The effect of metals on thermal degradation of polyethylenes

Gorghiu, Laura Monica; Jipa, S.; Zaharescu, Traian; Setnescu, Radu; Mihalcea, Ion

doi:10.1016/s0141-3910(03)00265-9

Cited by 67 publications

(35 citation statements)

References 15 publications

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“…The kinetic parameters obtained for oxidation at 170°C in oxygen suggest that HDPE is a more stable polymer than low-density polyethylene, linear low-density polyethylene, and isotactic polypropylene [12]. Gorghiu et al [13] have investigated the kinetic parameters of the degradation of LDPE and HDPE materials promoted by intimate metal/ polymer contact. Ahmad and Billiet [14] have used dioctylphthalate and carbonyl groups to probe the photooxidation processes that occur in commercial polymers.…”

Section: Introductionmentioning

confidence: 99%

Characterization of high-density polyethylene using laser-induced fluorescence (LIF)

Htun

2012

J Polym Res

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Fluorescence intensity decays of high-density polyethylene (HDPE) films have been studied by laserinduced fluorescence (LIF). An internally cavity-dumped dye laser synchronously pumped with a mode-locked argon-ion laser was used to excite the HDPE samples. The decay in the fluorescence intensity of HDPE film is due to the carbonyl present in the film, and was shown to be dependent on the power density of the incident UV light. The fluorescence intensity decay exhibits second-order kinetics. The experimental results obtained here demonstrate that the photostability of HDPE films can be characterized by the rate coefficient of the fluorescence intensity decay.

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Section: Introductionmentioning

confidence: 99%

Characterization of high-density polyethylene using laser-induced fluorescence (LIF)

Htun

2012

J Polym Res

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“…Transition metals such as Fe, Zn and Cu were reported to increase the degradation rate of either polymers or long molecular chain organic compounds [22-24, 27, 36, 37]. Copper used as central conductor material can produce significant catalytic effect on polymer oxidation during the thermal stress [3,[21][22][23] by hydroperoxides scissions into free radicals [24,25]:…”

Section: Introductionmentioning

confidence: 99%

“…The primary hypothesis of this study was the assumption that the thermal treatments in the range 80-120°C induce copper diffusion into the adjacent XLPE material. The secondary hypothesis of this work is the capability of measurement procedures, chemiluminescence (CL) and differential scanning calorimetry (DSC) to characterize the catalytic effect of diffused Cu at elevated temperatures [22,26,27]. Taking into account the univocal relationship between the oxidation induction time (OIT) and material stability [28,33], it is also foreseen that the samples containing Cu will present lower OIT values as compared to copper-free ones.…”

Section: Introductionmentioning

confidence: 99%

Copper diffusion in cable-insulating materials by chemiluminescence and DSC techniques

Jipa

Setnescu

Zaharescu³

et al. 2015

J Therm Anal Calorim

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Chemiluminescence (CL) and differential scanning calorimetry (DSC) were applied for proving the copper ion migration processes occurring within the lowdensity polyethylene (LDPE) electrical insulator as a consequence of intimate contact. Thin LDPE slides of 0.5 mm thick were subjected to short-time thermal stress at temperatures between 80 and 120°C. Both CL and DSC kinetic parameters revealed the acceleration of posttreatment oxidation at elevated temperatures (170-200°C) in copper-contacting polymer as in respect to the cases when Cu was absent. It was revealed that the oxidation rate measured by CL was more than two times higher for the samples heated in the presence of Cu than in its absence, while the oxidation induction time from DSC was considerably lowered for the same samples. Elemental analysis data provided by atomic absorption spectroscopy and particle-induced X-ray emission techniques as well as SEM investigations confirmed the presence of copper within the samples subjected to thermal treatment when the polymer insulation was in contact with the metallic conductor. Chemiluminescence procedure has a remarkable sensitivity to detect the effect of copper in the polymer matrix even at low concentrations.

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“…When these macroradicals are formed in the crystalline regions of the polymer, they are trapped there and are relatively stable, according to [20,21]. The very high molecular weight of UHMW-PE chains further enhances the stability of these macroradicals, as the low mobility of the chains hinders propagation reactions [22]. On the other hand, pure thermal aging (graph for 0 kGy) only led to a slight increase of YI.…”

Section: Uhmw-pementioning

confidence: 99%

Discoloration Effects of High-Dose γ-Irradiation and Long-Term Thermal Aging of (U)HMW-PE

Kömmling

Chatzigiannakis

Beckmann

et al. 2017

International Journal of Polymer Science

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Two polyethylene types with ultra-high (UHMW-PE) and high molecular weight (HMW-PE) used as neutron radiation shielding materials in casks for radioactive waste were irradiated with doses up to 600 kGy using a 60 Co gamma source. Subsequently, thermal aging at 125∘ C was applied for up to one year. Degradation effects in the materials were characterized using colorimetry, UV-Vis spectroscopy, IR spectroscopy, and DSC. Both materials exhibited a yellowing upon irradiation. The discoloration of UHMW-PE disappeared again after thermal aging. Therefore, the yellowing is assumed to originate from annealable color centers in the form of free radicals that are trapped in the crystalline regions of the polymer and recombine at elevated temperatures. For the antioxidantcontaining HMW-PE, yellowing was observed after both irradiation and thermal aging. The color change was correlated mainly to decomposition products of the antioxidant in addition to trapped radicals as in UHMW-PE. Additionally, black spots appeared after thermal aging of HMW-PE.

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The effect of metals on thermal degradation of polyethylenes

Cited by 67 publications

References 15 publications

Characterization of high-density polyethylene using laser-induced fluorescence (LIF)

Characterization of high-density polyethylene using laser-induced fluorescence (LIF)

Copper diffusion in cable-insulating materials by chemiluminescence and DSC techniques

Discoloration Effects of High-Dose γ-Irradiation and Long-Term Thermal Aging of (U)HMW-PE

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