revealed homogenous distribution of carbon, oxygen, and sulfur in SunDAF ₉₀ and SunDAF ₈₅ . The percent crystallinity exhibited by DAFS (37%), SunDAF ₉₀ (39%), and SunDAF ₈₅ (45%) was observed to be slightly lower than that of previous composites prepared from elemental sulfur and fats and oils. DAFS and SunDAF _x displayed compressive strengths (26.4–38.7 MPa) of up to 227% above that required (17 MPa) of ordinary Portland cement for residential building foundations. The composite decomposition temperatures ranged from 211 to 219 °C, with glass transition temperatures of − 37 °C to − 39 °C. These composites thus provide a potential route to reclaim wastewater organics for use in value-added structural materials having mechanical properties competitive with those of commercial products.

The unique properties and sustainability advantages of sulfur polymer cement have led to efforts to use them as alternatives to traditional Portland cement. The current study explores the impact of environmental stresses on the strength development of polymer composite SunBG₉₀, a material composed of animal and plant fats/oils vulcanized with 90 wt. % sulfur. The environmental stresses investigated include low temperature (−25 °C), high temperature (40 °C), and submersion in water, hexanes, or aqueous solutions containing strong electrolyte, strong acid, or strong base. Samples were analyzed for the extent to which exposure to these stresses influenced the thermo-morphological properties and the compressional strength of the materials compared to identical materials allowed to develop strength at room temperature. Differential scanning calorimetry (DSC) analysis revealed distinct thermos-morphological transitions in stressed samples and the notable formation of metastable γ-sulfur in hexane-exposed specimens. Powder X-ray diffraction confirmed that the crystalline domains identified by DSC were primarily γ-sulfur, with ~5% contribution of γ-sulfur in hexane-exposed samples. Compressive strength testing revealed high strength retention other than aging at elevated temperatures, which led to ~50% loss of strength. These findings reveal influences on the strength development of SunBG₉₀, lending important insight into possible use as an alternative to OPC.