Discoloration mechanism of polymer surface in contact with air–water interface

Kim, Mun Ho; Byun, Doo-Jin; You, Ji-Eun; Choi, Kil‐Yeong

doi:10.1016/j.jiec.2012.11.007

Cited by 9 publications

(4 citation statements)

References 24 publications

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“…Aged at 288 and 316°C, the surface of the aged polymer shows discoloration when illuminated with transmitted light, and the discoloration is attributed to the generation and accumulation of highly conjugated groups or other chromophores. 17 For aging at 204°C, no distinct discolored layer was observed even after 2000 h. The oxidized layer thickness in the sample aged at 316°C is less than the layer thickness produced by aging at 288°C, which is a typical diffusion/reaction result. 18 The oxidized layer that grows rapidly during high aging temperature retards further diffusion of oxygen.…”

Section: Resultsmentioning

confidence: 84%

Thermal oxidation of PEPA-terminated polyimide

Miyauchi

González

et al. 2018

High Performance Polymers

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The thermal oxidative stability of a 4-phenylethynyl phthalic anhydride (PEPA) endcapped polyimide (PI) was investigated. A surface reaction layer formed due to oxidization during thermal aging and grew in thickness with increasing aging time. Analysis of the surface layer revealed a partial loss of aromatic ring, ether linkage, and imide linkage in the aged polymer. The partial loss of the imide linkage and ether linkage in the surface layer was corroborated by the observed release of carbon monoxide and carbon dioxide reaction products. The oxidized layer exhibited discoloration and an increase in glass transition temperature. The surface discoloration was attributed to the formation of the conjugated unsaturated or aromatic carbonyl groups and/or the charge transfer complex. Interior regions of the oxidized samples were largely unaffected, except for a more compact molecular configuration. Compared with aging at high temperatures (288°C, 316°C), aging at 204°C produced similar chemical changes in the cured polymer, albeit with a low degradation rate. The oxidative stability of the imide polymer surpassed that of conventional nadic-endcapped PIs due to the greater intrinsic thermal stability of the PEPA endcap. The unusual oxidative stability of the PI, combined with superior mechanical properties, warrant consideration as a composite matrix for future applications in high-temperature service conditions.

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Section: Resultsmentioning

confidence: 84%

Thermal oxidation of PEPA-terminated polyimide

Miyauchi

González

et al. 2018

High Performance Polymers

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“…So, extended exposure can cause yellowing too. Based on the literature, 50 such discoloration can result from the interaction of additives or compounds in the polymer formulation and their accumulation on the material surface. It equally reveals a degradation process (breaking and rearranging of chemical bonds).…”

Section: Mechanism Of Yellowing and Shape Changementioning

confidence: 99%

Mechanical, thermal and physico-chemical behavior of virgin and hydrothermally aged polymeric pipes

Jemii

Hammiche

Boubakri

et al. 2020

Journal of Thermoplastic Composite Materials

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In this paper, an experimental study was conducted to characterize industrial PVC pipes and to investigate the effect of hydrothermal aging on their physico-chemical, thermal, and mechanical behavior. Three temperature (25°C, 60°C and 90°C) and full immersion in distilled water were retained as accelerated hydrothermal conditions. Kinetic of water absorption was examined and Fickian behavior was observed. The aging temperature was found to influence the water uptake behavior of PVC samples. Thermogravimetric analysis (TGA) has proved that the pipe material is not pure, while it consists of PVC reinforced with calcium carbonate (CaCO3). After exposure to accelerated aging, TGA and FTIR analysis exhibit preliminary signs of degradation of PVC samples under the retained conditions. Changes affecting the shape and the color of aged samples were examined. Mechanical properties have been characterized, after immersion of 30 days, with an improvement of strength and stiffness of the aged samples, in particular at elevated aging temperature. However, the aging response is accompanied by a loss of ductility for the aged material. These results, even for brief exposure, could help to understand the behavior of PVC composite pipes under hydrothermal conditions.

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“…Intrinsically the PDLC cannot completely block light because their blocking mode uses scattering not absorption. Under UV, PDLC is discolored owing to the polymer degradation (5)(6)(7).…”

Section: Introductionmentioning

confidence: 99%

P‐138: Broadband light shutter using electrophoresis of carbon black particles

Jeon,

Han,

Kang

et al. 2023

Symp Digest of Tech Papers

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In this work, we demonstrate a UV‐NIR broadband carbon black shutter that exhibits energy saving by NIR reflection, high contrast ratio in a visible wavelength, and no discoloration and blocking UV. The black and transparent state in a carbon black dispersed cell is realized by controlling position of particles with electrophoretic force. We believe that this approach can pave a way for developing new electrophoretic broadband shutters for privacy, energy efficient automobiles and buildings or a UV sensitive environment.

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Discoloration mechanism of polymer surface in contact with air–water interface

Cited by 9 publications

References 24 publications

Thermal oxidation of PEPA-terminated polyimide

Thermal oxidation of PEPA-terminated polyimide

Mechanical, thermal and physico-chemical behavior of virgin and hydrothermally aged polymeric pipes

P‐138: Broadband light shutter using electrophoresis of carbon black particles

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