The Effects of UV Light on the Chemical and Mechanical Properties of a Transparent Epoxy-Diamine System in the Presence of an Organic UV Absorber

Nikafshar, Saeid; Zabihi, Omid; Ahmadi, Mojtaba; Mirmohseni, Abdolreza; Taseidifar, Mojtaba; Naebe, Minoo

doi:10.3390/ma10020180

Cited by 176 publications

(101 citation statements)

References 52 publications

(63 reference statements)

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“…These may also be associated with the deformation of the polymer below its Tg or a change in flexibility of polymer chains arising from chain scission [23] or UV irradiation [24]. Wear tracks on PEEK discs formed by PEEK-sapphire and PEEK-steel contacts are shown in Figure 5.…”

Section: Summary Of Friction Test Resultsmentioning

confidence: 99%

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Properties of Polyetheretherketone (PEEK) transferred materials in a PEEK-steel contact

Puhan

Wong

2019

Tribology International

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Polyetheretherketone (PEEK) is a high performance polymer that can be an alternative to metal for some moving components in unlubricated conditions. During rubbing, PEEK is transferred to the counterface. The formation and properties of PEEK transfer films on steel and sapphire are studied by in-situ observations of PEEK wear process, contact temperatures and triboemission, as well as FTIR and Raman spectroscopies ex situ. Our results suggest that frictional heating alone may not be sufficient to generate PEEK degradation observed in the transfer materials. Triboplasma observed during rubbing, together with the mechanical shear, may promote generations of radicals and degradation of PEEK, which subsequently influence the properties of PEEK transfer film and performance of polymer-metal tribopair.

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Section: Summary Of Friction Test Resultsmentioning

confidence: 99%

“…The damage from UV irradiation is supported by the fracture of transfer films shown in Figure 4g and 4i [24].…”

Section: Potential Links Between Plasma Generations and Chemistry Of mentioning

confidence: 90%

Properties of Polyetheretherketone (PEEK) transferred materials in a PEEK-steel contact

Puhan

Wong

2019

Tribology International

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“…Scanning electron microscopy (SEM) can be used to provide less distorted, clear, and highresolution images of the particles in materials, and is a useful technique for investigating the variation of the surface, particle size and shape, homogeneity, and cross sections within the blends [49][50][51][52]. The surface morphology of the PVC films was examined by field-emission scanning electron microscopy (FESEM).…”

Section: Surface Analysis Of Pvcmentioning

confidence: 99%

Protection of Poly(Vinyl Chloride) Films against Photodegradation Using Various Valsartan Tin Complexes

et al. 2020

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Poly(vinyl chloride) is a common plastic that is widely used in many industrial applications. Poly(vinyl chloride) is mixed with additives to improve its mechanical and physical properties and to enable its use in harsh environments. Herein, to protect poly(vinyl chloride) films against photoirradiation with ultraviolet light, a number of tin complexes containing valsartan were synthesized and their chemical structures were established. Fourier-transform infrared spectroscopy, weight loss, and molecular weight determination showed that the non-desirable changes were lower in the films containing the tin complexes than for the blank polymeric films. Analysis of the surface morphology of the irradiated polymeric materials showed that the films containing additives were less rough than the irradiated blank film. The tin complexes protected the poly(vinyl chloride) films against irradiation, where the complexes with high aromaticity were particularly effective. The additives act as primary and secondary stabilizers that absorb the incident radiation and slowly remit it to the polymeric chain as heat energy over time at a harmless level.Polymers 2020, 12, 969 2 of 18 retardants [4]. In addition, PVC has good mechanical and chemical properties, is easy to produce in large quantitates, and resists ecological strain cracking [5].The performance of PVC can be enhanced by incorporating additives to enable its use in outdoor applications. PVC can be mixed with plasticisers to enable the production of flexible polymeric materials for certain applications [4,5]. PVC undergoes gradual degradation in harsh environments, such as under exposure to heat and direct ultraviolet (UV) light for a long period [6]. The degradation of PVC leads to a reduction in its mechanical integrity, change in color, and formation of micro-cracks within the surface. Therefore, PVC cannot be used on its own and must be combined with stabilizers to enhance its photostability [7]. The additives should be easy and cheap to produce and well incorporated within the PVC polymeric chains. Further, the additives should not alter the color of PVC and should be non-volatile, chemically stable, non-toxic, and should not pollute the surrounding environment. The most common PVC industrial additives act as smoke suppressors, flame retardants, thermal and impact modifiers, heat stabilizers, UV stabilizers, screeners, absorbers, and free radical scavengers [8][9][10]. PVC stabilizers are classified into various types [8], that is, primary stabilizers that deactivate the allylic chlorides that are generated in the photodegradation of the polymeric chains and secondary additives that act as scavengers of chloride radicals and hydrogen chloride [11]. Many non-toxic organic materials have been used as PVC additives [12].bis(2-Ethylhexyl)phthalate (Figure 1) can be obtained from phthalic acid and has been used as a PVC plasticizer in the past. It is non-volatile, oily, has a low production cost, and is compatible with PVC [8]. However, the safety and health hazards associ...

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“…The action of these additives against the UV weathering is different: in details, the inorganic particles behave by scattering the light; on the contrary, the organic UV absorbers convert UV light into heat and higher wavelengths, while radical interceptors (Hals) capture the free radicals of the starting polymeric decomposition and prevent to this process from continuing. The organic UV absorbers seem to be more efficient compared than the inorganic particles yet their durability is poor due to evaporation and migration from the surface [15].In the attempt to increase the waterproofness and the puncture resistance of a commercial technical polyester-based (PET) woven fabric for possible use in semi-rigid luggage production, this work studied the application of waterborne polyurethane dispersions to the fabric surface through the impregnation method. This technique was preferred to coating-the most common approach-in order to act as reinforcement and protection of the fabric weaving without covering the surface and altering the textile appearance.…”

mentioning

confidence: 99%

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confidence: 99%

The Puncture and Water Resistance of Polyurethane- Impregnated Fabrics after UV Weathering

Patti

Acierno²

2019

Polymers

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Polyurethane is a polymer adaptable to different scientific and industrial requirements; nevertheless it is also extremely susceptible to UV radiation, which compromises the physical and mechanical functionality. In this framework, our study investigated the effect of waterborne polyurethane dispersion (WPUD) applied to a polyester (PET)-based fabric, through the impregnation method, on the puncturing and water resistance of the pristine material, before and after UV weathering. Results confirmed an increment of both features in the prepared fabrics, attributed to the PUR textile treatment; but a partially loss of the gained properties in the samples due to the UV weathering. In order to improve the efficiency of the impregnating dispersions, in protecting the durability of the treated materials, the addition of different UV light stabilizers, or/and of crosslinking agent into WPUD was also tested. From the experimental data, it can be concluded that formulations based on WPUD, containing both the crosslinker and UV organic absorber, have displayed an increment of their perforation and water resistance for the treated samples with respect to the starting textile, and contemporary have preserved the features against the UV light. Finally, microscopic and spectroscopic analyses have been performed as further characterization techniques of the samples surface.Polymers 2020, 12, 15 2 of 14 and petroleum depletion concerns, scientific research attention has been paid to study eco-friendly alternatives, i.e., waterborne polyurethane dispersions (WPUDs), with very low VOC emissions and with water as a low-cost, safe for health and the environment, and non-toxic solvent [7]. The aqueous polyurethane characteristics derive essentially from the chemical structure of urethane groups, by which multiple hydrogen bonds between adjacent polymer chains can take place. The chemical arrangement is constituted through hard segments that align in a dry polymer, and self-assemble into strongly hydrogen-bonded areas via flexible soft segments. The multiplicity of strong hydrogen bonds provides the properties commonly associated with a covalently bonded network [8].In the literature, different works have explored the possibility of developing green methods for the synthesis of WPUDs which can be applied as coatings, adhesives and finishing agents, useful for industrial production and application. The results have confirmed that WPUD coatings are endowed with excellent thermal stability, waterproofness and good mechanical properties, in terms of elongation at break and tensile strength [9][10][11][12].In general, the exposure of a polymer to UV radiation causes breakage of the chemical bonds in the material, a subsequent reduction of its molecular weight and a loss in its mechanical features ("photo-oxidative degradation") [13]. Since polyurethane coatings are also utilized for outdoor applications, high durability and weathering resistance may be required for the ambient exposure to ultraviolet (UV) radiation, water/humidity, and tempe...

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The Effects of UV Light on the Chemical and Mechanical Properties of a Transparent Epoxy-Diamine System in the Presence of an Organic UV Absorber

Cited by 176 publications

References 52 publications

Properties of Polyetheretherketone (PEEK) transferred materials in a PEEK-steel contact

Properties of Polyetheretherketone (PEEK) transferred materials in a PEEK-steel contact

Protection of Poly(Vinyl Chloride) Films against Photodegradation Using Various Valsartan Tin Complexes

The Puncture and Water Resistance of Polyurethane- Impregnated Fabrics after UV Weathering

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