Photodegradation and Photostabilisation of Polymers

Scott, Gerald

doi:10.1016/b978-0-444-89616-2.50012-4

Cited by 7 publications

(6 citation statements)

References 96 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Throughout, we have only considered plastics composed of a single polymer type; however, evidence shows that polymer blends and copolymers can synergize or antagonize environmental degradation, broadening the range of potential k d . − Various compounds added to plastics or included in them as nonintentionally added substances can facilitate or inhibit the environmental degradation of plastics. For example, antioxidants and ultraviolet-light stabilizers are added to plastics to limit thermal degradation during processing and photochemical degradation during outdoor use. , Because plastics are typically thermally processed, most plastic products contain antioxidants, which can prolong plastic lifetimes compared to additive-free plastics. Other additives can intentionally (e.g., pro-oxidants, photocatalysts, enzymes, or microbes) or inadvertently (e.g., pigments, catalyst residues, and unsaturated bonds) enhance degradation.…”

Section: Resultsmentioning

confidence: 99%

Minimizing the Environmental Impacts of Plastic Pollution through Ecodesign of Products with Low Environmental Persistence

James,

Ward,

Hahn

et al. 2024

ACS Sustainable Chem. Eng.

View full text Add to dashboard Cite

While plastic pollution threatens ecosystems and human health, the use of plastic products continues to increase. Limiting its harm requires design strategies for plastic products informed by the threats that plastics pose to the environment. Thus, we developed a sustainability metric for the ecodesign of plastic products with low environmental persistence and uncompromised performance. To do this, we integrated the environmental degradation rate of plastic into established material selection strategies, deriving material indices for environmental persistence. By comparing indices for the environmental impact of on-the-market plastics and proposed alternatives, we show that accounting for the environmental persistence of plastics in design could translate to societal benefits of hundreds of millions of dollars for a single consumer product. Our analysis identifies the materials and their properties that deserve development, adoption, and investment to create functional and less environmentally impactful plastic products.

show abstract

Section: Resultsmentioning

confidence: 99%

Minimizing the Environmental Impacts of Plastic Pollution through Ecodesign of Products with Low Environmental Persistence

James,

Ward,

Hahn

et al. 2024

ACS Sustainable Chem. Eng.

View full text Add to dashboard Cite

show abstract

“…2,2,6,6-tetramethylpiperidine (1), 1,2,2,6,6-pentamethylpiperidine (2), N-methoxy-2,2,6,6-tetramethylpiperidine (3) and the industrially used HALS compounds bis(2,2,6,6-tetramethyl-4-piperidinyl)-sebacate (Tinuvinm) 770 (4), and an oligomeric ester of butanedioic acid with 4-hydroxy-2,2,6,6-tetramethyl-1-piperidineethanol (Tinuvinm 622) (5) were supplied by Ciba-Geigy. The piperidines were of analytical grade and in some cases purified by distillation in the presence of citric acid.…”

Section: Chemicalsmentioning

confidence: 99%

“…Although sterically hindered amines have long been used as stabilizers mainly against the light-induced degradation of polyolefins, the detailed mechanism of their action is still under discussion [1][2][3][4][5] . In a review of the mechanistic effects of photostabilization, Chirinos 6,7) emphasized the central role of alkylperoxy radicals and alkylhydroperoxides within the process of the photo-oxidation of polymers.…”

Section: Introductionmentioning

confidence: 99%

Transformation of sterically hindered amines (HALS) to nitroxyl radicals: What are the actual stabilizers?

Brede¹,

Göttinger

1998

Angew. Makromol. Chem.

View full text Add to dashboard Cite

“…Although sterically hindered amines have long been used as stabilizers mainly against the light-induced degradation of polyolefins, the detailed mechanism of their action is still under discussion . In a review of the mechanistic effects of photostabilization, Chirinos emphasized the central role of alkylperoxyl radicals and alkylhydroperoxides within the process of the photooxidation of polymers.…”

Section: Introductionmentioning

confidence: 99%

One-Electron Oxidation of Sterically Hindered Amines to Nitroxyl Radicals: Intermediate Amine Radical Cations, Aminyl, α-Aminoalkyl, and Aminylperoxyl Radicals

et al. 1998

View full text Add to dashboard Cite

Sterically hindered amines (2,2,6,6-tetramethyl-substituted piperidines) are easily oxidized (i) by electron transfer to parent cations in n-butyl chloride solution, (ii) by the sulfate radical anion in aqueous solution, and (iii) by sensitized electron transfer to carbonyl triplets. In nonpolar surroundings in the nanosecond time range, the radical cations of the tertiary piperidines have been directly observed by optical spectroscopy to exhibit absorption maxima below λ = 300 nm and around 550 nm. Subsequently, they deprotonate to α-alkylamine radicals, which are also the first observable products of oxidation with sulfate radical anions in water. In the case of secondary piperidines, the amine radical cations deprotonate to aminyl radicals in times < 10 ns. The triplet-sensitized electron transfer to the benzophenone as well as cyclohexanone triplet results in amine-derived and ketyl-type radicals formed at a nearly diffusion-controlled rate, which suggests an electron- and subsequent proton-transfer mechanism. In the presence of oxygen, the amine-derived radicals are oxidized to nitroxyl radicals by different pathways for secondary and tertiary piperidines. For the reaction of the nitroxyl radicals with other radicals, rate constants are found to be quite similar (about 5 × 108 M-1 s-1 ) for several alkyl radicals and for the tert-butyloxyl radical and less than 105 M-1 s-1 for alkylperoxyl radicals. Because of the minor importance of radical reactions with the sterically hindered amines (HALS), the antioxidant effect of these compounds ought to be explained by oxidation, primarily via cationic and subsequently radical intermediates to the persistent nitroxyl radicals, which scavenge other radicals very efficiently.

show abstract

Photodegradation and Photostabilisation of Polymers

Cited by 7 publications

References 96 publications

Minimizing the Environmental Impacts of Plastic Pollution through Ecodesign of Products with Low Environmental Persistence

Minimizing the Environmental Impacts of Plastic Pollution through Ecodesign of Products with Low Environmental Persistence

Transformation of sterically hindered amines (HALS) to nitroxyl radicals: What are the actual stabilizers?

One-Electron Oxidation of Sterically Hindered Amines to Nitroxyl Radicals: Intermediate Amine Radical Cations, Aminyl, α-Aminoalkyl, and Aminylperoxyl Radicals

Contact Info

Product

Resources

About