Extremely enhanced hydrolytic stability of poly(ethylene terephthalate) films

Shi, Zemin; Fujita, Akihide

doi:10.1002/pen.24562

Cited by 6 publications

(3 citation statements)

References 30 publications

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“…This suggests that the W A values of the PEsIs are also affected somewhat by a physical factor such as crystallinity, as discussed in our previous study [14], corresponding to a reasonable assumption that water molecules do not diffuse and penetrate easily into the crystal phases. The prominent effect of crystallinity on suppressing water uptake is also observed in poly(ethylene terephthalate) systems [39]. in the present PEsI systems does not conflict with the fact that an aromatic polyester (polyarylate) system without imide groups has a low but non-zero WA value (0.26% [38]), which approximates the above-mentioned lower limit of WA.…”

Section: Correlation Of Wa and Imide Group Contentsupporting

confidence: 75%

Section: Correlation Of Wa and Imide Group Contentmentioning

confidence: 77%

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Poly(ester imide)s Possessing Low Coefficients of Thermal Expansion and Low Water Absorption (V). Effects of Ester-linked Diamines with Different Lengths and Substituents

Hasegawa

Hishiki

2020

Polymers

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A series of ester-linked diamines, with different lengths and substituents, was synthesized to obtain poly(ester imide)s (PEsIs) having improved properties. A substituent-free ester-linked diamine (AB-HQ) was poorly soluble in N-methyl-2-pyrrolidone at room temperature, which forced the need for polyaddition by adding tetracarboxylic dianhydride solid into a hot diamine solution. This procedure enabled the smooth progress of polymerization, however, accompanied by a significant decrease in the molecular weights of poly(amic acid)s (PAAs), particularly when using hydrolytically less stable pyromellitic dianhydride. On the other hand, the incorporation of various substituents (–CH3, –OCH3, and phenyl groups) to AB-HQ was highly effective in improving diamine solubility, which enabled the application of the simple polymerization process without the initial heating of the diamine solutions, and led to PAAs with sufficiently high molecular weights. The introduction of bulkier phenyl substituent tends to increase the coefficients of thermal expansion (CTE) of the PEsI films, in contrast to that of the small substituents (–CH3, –OCH3). The effects of ester-linked diamines, consisting of longitudinally further extended structures, were also investigated. However, this approach was unsuccessful due to the solubility problems of these diamines. Consequently, the CTE values of the PEsIs, obtained using longitudinally further extended diamines, were not as low as we had expected initially. The effects of substituent bulkiness on the target properties, and the dominant factors for water uptake (WA) and the coefficients of hygroscopic expansion (CHE), are also discussed in this study. The PEsI derived from methoxy-sustituted AB-HQ analog and 3,3′,4,4′-biphenyltetracarboxylic dianhydride achieved well-balanced properties, i.e., a very high Tg (424 °C), a very low CTE (5.6 ppm K−1), a low WA (0.41%), a very low CHE value (3.1 ppm/RH%), and sufficient ductility, although the 26 μm-thick film narrowly missed certification of the V-0 standard in the UL-94V test. This PEsI film also displayed a moderate εr (3.18) and a low tan δ (3.14 × 10−3) at 10 GHz under 50% RH and at 23 °C. Thus, this PEsI system is a promising candidate as a novel dielectric substrate material for use in the next generation of high-performance flexible printed circuit boards operating at higher frequencies (≥10 GHz).

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Section: Correlation Of Wa and Imide Group Contentsupporting

confidence: 75%

Section: Correlation Of Wa and Imide Group Contentmentioning

confidence: 77%

Poly(ester imide)s Possessing Low Coefficients of Thermal Expansion and Low Water Absorption (V). Effects of Ester-linked Diamines with Different Lengths and Substituents

Hasegawa

Hishiki

2020

Polymers

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“…In order to avoid hydrolysis, PET for PV backsheets is usually formulated with antihydrolysis additives (such as carbodiimide‐based or esters of phosphorous acid) and is biaxial oriented, which increases the crystalline content of the PET and reduces water permeation . However, production of biaxial flat PET films and assembling them into laminates is multiple‐step process compared to one‐step coextrusion processes as applicable for polyolefin or polyamide backsheets .…”

Section: Introductionmentioning

confidence: 99%

Increased reliability of modified polyolefin backsheet over commonly used polyester backsheets for crystalline PV modules

Omazic

Oreški

Edler

et al. 2020

J of Applied Polymer Sci

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The weathering stability of polymeric backsheets is very important for the reliability of photovoltaic (PV) modules. In addition to reliability, cost reduction and sustainability are upcoming challenges the PV backsheet industry is facing with. The most commonly used material for PV backsheets is poly(ethylene-terephthalate)-PET. However, PET is in general very sensitive to hydrolysis, which leads to chain scission and causes embrittlement, cracking, delamination, and dimensional instability of the backsheet. Compared to that newly developed modified polyolefin backsheets have favorable selective permeation properties and high mechanical flexibility, which could be key properties for backsheets in terms of higher PV module reliability. In this work, the weathering stability of PET/fluoropolymer backsheet and an alternative coextruded polyolefin-backsheet was investigated in terms of thermal and mechanical stability. Both materials were artificially aged and the changes caused by aging were investigated. The polyester-based backsheet showed embrittlement and reduced elongation at break for 70%. The polyolefin-based backsheet retained its mechanical flexibility even after 2000 h of aging under damp-heat conditions, with no significant physical or chemical aging processes occurring. The comparison of the results of both backsheets suggests that the polyolefin backsheet is a promising candidate for the reduction of cracks and delamination in the field.

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Arc-shaped air layer bioinspired by ginkgo nut to resist high humidity environment for PET fabrics

Mao,

Shan,

Xue

et al. 2024

Polymer Degradation and Stability

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Extremely enhanced hydrolytic stability of poly(ethylene terephthalate) films

Cited by 6 publications

References 30 publications

Poly(ester imide)s Possessing Low Coefficients of Thermal Expansion and Low Water Absorption (V). Effects of Ester-linked Diamines with Different Lengths and Substituents

Poly(ester imide)s Possessing Low Coefficients of Thermal Expansion and Low Water Absorption (V). Effects of Ester-linked Diamines with Different Lengths and Substituents

Increased reliability of modified polyolefin backsheet over commonly used polyester backsheets for crystalline PV modules

Arc-shaped air layer bioinspired by ginkgo nut to resist high humidity environment for PET fabrics

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