Exploring the optical and dielectric properties of bifunctional and trifunctional epoxy polymers

Jdidi, Haythem; Fourati, Najla; Zerrouki, Chouki; Ibos, Laurent; Fois, Magali; Guinault, Alain; Jilani, W.; Guermazi, S.; Guermazi, H.

doi:10.1016/j.polymer.2021.123882

Cited by 9 publications

(10 citation statements)

References 49 publications

(65 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The dipolar segmental relaxations or dipolar group relaxations correspond to β ‐relaxations. The most important mechanisms of β ‐relaxation are movement of dipole side groups about the C‐C chain or a local motion of very short segment of the polymer (such as the twisting of the hydroxyl or carbonyl side groups) 11–13 . Another type of relaxations, known as γ ‐relaxation, is related to faster relaxation processes that occur below glass transition temperature of matrix (e.g., movement of the diphenyl propane group, rotation of the methylene sequence or the hydroxyl‐ether group, etc.).…”

Section: Introductionmentioning

confidence: 99%

Dielectric properties of epoxy/graphite flakes composites: Influence of loading and surface treatment

Maletić,

Jović Orsini,

Milić

et al. 2023

J of Applied Polymer Sci

View full text Add to dashboard Cite

Epoxy‐rich carbon‐based composites are well recognized materials in industries owing to their good mechanical properties and thermal stability. Here, dielectric properties of composites based on bisphenol‐A‐epoxy resin loaded with 5, 6, 10, and 15 wt% of graphite flakes (GF) have been studied. The frequency and temperature dependence of the dielectric permittivity, dielectric loss, and ac conductivity have been examined in temperature (−103 to 97°C) and frequency (20 Hz–200 kHz) range. Influence of the filler surface chemistry have been studied for composites loaded with 5 wt% GF obtained: (i) under wet milling, without or with adding Triton‐100x as a surfactant, or (ii) under dry milling in the presence of KOH. The composite made of epoxy loaded with 5 wt% exfoliated expanded graphite flakes (EEG), was also prepared. The surface treatment with KOH notably increased dielectric constant of the composite, keeping low dielectric loss, while treatment with Triton‐100x significantly increased tanδ. The composite loaded with exfoliated expanded graphite shows higher ac conductivity than those obtained with flaky graphite, GF. Possibility to change dielectric properties of the composites without changing the loading content can be used as an approach in tailoring one with desired dielectric properties.

show abstract

Section: Introductionmentioning

confidence: 99%

Dielectric properties of epoxy/graphite flakes composites: Influence of loading and surface treatment

Maletić,

Jović Orsini,

Milić

et al. 2023

J of Applied Polymer Sci

View full text Add to dashboard Cite

show abstract

“…4A, the absorption peaks at 3400, 2975 and 734 cm −1 of LMU1-3% were significantly enhanced, it seemed that the enzymatic polymerization had occurred, and the oligomers were formed. The side chains in urushiol and phenolic hydroxyl had converged to be oligomer [28]. And then, the absorption peaks at 1070-1110 cm −1 and 988 cm −1 of LMU1-3% were slightly reduced, which illustrated the structure of the conjugated alkatriene was decreased.…”

Section: Ft-ir Spectra Analysismentioning

confidence: 98%

Preparation and Properties of Chinese Lacquer Modified by Methylolureas

Xiao¹,

Cao²,

Tan³

et al. 2023

Journal of Renewable Materials

View full text Add to dashboard Cite

In this study, different molar of methylolureas (MMU) were used to improve the properties and drying speed of the raw lacquer (RL). The drying time, gloss, pencil hardness and impact resistance of the lacquer film were tested. The thermal behaviors and chemical structures of the lacquer membrane were also discussed by thermal gravimetric analysis (TGA), fourier infrared spectrometer (FT-IR) and nuclear magnetic resonance (NMR) analysis, respectively. The results demonstrated that lower molar ratio MMU can significantly improve the properties of lacquer. The TGA analysis showed that the modified lacquer had high thermal stability than that of the control. The FT-IR and 13C NMR analysis revealed that the structures of the modified lacquer were significantly improved by cross-linking with the hydroxymethyl groups and methylene methyl ethers of MMU. In addition, through scanning electron microscopy (SEM) characterization, it was found that the introduction of MMU can effectively improve the surface smoothness of the lacquer film.

show abstract

“…À72 1C and this is due to the g-relaxation. 72,73 The g-relaxation has been attributed to flexible glycidol segments that are formed after oxirane rings open during curing reaction. This relaxation is caused by a crankshaft type rotation of the glycidol group.…”

Section: Dielectric Relaxation Using Dielectric Thermal Analysismentioning

confidence: 99%

“…This relaxation is caused by a crankshaft type rotation of the glycidol group. 72,73 Please note that all the samples exhibit the g-relaxation around the same temperature. However, the changes in the intensity of these samples are somewhat interesting.…”

Section: Dielectric Relaxation Using Dielectric Thermal Analysismentioning

confidence: 99%

Influence of dodecyl surfactants on the cross-linking, plasticization and damping behavior of epoxy novolac resins

et al. 2022

View full text Add to dashboard Cite

show abstract

Exploring the optical and dielectric properties of bifunctional and trifunctional epoxy polymers

Cited by 9 publications

References 49 publications

Dielectric properties of epoxy/graphite flakes composites: Influence of loading and surface treatment

Dielectric properties of epoxy/graphite flakes composites: Influence of loading and surface treatment

Preparation and Properties of Chinese Lacquer Modified by Methylolureas

Influence of dodecyl surfactants on the cross-linking, plasticization and damping behavior of epoxy novolac resins

Contact Info

Product

Resources

About