Positron annihilation spectroscopy in carbon black–silica–styrene butadiene rubber (SBR) composites under deformation

Moh́sen, M.; Salam, M. H. Abd-El; Ashry, A.; Ismail, A. M.; Ismail, Hanafy M.

doi:10.1016/j.polymdegradstab.2004.01.004

Cited by 36 publications

(26 citation statements)

References 19 publications

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“…This suggests that irradiation under deformation induces changes in matrix structure and free volume. It is known that an application of deformation may result in an increase of the free volume . In fact, the free volume holes occupied by probe molecules are slightly enlarged, but at the same time, the total amount of regions with higher local density increases.…”

Section: Resultsmentioning

confidence: 99%

Preparation and dynamic properties of an anisotropic natural rubber film as viewed by electron spin resonance–spin probe method

Valić¹,

Bonato

Andreis

et al. 2013

Polymer Engineering & Sci

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Natural rubber (NR) films with the thickness of about 1 mm were prepared by removing the liquid phase from NR latex, which was previously irradiated. The primary radiation dose varied from 0 kGy (for unirradiated NR) to 200 kGy. Dry NR films were uniaxially stretched, and the degree of deformation, defined as λ = l/l0 (l0 and l being the lengths of relaxed and uniaxially deformed sample, respectively), was varied from λ = 1.0 (relaxed state) to λ = 2.7. Samples were then irradiated with secondary dose, which was chosen to be 100 or 200 kGy. NR films were characterized by differential scanning calorimetry and electron spin resonance–spin probe method. In addition, samples were exposed to accelerated thermal aging, and changes in molecular dynamics and structure were obtained. It has been shown that the application of deformation during the cross‐linking leads to the restriction in segmental mobility for the lower secondary dose, whereas for the higher secondary dose, larger values of λ induce an opposite effect originating from the structural changes. Thermally aged samples show higher amount of the gel phase and consequently higher fraction of slow motional chain segments. POLYM. ENG. SCI., 53:2284–2291, 2013. © 2013 Society of Plastics Engineers

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Section: Resultsmentioning

confidence: 99%

Preparation and dynamic properties of an anisotropic natural rubber film as viewed by electron spin resonance–spin probe method

Valić¹,

Bonato

Andreis

et al. 2013

Polymer Engineering & Sci

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“…3), and this indicates that the addition of silica creates new positron trapping sites at silica-rubber interfaces. 19 Correlation between the free-volume parameters and the electrical and mechanical properties in the blends Because, the electrical and mechanical data for EPDM/NBR blends have been published already 12 only some results will be given here. The correlation between the permittivity (e) at 1 kHz, stress, strain, V f , and f as a function of the weight percentage of NBR in EPDM/NBR blends is shown in Figure 4.…”

Section: Free-volume Properties Of Epdm/nbr (75/25) With Silica Contentsmentioning

confidence: 99%

Microstructure and miscibility of acrylonitrile–butadiene rubber/ethylene–propylene–diene monomer blends studied by positron annihilation spectroscopy

Gomaa

2007

J of Applied Polymer Sci

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The free-volume properties and miscibility of ethylene-propylene-diene monomer/acrylonitrile-butadiene rubber blends with poly(vinyl chloride) used for compatibilization were investigated with positron annihilation lifetime spectroscopy and Doppler broadening of annihilation radiation. The results showed that the ortho-positronium annihilation lifetimes and intensities as well as the S parameter had a linear relationship with a negative slope as a function of the weight percentage of acrylonitrile-butadiene rubber, which indicated the miscibility of the blend.The filling effect of silica on the free-volume properties of an ethylene-propylene-diene monomer/acrylonitrile-butadiene rubber (75/25) blend was also examined. On the other hand, a correlation between the size and concentration of the free-volume holes and the electrical and mechanical properties of the aforementioned blends was established.

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“…1 In order to cover the shortages of SBR, rubber antioxidants, such as 4010-NA and 4020, and reinforcing llers, say carbon black and silica, were used to improve the usability of SBR. Although the abrasive resistance, heat-resistant quality and aging-resistant performance of SBR are better than those of natural rubber, the double bonds and allyl-hydrogen groups on SBR molecular chains make rubber aging more likely in thermal or humid conditions.…”

Section: Introductionmentioning

confidence: 99%

Effect of nanosilica-based immobile antioxidant on thermal oxidative degradation of SBR

et al. 2015

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A new kind of nanosilica-based immobile antioxidant (RT-silica) consisting of nanosilica, antioxidant intermediate p-aminodiphenylamine (RT) and silane coupling agent 3-glycidoxypropyltrimethoxysilane (KH-560) was successfully synthesized via a grafting reaction in our laboratory. It was revealed that the anti-oxidation performance of the SBR/RT-silica composite was far superior to that of the SBR/silica composite, especially at high temperature, based on the results of non-isothermal oxidation induction time (OIT) tests. The calculation of protection factors (PFs) based on two non-Arrhenius temperature functions showed that silica possessed an acceleration effect on the aging of the SBR matrix. According to the results of tensile tests, the SBR/RT-silica composites exhibited more preeminent mechanical properties and residual rates during accelerated aging, in comparison with the SBR/silica composites. The affections of RT-silica on the cross-linking network of the SBR matrix were investigated via a tube model, demonstrating that RT-silica can't change the cross-linking density, but can induce the chain entanglement of rubber molecular chains. Moreover, the calculated values of degradation activation energy of SBR composites via the Kissinger-Akahira-Sunose (KAS) method and Friedman method showed that RT-silica changed the thermal-oxidative aging mechanism of the SBR matrix.

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Positron annihilation spectroscopy in carbon black–silica–styrene butadiene rubber (SBR) composites under deformation

Cited by 36 publications

References 19 publications

Preparation and dynamic properties of an anisotropic natural rubber film as viewed by electron spin resonance–spin probe method

Preparation and dynamic properties of an anisotropic natural rubber film as viewed by electron spin resonance–spin probe method

Microstructure and miscibility of acrylonitrile–butadiene rubber/ethylene–propylene–diene monomer blends studied by positron annihilation spectroscopy

Effect of nanosilica-based immobile antioxidant on thermal oxidative degradation of SBR

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