Ultraviolet degradation of plastics and the use of protective ultraviolet absorbers

Hirt, R. C.; Searle, N. Z.; Schmitt, R. G.

doi:10.1002/pen.760010106

Cited by 15 publications

(10 citation statements)

References 2 publications

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“…Because of the presence of tertiary carbons and unsaturated sites in polypropylene (PP), its oxidation potential is greatly enhanced [1][2][3] ; furthermore the dissociation energy of a primary carbon COH bond is about 100 kcal, whereas it is 79 kcal for tertiary carbon COH bonds. 4,5 The oxidation of PP leads to the formation of oxygen-containing groups such as O ʈ CAO, OCOO, O ʈ COOH, OCO O Ϫ and hydroperoxides, 6 which greatly affect the surface polarity and the adhesion properties of the polymer.…”

Section: Introductionmentioning

confidence: 99%

Oxidation of polypropylene in a solution of monochlorobenzene

Abdouss

Sharifi-Sanjani

Bataille

1999

J. Appl. Polym. Sci.

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ABSTRACT:The oxidation of polypropylene (PP) was performed in a solution of monochlorobenzene using tetrabutyl ammonium permanganate either in the presence or absence of purified air and dodecanol-1. The experiments were conducted under atmospheric pressure at 128 -130°C. The oxidized PP was found to contain polar groups such as carboxylates, carboxylic acids, ketones, esters, etc. as determined by Fourier transform infrared, ultraviolet, nuclear magnetic resonance, and electron spectroscopy for chemical analysis. The presence of the MnO 2 formed upon the decomposition of tetrabutyl ammonium permanganate was determined by electron spectroscopy for chemical analysis. The dodecanol-1 was used as an accelerator for the oxidation reaction of PP in presence of air. Solubility trials of oxidized PP in toluene and methyl ethyl ketone were performed. A reaction mechanism is proposed.

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Section: Introductionmentioning

confidence: 99%

Oxidation of polypropylene in a solution of monochlorobenzene

Abdouss

Sharifi-Sanjani

Bataille

1999

J. Appl. Polym. Sci.

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“…They can be used on textiles like cotton and other dyed fabrics but the protective effects can vary greatly (Coleman and Peacock 1958). Protective absorbers can photodecompose, but usually at a much slower rate than the materials they are protecting (Hirt et al 1961). Their photodecomposition is dependent on intrinsic properties of the materials and the wavelength of irradiation.…”

Section: Uv Absorbersmentioning

confidence: 99%

UV Effects on Materials

Kowalski

2009

Ultraviolet Germicidal Irradiation Handbook

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Ultraviolet exposure can cause a number of secondary effects on materials as a result of photochemical reactions and heat. These effects include solarization, photodiscoloration, photodegradation, damage to plants, and generation of ozone, which can itself degrade materials. These secondary effects are of concern to UVGI applications such as in-duct UVGI, cooling coil disinfection, Upper Room UVGI, hospital operating room systems, etc. This chapter addresses effects on materials not previously covered in other chapters, excluding health effects (see Chap. 12).UV exposure, especially for prolonged periods of time, can cause photodegradation of organic and synthetic materials through photolysis, photo-oxidation, and other processes. Damage to materials can cause equipment problems, fire hazards, and unexpected costs. Photodegradation can impact system design and cause safety hazards. Much of what is known about UV photodegradation comes from studies of sunlight, which has UV components, and research is currently in progress to determine which materials can safely be used around UVGI systems. This chapter addresses these potential problems insofar as the available knowledgebase permits, providing a theoretical background and some basic mathematical modeling to facilitate ongoing research.

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“…Therefore, the concentration of primary products is very small, and only highly degraded fragments usually are recovered. Benzophenones have yielded benzoic acid [5,7] and benzotriazoles have yielded benzotriazole [8,9,10] as shown in Figure 4. The phenolic moieties that would result from photolysis reactions such as these would be very unstable and undergo rapid photo-oxidation.…”

Section: Photophysics Of Uv Absorbersmentioning

confidence: 99%

“…The photo-decomposition was found to be dependent on a number of factors including the substrate in which the absorber is dispersed and the wavelength of irradiation [5], Unfortunately, little subsequent work was published to flesh out and substantiate this insight, and the photostability issues of UVA's disappeared from the common wisdom. Questions about coating failure mechanisms arose in the late 1980's and early 1990's that prompted reexamination of UVA lifetimes.…”

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confidence: 97%

Permanence of UV Absorbers in Plastics and Coatings

Pickett¹

2001

ACS Symposium Series

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Ultraviolet absorbers (UVA's) undergo photo-degradation with quantum yields on the order of 10 -6 even in glassy, unreactive matrices such as poly(methyl methacrylate) (PMMA). The kinetics of UVA loss in a film or coating can be described by the equation: A = log 10 [(1-T 0 )10 (A0-kt) + 1] where A is the absorbance at time t, T 0 is the initial transmission, A 0 is the initial absorbance, and k is a zero order rate constant. The rate constant can be found as the slope of log 10 (10 A -1) plotted vs. exposure. The derivation and implications of these equations and a general review of UVA degradation chemistry are discussed, including the effects of the matrix material, concentration, and hindered amine light stabilizers. The rate of UV absorber loss is of relatively minor consequence when the absorber is used as a bulk additive in a polymer, but is of critical importance in the service lifetime of coatings. The kinetics of photochemical UV absorber loss and use of loss rates in coating lifetime predictions are discussed in detail.

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Ultraviolet degradation of plastics and the use of protective ultraviolet absorbers

Cited by 15 publications

References 2 publications

Oxidation of polypropylene in a solution of monochlorobenzene

Oxidation of polypropylene in a solution of monochlorobenzene

UV Effects on Materials

Permanence of UV Absorbers in Plastics and Coatings

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