The reaction between dicumyl peroxide and butyl rubbers

Loan, L. D.

doi:10.1002/pol.1964.100020509

Cited by 17 publications

(29 citation statements)

References 5 publications

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“…Termination of the resulting primary macroradicals by combination can generate crosslinks. However, as noted by Loan, β‐scission is a dominant chain reaction, resulting in molecular weight losses when polyisobutylene is heated with DCP to 153 °C . Loan also reports that butyl rubber (IIR) containing less than 2 mole % isoprene is less susceptible to radical degradation than is polyisobutylene, since H‐atom abstraction from allylic positions yields allyl radical intermediates that prefer termination by combination to cleavage.…”

Section: Resultsmentioning

confidence: 96%

“…Although peroxide‐based cure formulations are generally much cleaner, IIR incurs radical degradation when activated by organic peroxides . This limitation can be overcome by introducing small amounts (between 0.05 and 0.20 mmol/g) of polymerizable functionality to the material to generate macromonomer derivatives that crosslink by radical homopolymerization of pendant groups, as opposed to the hydrogen abstraction + macro‐radical combination mechanism that underlies peroxide‐cures of saturated polymers .…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Resultsmentioning

confidence: 96%

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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“…Rather, their degradation response is consistent with unmodified IIR. [7] Our assessment of functional itaconate diesters began with studies of the cure dynamics and yields of macromonomers bearing dodec-1-enol (IIR-g-DDEI), farnesol (IIR-g-FI), perfluoroalkyl (IIR-g-PFOI), polyethylene oxide (IIR-g-PEOI), and amidopropyl trimethoxysilane (IIR-g-ASI) substituents. The data plotted in Figure 1b reveal the sensitivity of cure yields to their functional groups, both positive and negative.…”

Section: Materials and Process Designmentioning

confidence: 99%

“…[5] However, IIR cleaves under the action of organic peroxides, [6,7] and BIIR can only be peroxide-cured to a significant extent when compounded with maleimide co-agents. Although no longer produced commercially, a copolymer composed of isobutylene and divinylbenzene is highly responsive to peroxide cures, owing to the radical oligomerization of residual styrenic functionality.…”

Section: Introductionmentioning

confidence: 99%

Design of functional macromonomer derivatives of poly(isobutylene‐co‐isoprene)

et al. 2017

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The development of new peroxide-curable poly(isobutylene-co-isoprene) (IIR) elastomers is described, wherein pendant oligomerizable C¼C groups are introduced in combination with a range of serviceable functional groups. Ring-opening of itaconic anhydride with functional alcohols or amines, followed by esterification of the resulting acids with brominated IIR, yield macromonomers that crosslink efficiently under the action of dicumyl peroxide alone. More importantly, the additional graft functionality improves the physical and chemical properties of the resulting thermosets. The introduction of fluorocarbon functionality is shown to lower surface energy and improve the material's extrusion characteristics, and trialkoxysilane functionality is used to improve filler dispersion within silica-reinforced composites. This strategy is extended to prepare thermosets bearing polymer-bound phenolic antioxidant. Details of macromonomer production are followed by demonstrations of their utility as engineering materials.

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“…Peroxide‐initiated cure chemistry is used to produce crosslinked rubber articles whose carbon‐carbon crosslinks provide good thermal stability and compression set resistance . However, polyisobutylene and isobutylene‐rich copolymers incur radical degradation when activated by organic peroxides . The crosslink density of dicumyl peroxide (DCP) cured BIIR vulcanizates is low and the vulcanization reversion exists…”

Section: Introductionmentioning

confidence: 99%

Influence of 1,2‐polybutadiene on properties of dicumyl peroxide cured brominated butyl rubber

Xia

Wang

et al. 2015

J of Applied Polymer Sci

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Peroxide curing of brominated butyl rubber (BIIR) is an attractive topic, but the degradation of BIIR during the curing is a drawback needed to be overcome. Coagent assisted peroxide curing system is an attractive and effective choice in order to increase the crosslink density of rubbers. 1,2-polybutadiene (1,2-PB) is used as a crosslinking coagent for the curing of BIIR by dicumyl peroxide (DCP), and the effect of 1,2-PB on the curing characteristics, crosslink density, and mechanical properties is investigated. The addition of 1,2-PB affects the curing characteristics of BIIR compound and significantly increases the crosslink density of BIIR vulcanizates. With increasing 1,2-PB content, the tensile strength and stresses at a given extension of BIIR vulcanizates increase, but the elongation at break decreases. A stress-softening effect of the carbon black filled BIIR vulcanizates is observed and becomes more pronounced with increasing 1,2-PB content. The addition of 1,2-PB increases the stress relaxation index of BIIR. GPC and 13 C-NMR results indicate 1,2-PB participates in the crosslinking reaction, and the existence of 1,2-PB component in the insoluble fraction of BIIR/1,2-PB vulcanizates is confirmed by solid-state 13 C-NMR.

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The reaction between dicumyl peroxide and butyl rubbers

Cited by 17 publications

References 5 publications

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

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

Design of functional macromonomer derivatives of poly(isobutylene‐co‐isoprene)

Influence of 1,2‐polybutadiene on properties of dicumyl peroxide cured brominated butyl rubber

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