Different aspects of the accelerated oxidation of polypropylene at increased pressure in an autoclave with regard to temperature, pretreatment and exposure media

Bajer, Kamila; Braun, Ulrike

doi:10.1016/j.polymertesting.2014.05.006

Cited by 15 publications

(5 citation statements)

References 36 publications

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“…Similar behavior was reported from oven aging of VLDPE tunnel liner and PP geogrids, which were stabilized by an AO package P1 . Even high‐pressure autoclave tests of the oxidative resistance of HDPE and VLDPE GM, PP geogrids, and PP syringes stabilized by an AO package of type P1, which were immersed at 80°C into an alkaline liquid solution and exposed to an atmosphere of very high oxygen pressure (5 MPa), showed the characteristic step‐like feature of the degradation curve (virtually no change followed by catastrophic failure) of retained tensile strength versus exposure time .…”

Section: Resultssupporting

confidence: 72%

A study on antioxidant depletion and degradation in polyolefin-based geosynthetics: Sacrificial versus regenerative stabilization

et al. 2015

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Plastic products used in geotechnical engineering, socalled geosynthetics, are often made of polyolefins (polyethylene or polypropylene) and stabilized against oxidative degradation by antioxidants (AO). Three types of AO "packages" are used: (P1) phenols and phosphites/sulfides, (P2) hindered amines (HAS) with a marginal stabilization P1 of the basic resin, and (P3) a combination of packages P1 and P2 with comparable amounts of phenol and HAS. We report about long-lasting oven aging and water immersion tests at 808C of 29 different polyolefin-based products (geomembranes, geonets, and geotextiles). Pronounced differences in the degradation behavior were found depending solely on the type of AO package. In case of P1, the oxidative degradation is prevented by the AO. Autocatalytic oxidation only begins after depletion of AO and may lead to catastrophic failure depending on the environmental conditions. In case of P2, degradation starts right from the beginning. However, it is decelerated and proceeds gradually. In case of P3, the degradation behavior seems to be a superposition of the characteristics obtained for P1 and P2. Plotting the fractional loss of the AO in P1 and P2 as function of the square root of aging time, we identified two regimes of AO depletion. We suggest attributing this observation to the different mechanisms of AO depletion. POLYM. ENG. SCI.,

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Section: Resultssupporting

confidence: 72%

A study on antioxidant depletion and degradation in polyolefin-based geosynthetics: Sacrificial versus regenerative stabilization

et al. 2015

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“…The degradation of plastics is highly dependent on the polymer type and any chemical additives [ 20 , 21 ]. Polypropylene, the material most commonly used in the medical mask production, is susceptible to photodegradation [ 14 , 20 , 22 ], heat [ 23 ] and atmospheric oxygen [ 24 ]. Polypropylene is excellent in terms of water resistance, but inferior in terms of weathering resistance.…”

Section: Introductionmentioning

confidence: 99%

Environmental hazard of polypropylene microplastics from disposable medical masks: acute toxicity towards Daphnia magna and current knowledge on other polypropylene microplastics

et al. 2022

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The COVID-19 pandemic has increased the use of disposable plastics, including medical masks, which have become a necessity in our daily lives. As these are often improperly disposed of, they represent an important potential source of microplastics in the environment. We prepared microplastics from polypropylene medical masks and characterised their size, shape, organic chemical leaching, and acute toxicity to the planktonic crustacean Daphnia magna. The three layers of the masks were separately milled and characterised. Each of the inner frontal, middle filtering, and outer layers yielded different types of microplastics: fibres were obtained from the inner and outer layer, but irregular fragments from the middle layer. The shape of the obtained microplastics differed from the initial fibrous structure of the intact medical mask layers, which indicates that the material is deformed during cryo-milling. The chemical compositions of plastics-associated chemicals also varied between the different layers. Typically, the inner layer contained more chemicals related to antimicrobial function and flavouring. The other two layers also contained antioxidants and their degradation products, plasticisers, cross-linking agents, antistatic agents, lubricants, and non-ionic surfactants. An acute study with D. magna showed that these microplastics do not cause immobility but do physically interact with the daphnids. Further long-term studies with these microplastics are needed using a suite of test organisms. Indeed, studies with other polypropylene microplastics have shown numerous adverse effects on other organisms at concentrations that have already been reported in the environment. Further efforts should be made to investigate the environmental hazards of polypropylene microplastics from medical masks and how to handle this new source of environmental burden.

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“…In this latter case, accelerated ageing tests are not intended to simulate natural ageing but only to identify model parameters. It appears then that tests at variable oxygen pressures (Bajer, 2014;Richaud et al, 2008a), which were rarely used in the past, are likely to distort the degradation mechanism with the appearance of unexpected side reactions (Richaud et al, 2008b), but are especially interesting for the estimation of kinetic parameters (Richaud et al, 2006).…”

Section: Lifetime Prediction Methodsmentioning

confidence: 99%

Tensile properties of polypropylene fibers

Richaud

Fayolle

Davies

2018

Handbook of Properties of Textile and Technical Fibres

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Different aspects of the accelerated oxidation of polypropylene at increased pressure in an autoclave with regard to temperature, pretreatment and exposure media

Cited by 15 publications

References 36 publications

A study on antioxidant depletion and degradation in polyolefin-based geosynthetics: Sacrificial versus regenerative stabilization

A study on antioxidant depletion and degradation in polyolefin-based geosynthetics: Sacrificial versus regenerative stabilization

Environmental hazard of polypropylene microplastics from disposable medical masks: acute toxicity towards Daphnia magna and current knowledge on other polypropylene microplastics

Tensile properties of polypropylene fibers

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