The addition of carbalkoxycarbenes to conjugated diene polymers

Lishanskii, I.S.; Tsitokhtsev, V. A.

doi:10.1016/0032-3950(68)90179-2

Cited by 1 publication

(1 citation statement)

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“…[19] The effect of the modification onto the glass transition temperature T g was investigated by DSC as it is of special importance for the desired tire application (see Table 3). There appears to be a reduction in the segmental mobility due to reduction in rotation around the CH 2 bonds in the backbone of the macromolecules, corresponding to the increase in the number of polar ester groups, [3,39] as the T g of the virgin PI 3shows an increase from −67 C to −61 C and − 58 C for 5% modified PI, cyclopropanated by EDA (4) and t-BDA (5), respectively. On further increase of modification to 17% (see Table 3, Entry 6c.i), the T g of the cyclopropanated PI shows an increase of $23 C to −44 C. The regioselectivity of 1,4-and 3,4-PI was also investigated via 1 H-NMR spectroscopy (details see Appendix S1) revealing an almost constant ratio between both isomers before and after the modification.…”

Section: Cu(i)-catalyzed Cyclopropanation Of Pi With Diazoacetatesmentioning

confidence: 99%

Cyclopropanation of poly(isoprene) using NHC‐Cu(I) catalysts: Introducing carboxylates

Shinde

Michael

Rössle³

et al. 2020

Journal of Polymer Science

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The incorporation of functional groups into unsaturated polyolefine-polymers often represent a challenging task. Based on the known cyclopropanation of double bonds with diazoesters in the presence of metal-catalysts of low molecular weight compounds, we in this article develop an approach to decorate the polymer backbone of poly(diene)s with ester as well as carboxylic groups via cyclopropanation. Therefore, predominantly cis-1,4-poly(isoprene)s are converted with ethyl or tert-butyl diazoacetate using copper(I) N-heterocyclic carbene (NHC) catalysts, while focusing on the technically relevant cyclohexane as solvent. The application of commercially available NHC-Cu(I) catalysts results in modification degrees of 4-5%, while an increased solvent polarity, like dichloromethane, results in up to 17% modification. The resulting esters were further converted to the corresponding free carboxylic groups by deprotection using trifluoroacetic acid. Thus, an introduction of functional groups along the polymer backbone with a wide variety of application, like ionic interaction or hydrogen bonding motifs, was successfully demonstrated. Its potential for upscaling makes this approach feasible for an application in large-scale production processes, such as for manufacturing of modified synthetic rubbers.

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Section: Cu(i)-catalyzed Cyclopropanation Of Pi With Diazoacetatesmentioning

confidence: 99%