| Over the past 70 years, hydrogels have become one of the most ubiquitous classes of materials
and are used in many fields of science. These 3-dimensional, crosslinked polymer meshworks are
capable of absorbing large amounts of water or biological fluid due to the presence of many
polar hydrophilic groups. Since the development of the first soft contact lens in 1954, hydrogels
have been a mainstay material in the biomedical industry, and more recently, hydrogels research
began to expand to other applications like agriculture, environmental remediation, and energy
storage. However, there are very few examples of hydrogels containing sulfur, and none of which
have exceeded 5 mol% S incorporation. Since 2013, elemental sulfur has been used as a
feedstock to produce polymers exceeding 90 wt% S using inverse vulcanization (IV). These
polysulfides were traditionally synthesized using non-polar monomers to facilitate interactions
with hydrophobic elemental sulfur, limiting interactions with water. Recently, the substrate scope
has expanded to include polar and charged species, facilitating enhanced water solubility.
However, no efforts to utilize IV for hydrogel synthesis have been attempted to date. This
dissertation presents the synthesis and characterization of a novel sulfur-rich hydrogel made via
IV. By copolymerizing elemental sulfur with various acrylamides containing mono- and
difunctional alkene handles, a 12.2 mol% sulfur hydrogel capable of absorbing large amounts of
water was produced. This novel material illustrates that sulfur rich-polymers can interact with
water if a proper polar comonomer system is selected.
Keywords: hydrogels, inverse vulcanization, elemental sulfur, polysulfide, acrylamide |