High Resolution Solid State 13C NMR

Characterization439 Inherent viscosity before and after solid-sate polymerization is 0.46 and 3.20 dL/g, respectively (0.5 g/dL in pentafluorophenol at 25°C). DSC Tg = 135°C, Tm = 317°C. A copolyester of similar composition440 exhibited a liquid crystalline behavior with crystal-nematic and nematic-isotropic transition temperatures at 307 and 410°C, respectively (measured by DSC and hot-stage polarizing microscopy). The high-resolution solid-state 13C NMR study of a copolyester with a composition corresponding to z2/zi = 1-35 has been reported.441... 

Zinc complex formation with 1,3-diketones in aqueous solution has been investigated with pentane-2,4-dione, l,l,l-trifluoropentane-2,4-dione, and 4,4,4-trifluoro-l-(2-thienyl)butane-l, 3-dione. The buffer dimethylarsinic acid was shown to have a catalytic effect on complex formation with pentane-2,4-dione and the proton transfer reactions were affected.471,472 High-resolution solid state 13C NMR studies of bis(2,4-pentanedionato) zinc complexes have been carried out.473... 

Later on, when high-resolution solid-state 13C NMR became available, these questions concerning motions within the rings of poly(cycloalkyl methacrylates) and the assignment of the specific motion occurring in the case of poly(cyclohexyl methacrylate) were revisited [6]. 

The high resolution solid-state 13C NMR spectrum of the HMDA network observed at 80 °C leads to separate lines for the various aliphatic carbons DGEBA methyl carbons, HMDA methylene carbon in the p or y position with respect to the nitrogen atom, CH2 (of the hydroxypropyl ether) directly bonded to the nitrogen, and the CHOH - CH2 - O unit. For the aromatic... 

In addition to the carbons observed in the high resolution solid-state 13C NMR spectrum of the HMDA part, the 13C NMR spectrum of the HA60 system contains two more lines arising from the hexylamine carbons [63]. 

In this chapter we review the study of the solid structure of many crystalline polymers mainly with high-resolution solid-state 13C NMR, so we will briefly summarize here its principles for the convenience of the reader. For this purpose we first consider the Hamiltonian of an ensemble of nuclei possessing spin in a static field B0. The Hamiltonian to be considered of this spin system can be written as ... 

The mass fraction of the narrow component that corresponds to the rubbery noncrystalline amorphous phase is as small as 0.003-0.006. The mass fraction does not increase appreciably with increasing temperature, but stays almost unchanged up to 70 °C. Hence, it is concluded that solution-grown samples do not actually comprise a rubbery amorphous phase. This conclusion is confirmed by high-resolution solid-state 13C NMR with more detailed information. 

Carbon black filled NR vulcanisates have been studied by high-resolution solid-state 13C NMR at 75.5 MHz. It is shown that the detection of poly- and mono-sulfidic crosslinks with 13C MAS spectroscopy is also possible in the case of carbon black filled NR vulcanisates. Quantitative results suggest that the addition of carbon black leads to a decrease in crosslink density with increasing filler content [55]. 

This is observed directly in the high-resolution solid state 13C NMR spectrum by the fact that there are two peaks, separated by 6 ppm, due to carbonyl carbons. The peak at higher frequency is assigned as 13C in the hydrogen bonded carbonyl group [91,92]. 

Thus, the cis-trans and trans-trans conformations can be distinguished on the basis of the number of peaks in their high-resolution solid state 13C NMR spectra. 

The high-resolution solid state 13C NMR spectra of polymorphs of naphthazarin (5,8-dihydroxy-1,4-napthoquinone) and methyl derivatives have been rationalised in terms of hydrogen bonding effects [143]. There are three polymorphs (denoted A, B and C) of naphthazarin, in each of which, at room temperature, the molecules occupy crystallographic inversion centres. As shown below, there is a proton transfer reaction between the two forms la and lb. In solution, this proton transfer is fast on the H and 13C NMR timescales. 

Wang, J., Cheung, M. K., and Mi, Y. 2001. Miscibility of poly(ethyl oxazoline)/ poly(4-vinylphenol) blends as investigated by the high-resolution solid-state 13C NMR. Polymer 42 2077-2083. 

Liu, S. F. and Schmidt-Rohr, K. (2001) High-Resolution Solid-State 13C NMR of... 

Yamamoto, Y, Kishi, M., Amatharani, D., Sivakumar, M., Tsujita, Y, Yoshimizu, H. Study on. delta.-form complex in syndiotactic polystyrene-organic molecules system III. Fine structures of complexes with xylene isomers by means of high-resolution solid-state 13C NMR spectroscopy. Polymer, 35(6), 465 69 (2003). 

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