The structure of polybutadienes and butadiene-acrylonitrile copolymers

Livanova, N. M.; Карпова, С. Г.; Попов, А. А.

doi:10.1134/s0965545x0909003x

Cited by 8 publications

(9 citation statements)

References 7 publications

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“…For BNKS-18 and SKN-18 at room temperature, the EPR spectrum of the TEMPO probe is a classical triplet; for BNKS-28 and BMKS-40, the spectral pattern is characteristic of the heterogeneous structure; and, for SKN-26 and SKN-40, the spectral pattern is typical of the homogeneous structure with retarded motion. The Arrhenius dependences of τ с demonstrate relaxation transitions in the range of 293-343 K [6,7,11]. The activation energy for the rotational mobility of radicals was calculated from different portions of the curves (Fig.…”

Section: Methodsmentioning

confidence: 99%

“…Our task was to determine differences in the microstructures of chains: the distribution of polar AN units and disruptions of stereoregularity of butadiene units mainly occurring in the trans-1,4 configuration [6]. Trans-1,4 units form ordered structures, and the size distribution of these structures depends on the number of disruptions of the geometric similarity of butadiene chain fragments [6][7][8]. It was of interest to study the differences in the structures of block samples, in the sizes of ordered structures of butadiene units.…”

Section: Introductionmentioning

confidence: 99%

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The Structure of Acrylonitrile-Butadiene Rubbers: Paramagnetic-Probe Study

Livanova

Карпова²,

Заиков³

2013

ChChT

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Chain microstructures and supramolecular structures of nitrile-butadiene rubbers are studied by ESR spectroscopy. On the temperature dependences of the rotational mobility (correlation time τ c) of paramagnetic probe 2,2,6,6-tetramethylpiperidine-1-oxyl, relaxation transitions are observed. It is shown that there is a correlation between the Arrhenius parameters of rotational mobility of radical and the copolymer composition and that different brands of rubbers differ in microstructure and supramolecular structure.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The Structure of Acrylonitrile-Butadiene Rubbers: Paramagnetic-Probe Study

Livanova

Карпова²,

Заиков³

2013

ChChT

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“…It is known that polymer degradation is not homogeneous on the macroscopic scale. Degradation under accelerated conditions often occurs as a heterogeneous process controlled by oxygen diffusion 17–27. In thick polymer samples, where oxygen consumption exceeds the rate of oxygen permeation, oxidation of the surface layers is generally observed, with the core of the sample remaining unaffected.…”

Section: Introductionmentioning

confidence: 99%

Spatial Heterogeneity of Thermo‐Oxidative Degradation in Impact Poly(propylene) Copolymers

Goede

Mallon

Rode³

et al. 2011

Macro Materials & Eng

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The spatial degradation in impact PP copolymers with different ethylene contents is studied by FTIR microscopy and layer‐by‐layer milling of the sample surfaces, followed by ATR‐FTIR, SEC, and CRYSTAF analysis. FTIR allows for tracking of the rate of degradation, providing information on the depth profiling of the degradation. Results show that samples with lower ethylene content degrade faster at all depths than those with higher ethylene content. The latter show a more uniform degradation from the surface to the bulk of the material at longer degradation times. This is ascribed to the higher amorphous content which results in a larger oxygen diffusion to the centre of the material while its slower rate of degradation is ascribed to the lower tertiary carbon content.

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“…In [1], the micro-and supramolecular structure of ethylene-propylene-diene ternary copolymers was studied by IR and EPR spectroscopy. Paramagnetic probe measurements showed that the temperature dependences of correlation time τ с plotted in Arrhenius coordinates for microblock copolymers with high degrees of isotacticity of propylene units demonstrate transitions relevant to the breakdown of supramolecular structures composed of not only ethylene sequences but also propylene sequences [1]. Later on, the existence of these transitions was confirmed by the thermomechanical analysis of the copolymers [2].…”

Section: Introductionmentioning

confidence: 99%

The Structure of Polybutadienes and Butadiene-Acrylonitrile Copolymers

Livanova¹,

Карпова²

2011

ChChT

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The paramagnetic probe method with the use of free radicals of different dimensions (2,2,6,6-tetramethyl-1-piperidinyloxy and 4-benzoate-2,2,6,6-tetramethyl-1piperidinyloxy) has been employed to study the effect of the isomeric composition of butadiene units in polybutadienes and butadiene-acrylonitrile copolymers on the number and dimensions of ordered structures. The nature of density fluctuations and defective regions, that is, the regions in which the radicals are sorbed, has been ascertained. It has been shown that the ordered regions are composed of stereoregular chain fragments, while defective regions are enriched with butadiene isomers different from those present in prevailing amounts.

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The structure of polybutadienes and butadiene-acrylonitrile copolymers

Cited by 8 publications

References 7 publications

The Structure of Acrylonitrile-Butadiene Rubbers: Paramagnetic-Probe Study

The Structure of Acrylonitrile-Butadiene Rubbers: Paramagnetic-Probe Study

Spatial Heterogeneity of Thermo‐Oxidative Degradation in Impact Poly(propylene) Copolymers

The Structure of Polybutadienes and Butadiene-Acrylonitrile Copolymers

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