Dependence of ultraviolet absorbers' performance on ultraviolet wavelength

Dobashi, Yoshiyuki; Ohkatsu, Yasukazu

doi:10.1016/j.polymdegradstab.2007.11.011

Cited by 27 publications

(24 citation statements)

References 22 publications

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“…Comparing the additives, HALS was the most efficient and the UV absorber not very different from the pure PP, especially after 15 weeks exposure. This may be caused by the consumption of the absorber by chemical reactions or by additive losses caused by diffusion and evaporation . The low efficient of the UV absorber is somewhat surprising as this is one of the types suggested to be used with PP and the concentration chosen is within the range that the manufacturer recommends.…”

Section: Resultsmentioning

confidence: 99%

Use of acoustic emission in the analysis of polypropylene failure caused by photodegradation

Silva

Nunes

Rabello

2018

J of Applied Polymer Sci

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Photodegradation is among the most frequent causes for the low performance of polypropylene (PP) products during service. This type of failure has been investigated extensively throughout the years using conventional methods including infrared spectroscopy and molar mass measurements. The use of acoustic emission, conversely, is not a common technique to evaluate polymer behavior, even though showed to be very useful to detect and locate damage during loading, contributing to the understanding and, hence, to the prevention of failure. In this investigation, injection molded tensile bars were exposed to the ultraviolet radiation in the laboratory for periods of up to 35 weeks and then characterized by Fourier transform infrared spectroscopy, X‐ray diffraction, tensile properties, and scanning electron microscopy. During tensile testing, the acoustic emission technique was applied to monitor parameters like intensity of hits, events, and energy released during deformation. The results confirmed the high efficiency of hindered amines light stabilizers to inhibit chemical degradation of PP and the high sensitivity of the neat polymer toward UV exposure. The several steps of polymer failure were detected by acoustic emission, being a very important tool to understand the differences in mechanical behavior of the types of samples under investigation. It showed the beginning of the failure process as well as significant events that occurred during the test, such as the formation of shear bands, cracking, and material fracture. These observations, combined with the traditional degradation monitoring procedures, allowed a good understanding of the effect of UV radiation on PP failure mechanism. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 46943.

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Section: Resultsmentioning

confidence: 99%

Use of acoustic emission in the analysis of polypropylene failure caused by photodegradation

Silva

Nunes

Rabello

2018

J of Applied Polymer Sci

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“…But the catalyst loading is high (3.3%) and the coupling between acetyl chloride with boronic acid remains unsuccessful 6g,7a or only in moderate yields. Also the coupling between acetic anhydride with arylboronic acid has been reported by Gooben 5f by using Pd(OAc) 2 as catalyst, expensive P(p-MeOPh) 3 as ligand, and excess of arylboronic acid. Scheme 2.…”

Section: Studies On the Acylodeboronation Reaction Of Arylboronic Acimentioning

confidence: 93%

“…As shown in Table 4, the carbonylation yields were influenced by electron effect. Arylboronic acids with electron-rich groups such as CH 3 or CH 3 O, as well as 1-naphthyl motif could be coupled with acetic anhydride in moderate to good yields (Table 4, entries 1-5). When arylboronic acids bearing electron-deficient groups were applied, moderate yields were still obtained (Table 4, entries 6-8).…”

Section: Studies On the Acylodeboronation Reaction Of Arylboronic Acimentioning

confidence: 99%

“…Due to the wide occurrence of aryl ketone moiety in a large number of biologically active compounds 1 , natural products, 2 cosmetics, 3 pharmaceutical, fragrance, dye, agrochemicals and functional material industries as well as in organic synthesis, 4 considerable efforts have been made for its synthesis. Aromatic ketones can be effectively prepared by palladium catalyzed carbonylation reaction of acyl chlorides with boronic acid.…”

Section: Introductionmentioning

confidence: 99%

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Pd-tetraethyl tetra-t-butylcalixarene-tetra(oxyacetate) complex catalyzed acylodeboronation of arylboronic acids with benzoyl chloride or acetic anhydride

Zhang¹,

Han²,

Li³

et al. 2013

Arkivoc

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The palladium-tetraethyl tetra-t-butylcalixarene-tetra(oxyacetate) complex, in the form of [NaL], exhibited high catalytic efficiency for the acylodeboronation reaction of arylboronic acids with benzoyl chloride or acetic anhydride, producing the corresponding ketones in good to excellent yields under mild reaction conditions. Various arylboronic acids, benzoyl chlorides and acetic anhydrides were tolerated in this method. Moreover, a typical method for synthesis of acetyl aryl ketones was obtained.

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“…These substances have a high steric hindrance in the molecule and must be highly stable in order not to be consumed so fast in secondary reactions other than stabilization [12,13].…”

Section: Introductionmentioning

confidence: 99%

Photostabilized LDPE Films with UV Absorber and HALS as Protection against the Light for Rosé Sparkling Wine

Zeni¹

2017

J Food Process Technol

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Dependence of ultraviolet absorbers' performance on ultraviolet wavelength

Cited by 27 publications

References 22 publications

Use of acoustic emission in the analysis of polypropylene failure caused by photodegradation

Use of acoustic emission in the analysis of polypropylene failure caused by photodegradation

Pd-tetraethyl tetra-t-butylcalixarene-tetra(oxyacetate) complex catalyzed acylodeboronation of arylboronic acids with benzoyl chloride or acetic anhydride

Photostabilized LDPE Films with UV Absorber and HALS as Protection against the Light for Rosé Sparkling Wine

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