Sulfur is fairly inexpensive and abundant because of its production as a by product in oil refining. In this experiment, elemental sulfur is polymerized with divinylbenzene, creating a highly cross linked polymer via inverse vulcanization. Inverse vulcanization is a solvent free and fast reaction method to form polysulfides. The sulfur is heated, breaking the sulfur ring into radicals, where DVB is then incorporated, producing poly(S-DVB). Poly(S-DVB) is then reduced using sodium borohydride as the reducing agent and dichloromethane as the solvent. The reduction of poly(S-DVB) creates thiol functional groups as a result of cleaving the disulfide bonds. This reaction also eliminates the need for protecting groups to prevent other compounds from binding during polymerization. The poly(S-DVB) is characterized using gel permeation chromatography (GPC) and nuclear magnetic resonance (NMR) to examine the polymer molecular weights and structure respectively both before and after reduction. Poly(S-DVB) with different ratios of elemental sulfur and DVB will be made and analyzed using GPC to test for different starting molecular weights and observe changes to the molecular weight after it has been reduced. NMR data indicates a new peak growing in after being reduced indicative of thiol formation. Thiol groups can react with a variety of different functional groups via click chemistry. This will allow the structure of the poly(S-DVB) to be easily modified. Model compounds such as bromoanthracine were bound to reduced poly(S-DVB). This reaction was characterized using UV-Vis spectroscopy.

Investigation of reducing highly cross-linked polysulfides to polythiols

2019 Spring National Meeting

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