Physical Factors Which Influence Photodegradation

Rabek, Jan F.

doi:10.1007/978-3-642-80090-0_5

Cited by 19 publications

(23 citation statements)

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“…This implies that ROO9 radicals are nearly 2000 time less reactive [60].) Peroxy radicals, however, can easily abstract the H-atom from any type of H-donor molecule [52,61,62], e. g. from a monomer, in this way initiating a new reactive radical. The ROO9 radicals can also participate in the termination and other side reactions.…”

Section: Effects Of Oxygen On the Cq-amh Photoinitiated Polymerizatiomentioning

confidence: 99%

A reappraisal of the photopolymerization kinetics of triethyleneglycol dimethacrylate initiated by camphorquinone-N,N-dimethyl-p-toluidine for dental purposes

Nie

Lindén

Rabek³

et al. 1998

Acta Polym.

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Section: Effects Of Oxygen On the Cq-amh Photoinitiated Polymerizatiomentioning

confidence: 99%

A reappraisal of the photopolymerization kinetics of triethyleneglycol dimethacrylate initiated by camphorquinone-N,N-dimethyl-p-toluidine for dental purposes

Nie

Lindén

Rabek³

et al. 1998

Acta Polym.

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“…1). This indicates the auto-catalytic character of the photooxidative degradation [2], which is also known to occur in the case of thermo-oxidative degradation [4].…”

Section: Gel Contentmentioning

confidence: 74%

“…The effect of photo-oxidation on the properties of polymers has been studied extensively [1,2]. It is known that this type of degradation causes chain scission and crosslinking, although secondary reactions like chain branching can also occur as a consequence of the free radical polymerization, similar to thermal oxidation [2].…”

Section: Introductionmentioning

confidence: 99%

“…Considering that photo-oxidative degradation of polymers occurs by free radical mechanisms, similar to thermal oxidation [2], it is the objective of the present contribution to investigate the effects of photooxidative degradation on LDPE with special emphasis on the changes observed in the both the linear and nonlinear behavior. The uniaxial elongational viscosity data are compared to predictions of the Rubber-Like Liquid (RLL) model and the MSF model.…”

Section: Introductionmentioning

confidence: 99%

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Elongational viscosity of photo-oxidated LDPE

Rolón-Garrido¹,

Wagner²

2014

AIP Conference Proceedings

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-Sheets of low-density polyethylene (LDPE) were photo-oxidatively treated at room temperature, and subsequently characterized rheologically in the melt state by shear and uniaxial extensional experiments. For photo-oxidation, a xenon lamp was used to irradiate the samples for times between 1 day and 6 weeks. Linear-viscoelastic characterization was performed in a temperature range of 130 to 220°C to obtain the master curve at 170°C, the reference temperature at which the elongational viscosities were measured. Linear viscoelasticity is increasingly affected by increasing photo-oxidation due to crosslinking of LDPE, as corroborated by an increasing gel fraction as determined by a solvent extraction method. The elongational measurements reveal a strong enhancement of strain hardening until a saturation level is achieved. The elongational data are analyzed in the frame work of two constitutive equations, the rubber-like liquid and the molecular stress function models. Within the experimental window, timedeformation separability is confirmed for all samples, independent of the degree of photo-oxidation.

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“…Seybold (1994) stated that changes in PAM chemical composition were related to environmental factors such as sunlight, chemical hydrolysis, and mechanical degradation. Research has shown that the majority of PAM photodegradation caused changes in both the physical and chemical properties of polymer due to the absorption of energy via photons of sunlight having a sufficient energy to disrupt chemical bonds and to reduce the molecular weight of the degraded PAM (Caulfield et al, 2002;Kishore and Bhanu, 1988;Rabek, 1996). According to Sohma (1989), when a sufficient mechanical energy is transferred to the polymer chain, bond separation occurs causing the formation of free unstable radical species that further degrades PAM.…”

Section: Treatment Effectsmentioning

confidence: 99%

Effectiveness of Post-Harvest Sugarcane Residue and Polyacrylamide on Reducing Soil Deposition in Quarter-Drains

Kornecki¹,

Grigg²,

Fouss³

et al. 2006

Applied Engineering in Agriculture

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ABSTRACT. Each spring, small ditches perpendicular to sugarcane rows (quarter-drains) Based on the data, soil deposition in quarter-drains was the main process and the measurements represent the combined effect of treatments on the field and sediment transport through the quarter-drains. The sediment deposited in quarter-drains originated both from furrows and from side walls of quarter-drains. Sediment deposition rather than typically expected soil erosion in quarter-drains was related to unusually dry weather during the experiment. The sediment was measured at four locations along the length of the quarter-drain. A custom-made portable device was used to determine cross-sectional area of each semicircular quarter-drain at selected grid points. Based on four rainfall events with a cumulative depth of

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Physical Factors Which Influence Photodegradation

Cited by 19 publications

References 0 publications

A reappraisal of the photopolymerization kinetics of triethyleneglycol dimethacrylate initiated by camphorquinone-N,N-dimethyl-p-toluidine for dental purposes

A reappraisal of the photopolymerization kinetics of triethyleneglycol dimethacrylate initiated by camphorquinone-N,N-dimethyl-p-toluidine for dental purposes

Elongational viscosity of photo-oxidated LDPE

Effectiveness of Post-Harvest Sugarcane Residue and Polyacrylamide on Reducing Soil Deposition in Quarter-Drains

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