Investigations of stabilizing additives. I. A model system for studying radical scavenging activity in solution

Dunn, Terry S.; Williams, E.E.; Williams, J. L.

doi:10.1002/pol.1982.170200620

Cited by 9 publications

(1 citation statement)

References 3 publications

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“…Clays, molecular sieves, and other common desiccants have been used as water scavengers. Antioxidants, such as BHT (164), are often used as organoleptic scavengers.…”

Section: Facilitated Transport Facilitated Transport Involves the Cou-mentioning

confidence: 99%

Polymer Transport Properties

Koros

Burgess

Chen

2015

Encyclopedia of Polymer Science and Technology

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“…Clays, molecular sieves, and other common desiccants have been used as water scavengers. Antioxidants, such as BHT (164), are often used as organoleptic scavengers.…”

Section: Facilitated Transport Facilitated Transport Involves the Cou-mentioning

confidence: 99%

Polymer Transport Properties

Koros

Burgess

Chen

2015

Encyclopedia of Polymer Science and Technology

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Transport Properties

Koros¹,

Madden²

2004

Encyclopedia of Polymer Science and Technology

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This article covers the transport properties of gases, low activity vapors, and intermediate‐sized penetrants through rubbery, semicrystalline, and glassy polymers. The article emphasizes polymer transport properties under conditions of low to intermediate penetrant concentration where extraordinary differences can exist between the diffusivities of penetrants having relatively small differences in molecular size or shape. Nonideal transport effects, such as plasticization, clustering, and non‐Fickian transport, are covered. Particular attention is given to the nonequilibrium nature of glassy polymers and the resulting effects on penetrant transport. The recent development of positron annihilation lifetime spectroscopy (PALS) and molecular modeling of diffusion are described. Transport through porous polymers and reptation of macromolecules within a macromolecular matrix are not covered in this article.

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The effect of hindered amine light stabilizers on the photooxidative stability of high‐density polyethylene

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Delatycki

1989

J. Polym. Sci. A Polym. Chem.

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SynopsisThe photoprotective effectiveness of various polymeric and nonpolymeric hindered amine light stabilizers (HALS) was determined by exposing samples of high-density polyethylene (HDPE) containing these additives to ultraviolet (UV) light and measuring the resultant oxygen uptake characteristics. Values of the initial quantum yield for oxygen uptake calculated for these formulations indicate that the higher molecular weight HALS compounds are less effective photostabilizers than the nonpolymeric HALS, and this is partly attributable to their decreased mobility in the polymer matrix. It was further found that the addition of an ultraviolet absorber ( W A ) to a formulation containing a polymeric HALS compound enhances its photostability, although this phenomenon may be partly due to synergism between the UVA and the antioxidant, the latter having been added as part of the base stabilization. The antagonism which exists between certain sulfur-containing antioxidants and HALS compounds was also investigated and it was found that the lower molecular weight sulfur-containing antioxidants exhibit the greatest degree of antagonism. The results confirm that the mobility in the polymer matrix of the stabilizer system can serve as an explanation of its effectiveness. The article provides evidence that the technique of oxygen uptake monitoring is a sensitive and rapid method of assessment of polymer photostability in the presence of stabilizer systems.It is believedlg that during the uninhibited photooxidation of polyolefins, the chain reaction is normally terminated by the interaction of two propagating radicals, which results in inactive products. It is reasonable to assume that photostabilization can be achieved by scavenging free radical species (such as hydroperoxyl, hydroxyl, and macroalkyl radicals), which are formed during propagation and chain branching. In fact, free radical scavenging is the main mechanism by which phenolic antioxidants protect polymers against thermo-

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Investigations of stabilizing additives. I. A model system for studying radical scavenging activity in solution

Cited by 9 publications

References 3 publications

Polymer Transport Properties

Polymer Transport Properties

Transport Properties

The effect of hindered amine light stabilizers on the photooxidative stability of high‐density polyethylene

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