Crystal growth in EPDM by chemi-crystallisation as a function of the neutron irradiation dose and flux level

Lambri, O.A.; Salvatierra, Lucas Matías; Sánchez, Fernando; Matteo, C.L.; Sorichetti, P.A.; Celauro, Clara

doi:10.1016/j.nimb.2005.03.012

Cited by 20 publications

(45 citation statements)

References 16 publications

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“…Then, despite the non-monotonous behaviour of the measured points, an increase on the volume fraction of crystals as the dose increases can be proposed. The increase in the volume fraction of crystallites was already explained through a chemicrystallization process promoted by neutron impacts [2, 6,10,15,16]. In fact, neutron irradiation produces chain scissions, the scission products having less restricted mobility.…”

Section: Resultsmentioning

confidence: 99%

“…The estimated uncertainties for tan() and G' were less than 3% and 10%, respectively. Figure 1 shows the tan() and G´ values measured at 300 K, temperature which is near the maximum in damping corresponding to the melting of crystals in EPDM [2, 5,6]. As it can be seen from the Figure, tan() values increase as the irradiation dose increases indicating that the volume fraction of crystallites increases as the doses increases [5,6].…”

Section: Measurementsmentioning

confidence: 97%

“…In all the irradiated samples the activity was smaller than 5.6 x 10 4 Bq. By considering the whole reactions of the neutron irradiation process over the Bayerite [12], the following  doses corresponding to the neutron ones can be obtained (less than) 3, 6, 15 and 30 Gy, respectively [6].…”

Section: Neutron Irradiationmentioning

confidence: 99%

“…In fact, controlled neutron irradiation is an excellent aging tool in order to promoted different volume fraction and size of crystalline zones [5,6,9,10]. Results are discussed and correlated with studies of differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA) and positron annihilation lifetime spectroscopy (PALS) from where, the changes in crystallinity in EPDM were indirectly studied.…”

Section: Introductionmentioning

confidence: 99%

“…Therefore, the tools for determining the crystalline degree in EPDM have high interest in the field of the power electrical engineering. Nevertheless, the determination of the crystalline changes in EPDM, during outdoor service or in accelerated ageing at the laboratory, by means of direct techniques as infrared absorption spectroscopy or X-ray diffraction is often very difficult or an impossible work [2,[4][5][6]. In fact, the small volume fraction of crystallites in EPDM and its small changes both in volume fraction and size make a difficult task for the experimental work [2,[4][5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

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Changes in the crystalline degree in neutron irradiated EPDM viewed through infrared spectroscopy and inelastic neutron scattering

et al. 2018

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The changes in the degree of crystallinity in commercial Ethylene Propylene Diene rubber-type M (EPDM) irradiated with neutrons at different doses has been studied by means of inelastic neutron scattering and infrared absorption spectroscopy experiments. EPDM samples were taken from the housing of non-ceramic electrical insulators which are used in outdoor transmission lines of 66 kV. Inelastic neutron scattering spectra were recorded at 5 K with an accessible energy-transfer range between 180 -3500 cm -1 . Infrared studies were performed at room temperature with an energy transfer between 4000 -400 cm -1 . Controlled neutron irradiation allows to obtain different volume fraction and size of crystalline zones in EPDM. The obtained results are discussed and correlated with studies of differential scanning calorimetry, dynamic mechanical analysis and positron annihilation lifetime spectroscopy from where the changes in crystallinity in EPDM were indirectly studied. Inelastic neutron scattering studies were not appropriate for determining the changes in the crystallinity degree in neutron irradiated commercial EPDM. In contrast, from infrared absorption spectroscopy the changes in crystallinity could be determined successfully.

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Section: Resultsmentioning

confidence: 99%

Section: Measurementsmentioning

confidence: 97%

Section: Neutron Irradiationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Changes in the crystalline degree in neutron irradiated EPDM viewed through infrared spectroscopy and inelastic neutron scattering

et al. 2018

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Mechanical energy losses in commercial crosslinked low‐density polyethylene in the temperature range between 200 and 400 K

Lambri

Bonifacich

Garcı́a

et al. 2019

J of Applied Polymer Sci

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Aging treatments in water and in air and controlled neutron irradiation were performed on commercial crosslinked lowdensity polyethylene (XLPE) for promoting different mesostructural arrangements of crystallites and crosslinking degree. Infrared spectroscopy, differential scanning calorimetry, differential thermal analysis, thermogravimetry, and dynamic mechanical analysis were used as characterization techniques. The relaxation peak related to the mobility of the grain boundaries from crystalline zones in XLPE was identified at around 260 K (at 7 Hz), involving an activation energy of 90 AE 4 kJ mol −1 . The usual equation for describing the grain boundary mobility in metals involving the movement of grain boundary dislocations was adapted for studying the mobility of the boundaries among the crystalline zones, successfully. In addition, a new mechanical relaxation peak that appears at around 300 K (at 7 Hz), which involves an activation energy of 94 AE 5 kJ mol −1 , was found. The driving force controlling this peak was determined as the dragging of the polymer chains at the amorphous zones adjacent to the crystals controlled by the mobility of the crystallites boundaries. The chains movement was done with break away from the physical pinning points.

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The hydrogen bond and free volume property of poly(ether‐urethane) irradiated by neutron

Chen

Huang

Fang

et al. 2009

J Polym Sci B Polym Phys

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Poly(ether-urethane) (PEU) was irradiated by neutron in different atmospheres. The hydrogen bonding interaction was analyzed by Fourier transform infrared (FTIR), and the microstructure of PEU had been investigated by positron annihilation lifetime spectroscopy (PALS). The gas products were detected by gas chromatography after irradiation. The results demonstrated that the irradiation led to more hydrogen bonded carbonyl in PEU, smaller relative free volume fraction, and narrower free volume distribution. It suggested that increasing hydrogen bonds would result in the collapse of free volume.The irradiation induced micro-phase merging together and the presence of oxygen would accelerate this tendency, which was revealed by PALS. All the results indicated that the chain relaxation led to more hydrogen bonds, and the hydrogen bonding interaction suppressed the free volume. V C 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: [381][382][383][384][385][386][387][388] 2010

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Crystal growth in EPDM by chemi-crystallisation as a function of the neutron irradiation dose and flux level

Cited by 20 publications

References 16 publications

Changes in the crystalline degree in neutron irradiated EPDM viewed through infrared spectroscopy and inelastic neutron scattering

Changes in the crystalline degree in neutron irradiated EPDM viewed through infrared spectroscopy and inelastic neutron scattering

Mechanical energy losses in commercial crosslinked low‐density polyethylene in the temperature range between 200 and 400 K

The hydrogen bond and free volume property of poly(ether‐urethane) irradiated by neutron

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