Accelerated photodegradation of poly(lactic acid) with weathering test chamber and laser exposure – A comparative study

Litauszki, Katalin; Kovács, Zsolt; Mészáros, László; Kmetty, Ákos

doi:10.1016/j.polymertesting.2019.03.038

Cited by 18 publications

(12 citation statements)

References 26 publications

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“…Only one degradation step was observed for the neat polymer and the nanocomposite. A single-step degradation process was a good indicator that the degradation was homogeneous throughout the thickness of the specimen [ 102 ].…”

Section: Resultsmentioning

confidence: 99%

Accelerated Weathering Effects on Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and PHBV/TiO2 Nanocomposites

et al. 2020

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The effect of accelerated weathering on poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and PHBV-based nanocomposites with rutile titanium (IV) dioxide (PHBV/TiO2) was investigated. The accelerated weathering test applied consecutive steps of UV irradiation (at 340 nm and 0.76 W m−2 irradiance) and moisture at 50 °C following the ASTM D4329 standard for up to 2000 h of exposure time. The morphology, chemical structure, crystallization, as well as the mechanical and thermal properties were studied. Samples were characterized after 500, 1000, and 2000 h of exposure time. Different degradation mechanisms were proposed to occur during the weathering exposure and were confirmed based on the experimental data. The PHBV surface revealed cracks and increasing roughness with the increasing exposure time, whereas the PHBV/TiO2 nanocomposites showed surface changes only after 2000 h of accelerated weathering. The degradation of neat PHBV under moisture and UV exposure occurred preferentially in the amorphous phase. In contrast, the presence of TiO2 in the nanocomposites retarded this process, but the degradation would occur simultaneously in both the amorphous and crystalline segments of the polymer after long exposure times. The thermal stability, as well as the temperature and rate of crystallization, decreased in the absence of TiO2. TiO2 not only provided UV protection, but also restricted the physical mobility of the polymer chains, acting as a nucleating agent during the crystallization process. It also slowed down the decrease in mechanical properties. The mechanical properties were shown to gradually decrease for the PHBV/TiO2 nanocomposites, whereas a sharp drop was observed for the neat PHBV after an accelerated weathering exposure. Atomic force microscopy (AFM), using the amplitude modulation–frequency modulation (AM–FM) tool, also confirmed the mechanical changes in the surface area of the PHBV and PHBV/TiO2 samples after accelerated weathering exposure. The changes in the physical and chemical properties of PHBV/TiO2 confirm the barrier activity of TiO2 for weathering attack and its retardation of the degradation process.

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Section: Resultsmentioning

confidence: 99%

Accelerated Weathering Effects on Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and PHBV/TiO2 Nanocomposites

et al. 2020

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“… Comparison between the characteristic radiation spectrum of the xenon lamp (with a filter approximating the spectrum of sunlight), blue line; and the spectrum of sunlight, yellow line. Reprinted with permission [ 19 ]. …”

Section: Figurementioning

confidence: 99%

Can Accelerated Aging Procedures Predict the Long Term Behavior of Polymers Exposed to Different Environments?

Frigione

Rodríguez-Prieto

2021

Polymers

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During their useful life, polymers are subject to degradation processes due to exposure to specific environmental conditions over long times. These processes generally lead to changes, almost always irreversible, of properties and performances of polymers, changes which would be useful to be able to predict in advance. To meet this need, numerous investigations have been focused on the possibility to predict the long-term performance of polymers, if exposed to specific environments, by the so called “accelerated aging” tests. In such procedures, the long-term behavior of polymeric materials is typically predicted by subjecting them to cycles of radiations, temperatures, vapor condensation, and other external agents, at levels well above those found in true conditions in order to accelerate the degradation of polymers: this can produce effects that substantially deviate from those observable under natural exposure. Even following the standard codes, different environmental parameters are often used in the diverse studies, making it difficult to compare different investigations. The correlation of results from accelerated procedures with data collected after natural exposure is still a debated matter. Furthermore, since the environmental conditions are a function of the season and the geographical position, and are also characteristic of the type of exposure area, the environmental parameters to be used in accelerated aging tests should also consider these variables. These and other issues concerning accelerated aging tests applied to polymers are analyzed in the present work. However, bearing in mind the limitations of these practices, they can find useful applications for rating the durability of polymeric materials.

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“…The degradation of polymers is associated with changes in characteristics such as shape, color, surface morphology and mechanical properties of the materials [32] . Some works in the literature related that PLA takes a long time to degrade in other media such as photodegradation, laser exposure and accelerated aging test [33,34] . Grigull et al [34] performed the accelerated aging test on PLA films.…”

Section: Evaluation Of Biodegradation Tests Of Pla/lignin/ Carbon Black Compositesmentioning

confidence: 99%

Synergistic effect of adding lignin and carbon black in poly(lactic acid)

et al. 2020

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Accelerated photodegradation of poly(lactic acid) with weathering test chamber and laser exposure – A comparative study

Cited by 18 publications

References 26 publications

Accelerated Weathering Effects on Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and PHBV/TiO2 Nanocomposites

Accelerated Weathering Effects on Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and PHBV/TiO2 Nanocomposites

Can Accelerated Aging Procedures Predict the Long Term Behavior of Polymers Exposed to Different Environments?

Synergistic effect of adding lignin and carbon black in poly(lactic acid)

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