Solid State Carbon-13 NMR Studies of Vulcanized Elastomers. II, Sulfur Vulcanization of Natural Rubber

Abstract In summary, the solid-state C-13 NMR technique has proven to be a significant method for the detection of crosslinks and other structural modifications in sulfur-vulcanized NR systems. The use of sulfur as a crosslinking agent by itself generates a considerable amount of main-chain structural modifications. Cyclic sulfide structures and cis-to-trans chain isomerization are detected in addition to polysulfidic crosslinks which are found attached to different carbons of the NR repeat unit. The phenomenon of reversion has also been detected in this study. The nature of the spectral broadening in the NMR spectra of the highly cured vulcanizates has two origins. The broadening arises from lack of molecular motion in the system and from an increase in chemical shift dispersion due to the new structures formed with crosslinking.

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Solid State Carbon-13 NMR Studies of Vulcanized Elastomers. III, Accelerated Sulfur Vulcanization of Natural Rubber

Rubber Chemistry and Technology ◽

10.5254/1.3536130 ◽

1987 ◽

Vol 60 (2) ◽

pp. 278-297 ◽

Cited By ~ 21

Author(s):

A. M. Zaper ◽

J. L. Koenig

Keyword(s):

Solid State ◽

Natural Rubber ◽

Nmr Spectra ◽

Structural Modification ◽

Main Chain ◽

Nmr Studies ◽

Structural Modifications ◽

Sulfur Vulcanization ◽

Chain Isomerization ◽

Cyclic Sulfide

Abstract In summary, the solid state C-13 NMR technique has proven to be a significant method for the detection of crosslinks and other structural modifications in accelerated sulfur-vulcanized NR systems. When the amount of accelerator is high in proportion to the amount of sulfur used, the network structure appears to be simpler with less crosslinking, less main chain structural modification, and fewer cyclic sulfide structures as observed in the C-13 NMR spectra. Polysulfidic crosslinks have been detected in addition to polysulfides terminated by accelerator residues. Cis-to-trans chain isomerization is also evident in these vulcanizates.

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Thermosetting Mechanism Study of Organosilicon Polymer Containing Carborane by Solid-State NMR Spectroscopy

MRS Proceedings ◽

10.1557/proc-576-89 ◽

1999 ◽

Vol 576 ◽

Author(s):

H. Kimura ◽

K. Okita ◽

M. Ichitani ◽

M. Yonezawa ◽

T. Sugimoto

Keyword(s):

Solid State ◽

Solid State Nmr ◽

Nmr Spectra ◽

Main Chain ◽

Addition Reaction ◽

Side Chain ◽

Mechanism Study ◽

Nmr Method ◽

Organosilicon Polymer ◽

Thermal Stable

ABSTRACTThe thermosetting mechanism of an organosilicon polymer containing carborane has been studied utilizing the 13and 29Si solid-state NMR method. The polymer having C≡C bonds in the main chain and CH═CH2, Si-H bonds, and carborane in the bulky side chain, shows a very highly thermal stability in air by curing. From 13C and 29Si NMR spectra of the polymer, it was found that the intermolecular cross-linking reactions of the polymer was due to (1) the diene reaction between Ph-C≡C and C≡C and (2) the addition reaction between side chain terminal and Ph-C≡C and between CH═CH2 and Si–H, and a very highly thermal stable structure is formed.

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Solid-State NMR Studies of Molecular Motion

Annual Reports on NMR Spectroscopy ◽

10.1016/s0066-4103(06)59002-7 ◽

2006 ◽

pp. 41-116 ◽

Cited By ~ 4

Author(s):

Melinda J. Duer

Keyword(s):

Solid State ◽

Solid State Nmr ◽

Molecular Motion ◽

Nmr Studies

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[6] Solid state NMR studies of molecular motion in collagen fibrils

Methods in Enzymology - Structural and Contractile Proteins Part A: Extracellular Matrix ◽

10.1016/0076-6879(82)82063-6 ◽

1982 ◽

pp. 174-186 ◽

Cited By ~ 27

Author(s):

D.A. Torchia

Keyword(s):

Solid State ◽

Solid State Nmr ◽

Molecular Motion ◽

Collagen Fibrils ◽

Nmr Studies

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ChemInform Abstract: 13C NMR Studies of Chemical-Shielding Tensors and Molecular Motion in Meldrum′s Acid in the Solid State.

ChemInform ◽

10.1002/chin.198712050 ◽

1987 ◽

Vol 18 (12) ◽

Author(s):

K. TAKEGOSHI ◽

C. A. MCDOWELL

Keyword(s):

Solid State ◽

13C Nmr ◽

Molecular Motion ◽

Chemical Shielding ◽

Nmr Studies ◽

Shielding Tensors

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Solid-state NMR studies of the molecular motion in the kaolinite: DMSO intercalate

Journal of the American Chemical Society ◽

10.1021/ja00043a036 ◽

1992 ◽

Vol 114 (17) ◽

pp. 6867-6874 ◽

Cited By ~ 34

Author(s):

Melinda J. Duer ◽

Joao Rocha ◽

Jacek Klinowski

Keyword(s):

Solid State ◽

Solid State Nmr ◽

Molecular Motion ◽

Nmr Studies

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Solid-state NMR studies of molecular motion

Annual Reports on NMR Spectroscopy ◽

10.1016/s0066-4103(01)43008-0 ◽

2001 ◽

pp. 1-58 ◽

Cited By ~ 14

Author(s):

Melinda J. Duer

Keyword(s):

Solid State ◽

Solid State Nmr ◽

Molecular Motion ◽

Nmr Studies

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ChemInform Abstract: Solid-State NMR Studies of Molecular Motion

ChemInform ◽

10.1002/chin.200117278 ◽

2001 ◽

Vol 32 (17) ◽

pp. no-no

Author(s):

Melinda J. Duer

Keyword(s):

Solid State ◽

Solid State Nmr ◽

Molecular Motion ◽

Nmr Studies

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13C CP/MAS NMR spectra of poly-β-D(1 → 4) mannose: mannan

Canadian Journal of Chemistry ◽

10.1139/v90-184 ◽

1990 ◽

Vol 68 (7) ◽

pp. 1192-1195 ◽

Cited By ~ 15

Author(s):

R. H. Marchessault ◽

M. G. Taylor ◽

W. T. Winter

Keyword(s):

Hydrogen Bonding ◽

Solid State ◽

Solid State Nmr ◽

Nmr Spectra ◽

Repeat Unit ◽

Intramolecular Hydrogen Bonding ◽

Lower Mobility ◽

Intramolecular Hydrogen ◽

Cp Mas Nmr ◽

13C Cp Mas Nmr

13C solid-state NMR spectra (CP/MAS) were recorded for mannan polymorphs: mannan I ("ivory nut") and mannan II (Codiumfragile). These pure mannans, poly-β-(1 → 4) mannopyranose, show a single resonance for each carbon of the chemical repeat unit. This is the expected result based on the crystalline P212121 and 1222 symmetries. The T1 values were also recorded and the results are compared to those for cellulose obtained from the literature. The much lower mobility of C-6, even in noncrystalline mannan, compared to native cellulose is attributed to the epimeric difference at C-2 between cellulose and mannan allowing intramolecular hydrogen bonding in the former but not the latter. Keywords: mannan, solid state NMR, T1 relaxation, polysaccharide, ivory nut.

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