Thanks are owed to The American Chemical Society Petroleum Research Fund (PRF # 58416-UNI7) for financial support. The authors would like to thank Indiana STEM Louis Stokes Alliance for Minority Participation for student support provided by the National Science Foundation under Grant No. HRD1618-408.

1. Synthesis of poly(S-divinylbenzene)
<ol>
	<li>To prepare poly(S-divinylbenzene), combine elemental sulfur (S8) and divinylbenzene (DVB) at various weight ratios (30:70, 40:60, 50:50, 60:40, 70:30, 80:20, and 90:10 of S8:DVB). Prepare the reaction according to prior methods described below3,25. 
	NOTE: All reactions here were conducted on a 1.00 g scale. A typical reaction contains 500 mg of S8 and 500 mg of DVB.
	<ol>
		...

<ol>
	<li>Griebel, J. J., Glass, R. S., Char, K., Pyun, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Polymerizations+with+Elemental+Sulfur:+A+Novel+Route+to+High+Sulfur+Content+Polymers+for+Sustainability,+Energy+and+Defense.">Polymerizations with Elemental Sulfur: A Novel Route to High Sulfur Content Polymers for Sustainability, Energy and Defense.</a> Progress in Polymer Science. 58, 90-125 (2016).</li><li>Chung, W. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Elemental+Sulfur+as+a+Reactive+Medium+for+Gold+Nanoparticles+and+Nanocomposite+Materials.">Elemental Sulfur as a Reactive Medium for Gold Nanoparticles and Nanocomposite Materials.</a> Angewandte Chemie International Edition. 50, 11409-11412 (2011).</li><li>Chung, W. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Use+of+Elemental+Sulfur+as+an+Alternative+Feedstock+for+Polymeric+Materials.">The Use of Elemental Sulfur as an Alternative Feedstock for Polymeric Materials.</a> Nature Chemistry. 5, 518-524 (2013).</li><li>Shukla, S., Ghosh, A., Roy, P. K., Mitra, S., Lochab, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cardanol+Benzoxazines+-+A+Sustainable+Linker+for+Elemental+Sulphur+Based+Copolymers+via+Inverse+Vulcanisation.">Cardanol Benzoxazines - A Sustainable Linker for Elemental Sulphur Based Copolymers via Inverse Vulcanisation.</a> Polymer. 99, 349-357 (2016).</li><li>Worthington, M. J. H., Kucera, R. L., Chalker, J. 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K., Mitra, S., Lochab, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cardanol+Benzoxazine&#8208;Sulfur+Copolymers+for+Li&#8208;S+Batteries:+Symbiosis+of+Sustainability+and+Performance.">Cardanol Benzoxazine&#8208;Sulfur Copolymers for Li&#8208;S Batteries: Symbiosis of Sustainability and Performance.</a> Chemistry Select. 1, 594-600 (2016).</li><li>Griebel, J. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dynamic+Covalent+Polymers+via+Inverse+Vulcanization+of+Elemental+Sulfur+for+Healable+Infrared+Optical+Materials.">Dynamic Covalent Polymers via Inverse Vulcanization of Elemental Sulfur for Healable Infrared Optical Materials.</a> ACS Macro Letters. 4, 862-866 (2015).</li><li>Griebel, J. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=New+Infrared+Transmitting+Material+via+Inverse+Vulcanization+of+Elemental+Sulfur+to+Prepare+High+Refractive+Index+Polymers.">New Infrared Transmitting Material via Inverse Vulcanization of Elemental Sulfur to Prepare High Refractive Index Polymers.</a> Advandced Materials. 26, 3014-3018 (2014).</li><li>Crockett, M. P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sulfur-Limonene+Polysulfide:+A+Material+Synthesized+Entirely+from+Industrial+By-Products+and+Its+Use+in+Removing+Toxic+Metals+from+Water+and+Soil.">Sulfur-Limonene Polysulfide: A Material Synthesized Entirely from Industrial By-Products and Its Use in Removing Toxic Metals from Water and Soil.</a> Angewandte Chemie International Edition. 55, 1714-1718 (2016).</li><li>Hasell, T., Parker, D. J., Jones, H. A., McAllister, T., Howdle, S. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Porous+Inverse+Vulcanized+Polymers+for+Mercury+Capture.">Porous Inverse Vulcanized Polymers for Mercury Capture.</a> Chemical Communications. 52, 5383-5386 (2016).</li><li>Thielke, M. W., Bultema, L. A., Brauer, D. D., Richter, B., Fischer, M., Theato, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rapid+Mercury(II)+Removal+by+Electrospun+Sulfur+Copolymers.">Rapid Mercury(II) Removal by Electrospun Sulfur Copolymers.</a> Polymers. 8, 266 (2016).</li><li>Worthington, M. J. H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Laying+Waste+to+Mercury:+Inexpensive+Sorbents+Made+from+Sulfur+and+Recycled+Cooking+Oils.">Laying Waste to Mercury: Inexpensive Sorbents Made from Sulfur and Recycled Cooking Oils.</a> Chemistry A European Journal. 23, 16219-16230 (2017).</li><li>Worthington, M. J. H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sustainable+Polysulfides+for+Oil+Spill+Remediation:+Repurposing+Industrial+Waste+for+Environmental+Benefit.">Sustainable Polysulfides for Oil Spill Remediation: Repurposing Industrial Waste for Environmental Benefit.</a> Advanced Sustainable Systems. 2, 1800024 (2018).</li><li>Abraham, A. M., Kumar, S. V., Alhassan, S. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Porous+Sulphur+Copolymer+for+Gas-phase+Mercury+Removal+and+Thermal+Insulation.">Porous Sulphur Copolymer for Gas-phase Mercury Removal and Thermal Insulation.</a> Chemical Engineering Journal. 332, 1-7 (2018).</li><li>Mann, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sulfur+Polymer+Composites+as+Controlled-release+Fertilisers.">Sulfur Polymer Composites as Controlled-release Fertilisers.</a> Organic and Biomolecular Chemistry. , (2018).</li><li>Deng, D., Hoefling, A., Th&#233;ato, P., Lienkamp, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Surface+Properties+and+Antimicrobial+Activity+of+Poly(sulfur&#8208;co&#8208;1,3&#8208;diisopropenylbenzene)+Copolymers.">Surface Properties and Antimicrobial Activity of Poly(sulfur&#8208;co&#8208;1,3&#8208;diisopropenylbenzene) Copolymers.</a> Macromolecular Chemistry and Physics. 219, 1700497 (2018).</li><li>Diez, S., Hoefling, A., Theato, P., Pauer, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mechanical+and+Electrical+Properties+of+Sulfur-Containing+Polymeric+Materials+Prepared+via+Inverse+Vulcanization.">Mechanical and Electrical Properties of Sulfur-Containing Polymeric Materials Prepared via Inverse Vulcanization.</a> Polymers. 9, 59 (2017).</li><li>Parker, D. J., Chong, S. T., Hasell, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sustainable+Inverse-vulcanised+Sulfur+Polymers.">Sustainable Inverse-vulcanised Sulfur Polymers.</a> RSC Advances. 8, 27892-27899 (2018).</li><li>Arslan, M., Kiskan, B., Yagci, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Recycling+and+Self-Healing+of+Polybenzoxazines+with+Dynamic+Sulfide+Linkages.">Recycling and Self-Healing of Polybenzoxazines with Dynamic Sulfide Linkages.</a> Scientific Reports. 7, 5207 (2017).</li><li>Zhang, Y. Y., Konopka, K. M., Glass, R. S., Char, K., Pyun, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chalcogenide+Hybrid+Inorganic/Organic+Polymers+(CHIPs)+via+Inverse+Vulcanization+and+Dynamic+Covalent+Polymerizations.">Chalcogenide Hybrid Inorganic/Organic Polymers (CHIPs) via Inverse Vulcanization and Dynamic Covalent Polymerizations.</a> Polym Chemistry. 8, 5167-5173 (2017).</li><li>Zhang, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nucleophilic+Activation+of+Elemental+Sulfur+for+Inverse+Vulcanization+and+Dynamic+Covalent+Polymerizations.">Nucleophilic Activation of Elemental Sulfur for Inverse Vulcanization and Dynamic Covalent Polymerizations.</a> Journal of Polymer Science Part A: Polymer Chemistry. 57, 7-12 (2019).</li><li>Tobolsky, A. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Polymeric+Sulfur+and+Related+Polymers.">Polymeric Sulfur and Related Polymers.</a> Journal of Polymer Science: Polymer Symposia. 12, 71-78 (1966).</li><li>Westerman, C. R., Jenkins, C. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Polysulfides+Initiate+Dynamic+Monomer+Incorporation+Forming+Cross-linked+Terpolymers.">Polysulfides Initiate Dynamic Monomer Incorporation Forming Cross-linked Terpolymers.</a> Macromolecules. 51, 7233-7238 (2018).</li><li>Arslan, M., Kiskan, B., Cengiz, E. C., Demir-Cakan, R., Yagci, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Inverse+Vulcanization+of+Bismaleimide+and+Divinylbenzene+by+Elemental+Sulfur+for+Lithium+Sulfur+Batteries.">Inverse Vulcanization of Bismaleimide and Divinylbenzene by Elemental Sulfur for Lithium Sulfur Batteries.</a> European Polymer Journal. 80, 70-77 (2016).</li><li>Pickering, T. L., Saunders, K. J., Tobolsky, A. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Disproportionation+of+Organic+Polysulfides.">Disproportionation of Organic Polysulfides.</a> Journal of the American Chemical Society. 89, 2364-2367 (1967).</li><li>Zhang, Y. Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Inverse+Vulcanization+of+Elemental+Sulfur+and+Styrene+for+Polymeric+Cathodes+in+Li-S+Batteries.">Inverse Vulcanization of Elemental Sulfur and Styrene for Polymeric Cathodes in Li-S Batteries.</a> Journal of Polymer Science Part A: Polymer Chemistry. 55, 107-116 (2017).</li><li>Zubov, V. P., Kumar, M. V., Masterova, M. N., Kabanov, V. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reactivity+of+Allyl+Monomers+in+Radical+Polymerization.">Reactivity of Allyl Monomers in Radical Polymerization.</a> Journal of Macromolecular Science: Part A. 13, 111-131 (1979).</li><li>Wei, Y. 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The primary benefit of this method is the ability to form polysulfides at mild temperatures, 90 &#176;C versus &#62;159 &#176;C for traditional inverse vulcanization. The extended sulfur chains and sulfur loops in poly(S-DVB) are less stable than S-S bonds in S823,26. Lower temperatures can then be used to cause homolytic scission and thiyl radical formation24. For monomers with melting points well below the reaction temperature...

Conversion of organosulfur compounds to S8 during petroleum refinement has led to the amassing of large stockpiles of sulfur1. Elemental sulfur is primarily used for the production of sulfuric acid and phosphates for fertilizers2. The relative abundance provides a readily available and inexpensive reagent making elemental sulfur an ideal feedstock for materials development.
Inverse vulcanization is a relatively new polymerization technique that repurposes sulfur into functional materials3. The S8 ring converts to a diradical, linear chain upon heating above 159 &#176;C. The thiyl radicals then initiate polymerization with monomers to form polysulfides3. In addition to traditional radical polymerizations, inverse vulcanization has been utilized to initiate polymerization with benzoxazines4. The resulting polymers have been used for a wide range of applications including cathodes in Li-S batteries1,5,6,7, self-healing optical lenses8,9, mercury and oil sorbents5,10,11,12,13,14,15, thermal insulators15, to aid in the slow release of fertilizer16 as well as demonstrating some antimicrobial activity17. One group has provided a thorough systematic analysis of these polysulfides providing more information about the insulating character and mechanical properties with varied S content18. The specific details may aid in further applications development. The dynamic bonds present in these materials have also been utilized to recycle the polysulfides19,20. However, the high temperatures required by inverse vulcanization, typically 185 &#176;C, and lack of miscibility with S8, limit the monomers that can be used3.
Early efforts focused on the polymerization of aromatic hydrocarbons, extended hydrocarbons, and natural monomers with high boiling points5. These methods have been expanded by using poly(S-styrene) as a prepolymer improving miscibility between S8 and more polar monomers including acrylic, allylic, and functionalized styrenic monomers21. Another method utilizes nucleophilic amine activators to enhance reaction rates and lower reaction temperatures22. However, many monomers have boiling points well below 159 &#176;C and thus require an alternate method for polysulfide formation.
In the stable crown form, S-S bonds are the strongest, thus requiring high temperatures for cleavage23. In polysulfides, sulfur is present as linear chains or loops, allowing S-S bonds to be cleaved at much lower temperatures1,24. By using poly(S-DVB) (DVB, divinylbenzene)as a prepolymer, a second monomer with a lower boiling point such as 1,4-cyclohexanedimethanol divinylether (CDE, boiling point of 126 &#176;C), can be introduced24. This work demonstrates further improvement by lowering the reaction temperature to 90 &#176;C with a family of allyl and vinyl ether monomers. Reactions incorporating a second monomer remain solvent-free.

<table>
	<tbody>
		<tr>
			<td>Sulfur, 99.5%, sublimed, ACROS Organics</td>
			<td>Fisher Scientific</td>
			<td>AC201250250SDS</td>
			<td></td>
		</tr>
		<tr>
			<td>divinylbenzene</td>
			<td>Fisher Scientific</td>
			<td>AA4280422</td>
			<td></td>
		</tr>
		<tr>
			<td>1,4-Cyclohexanedimethanol divinyl ether, mixture of isomers</td>
			<td>Sigma Aldrich</td>
			<td>406171</td>
			<td></td>
		</tr>
		<tr>
			<td>Cyclohexyl vinyl ether</td>
			<td>Fisher Scientific</td>
			<td>AC395420500</td>
			<td></td>
		</tr>
		<tr>
			<td>Allyl ether</td>
			<td>Sigma Aldrich</td>
			<td>259470</td>
			<td></td>
		</tr>
		<tr>
			<td>maleimide</td>
			<td>Sigma Aldrich</td>
			<td>129585</td>
			<td></td>
		</tr>
		<tr>
			<td>dichlormethane</td>
			<td>Fisher Scientific</td>
			<td>D37</td>
			<td></td>
		</tr>
		<tr>
			<td>N,N-dimethylformamide</td>
			<td>Fisher Scientific</td>
			<td>D119</td>
			<td></td>
		</tr>
		<tr>
			<td>Auto sampler Aluminum Sample Pans, 50&#181;L, 0.1mm, Sealed</td>
			<td>Perkin Elmer</td>
			<td>B0143017</td>
			<td></td>
		</tr>
		<tr>
			<td>Auto sampler Aluminum Sample Covers</td>
			<td>Perkin Elmer</td>
			<td>B0143003</td>
			<td></td>
		</tr>
		<tr>
			<td>EMD Millipore 13mm Nonsterile Millex Syringe Filters - Hydrophobic PTFE Membrane, 0.45 um</td>
			<td>Fisher Scientific</td>
			<td>SLFHX13NL</td>
			<td></td>
		</tr>
	</tbody>
</table>

synthesis of terpolymers at mild temperatures using dynamic sulfur bonds in poly(s-divinylbenzene)

Elemental sulfur (S8) is a byproduct of the petroleum industry with millions of tons produced annually. Such abundant production and limited applications lead to sulfur as a cost-efficient reagent for polymer synthesis. Inverse vulcanization combines elemental sulfur with a variety of monomers to form functional polysulfides without the need for solvents. Short reaction times and straight forward synthetic methods have led to rapid expansion of inverse vulcanization. However, high reaction temperatures (&#62;160 &#176;C) limit the types of monomers that can be used. Here, the dynamic sulfur bonds in poly(S-divinylbenzene) are used to initiate polymerization at much lower temperatures. The S-S bonds in the prepolymer are less stable than S-S bonds in S8, allowing radical formation at 90 &#176;C rather than 159 &#176;C. A variety of allyl and vinyl ethers have been incorporated to form terpolymers. The resulting materials were characterized by 1H NMR, gel permeation chromatography, and differential scanning calorimetry, as well as examining changes in solubility. This method expands on the solvent-free, thiyl radical chemistry utilized by inverse vulcanization to create polysulfides at mild temperatures. This development broadens the range of monomers that can be incorporated thus expanding the accessible material properties and possible applications.

Poly(S-DVB) was synthesized according to published protocols using high temperatures (185 &#176;C) to initiate S8 ring cleavage forming radicals3. These radicals then initiate polymerization with DVB. The molten sulfur and liquid DVB eliminate the need for solvents. Within 30 min, sulfur and DVB react completely for form poly(S-DVB). Upon removal from the vial, the polymer is a hard, brittle material at lower sulfur content (30-40%). Mid-range sulfur con...

Watch this Scientific Journal Video about Synthesis of Terpolymers at Mild Temperatures Using Dynamic Sulfur Bonds in PolyS-Divinylbenzene at JoVE.com

Synthesis of Terpolymers at Mild Temperatures Using Dynamic Sulfur Bonds in PolyS-Divinylbenzene

The goal of this protocol is to initiate polymerization using dynamic sulfur bonds in poly(S-divinylbenzene) at mild temperatures (90 &#176;C) without using solvents. Terpolymers are characterized by GPC, DSC and 1H NMR, and tested for changes in solubility.

Synthesis of Terpolymers at Mild Temperatures Using Dynamic Sulfur Bonds in Poly(S-Divinylbenzene)

Elemental sulfur (S8) is a byproduct of the petroleum industry with millions of tons produced annually. Such abundant production and limited applications ...

We've developed a method to initiate polymerization using dynamic sulfur bonds in poly(sulfur-divinylbenzene)at 90 degrees Celsius without the need for solvents. This is substantially lower than traditional methods which require temperatures above 160 degrees Celsius. Lowering the polymerization temperature broadens the range of monomers that can be incorporated into polysulfides by inverse vulcanization.This expands possible materials'properties and possible applications. Inverse vulcanization has produced polysulfides that have been used in lithium sulfide batteries, as infra-red transparent lenses, as mercury and oil sorbents among other applications. This method would enable the development of new materials and likely additional applications.One of the key benefits of this method is the relative ease of the synthesis. This video provides the opportunity to demonstrate how the reaction progresses over time, as well as showing how much the polymers can vary based on the sulfur content and the ratio of the monomers present. To prepare poly(S-divinylbenzene)combine elemental sulfur and divinylbenzene at the desired weight ratio in a one-dram vial equipped with a magnetic stir bar.Place the vial in an oil bath at 185 degrees Celsius for 30 minutes. After the reaction is complete, remove the vial from the oil bath and immediately quench by placing the vial in liquid nitrogen. Then break open the vial to remove the polymer, and repeat this step for each polymer prepared.To synthesize terpolymers, first crush the poly(S-divinylbenzene)with a mortar and pestle for higher surface area interaction with the monomer 1, 4-Cyclohexanedimethanol divinyl ether, or CDE. Then combine the poly(S-divinylbenzene)and CDE at the desired weight ratio on a 600-milligram scale. Place the sample in a oil bath at 90 degrees Celsius for 24 hours.Then cool the sample to room temperature. For reactions that do not result in complete monomer incorporation, dissolve the soluble polymer portions in dichloromethane, and precipitate in cold methanol. For samples with limited solubility, wash the solid polymer samples with cold methanol to remove any unreacted monomer.To synthesize terpolymers using maleimide, combine sulfur and divinylbenzene at a 30-to-70 weight ratio on a five-gram scale as previously described. Combine the pre-polymer with maleimide at a three-to-one weight ratio in a one-dram glass vial equipped with a magnetic stir bar. Dissolve the mixture in 10 milligrams per microliter of dimethylformamide.Then place the vial in an oil bath at 100 degrees Celsius for 24 hours. Next combine poly(S-divinylbenzene)and the desired monomer at a one-to-one weight ratio as described previously to prepare various terpolymers. Remove a sample of the mixture at various time points during the reaction, and dissolve the polymer in 600 microliters of deuterated chloroform for proton NMR analysis.To confirm that sulfur from the polymer rather than elemental sulfur is required for polymerization, prepare samples of sulfur alone, and with CDE, divinylbenzene, and allyl ether as previously described. Analyze the polymers by proton NMR in deuterated chloroform. Integrate the resulting proton NMR spectra to determine the extent of the reaction.Due to the relative low solubility and high polydispersity of most terpolymers, dissolve each polymer in dichloromethane at a high concentration of 75 milligrams per milliliter. Then remove particulates from the soluble portion using a 0.45-micron hydrophobic filter. Analyze the samples by gel permeation chromatography using dichloromethane as the eluent, two MesoPore columns in sequence, and a refractive index detector for analysis.Determine the number average and weight average molecular weights based on the calibration curve of polystyrene standards. To study thermal properties, fill aluminum pans with 30 to 50 milligrams of each polymer, providing enough sample to adequately discern the glass transition temperature from the resulting thermograms. Scan the samples and obtain the thermogram values from the second scan.For solubility studies, weigh approximately 150 milligrams of each polymer into a pre-weighed vial, and dissolve in dichloromethane to reach a concentration of 75 milligrams per milliliter. After eight hours, remove the soluble portion, and wash the insoluble portion with dichloromethane two times. Dry the remaining insoluble sample in an oven for 10 minutes to remove the remaining solvent.After cooling the vial to room temperature, weigh it, and calculate the percent solubility by determining the difference in starting and final weights. Poly(S-divinylbenzene)was synthesized using high temperatures to initiate sulfur ring cleavage-forming radicals, which then initiate polymerization with divinylbenzene. Dynamic sulfur bonds within poly(S-divinylbenzene)can be utilized to initiate polymerization with additional monomers at much lower temperatures.Mono-functional and di-function vinyl and allyl monomers were evaluated, and all were successfully polymerized as confirmed by NMR. The monomer content for all polymerizations were monitored over the course of 48 hours. Control reactions were performed to determine the role of poly(S-divinylbenzene)versus sulfur in the polymerization.The products were examined by proton NMR and TLC to examine changes to the polymer structure, monomer incorporation, and to determine if sulfur was fully incorporated. Various polymerizations were conducted to examine the polymer structure of poly(S-divinylbenzene)CDE. Both increased sulfur content, and the addition of CDE led to a decrease in the glass transition temperature.After an initial decrease in the molecular weight, the addition of CDE led to an overall increase in chain length. Maximum solubility was achieved for poly(s-divinylbenzene)synthesized with 40%to 50%sulfur. The addition of CDE led to decreased polymer solubility.For high-sulfur-content poly(S-divinylbenzene)low solubility was observed, but incorporating CDE substantially improved the solubility. Developing a solvent-free polymerization that occurs at substantially lower temperatures than previously reported broadens the range of monomers that can be incorporated into polysulfides. This may open the door to new applications, or allow materials to be better tailored for a desired function.A small amount of gas is produced during the synthesis of poly(sulfur-divinylbenzene)Vials should only be filled half-full to prevent a buildup of pressure. Samples should be vented prior from removing them from the hood to ensure the gas is not inhaled.

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Reactions of Alkenes

SCIENTISTS IN ACTION

7.5K visualizações.  Ball State University. Desenvolvemos um método para iniciar a polimerização usando ligações dinâmicas de enxofre em poli (sulfúrico-divinylbenzeno) a 90 graus Celsius sem a necessidade de solventes. Isto é substancialmente menor do que os métodos tradicionais que requerem temperaturas acima de 160 graus Celsius. A redução da temperatura de polimerização amplia a gama de monômeros que podem ser incorporados em polissulfetos pela vulcanização inversa.Isso expande possíveis propriedades de mate...