Comparison of Crosslinking Kinetics of UV-Transparent Ethylene-Vinyl Acetate Copolymer and Polyolefin Elastomer Encapsulants

Wallner, Gernot M.; Adothu, Baloji; Pugstaller, Robert; Costa, Francis Reny; Mallick, Sudhanshu

doi:10.3390/polym14071441

Cited by 15 publications

(5 citation statements)

References 36 publications

(86 reference statements)

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“…The dependence of t gel on the heating temperature followed the Arrhenius function (Figure 3b), indicating the main origin (i.e., cross-linking mechanism) was the same within the present temperature range. 34,35 From the slope, the activation energy (E a,gel ) for the gelation was estimated and the value was 48 kJ/mol. The G′ reached nearly constant at t heat = 3 h, and the constant value was ca.…”

Section: ■ Resultsmentioning

confidence: 99%

Clarifying the Role of Epoxy Molecules and Base Catalysts for Vitrimer Transformation from Linear Polyesters

Hayashi,

Uchiyama,

Kato

2023

ACS Appl. Polym. Mater.

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Vitrimers are cross-linked materials with associative bond exchange mechanisms, exhibiting sustainable functions such as healability and recyclability. Transformation of commercial polyesters into vitrimers has been recently explored and regarded as an important tool for practical application of the vitrimer concept. However, the mechanism of such vitrimer transformation processes has not been adequately understood. In this study, we thus tackle this point based on the system using amorphous polyesters, multifunctional epoxy cross-linkers, and base catalysts through relatively simple experimental tools, such as size extrusion chromatography, spectroscopy, and rheology measurement. Concretely, we assess chain decomposition due to the presence of base catalysts, chain extension via the epoxy opening reaction, and network formation via bond exchange (i.e., transesterification), which occurs during the melt blending in a twin extruder and subsequent heat treatment. Particularly, we find the generation of some fraction of short sol chains and formation of branched dangling points on the network strands, which may be indications of the occurrence of transesterification. Overall, this study provides some important insights into the vitrimer transformation from polyesters.

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Section: ■ Resultsmentioning

confidence: 99%

Clarifying the Role of Epoxy Molecules and Base Catalysts for Vitrimer Transformation from Linear Polyesters

Hayashi,

Uchiyama,

Kato

2023

ACS Appl. Polym. Mater.

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“…The EVA encapsulant contained a peroxide crosslinking formulation, a vinyl silane adhesion promoter, and a UV stabilizer. A thoroughly structural and crosslinking kinetics analysis of the EVA encapsulant is provided in [19]. For lamination, two EVA films with an initial thickness of 0.48 mm were placed between two glass substrates.…”

Section: Methodsmentioning

confidence: 99%

Environmental fatigue crack growth of PV glass/EVA laminates in the melting range

Riedl,

Haselsteiner,

Säckl

et al. 2024

Progress in Photovoltaics

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The delamination of encapsulants in photovoltaic (PV) modules is a common issue that leads to power loss due to optical losses. Encapsulant debonding is usually examined under monotonic loading conditions subsequent to environmental exposure such as damp heat. Service‐relevant, superimposed environmental‐mechanical fatigue loads are not considered adequately. Hence, the environmental fatigue delamination resistance of thermally toughened double glass laminates with an ethylene vinyl acetate copolymer (EVA) adhesive layer was investigated in this study. Focus was given to the melting range of EVA, in which the non‐crosslinked crystalline phase fraction is already in the partly molten state. Double cantilever beam specimens were tested on an electrodynamic test machine at temperatures of 60, 70, 80, and 90°C and relative humidity (rh) levels of 2%, 30%, 50%, and 80%. The fractured surfaces were characterized by digital microscopy, Fourier transform infrared spectroscopy (FTIR), X‐ray photoelectron spectroscopy (XPS), and differential scanning calorimetry (DSC). The cyclic fatigue tests revealed a decay in delamination resistance at elevated temperature and humidity levels. At 70°C, the delamination resistance was low, regardless of the relative humidity. Most of the laminates failed by debonding. XPS analysis showed a reduction of the C=O and C–O content, along with an increase in Si–O content with increasing relative humidity. For laminates tested at 60 and 70°C, an EVA recrystallization peak was observed in DSC experiments. This peak was shifted to significantly higher temperatures at 80% rh. XPS and DSC indicated local hydrolysis within the porous fracture process zone ahead of the crack tip. Consequently, acetic acid formation led to a decrease in delamination resistance, resulting in lower fatigue threshold values. The investigations confirmed the significant impact of environmental conditions on the fatigue delamination resistance within glass/encapsulant laminates. Notably, acetic acid formation and a significant reduction in delamination properties were observed after around 100 h of environmental fatigue exposure.

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“…Post-processing methods, such as curing, crosslinking, or surface treatments, can also influence the release kinetics and stability of the incorporated antioxidants ( Wallner et al, 2022 ). These methods can further modify the material properties, including porosity, degradation rate, and surface characteristics, thereby impacting the release behavior.…”

Section: Impact Of Materials Properties On Antioxidant Release Kineti...mentioning

confidence: 99%

Enhancing antioxidant delivery through 3D printing: a pathway to advanced therapeutic strategies

Alogla

2023

Front. Bioeng. Biotechnol.

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The rapid advancement of 3D printing has transformed industries, including medicine and pharmaceuticals. Integrating antioxidants into 3D-printed structures offers promising therapeutic strategies for enhanced antioxidant delivery. This review explores the synergistic relationship between 3D printing and antioxidants, focusing on the design and fabrication of antioxidant-loaded constructs. Incorporating antioxidants into 3D-printed matrices enables controlled release and localized delivery, improving efficacy while minimizing side effects. Customization of physical and chemical properties allows tailoring of antioxidant release kinetics, distribution, and degradation profiles. Encapsulation techniques such as direct mixing, coating, and encapsulation are discussed. Material selection, printing parameters, and post-processing methods significantly influence antioxidant release kinetics and stability. Applications include wound healing, tissue regeneration, drug delivery, and personalized medicine. This comprehensive review aims to provide insights into 3D printing-assisted antioxidant delivery systems, facilitating advancements in medicine and improved patient outcomes for oxidative stress-related disorders.

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Comparison of Crosslinking Kinetics of UV-Transparent Ethylene-Vinyl Acetate Copolymer and Polyolefin Elastomer Encapsulants

Cited by 15 publications

References 36 publications

Clarifying the Role of Epoxy Molecules and Base Catalysts for Vitrimer Transformation from Linear Polyesters

Clarifying the Role of Epoxy Molecules and Base Catalysts for Vitrimer Transformation from Linear Polyesters

Environmental fatigue crack growth of PV glass/EVA laminates in the melting range

Enhancing antioxidant delivery through 3D printing: a pathway to advanced therapeutic strategies

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