Ozone degradation of polychloroprene rubber in solution

Anachkov, M.P.; Rakovsky, Slavcho; Stefanova, R.; Stoyanov, Andrey

doi:10.1016/0141-3910(93)90042-h

Cited by 11 publications

(5 citation statements)

References 5 publications

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“…The intensive band detected at 1795 cm -1 in the IR spectrum of ozonized Denka M40 solutions (Fig. 8) is characteristic of chloroanhydride group [39]. This fact correlated well with the conclusion about the direction of the primary ozonide decomposition.…”

Section: Polychloroprenesupporting

confidence: 79%

“…On ozonolysis of 1,4-trans-polychloroprene the share of CI of the MCI type is over 80 %, in agreement with the induction effect of the chlorine atom [23]. However, no aldehyde groups in the ozonized polymer solution were found [39]. It follows that the interaction between MCI entites, if any, is not the dominating deactivation reaction with these intermediates.…”

Section: Assignment Of the Signals In The 1 H-nmr Spectra Of Partiallsupporting

confidence: 53%

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Ozone and its Reactions with Diene Rubbers

Заиков¹,

Rakovsky²,

Anachkov³

2012

ChChT

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The reactions of ozone with 1,4-cispolybutadiene (SKD); Diene 35 NFA (having the following linking of the butadiene units in the rubber macromolecules: 1,4-cis (47 %), 1,4-trans (42 %), 1,2-(11 %); 1,4-cis-polyisoprene (Carom IR 2200), 1,4-trans-polychloroprene (Denka M 40), and 1,4-transpolyisoprene have been investigated in CCl 4 solutions. The changes of the viscosity of the polymer solutions during the ozonolysis have been characterized by the number of chain scissions per molecule of reacted ozone (φ). The influence of the conditions of mass-transfer of the reagents in a bubble reactor on the respective φ values has been discussed. The basic functional groups-products from the rubbers ozonolysis have been identified and quantitatively characterized by means of IR-spectroscopy and 1 H NMR spectroscopy. A reaction mechanism that explains the formation of all identified functional groups has been proposed. It has been shown that the basic route of the reaction of ozone with elastomer double bondsformation of normal ozonides-does not lead directly to a decrease in the molecular mass of the elastomer macromolecules, because the respective 1,2,4-trioxolanes are relatively stable at ambient temperature. The most favourable conditions for ozone degradation emerge when the cage interaction between Criеgee's intermediates and respective carbonyl groups does not proceed. The amounts of measured different carbonyl groups have been used as an alternative way for evaluation of the intensity and efficiency of the ozone degradation. The thermal decomposition of partially ozonized diene rubbers has been investigated by DSC. The respective values of the enthalpy, the activation energy and the reaction order of the 1, 2, 4-trioxolanes have been determined.

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Section: Polychloroprenesupporting

confidence: 79%

Section: Assignment Of the Signals In The 1 H-nmr Spectra Of Partiallsupporting

confidence: 53%

Ozone and its Reactions with Diene Rubbers

Заиков¹,

Rakovsky²,

Anachkov³

2012

ChChT

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“…The larger the partial derivative, the greater the effect of the input vector on the stress relaxation property. 39 Zhao et al 15 studied the stress relaxation property of NBR aged in air. 4 shows the absolute values of sensitivity, as the partial derivative values of the input ozone concentration at different ozonation times in Fig.…”

Section: Sensitivity Analysismentioning

confidence: 99%

“…This could be attributed to highly polar C-Cl bonds in CR, which is not favorable for the ozone attack of double bonds by electrophilic addition. 39 Zhao et al 15 studied the stress relaxation property of NBR aged in air. They found that the smaller the compression ratio, the higher the value of F/F 0 .…”

Section: Stress Relaxation Predictionmentioning

confidence: 99%

Prediction of the stress relaxation property of diene rubber composites by artificial neural network approaches

Wang

et al. 2015

RSC Adv.

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An artificial neural network (ANN) based on an improved radial basis function (RBF) was established to predict the stress relaxation property of diene rubber composites during ozone aging. The compression ratio, ozone concentration, ozonation time, and rubber type were used as the input vectors, and the stress relaxation coefficient (F/F 0 ) was used as the output vector. Regularization was introduced into the RBF ANN, and the average prediction accuracy of the established ANN for three types of diene rubber was 98.1%. Compared with back-propagation (BP) ANN, the proposed model displays better prediction performance. Moreover, a sensitivity analysis based on the analytical expression generated by the RBF indicates that compression ratio is the most important factor affecting the stress relaxation response.The RBF prediction shows that rubber under a high compression ratio possesses a higher F/F 0 than that under a low compression ratio in the range of 25% to 35%, indicating that highly compressed rubber experiences a low degree of ozone attack. Analysis of the relationship between the microstructure and the stress relaxation property of the polymer reveals that application of a high compression ratio reduces the free volume and degree of cracks and that rubber under a high compression ratio has high ozone resistance. This finding is in agreement with the above RBF prediction. Comparisons between the RBF model predictions and the experimental data indicate that the well-trained model provides a deep understanding of the stress relaxation property and has the potential to guide development of materials highly resistant to ozonation.

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“…The predominant product of ozonolysis of polybutadienes and polyisoprenes in inert solutions is the o~o n i d e .~, '~~'~ It is accepted that the amount of polymer peroxides and dimmer peroxides, if formed with the polyisoprenes, is on the order of a few percent with respect to the amount of o z~n i d e s .~,~,~~ For the present the nature of the functional groups of the peroxide type in polychloroprenes cannot be identified. 21 The mechanism of ozonide thermal decomposition has not been clarified in detail, but from the values of the activation energy one can expect that the limiting step of the reaction is the homolytic scission of the 0=0 b~n d . '~.…”

Section: Enthalpic Analysismentioning

confidence: 99%

DSC study of thermal decomposition of partially ozonized diene rubbers

Anachkov

Rakovski

Stoyanov

1996

J. Appl. Polym. Sci.

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SYNOPSISThe thermal decompositions of partially ozonized 1,4-cis-polybutadiene (E-BR), 1,4-cispolyisoprene (E-IR), 1,4-truns-polyisoprene (Z-IR), 1,4-trans-polychloroprene (Z-PCh), and of polybutadiene elastomer (BR) (microstructure: 1,4-cis, 47%; 1,4-trum, 42%; 1,2, 11%) were studied. The respective thermograms were described by the presence of an intense and relatively broad exothermic peak in the 60-200°C range, which is the result of thermolysis of functional groups of the peroxide type. The measured values of the enthalpy of the reaction, normalized with respect to the amount of reacted ozone (kJ/mol 03), were as follows: 337 (E-BR), 260 (BR), 197 (E-IR), 180 (Z-IR), and 239 (Z-PCh). Values of the activation energy and reaction order were also determined 122.6, 118.5, 108, 113, 101.5 and 1.0, 0.96, 1.04,1.08, and 1.25, respectively. The enthalpy values, obtained by means of differential scanning calorimetry, should be used for quantitative determination of ozonides from polydienes and polyisoprenes.

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Ozone degradation of polychloroprene rubber in solution

Cited by 11 publications

References 5 publications

Ozone and its Reactions with Diene Rubbers

Ozone and its Reactions with Diene Rubbers

Prediction of the stress relaxation property of diene rubber composites by artificial neural network approaches

DSC study of thermal decomposition of partially ozonized diene rubbers

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