Polymer durability estimates based on apparent activation energies for thermal oxidative degradation

Ding, Samuel Y.; Khare, Atul; Ling, Michael T.K.; Sandford, Craig; Woo, Lecon

doi:10.1016/s0040-6031(00)00677-8

Cited by 10 publications

(10 citation statements)

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“…The peroxide free radical reacts with a polymer molecule forming an additional free radical and a highly unstable hydroperoxide (ROOH) and an ensuing chain reaction, causing loss of structural integrity due to polymer chain shortening. 16,28,46,47 This thermal degradation mechanism (eqs 1−4) applies to all polyolefins 28,46 RH R H heat or UV…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…This cleavage forms hydrocarbon free radicals (R • ), which then form peroxide radicals (ROO • ) in the presence of oxygen. The peroxide free radical reacts with a polymer molecule forming an additional free radical and a highly unstable hydroperoxide (ROOH) and an ensuing chain reaction, causing loss of structural integrity due to polymer chain shortening. ,,, This thermal degradation mechanism (eqs –) applies to all polyolefins , Primary and secondary antioxidants added to the polymer matrix hinder this thermal degradation. Primary antioxidants (due to aromaticity) work as a scavenger for the unstable peroxide free radical by reacting with it to form a resonance-stabilized free radical, while secondary antioxidants (e.g., sulfur-based) stabilize the hydroperoxide by preventing decomposition into additional free radicals .…”

Section: Resultsmentioning

confidence: 99%

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Coal-Filler-Based Thermoplastic Composites as Construction Materials: A New Sustainable End-Use Application

Al-Majali¹,

Chirume²,

Marcum³

et al. 2019

ACS Sustainable Chem. Eng.

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This paper reports investigations into coal's viability as an alternative filler to wood flour in wood plastic composites (WPCs)a class of materials used in building applications in lieu of pressure-treated wood coal plastic composites (CPCs) were fabricated with 15−60 wt % coal combined with high-density polyethylene and their physical (mechanical, water absorption, and metal leaching) and chemical (oxidative degradation and flammability) properties were compared with commercial WPCs. In addition, mass and energy balances (10 ton/h basis) and life cycle analyses (60 wt % filler and 1 ton basis) were conducted on CPCs and WPCs to assess environmental impact during manufacturing. At 60 wt %, CPCs had higher flexural strength, slower oxidative degradation and burn rate, and lower water absorption in comparison to commercial WPCs, suggesting better performance and stability in building applications. Furthermore, CPC manufacturing showed 44% lower greenhouse gas emissions and 62% less energy usage in comparison with WPC. These results indicate that the direct utilization of coal as a filler in construction composite applications may yield lower-cost products with lower associated emissions and energy demand compared to that of existing WPC materials, potentially yielding a more sustainable end use for coal than current uses such as power production.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Coal-Filler-Based Thermoplastic Composites as Construction Materials: A New Sustainable End-Use Application

Al-Majali¹,

Chirume²,

Marcum³

et al. 2019

ACS Sustainable Chem. Eng.

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“…Like other methods working with a constant Arrhenius activation energy determined at rather high temperatures, the evaluation should be improved further in this respect. In particular, there is increasing evidence 9 for deviations at lower temperatures, resulting from the assumption of a constant effective activation energy E A . According to Ding 9 , for temperatures at or below room temperature activation energies signifi cantly lower than 50 kJ/ mol have to be considered.…”

Section: Discussionmentioning

confidence: 99%

A New Method for Testing and Evaluating the Long-Time Resistance to Oxidation of Polyolefinic Products

Schröder

Munz

Böhning

2008

Polymers and Polymer Composites

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Oxidative long time resistance is essential for many polyolefinic products, especially if repair or exchange is not possible as encountered in many building applications. For the time being, CE-standards for geosynthetics are covering the needs of a minimum lifetime of 25 years only, though many applications require longer lifetimes (up to 100 years and more). Testing long time oxidation resistance is complicated by the complex interplay of physico-chemical processes and reactions in combination with the need for relatively short testing durations, usually not exceeding 12 months. Thus, for normal atmospheric oven testing the use of temperatures clearly higher than 80 °C is inevitable. It should be noted that Arrhenius extrapolation exceeding the temperature range of experimental data by more than 20 K requires the consideration of additional safety factors in order to allow for possible changes of the apparent activation energy EA. In general, at elevated testing temperatures care has to be taken that oxygen diffusion does not become the rate limiting process. Furthermore, in many application environments the loss of antioxidants (and other components) is - besides oxidative deactivation - mainly due to extraction by aqueous media and not due to evaporation. For oven testing, however, frequently the latter is the case. With these limiting conditions in mind a test has been designed which in addition to elevated temperatures is accelerated by the presence of an increased oxygen pressure and a stirred aqueous medium. This enables us to perform durability tests at markedly lower temperatures with reasonable testing durations and significantly reduced diffusion limited oxidation (DLO) effects. Also it allows for physical and chemical impacts of aqueous media. Assessments of oxidative durability can be performed by autoclave immersion exposures at three different temperatures (usually 60, 70 and 80 °C) and 50 bar oxygen pressure and additionally at 80 °C and two different oxygen pressures (usually 10 and 20 bar). Results of such accelerated tests are evaluated by means of modified Arrhenius equations with the application of a 3D-regression analysis. Validation of the method is still at an early stage, like for most other lifetime test methods. For purpose of comparison, materials of approved durability were used, such as pipe materials of quality PE100 and PE 80 with well-known minimum lifetime determined according to ISO/TR 9010, i.e. by long-term failure tests under internal hydrostatic pressure at different temperatures and by evaluation using the Arrhenius law. Based on results of such tests it is supposed that a rather quick and relevant method is now at hand for testing the oxidation life of olefinic polymeric materials (like pressed plaques) or specimens of finished products like textiles, sheets, liners, pipes or composites. This test method should be very useful for the effective design of polymer formulations.

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“…In the third step, for the calculated number of fatigue load cycles, the effect of heat and the consequent increase in temperature on the acceleration of aging deterioration was determined using the following Arrhenius equation [32]:…”

Section: Evaluation Of Fatigue Resistance Difference Due To Facade Rementioning

confidence: 99%

Sealant aging and its correlation with facade reflectance

Ihara

Gustavsen

Jelle

2014

Construction and Building Materials

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Polymer durability estimates based on apparent activation energies for thermal oxidative degradation

Cited by 10 publications

References 1 publication

Coal-Filler-Based Thermoplastic Composites as Construction Materials: A New Sustainable End-Use Application

Coal-Filler-Based Thermoplastic Composites as Construction Materials: A New Sustainable End-Use Application

A New Method for Testing and Evaluating the Long-Time Resistance to Oxidation of Polyolefinic Products

Sealant aging and its correlation with facade reflectance

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