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A magnetic responsive composite was made from a sulfur-rich polymer and iron nanoparticles. Diverse applications in mercury remediation, microwave curing, and magnetic responsive actuators were demonstrated.

Inverse vulcanization provides dynamic and responsive materials made from elemental sulfur and unsaturated cross-linkers. These polymers have been used in a variety of applications such as energy storage, infrared optics, repairable materials, environmental remediation, and precision fertilizers. In spite of these advances, there is a need for methods to recycle and reprocess these polymers. In this study, polymers prepared by inverse vulcanization are shown to undergo reactive compression molding. In this process, the reactive interfaces of sulfur polymers are brought into contact by mechanical compression. Upon heating these molds at relatively low temperatures (≈100 °C), chemical bonding occurs at the polymer interfaces by S-S metathesis. This method of processing is distinct from previous studies on inverse vulcanization because the polymers examined in this study do not form a liquid phase when heated. Neither compression nor heating alone was sufficient to mold these polymers into new architectures, so this is a new concept in the manipulation of sulfur polymers. Additionally, high-level ab initio calculations revealed that the weakest S-S bond in organic polysulfides decreases linearly in strength from a sulfur rank of 2 to 4, but then remains constant at about 100 kJ mol-1 for higher sulfur rank. This is critical information in engineering these polymers for S-S metathesis. Guided by this insight, polymer repair, recycling, and repurposing into new composites was demonstrated.

A polymer made from sulfur and limonene was used to coat silica gel and then evaluated as a mercury sorbent. A kinetic model of mercury uptake was established for a range of pH values and concentrations of sodium chloride. Mercury uptake was generally rapid from pH = 3 to pH = 11. At neutral pH, the sorbent (500 mg with a 10 : 1 ratio of silica to polymer) could remove 90% of mercury within one minute from a 100 mL solution containing 5 ppm HgCl

A polymer made from sulfur and limonene was used to coat silica gel and then evaluated as a mercury sorbent. A kinetic model of mercury uptake was established for a range of pH values and concentrations of sodium chloride. Mercury uptake was generally rapid from pH = 3 to pH = 11. At neutral pH, the sorbent (500 mg with a 10:1 ratio of silica to polymer) could remove 90% of mercury within one minute from a 100 mL solution 5 ppm in HgCl2 and 99% over 5 minutes. It was found that sodium chloride, at concentrations comparable to seawater, dramatically reduced mercury uptake rates and capacity. It was also found that the spent sorbent was stable in acidic and neutral media, but degraded at pH 11 which led to mercury leaching. These results help define the conditions under which the sorbent could be used, which is an important advance for using this material in remediation processes.

The reaction between sulfur and dicyclopentadiene was optimised to form a shelf stable and soluble low molecular weight oligomer. After a simple curing process at 140 °C the material was rendered insoluble and resistant to acids and solvents. Taking advantage of the soluble oligomer, a metal surface was coated with the dissolved material which was then cured to show that a copolymer layer can act as a corrosion resistant material. Further, silica gel was coated with the soluble oligomer to test mercury removal applications. Even after curing, the polymer coated silica was an effective mercury sorbent. Additionally, the sorbent was also used to remove mercury form a diesel and water mixture indicating that mercury removal from a mixture of organic and aqueous substances is possible with this system.

The reaction between sulfur and dicyclopentadiene was optimised to form a shelf stable and soluble low molecular weight oligomer. After a simple curing process at 140 °C the material was rendered insoluble and resistant to acids and solvents. Taking advantage of the soluble oligomer, a metal surface was coated with the dissolved material which was then cured to show that a copolymer layer can act as a corrosion resistant material. Further, silica gel was coated with the soluble oligomer to test mercury removal applications. Even after curing, the polymer coated silica was an effective mercury sorbent. Additionally, the sorbent was also used to remove mercury form a diesel and water mixture indicating that mercury removal from a mixture of organic and aqueous substances is possible with this system.

A polymer made from equal masses of sulfur and canola oil was carbonised at 600 °C for 30 minutes. The resulting material exhibited improved uptake of mercury from water compared to the polymer. The carbonisation could also be done after using the polymer to clean up oil spills, which suprisingly improved mercury uptake to levels rivaling commercial carbons.

Sulfur polymer composites were prepared by the reaction of canola oil and elemental sulfur in the presence of the NPK fertiliser components ammonium sulfate, calcium hydrogen phosphate, and potassium chloride. These composites released nutrients in a controlled fashion, resulting in less wasted fertiliser and better health for potted tomato plants when compared to free NPK.