Sulfuration and reversion reactions of brominated poly(isobutylene‐<i>co</i>‐isoprene)

Parent, J. Scott; White, Greg D. F.; Thom, Darren J.; Whitney, Ralph A.; Hopkins, William T.

doi:10.1002/pola.10744

Cited by 29 publications

(30 citation statements)

References 27 publications

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“…Because of the presence of the active allylic bromide functionality, the bromobutyl rubbers significantly improved the rate of sulfur vulcanization and enhanced the curing compatibility with unsaturated elastomers. [13][14][15][16][17] Recently, Amit et al 18 developed a selfhealing elastomeric material based on BIIR through the chemical modification of BIIR with butyl imidazolium into an imidazolium-modified BIIR. 9 When BIIR was reacted with ZnO at high temperatures, the exomethylene isomer of the bromobutyl rubber produced the conjugated diene butyl via the dehydrobromination reaction.…”

Section: Introductionmentioning

confidence: 99%

“…[10][11][12] Over the past decade, the Whitney research group has reported various nucleophilic substitution reactions of BIIR to introduce amine, ester, ether, sulfur, ammonium, and phosphonium salt functionalities onto butyl rubbers. [13][14][15][16][17] Recently, Amit et al 18 developed a selfhealing elastomeric material based on BIIR through the chemical modification of BIIR with butyl imidazolium into an imidazolium-modified BIIR.…”

Section: Introductionmentioning

confidence: 99%

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Thermally stable bromobutyl rubber with a high crosslinking density based on a 4,4′‐bismaleimidodiphenylmethane curing agent

Sathi

Jang

Jeong

et al. 2016

J of Applied Polymer Sci

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The development of thermally stable bromobutyl rubbers has been a challenge in rubber chemistry and engineering. In this circumstance, 4,4 0 -bismaleimidodiphenylmethane (BMI) was newly applied as a novel crosslinking agent for thermally stable brominated isobutylene-isoprene rubber (BIIR) with a high crosslinking density. With oscillating disk rheometry and differential scanning calorimetry, the curing characteristics of BIIR were systematically investigated with respect to the content of BMI. We found that BMI alone could crosslink BIIR at higher temperature, and a corresponding possible chemical reaction mechanism was proposed. With the introduction of zinc oxide, the curing reaction of BIIR with BMI was significantly accelerated, and the resulting vulcanizate provided a higher state of curing with excellent overcure reversion stability even at a temperature of 190 8C for 2 h. The content of the dicumyl peroxide (DCP) reaction accelerator was also optimized to be BMI/DCP 5 1:0.05 on the basis of considerations of the curing rate, scorch safety, maximum rheometric torque, and reversion resistance at 160 8C. Compared with the conventional sulfurcured BIIR, the BMI-cured BIIR exhibited a higher crosslinking density with a superior low compression set property at elevated temperatures and an excellent thermal stability.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Thermally stable bromobutyl rubber with a high crosslinking density based on a 4,4′‐bismaleimidodiphenylmethane curing agent

Sathi

Jang

Jeong

et al. 2016

J of Applied Polymer Sci

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“…This elastomeric material owes its superior oxidative stability and gas impermeability to its isobutylene‐rich polymer backbone, whereas the residual unsaturation provided by isoprene isomers supports the sulfur vulcanization reactivity needed to transform IIR into thermoset articles . Cure reactivity is significantly improved by halogenating isoprene‐derived unsaturation to yield brominated poly(isobutylene‐ co ‐isoprene) (BIIR), whose allylic halide functionality is highly reactive to sulfur nucleophiles . Unfortunately, sulfur‐cure formulations require accelerators and co‐curing agents, resulting in a vulcanized product containing leachable and extractable residues.…”

Section: Introductionmentioning

confidence: 99%

Isobutylene‐rich macromonomers: Dynamics and yields of peroxide‐initiated crosslinking

Dakin

Shanmugam

Twigg

et al. 2014

J. Polym. Sci. Part A: Polym. Chem.

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New isobutylene-rich elastomers bearing multiple pendant styrenic, acrylic, maleimidic, vinylic, and allylic functional groups have been prepared and examined in the context of peroxide-initiated crosslinking. Halide displacement from brominated poly(isobutylene-co-isoprene) (BIIR) by the requisite carboxylate nucleophiles in homogeneous toluene solutions provide the desired esters in quantitative yield without complications from dehydrohalogenation or premature crosslinking. Heating the resulting macromonomers with dicumyl peroxide to 160 C under solvent-free conditions gives thermoset derivatives, with reaction rates and yields depending markedly on functional group structure. In general, high cure extents can only be achieved using highly reactive pendant functional groups, owing to the competitive balance between crosslinking through C@C oligomerization, and degradation through b-scission of backbone macroradical intermediates. Independent control of crosslinking rates and cure extents is gained through the use of nitroxyl radical traps bearing acrylate functionality.

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“…Our studies of the reactions of brominated poly(isobutyleneco-isoprene), or BIIR, with uncharged nucleophiles 4,5 have demonstrated the propensity of the 1-2% of allylic bromide functionality within this polymer to undergo bromide displacement under solvent-free conditions. However, analogous reactions involving alkanethiols required strong organic bases to deprotonate the substrate and render the thiolate nucleophile soluble in the elastomer phase.…”

Section: Introductionmentioning

confidence: 97%

Synthesis of Ester Derivatives of Brominated Poly(isobutylene-co-isoprene): Solvent-Free Phase Transfer Catalysis

2006

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The principles of phase transfer catalysis (PTC) are adapted to facilitate solvent-free nucleophlic substitution reactions of brominated poly(isobutylene-co-isoprene) (BIIR). Catalytic amounts of tetraalkylammonium halides are shown to activate alkali metal carboxylate salts to generate ester derivatives in moderate to high yields without incurring complications associated with ammonium carboxylate salt instability and BIIR dehydrobromination. The structures of a range of new aliphatic and aromatic allylic esters are characterized unambiguously through comparisons with products derived from brominated 2,2,4,8,8-pentamethyl-4-nonene (BPMN), which serves as a model for the reactive functionality found within BIIR. The dynamics of the intrinsic substitution process are examined along with factors that affect the rate and selectivity of phase-partitioned, solvent-free PTC systems.

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Sulfuration and reversion reactions of brominated poly(isobutylene‐co‐isoprene)

Cited by 29 publications

References 27 publications

Thermally stable bromobutyl rubber with a high crosslinking density based on a 4,4′‐bismaleimidodiphenylmethane curing agent

Thermally stable bromobutyl rubber with a high crosslinking density based on a 4,4′‐bismaleimidodiphenylmethane curing agent

Isobutylene‐rich macromonomers: Dynamics and yields of peroxide‐initiated crosslinking

Synthesis of Ester Derivatives of Brominated Poly(isobutylene-co-isoprene): Solvent-Free Phase Transfer Catalysis

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