Spectroscopy, sequence analysis

The advantages of 2D NMR spectroscopy in monomer sequence analysis have been demonstrated for several copolymers. The copolymer of vinyl-idene chloride (V) and isobutylene (I) shows no correlation in the H COSY spectrum, since it has no /-coupled protons. However, 2D NOE spectroscopy... 

MHz high resolution solid-state NMR spectroscopy [53, 54]. All the samples used for this NMR study are random copolymers and not mixtures of random copolymers as confirmed by the solution NMR sequence analysis and by DSC melting-point measurements [43, 54]. Before taking NMR measurements, possible effects of the thermal history and recrystallization are avoided as mentioned above. 

Blends of polyethylene terephthalate and linear low-density polyethylene were compatibilised using diethylmaleate grafted polyethylene, and characterised using Fourier transform infra-red spectroscopy, thermogravimetric analysis and scanning electron microscopy. Interactions between the components in the blends were observed, which affected the glycol sequences of the polyester and also improved the thermal oxidative stability of the blends. The introduction of the compatibiliser resulted in a particle size reduction of the dispersed phase and better adhesion between the phase and the matrix. 15 refs. 

The structure of EPDM grafted onto polyamide 66 was analysed with high resolution solid state carbon-13 NMR and IR spectroscopy. Details about the EPDM rubber include the amount of mbber incorporated into this blend, the sequence analysis of the EPDM mbber and an estimate... 

In order to rank performance of catalysts in copol)unerization with respect to comonomer incorporation and comonomer sequence distribution, copolymerization parameters have proven to be very useful. They are determined by means of nuclear magnetic resonance spectroscopy (NMR copolymer sequence analysis) taking into account the Markovian statistics of chain growth, as reviewed by Randall [4], Galimberti and coworkers [5] described the analysis of EPM prepared by means of... 

Ultraviolet and visible light spectroscopy Sequence length conformation and spatial analysis. (f)... 

A very unusual reaction of 2-isopropyl-2-oxazoline 71 (R=H) needs mention. Nehring and Seelinge/ reported that on refluxing a 1,2-dichloroethane solution of 71 and MA, a 77% yield of the product 72 was obtained. When R = methyl, a 48% yield of a similar adduct was formed. The structure was proved by NMR, IR spectroscopy, elemental analysis, and hydrolysis studies. It is interesting to note that the hydrogen atom of the isopropyl group is so active for Michael addition, since that would be required as part of the sequence. 

Earlier studies using thermal denaturation analysis and spectrophotomet-ric titration with TxA T and CxC-C" containing DNA triplexes showed that coralyne binds strongly to these triplexes by intercalation and does not exhibit a significant sequence-selectivity [222]. In a later study by Morau Allen et al. [217], employing DNase footprinting, thermal denaturation analysis, UV-visible spectrophotometric titrations, circular dichroism and NMR spectroscopy, showed that coralyne is fully intercalated into TxA T triplex DNA whereas in C GxC triplex, it is partially intercalated due to electrostatic repulsion between the cationic alkaloid and the protonated cytosine [217]. Kepler et al. [223] demonstrated that coralyne intercalated to parallel triplex DNA but did not intercalate to antiparallel triplex DNA. Recently Hud and coworkers [219,224] demonstrated that duplex poly(dA) poly(dT) is trans-... 

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