The effect of the network structure of the thermal properties ofcis-1,4-polyisoprene vulcanizates

Ślusarski, L.; Janowska, G.

doi:10.1007/bf02069944

Cited by 27 publications

(14 citation statements)

References 11 publications

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“…Thermal analysis of IR vulcanizates was performed with a derivatograph [2]. Samples for the analysis were prepared from non-extracted vulcanizates in a disintegrated form.…”

Section: Methodsmentioning

confidence: 99%

“…The molecular weight of IR was measured by viscosimetry [2]. Rubber mixtures were prepared by means of a laboratory rolling mill.…”

Section: Methodsmentioning

confidence: 99%

“…The optimal vulcanization times, t09, for mixtures I1, 12 and 13 were 74, 37 and 27 min., respectively. The rubber mixtures were vulcanized in an electric press at 4 MPa and 150 ~ The cross-linking density was calculated from measurements of the equilibrium swelling [2].…”

Section: Methodsmentioning

confidence: 99%

“…These processes are initiated by the formation of unstable peroxide groups, whose decomposition gives rise to the degradation and thermal destruction or crossqinking of the macromolecules [1][2][3]. The role of initiator in these processes can also be played by a low-molecular peroxide added to the elastomer [1 ].…”

mentioning

confidence: 99%

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The thermal behaviour of cis-1,4-polyisoprene in the presence of cobalt salt

Janowska¹,

Janczak²,

Ślusarski³

1988

Journal of Thermal Analysis

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The effects of synthetic fatty acids ("Versatic 10", average formula CIjH2202) and the cobalt salts of these acids (cobalt siccative) on the thermal properties of cis-1,4-polyisoprene were examined, using a rheometer and a derivatograph. It was found that both Versatic 10 and the cobalt siccative accelerate the peroxide vulcanization of the isoprene rubber considerably, simultaneously decreasing the cross-linking density and increasing the sol fraction eonter~t in the vuI.canizates. This is brought about by parallel radical and ionic decomposition of the peroxide initiator in the presence of these compounds. The addition of Versatic 10 or the cobalt siccative to the polyisoprene rubber does not alter the general character of its thermal changes, rut decreases the temperatures of these processes and the degradation degree of the elastomer.Studies carried out in our institute led to the conclusion that thermal processes in elastomers in an atmosphere of air are controlled by the rate of diffusion of oxygen into the reaction zone. These processes are initiated by the formation of unstable peroxide groups, whose decomposition gives rise to the degradation and thermal destruction or crossqinking of the macromolecules [1][2][3]. The role of initiator in these processes can also be played by a low-molecular peroxide added to the elastomer [1 ]. It is known from the theory and practice of radical polymerization that peroxides show particular activity in the presence of salts of metals with variable valency (in redox systems). Thus, we decided to establish whether this mechanism of peroxide activation also operates in the case of reactions taking place at a considerably elevated temperature in the elastomer system. Therefore, we have examined the effects of the cobalt salts of organic acids in the form of a siccative on the thermal properties of cis-1,4-polyisoprene.

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“…Thermal analysis of IR vulcanizates was performed with a derivatograph [2]. Samples for the analysis were prepared from non-extracted vulcanizates in a disintegrated form.…”

Section: Methodsmentioning

confidence: 99%

“…The molecular weight of IR was measured by viscosimetry [2]. Rubber mixtures were prepared by means of a laboratory rolling mill.…”

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

The thermal behaviour of cis-1,4-polyisoprene in the presence of cobalt salt

Janowska¹,

Janczak²,

Ślusarski³

1988

Journal of Thermal Analysis

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“…In cis-1,4-polyisoprene vulcanizates, the transitions which occur above 300˚C have been found to be of greater significance because of a strong correlation between the thermal properties and the elastomer combustibility [24]. Therefore, the kinetic parameters have been evaluated only for the major decomposition observed between 300˚C and 400˚C.…”

Section: Kinetics Of Thermal Degradationmentioning

confidence: 99%

Infrared Spectroscopy and Thermal Stability Studies of Natural Rubber-Barium Ferrite Composites

Mahmoud¹,

Makled²

2012

ACES

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Natural Rubber (NR)-barium ferrite (BaF) composites (RFCs) have been prepared. Structural features of the composites were characterized by Infrared spectroscopy and scanning electron microscope (SEM). Differential scanning calorimetry (DSC) analysis showed that there is small variation of glass transition temperature (≈-1˚C). The activation energy of glass transition was calculated by Kissinger method and has values between (53 -110 kJ/mol). Thermodynamic parameters such as activated entropy, enthalpy and Gibbs free energy were calculated for glass transition also. Thermogravimetric analysis TG and its derivative DTG showed one stage thermal decomposition between 300˚C -400˚C with weight loss between (19.47% -52.13%). Increasing barium ferrite loading will increase the thermal stability of natural rubber. The kinetic parameters such as activation energy, entropy, enthalpy and Gibbs free energy for composites in the decomposition region were calculated and analyzed using Coats-Redfern technique.

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The effect of oxygen pressure on the kinetics of thermo-oxidative degradation of the copolymer EVA and nitrile-butadiene rubber

Budrugeac

2000

J. Appl. Polym. Sci.

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ABSTRACT:The results of nonisothermal kinetic analysis of the thermo-oxidative degradation in air and in oxygen of the copolymer EVA and nitrile-butadiene rubber (NBR) are presented. It was observed that similar processes take place at thermooxidative degradation in air as well as in oxygen of both investigated polymeric materials. The first process, which leads to solid products, is followed by thermo-oxidative degradation with the generation of volatile products. It has been shown that the first process of thermo-oxidation occurs at lower temperatures in oxygen than in air. For this process, the nonisothermal kinetic analysis was carried out using the Kissinger method. The obtained results revealed the importance of the oxygen pressure as an accelerator in the thermo-oxidative degradation of copolymer EVA and NBR.

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The effect of the network structure of the thermal properties ofcis-1,4-polyisoprene vulcanizates

Cited by 27 publications

References 11 publications

The thermal behaviour of cis-1,4-polyisoprene in the presence of cobalt salt

The thermal behaviour of cis-1,4-polyisoprene in the presence of cobalt salt

Infrared Spectroscopy and Thermal Stability Studies of Natural Rubber-Barium Ferrite Composites

The effect of oxygen pressure on the kinetics of thermo-oxidative degradation of the copolymer EVA and nitrile-butadiene rubber

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