Nuclear magnetic resonance polyisoprene

The determination of the various types of geometric isomers associated with unsaturation in Polymer chains is of great importance, for example, in the study of the structure of modern synthetic rubbers. In table below are listed some of the important infrared absorption bands which arise from olefinic groups. In synthetic "natural" rubber, cis-1, 4-polyisoprene, relatively small amounts of 1, 2 and 3, 4-addition can easily be detected, though it is more difficult to distinguish between the cis and trans-configurations. Nuclear magnetic resonance spectroscopy is also useful for this analysis. 

Spec. Pap. 261, 17—35. Boulder Geol. Soc. of America. SchaefferJ. (1972) Comparison of the carbon-13 nuclear magnetic resonance of some solid cis- and trans-polyisoprenes. 

Miller, J. B., K. J. McGrath, C. M. Roland, C. A. Trask, and A. N. Garroway. 1990. Nuclear-magnetic-resonance study of polyisoprene poly(vinylethylene) miscible blends. Macromolecules 23 4543 547. 

In the present wcffk, proton and carbon-13 nuclear magnetic resonance (% H . and i ) spectroscopy are used in tandem to acconplish the original goal of the chemical methods, namely, determination of the nature and level of the remaining olefinic unsaturation in order to determine cyclicity (as well as bo yield other micros tructural information). This >proach has not been reported for cyclized polyisoprene althou essentially (infrared spectroscopy plays the role pl ed by IWR in our work) the approach has recently been reported for cyclized polybutadiene. 

The use of nuclear magnetic resonance spectroscopy has been useful for detecting the presence of 3,4- structures in polyisoprenes as well as 1,2- units in polybutadienes. The method has great potential value in that calibration with standards of known composition are not required (see for example Golub et ai, 1962 Chen, 1%6). 

Glowinkowski S, Gisser DJ, Ediger MD (1990) C-13 nuclear-magnetic-resonance measurements of local segmental dynamics of polyisoprene in dilute-solution— nonlinear viscosity dependence. Macromolecules 23(14) 3520-3530. doi 10.1021/ma00216a021... 

High-resolution nuclear magnetic resonance studies of MA modified c/5-l,4-polyisoprene shows that MA is preferentially linked by inter or intramolecular additions to the double bond of the isoprene unit. The reaction is accompanied by ring formation and oxidation of the rubber. 

Nuclear magnetic resonance spectroscopy CTC detection tool, 208-211 Diels-Alder structure proof, 117 ene reaction mechanism study, 168 MA copolymer studies, 281, 290 MA-ene adduct structure proof, 153 MA grafted polyisoprene, 466 for maleate isomerization analysis, 484 MA monomer spectrum, 8, 10 MA polymer analyses, 241, 245, 249, 256, 259 MA protonation study, 211 polyester structural analysis, 484 Nylons, MA grafted, 477... 

Gisser and Ediger(41) studied solvent and solute rotation with C and nuclear magnetic resonance. The selectivity of NMR allows separate measurement of reorientation times for multiple components of a mixture. Dilute polystyrene, polyisoprene, and polybutadiene were found to retard the rotational diffusion of the toluene solvent, polystyrene being modestly more effective as a retardant. Solvent Tr depends exponentially on polymer c, at least up to 90 g/1 of polymer. Gisser and Ediger also examined the small-molecule mixture chloronaphthalene ... 

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