Antioxidant Depletion Lifetime in High Density Polyethylene Geomembranes

Hsuan, Y. G.; Koerner, Robert M.

doi:10.1061/(asce)1090-0241(1998)124:6(532)

Cited by 215 publications

(168 citation statements)

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“…From an engineering perspective, the oxidation reactions described above are thought to cause the degradation of a HDPE GMB through three distinct (conceptual) stages until nominal failure (Viebke et al 1994;Hsuan and Koerner 1998). In stage I (antioxidant depletion), the GMB loses its antioxidants either by consumption of free radicals or physical extraction (e.g.…”

Section: Annealing Effect On Mechanical Propertiesmentioning

confidence: 99%

“…Stage II (induction time) is considered to begin after the antioxidants have depleted and can no longer protect the GMB from auto-oxidation reactions that then propagate giving hydroperoxides. However, the amount of hydroperoxides in the polymer is still not high enough to cause a change in the GMB bulk properties (Hsuan and Koerner 1998) and thus this stage represents the onset of polymer degradation. During stage II, oxidation continues to the point at which the concentration of hydroperoxides reaches a critical level wherein there are sufficient new free radicals to cause a clear and measurable degradation in polymer properties; this defines the end of stage II and start of stage III.…”

Section: Annealing Effect On Mechanical Propertiesmentioning

confidence: 99%

“…From this point, degradation continues until nominal failure (e.g. the time when an engineering property has decreased to 50% of either the initial value (Hsuan and Koerner 1998) or 50% of the specified value (Rowe et al 2009)). …”

Section: Annealing Effect On Mechanical Propertiesmentioning

confidence: 99%

“…According to Hsuan and Koerner (1998) changes in the MI can infer changes in the molecular weight of the polymer as a result of polymer degradation. Chain scission and/or crosslinking reactions associated with polymer degradation results in an increase or a decrease in the MI, respectively (Hsuan and Koerner 1998).…”

Section: Physical and Mechanical Propertiesmentioning

confidence: 99%

“…The temperature range commonly used in accelerating ageing studies for HDPE GMBs is from 55-85°C and in rare cases to 95°C (Hsuan and Koerner 1998;Rowe et al 2009Rowe et al , 2010aAbdelaal and Rowe 2014). Accelerating ageing temperatures usually do not exceed 85°C to avoid the risk of significant polymeric changes to the GMB.…”

Section: Introductionmentioning

confidence: 99%

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Effect of high temperatures on the physical and mechanical properties of HDPE geomembranes in air

Abdelaal

Rowe

Hsuan

et al. 2015

Geosynthetics International

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The effect of elevated temperatures, particularly between 95 and 115°C as encountered in some geoenvironmental applications, on the physical and mechanical properties of high-density polyethylene (HDPE) geomembranes (GMBs) is examined. Four commercially available HDPE GMBs were incubated in air at temperatures ≥ 85°C. Investigation of the thermograms by differential scanning calorimetry showed a significant change in the polymer morphology with an increase of the incubation temperature and duration, especially at 105 and 115°C. The morphological changes due to annealing involve thickening of the lamella crystals of the polymer and a change in the tie molecules joining the lamella crystals. The effect of annealing was most evident in the stress crack resistance of the GMB incubated at 105 and 115°C prior to polymer degradation. In particular, an increase in stress crack resistance due to annealing could mask the effects of polymer degradation at temperatures above 95°C. Changes in morphology did not affect melt index whose changes were largely attributed to polymer degradation.

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Section: Annealing Effect On Mechanical Propertiesmentioning

confidence: 99%

Section: Annealing Effect On Mechanical Propertiesmentioning

confidence: 99%